Merge pull request #4575 from nitinsoniism/show_mac_arp_cache_vni_json_fix

[mirror_frr.git] / lib / vty.c

/*
 * Virtual terminal [aka TeletYpe] interface routine.
 * Copyright (C) 1997, 98 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; see the file COPYING; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <zebra.h>

#include <lib/version.h>
#include <sys/types.h>
#include <regex.h>
#include <stdio.h>

#include "linklist.h"
#include "thread.h"
#include "buffer.h"
#include "command.h"
#include "sockunion.h"
#include "memory.h"
#include "log.h"
#include "prefix.h"
#include "filter.h"
#include "vty.h"
#include "privs.h"
#include "network.h"
#include "libfrr.h"
#include "frrstr.h"
#include "lib_errors.h"
#include "northbound_cli.h"
#include "printfrr.h"

#include <arpa/telnet.h>
#include <termios.h>

#ifndef VTYSH_EXTRACT_PL
#include "lib/vty_clippy.c"
#endif

DEFINE_MTYPE_STATIC(LIB, VTY, "VTY")
DEFINE_MTYPE_STATIC(LIB, VTY_OUT_BUF, "VTY output buffer")
DEFINE_MTYPE_STATIC(LIB, VTY_HIST, "VTY history")

/* Vty events */
enum event {
        VTY_SERV,
        VTY_READ,
        VTY_WRITE,
        VTY_TIMEOUT_RESET,
#ifdef VTYSH
        VTYSH_SERV,
        VTYSH_READ,
        VTYSH_WRITE
#endif /* VTYSH */
};

static void vty_event(enum event, int, struct vty *);

/* Extern host structure from command.c */
extern struct host host;

/* Vector which store each vty structure. */
static vector vtyvec;

/* Vty timeout value. */
static unsigned long vty_timeout_val = VTY_TIMEOUT_DEFAULT;

/* Vty access-class command */
static char *vty_accesslist_name = NULL;

/* Vty access-calss for IPv6. */
static char *vty_ipv6_accesslist_name = NULL;

/* VTY server thread. */
static vector Vvty_serv_thread;

/* Current directory. */
char vty_cwd[MAXPATHLEN];

/* Login password check. */
static int no_password_check = 0;

/* Integrated configuration file path */
static char integrate_default[] = SYSCONFDIR INTEGRATE_DEFAULT_CONFIG;

static bool do_log_commands;
static bool do_log_commands_perm;

void vty_frame(struct vty *vty, const char *format, ...)
{
        va_list args;

        va_start(args, format);
        vsnprintfrr(vty->frame + vty->frame_pos,
                    sizeof(vty->frame) - vty->frame_pos, format, args);
        vty->frame_pos = strlen(vty->frame);
        va_end(args);
}

void vty_endframe(struct vty *vty, const char *endtext)
{
        if (vty->frame_pos == 0 && endtext)
                vty_out(vty, "%s", endtext);
        vty->frame_pos = 0;
}

bool vty_set_include(struct vty *vty, const char *regexp)
{
        int errcode;
        bool ret = true;
        char errbuf[256];

        if (!regexp) {
                if (vty->filter) {
                        regfree(&vty->include);
                        vty->filter = false;
                }
                return true;
        }

        errcode = regcomp(&vty->include, regexp,
                          REG_EXTENDED | REG_NEWLINE | REG_NOSUB);
        if (errcode) {
                ret = false;
                regerror(ret, &vty->include, errbuf, sizeof(errbuf));
                vty_out(vty, "%% Regex compilation error: %s", errbuf);
        } else {
                vty->filter = true;
        }

        return ret;
}

/* VTY standard output function. */
int vty_out(struct vty *vty, const char *format, ...)
{
        va_list args;
        ssize_t len;
        char buf[1024];
        char *p = NULL;
        char *filtered;

        if (vty->frame_pos) {
                vty->frame_pos = 0;
                vty_out(vty, "%s", vty->frame);
        }

        va_start(args, format);
        p = vasnprintfrr(MTYPE_VTY_OUT_BUF, buf, sizeof(buf), format, args);
        va_end(args);

        len = strlen(p);

        /* filter buffer */
        if (vty->filter) {
                vector lines = frrstr_split_vec(p, "\n");

                /* Place first value in the cache */
                char *firstline = vector_slot(lines, 0);
                buffer_put(vty->lbuf, (uint8_t *) firstline, strlen(firstline));

                /* If our split returned more than one entry, time to filter */
                if (vector_active(lines) > 1) {
                        /*
                         * returned string is MTYPE_TMP so it matches the MTYPE
                         * of everything else in the vector
                         */
                        char *bstr = buffer_getstr(vty->lbuf);
                        buffer_reset(vty->lbuf);
                        XFREE(MTYPE_TMP, lines->index[0]);
                        vector_set_index(lines, 0, bstr);
                        frrstr_filter_vec(lines, &vty->include);
                        vector_compact(lines);
                        /*
                         * Consider the string "foo\n". If the regex is an empty string
                         * and the line ended with a newline, then the vector will look
                         * like:
                         *
                         * [0]: 'foo'
                         * [1]: ''
                         *
                         * If the regex isn't empty, the vector will look like:
                         *
                         * [0]: 'foo'
                         *
                         * In this case we'd like to preserve the newline, so we add
                         * the empty string [1] as in the first example.
                         */
                        if (p[strlen(p) - 1] == '\n' && vector_active(lines) > 0
                            && strlen(vector_slot(lines, vector_active(lines) - 1)))
                                vector_set(lines, XSTRDUP(MTYPE_TMP, ""));

                        filtered = frrstr_join_vec(lines, "\n");
                }
                else {
                        filtered = NULL;
                }

                frrstr_strvec_free(lines);

        } else {
                filtered = p;
        }

        if (!filtered)
                goto done;

        switch (vty->type) {
        case VTY_TERM:
                /* print with crlf replacement */
                buffer_put_crlf(vty->obuf, (uint8_t *)filtered,
                                strlen(filtered));
                break;
        case VTY_SHELL:
                fprintf(vty->of, "%s", filtered);
                fflush(vty->of);
                break;
        case VTY_SHELL_SERV:
        case VTY_FILE:
        default:
                /* print without crlf replacement */
                buffer_put(vty->obuf, (uint8_t *)filtered, strlen(filtered));
                break;
        }

done:

        if (vty->filter && filtered)
                XFREE(MTYPE_TMP, filtered);

        /* If p is not different with buf, it is allocated buffer.  */
        if (p != buf)
                XFREE(MTYPE_VTY_OUT_BUF, p);

        return len;
}

static int vty_log_out(struct vty *vty, const char *level,
                       const char *proto_str, const char *msg,
                       struct timestamp_control *ctl)
{
        int ret;
        int len;
        char buf[1024];

        if (!ctl->already_rendered) {
                ctl->len = quagga_timestamp(ctl->precision, ctl->buf,
                                            sizeof(ctl->buf));
                ctl->already_rendered = 1;
        }
        if (ctl->len + 1 >= sizeof(buf))
                return -1;
        memcpy(buf, ctl->buf, len = ctl->len);
        buf[len++] = ' ';
        buf[len] = '\0';

        if (level)
                ret = snprintf(buf + len, sizeof(buf) - len, "%s: %s: ", level,
                               proto_str);
        else
                ret = snprintf(buf + len, sizeof(buf) - len, "%s: ", proto_str);
        if ((ret < 0) || ((size_t)(len += ret) >= sizeof(buf)))
                return -1;

        if (((ret = snprintf(buf + len, sizeof(buf) - len, "%s", msg)) < 0)
            || ((size_t)((len += ret) + 2) > sizeof(buf)))
                return -1;

        buf[len++] = '\r';
        buf[len++] = '\n';

        if (write(vty->wfd, buf, len) < 0) {
                if (ERRNO_IO_RETRY(errno))
                        /* Kernel buffer is full, probably too much debugging
                           output, so just
                           drop the data and ignore. */
                        return -1;
                /* Fatal I/O error. */
                vty->monitor =
                        0; /* disable monitoring to avoid infinite recursion */
                flog_err(EC_LIB_SOCKET,
                         "%s: write failed to vty client fd %d, closing: %s",
                         __func__, vty->fd, safe_strerror(errno));
                buffer_reset(vty->obuf);
                buffer_reset(vty->lbuf);
                /* cannot call vty_close, because a parent routine may still try
                   to access the vty struct */
                vty->status = VTY_CLOSE;
                shutdown(vty->fd, SHUT_RDWR);
                return -1;
        }
        return 0;
}

/* Output current time to the vty. */
void vty_time_print(struct vty *vty, int cr)
{
        char buf[QUAGGA_TIMESTAMP_LEN];

        if (quagga_timestamp(0, buf, sizeof(buf)) == 0) {
                zlog_info("quagga_timestamp error");
                return;
        }
        if (cr)
                vty_out(vty, "%s\n", buf);
        else
                vty_out(vty, "%s ", buf);

        return;
}

/* Say hello to vty interface. */
void vty_hello(struct vty *vty)
{
        if (host.motdfile) {
                FILE *f;
                char buf[4096];

                f = fopen(host.motdfile, "r");
                if (f) {
                        while (fgets(buf, sizeof(buf), f)) {
                                char *s;
                                /* work backwards to ignore trailling isspace()
                                 */
                                for (s = buf + strlen(buf);
                                     (s > buf) && isspace((int)*(s - 1)); s--)
                                        ;
                                *s = '\0';
                                vty_out(vty, "%s\n", buf);
                        }
                        fclose(f);
                } else
                        vty_out(vty, "MOTD file not found\n");
        } else if (host.motd)
                vty_out(vty, "%s", host.motd);
}

/* Put out prompt and wait input from user. */
static void vty_prompt(struct vty *vty)
{
        if (vty->type == VTY_TERM) {
                vty_out(vty, cmd_prompt(vty->node), cmd_hostname_get());
        }
}

/* Send WILL TELOPT_ECHO to remote server. */
static void vty_will_echo(struct vty *vty)
{
        unsigned char cmd[] = {IAC, WILL, TELOPT_ECHO, '\0'};
        vty_out(vty, "%s", cmd);
}

/* Make suppress Go-Ahead telnet option. */
static void vty_will_suppress_go_ahead(struct vty *vty)
{
        unsigned char cmd[] = {IAC, WILL, TELOPT_SGA, '\0'};
        vty_out(vty, "%s", cmd);
}

/* Make don't use linemode over telnet. */
static void vty_dont_linemode(struct vty *vty)
{
        unsigned char cmd[] = {IAC, DONT, TELOPT_LINEMODE, '\0'};
        vty_out(vty, "%s", cmd);
}

/* Use window size. */
static void vty_do_window_size(struct vty *vty)
{
        unsigned char cmd[] = {IAC, DO, TELOPT_NAWS, '\0'};
        vty_out(vty, "%s", cmd);
}

#if 0  /* Currently not used. */
/* Make don't use lflow vty interface. */
static void
vty_dont_lflow_ahead (struct vty *vty)
{
  unsigned char cmd[] = { IAC, DONT, TELOPT_LFLOW, '\0' };
  vty_out (vty, "%s", cmd);
}
#endif /* 0 */

/* Authentication of vty */
static void vty_auth(struct vty *vty, char *buf)
{
        char *passwd = NULL;
        enum node_type next_node = 0;
        int fail;
        char *crypt(const char *, const char *);

        switch (vty->node) {
        case AUTH_NODE:
                if (host.encrypt)
                        passwd = host.password_encrypt;
                else
                        passwd = host.password;
                if (host.advanced)
                        next_node = host.enable ? VIEW_NODE : ENABLE_NODE;
                else
                        next_node = VIEW_NODE;
                break;
        case AUTH_ENABLE_NODE:
                if (host.encrypt)
                        passwd = host.enable_encrypt;
                else
                        passwd = host.enable;
                next_node = ENABLE_NODE;
                break;
        }

        if (passwd) {
                if (host.encrypt)
                        fail = strcmp(crypt(buf, passwd), passwd);
                else
                        fail = strcmp(buf, passwd);
        } else
                fail = 1;

        if (!fail) {
                vty->fail = 0;
                vty->node = next_node; /* Success ! */
        } else {
                vty->fail++;
                if (vty->fail >= 3) {
                        if (vty->node == AUTH_NODE) {
                                vty_out(vty,
                                        "%% Bad passwords, too many failures!\n");
                                vty->status = VTY_CLOSE;
                        } else {
                                /* AUTH_ENABLE_NODE */
                                vty->fail = 0;
                                vty_out(vty,
                                        "%% Bad enable passwords, too many failures!\n");
                                vty->status = VTY_CLOSE;
                        }
                }
        }
}

/* Command execution over the vty interface. */
static int vty_command(struct vty *vty, char *buf)
{
        int ret;
        const char *protocolname;
        char *cp = NULL;

        assert(vty);

        /*
         * Log non empty command lines
         */
        if (do_log_commands)
                cp = buf;
        if (cp != NULL) {
                /* Skip white spaces. */
                while (isspace((int)*cp) && *cp != '\0')
                        cp++;
        }
        if (cp != NULL && *cp != '\0') {
                unsigned i;
                char vty_str[VTY_BUFSIZ];
                char prompt_str[VTY_BUFSIZ];

                /* format the base vty info */
                snprintf(vty_str, sizeof(vty_str), "vty[??]@%s", vty->address);

                for (i = 0; i < vector_active(vtyvec); i++)
                        if (vty == vector_slot(vtyvec, i)) {
                                snprintf(vty_str, sizeof(vty_str), "vty[%d]@%s",
                                         i, vty->address);
                                break;
                        }

                /* format the prompt */
                snprintf(prompt_str, sizeof(prompt_str), cmd_prompt(vty->node),
                         vty_str);

                /* now log the command */
                zlog_notice("%s%s", prompt_str, buf);
        }

#ifdef CONSUMED_TIME_CHECK
        {
                RUSAGE_T before;
                RUSAGE_T after;
                unsigned long realtime, cputime;

                GETRUSAGE(&before);
#endif /* CONSUMED_TIME_CHECK */

                ret = cmd_execute(vty, buf, NULL, 0);

                /* Get the name of the protocol if any */
                protocolname = frr_protoname;

#ifdef CONSUMED_TIME_CHECK
                GETRUSAGE(&after);
                if ((realtime = thread_consumed_time(&after, &before, &cputime))
                    > CONSUMED_TIME_CHECK)
                        /* Warn about CPU hog that must be fixed. */
                        flog_warn(
                                EC_LIB_SLOW_THREAD,
                                "SLOW COMMAND: command took %lums (cpu time %lums): %s",
                                realtime / 1000, cputime / 1000, buf);
        }
#endif /* CONSUMED_TIME_CHECK */

        if (ret != CMD_SUCCESS)
                switch (ret) {
                case CMD_WARNING:
                        if (vty->type == VTY_FILE)
                                vty_out(vty, "Warning...\n");
                        break;
                case CMD_ERR_AMBIGUOUS:
                        vty_out(vty, "%% Ambiguous command.\n");
                        break;
                case CMD_ERR_NO_MATCH:
                        vty_out(vty, "%% [%s] Unknown command: %s\n",
                                protocolname, buf);
                        break;
                case CMD_ERR_INCOMPLETE:
                        vty_out(vty, "%% Command incomplete.\n");
                        break;
                }

        return ret;
}

static const char telnet_backward_char = 0x08;
static const char telnet_space_char = ' ';

/* Basic function to write buffer to vty. */
static void vty_write(struct vty *vty, const char *buf, size_t nbytes)
{
        if ((vty->node == AUTH_NODE) || (vty->node == AUTH_ENABLE_NODE))
                return;

        /* Should we do buffering here ?  And make vty_flush (vty) ? */
        buffer_put(vty->obuf, buf, nbytes);
}

/* Basic function to insert character into vty. */
static void vty_self_insert(struct vty *vty, char c)
{
        int i;
        int length;

        if (vty->length + 1 >= VTY_BUFSIZ)
                return;

        length = vty->length - vty->cp;
        memmove(&vty->buf[vty->cp + 1], &vty->buf[vty->cp], length);
        vty->buf[vty->cp] = c;

        vty_write(vty, &vty->buf[vty->cp], length + 1);
        for (i = 0; i < length; i++)
                vty_write(vty, &telnet_backward_char, 1);

        vty->cp++;
        vty->length++;

        vty->buf[vty->length] = '\0';
}

/* Self insert character 'c' in overwrite mode. */
static void vty_self_insert_overwrite(struct vty *vty, char c)
{
        if (vty->cp == vty->length) {
                vty_self_insert(vty, c);
                return;
        }

        vty->buf[vty->cp++] = c;
        vty_write(vty, &c, 1);
}

/**
 * Insert a string into vty->buf at the current cursor position.
 *
 * If the resultant string would be larger than VTY_BUFSIZ it is
 * truncated to fit.
 */
static void vty_insert_word_overwrite(struct vty *vty, char *str)
{
        if (vty->cp == VTY_BUFSIZ)
                return;

        size_t nwrite = MIN((int)strlen(str), VTY_BUFSIZ - vty->cp - 1);
        memcpy(&vty->buf[vty->cp], str, nwrite);
        vty->cp += nwrite;
        vty->length = MAX(vty->cp, vty->length);
        vty->buf[vty->length] = '\0';
        vty_write(vty, str, nwrite);
}

/* Forward character. */
static void vty_forward_char(struct vty *vty)
{
        if (vty->cp < vty->length) {
                vty_write(vty, &vty->buf[vty->cp], 1);
                vty->cp++;
        }
}

/* Backward character. */
static void vty_backward_char(struct vty *vty)
{
        if (vty->cp > 0) {
                vty->cp--;
                vty_write(vty, &telnet_backward_char, 1);
        }
}

/* Move to the beginning of the line. */
static void vty_beginning_of_line(struct vty *vty)
{
        while (vty->cp)
                vty_backward_char(vty);
}

/* Move to the end of the line. */
static void vty_end_of_line(struct vty *vty)
{
        while (vty->cp < vty->length)
                vty_forward_char(vty);
}

static void vty_kill_line_from_beginning(struct vty *);
static void vty_redraw_line(struct vty *);

/* Print command line history.  This function is called from
   vty_next_line and vty_previous_line. */
static void vty_history_print(struct vty *vty)
{
        int length;

        vty_kill_line_from_beginning(vty);

        /* Get previous line from history buffer */
        length = strlen(vty->hist[vty->hp]);
        memcpy(vty->buf, vty->hist[vty->hp], length);
        vty->cp = vty->length = length;
        vty->buf[vty->length] = '\0';

        /* Redraw current line */
        vty_redraw_line(vty);
}

/* Show next command line history. */
static void vty_next_line(struct vty *vty)
{
        int try_index;

        if (vty->hp == vty->hindex)
                return;

        /* Try is there history exist or not. */
        try_index = vty->hp;
        if (try_index == (VTY_MAXHIST - 1))
                try_index = 0;
        else
                try_index++;

        /* If there is not history return. */
        if (vty->hist[try_index] == NULL)
                return;
        else
                vty->hp = try_index;

        vty_history_print(vty);
}

/* Show previous command line history. */
static void vty_previous_line(struct vty *vty)
{
        int try_index;

        try_index = vty->hp;
        if (try_index == 0)
                try_index = VTY_MAXHIST - 1;
        else
                try_index--;

        if (vty->hist[try_index] == NULL)
                return;
        else
                vty->hp = try_index;

        vty_history_print(vty);
}

/* This function redraw all of the command line character. */
static void vty_redraw_line(struct vty *vty)
{
        vty_write(vty, vty->buf, vty->length);
        vty->cp = vty->length;
}

/* Forward word. */
static void vty_forward_word(struct vty *vty)
{
        while (vty->cp != vty->length && vty->buf[vty->cp] != ' ')
                vty_forward_char(vty);

        while (vty->cp != vty->length && vty->buf[vty->cp] == ' ')
                vty_forward_char(vty);
}

/* Backward word without skipping training space. */
static void vty_backward_pure_word(struct vty *vty)
{
        while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
                vty_backward_char(vty);
}

/* Backward word. */
static void vty_backward_word(struct vty *vty)
{
        while (vty->cp > 0 && vty->buf[vty->cp - 1] == ' ')
                vty_backward_char(vty);

        while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
                vty_backward_char(vty);
}

/* When '^D' is typed at the beginning of the line we move to the down
   level. */
static void vty_down_level(struct vty *vty)
{
        vty_out(vty, "\n");
        cmd_exit(vty);
        vty_prompt(vty);
        vty->cp = 0;
}

/* When '^Z' is received from vty, move down to the enable mode. */
static void vty_end_config(struct vty *vty)
{
        vty_out(vty, "\n");

        if (vty->config) {
                vty_config_exit(vty);
                vty->node = ENABLE_NODE;
        }

        vty_prompt(vty);
        vty->cp = 0;
}

/* Delete a charcter at the current point. */
static void vty_delete_char(struct vty *vty)
{
        int i;
        int size;

        if (vty->length == 0) {
                vty_down_level(vty);
                return;
        }

        if (vty->cp == vty->length)
                return; /* completion need here? */

        size = vty->length - vty->cp;

        vty->length--;
        memmove(&vty->buf[vty->cp], &vty->buf[vty->cp + 1], size - 1);
        vty->buf[vty->length] = '\0';

        if (vty->node == AUTH_NODE || vty->node == AUTH_ENABLE_NODE)
                return;

        vty_write(vty, &vty->buf[vty->cp], size - 1);
        vty_write(vty, &telnet_space_char, 1);

        for (i = 0; i < size; i++)
                vty_write(vty, &telnet_backward_char, 1);
}

/* Delete a character before the point. */
static void vty_delete_backward_char(struct vty *vty)
{
        if (vty->cp == 0)
                return;

        vty_backward_char(vty);
        vty_delete_char(vty);
}

/* Kill rest of line from current point. */
static void vty_kill_line(struct vty *vty)
{
        int i;
        int size;

        size = vty->length - vty->cp;

        if (size == 0)
                return;

        for (i = 0; i < size; i++)
                vty_write(vty, &telnet_space_char, 1);
        for (i = 0; i < size; i++)
                vty_write(vty, &telnet_backward_char, 1);

        memset(&vty->buf[vty->cp], 0, size);
        vty->length = vty->cp;
}

/* Kill line from the beginning. */
static void vty_kill_line_from_beginning(struct vty *vty)
{
        vty_beginning_of_line(vty);
        vty_kill_line(vty);
}

/* Delete a word before the point. */
static void vty_forward_kill_word(struct vty *vty)
{
        while (vty->cp != vty->length && vty->buf[vty->cp] == ' ')
                vty_delete_char(vty);
        while (vty->cp != vty->length && vty->buf[vty->cp] != ' ')
                vty_delete_char(vty);
}

/* Delete a word before the point. */
static void vty_backward_kill_word(struct vty *vty)
{
        while (vty->cp > 0 && vty->buf[vty->cp - 1] == ' ')
                vty_delete_backward_char(vty);
        while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
                vty_delete_backward_char(vty);
}

/* Transpose chars before or at the point. */
static void vty_transpose_chars(struct vty *vty)
{
        char c1, c2;

        /* If length is short or point is near by the beginning of line then
           return. */
        if (vty->length < 2 || vty->cp < 1)
                return;

        /* In case of point is located at the end of the line. */
        if (vty->cp == vty->length) {
                c1 = vty->buf[vty->cp - 1];
                c2 = vty->buf[vty->cp - 2];

                vty_backward_char(vty);
                vty_backward_char(vty);
                vty_self_insert_overwrite(vty, c1);
                vty_self_insert_overwrite(vty, c2);
        } else {
                c1 = vty->buf[vty->cp];
                c2 = vty->buf[vty->cp - 1];

                vty_backward_char(vty);
                vty_self_insert_overwrite(vty, c1);
                vty_self_insert_overwrite(vty, c2);
        }
}

/* Do completion at vty interface. */
static void vty_complete_command(struct vty *vty)
{
        int i;
        int ret;
        char **matched = NULL;
        vector vline;

        if (vty->node == AUTH_NODE || vty->node == AUTH_ENABLE_NODE)
                return;

        vline = cmd_make_strvec(vty->buf);
        if (vline == NULL)
                return;

        /* In case of 'help \t'. */
        if (isspace((int)vty->buf[vty->length - 1]))
                vector_set(vline, NULL);

        matched = cmd_complete_command(vline, vty, &ret);

        cmd_free_strvec(vline);

        vty_out(vty, "\n");
        switch (ret) {
        case CMD_ERR_AMBIGUOUS:
                vty_out(vty, "%% Ambiguous command.\n");
                vty_prompt(vty);
                vty_redraw_line(vty);
                break;
        case CMD_ERR_NO_MATCH:
                /* vty_out (vty, "%% There is no matched command.\n"); */
                vty_prompt(vty);
                vty_redraw_line(vty);
                break;
        case CMD_COMPLETE_FULL_MATCH:
                if (!matched[0]) {
                        /* 2016-11-28 equinox -- need to debug, SEGV here */
                        vty_out(vty, "%% CLI BUG: FULL_MATCH with NULL str\n");
                        vty_prompt(vty);
                        vty_redraw_line(vty);
                        break;
                }
                vty_prompt(vty);
                vty_redraw_line(vty);
                vty_backward_pure_word(vty);
                vty_insert_word_overwrite(vty, matched[0]);
                vty_self_insert(vty, ' ');
                XFREE(MTYPE_COMPLETION, matched[0]);
                break;
        case CMD_COMPLETE_MATCH:
                vty_prompt(vty);
                vty_redraw_line(vty);
                vty_backward_pure_word(vty);
                vty_insert_word_overwrite(vty, matched[0]);
                XFREE(MTYPE_COMPLETION, matched[0]);
                break;
        case CMD_COMPLETE_LIST_MATCH:
                for (i = 0; matched[i] != NULL; i++) {
                        if (i != 0 && ((i % 6) == 0))
                                vty_out(vty, "\n");
                        vty_out(vty, "%-10s ", matched[i]);
                        XFREE(MTYPE_COMPLETION, matched[i]);
                }
                vty_out(vty, "\n");

                vty_prompt(vty);
                vty_redraw_line(vty);
                break;
        case CMD_ERR_NOTHING_TODO:
                vty_prompt(vty);
                vty_redraw_line(vty);
                break;
        default:
                break;
        }
        XFREE(MTYPE_TMP, matched);
}

static void vty_describe_fold(struct vty *vty, int cmd_width,
                              unsigned int desc_width, struct cmd_token *token)
{
        char *buf;
        const char *cmd, *p;
        int pos;

        cmd = token->text;

        if (desc_width <= 0) {
                vty_out(vty, "  %-*s  %s\n", cmd_width, cmd, token->desc);
                return;
        }

        buf = XCALLOC(MTYPE_TMP, strlen(token->desc) + 1);

        for (p = token->desc; strlen(p) > desc_width; p += pos + 1) {
                for (pos = desc_width; pos > 0; pos--)
                        if (*(p + pos) == ' ')
                                break;

                if (pos == 0)
                        break;

                memcpy(buf, p, pos);
                buf[pos] = '\0';
                vty_out(vty, "  %-*s  %s\n", cmd_width, cmd, buf);

                cmd = "";
        }

        vty_out(vty, "  %-*s  %s\n", cmd_width, cmd, p);

        XFREE(MTYPE_TMP, buf);
}

/* Describe matched command function. */
static void vty_describe_command(struct vty *vty)
{
        int ret;
        vector vline;
        vector describe;
        unsigned int i, width, desc_width;
        struct cmd_token *token, *token_cr = NULL;

        vline = cmd_make_strvec(vty->buf);

        /* In case of '> ?'. */
        if (vline == NULL) {
                vline = vector_init(1);
                vector_set(vline, NULL);
        } else if (isspace((int)vty->buf[vty->length - 1]))
                vector_set(vline, NULL);

        describe = cmd_describe_command(vline, vty, &ret);

        vty_out(vty, "\n");

        /* Ambiguous error. */
        switch (ret) {
        case CMD_ERR_AMBIGUOUS:
                vty_out(vty, "%% Ambiguous command.\n");
                goto out;
                break;
        case CMD_ERR_NO_MATCH:
                vty_out(vty, "%% There is no matched command.\n");
                goto out;
                break;
        }

        /* Get width of command string. */
        width = 0;
        for (i = 0; i < vector_active(describe); i++)
                if ((token = vector_slot(describe, i)) != NULL) {
                        unsigned int len;

                        if (token->text[0] == '\0')
                                continue;

                        len = strlen(token->text);

                        if (width < len)
                                width = len;
                }

        /* Get width of description string. */
        desc_width = vty->width - (width + 6);

        /* Print out description. */
        for (i = 0; i < vector_active(describe); i++)
                if ((token = vector_slot(describe, i)) != NULL) {
                        if (token->text[0] == '\0')
                                continue;

                        if (strcmp(token->text, CMD_CR_TEXT) == 0) {
                                token_cr = token;
                                continue;
                        }

                        if (!token->desc)
                                vty_out(vty, "  %-s\n", token->text);
                        else if (desc_width >= strlen(token->desc))
                                vty_out(vty, "  %-*s  %s\n", width, token->text,
                                        token->desc);
                        else
                                vty_describe_fold(vty, width, desc_width,
                                                  token);

                        if (IS_VARYING_TOKEN(token->type)) {
                                const char *ref = vector_slot(
                                        vline, vector_active(vline) - 1);

                                vector varcomps = vector_init(VECTOR_MIN_SIZE);
                                cmd_variable_complete(token, ref, varcomps);

                                if (vector_active(varcomps) > 0) {
                                        char *ac = cmd_variable_comp2str(
                                                varcomps, vty->width);
                                        vty_out(vty, "%s\n", ac);
                                        XFREE(MTYPE_TMP, ac);
                                }

                                vector_free(varcomps);
                        }
#if 0
        vty_out (vty, "  %-*s %s\n", width
                 desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
                 desc->str ? desc->str : "");
#endif /* 0 */
                }

        if ((token = token_cr)) {
                if (!token->desc)
                        vty_out(vty, "  %-s\n", token->text);
                else if (desc_width >= strlen(token->desc))
                        vty_out(vty, "  %-*s  %s\n", width, token->text,
                                token->desc);
                else
                        vty_describe_fold(vty, width, desc_width, token);
        }

out:
        cmd_free_strvec(vline);
        if (describe)
                vector_free(describe);

        vty_prompt(vty);
        vty_redraw_line(vty);
}

static void vty_clear_buf(struct vty *vty)
{
        memset(vty->buf, 0, vty->max);
}

/* ^C stop current input and do not add command line to the history. */
static void vty_stop_input(struct vty *vty)
{
        vty->cp = vty->length = 0;
        vty_clear_buf(vty);
        vty_out(vty, "\n");

        if (vty->config) {
                vty_config_exit(vty);
                vty->node = ENABLE_NODE;
        }

        vty_prompt(vty);

        /* Set history pointer to the latest one. */
        vty->hp = vty->hindex;
}

/* Add current command line to the history buffer. */
static void vty_hist_add(struct vty *vty)
{
        int index;

        if (vty->length == 0)
                return;

        index = vty->hindex ? vty->hindex - 1 : VTY_MAXHIST - 1;

        /* Ignore the same string as previous one. */
        if (vty->hist[index])
                if (strcmp(vty->buf, vty->hist[index]) == 0) {
                        vty->hp = vty->hindex;
                        return;
                }

        /* Insert history entry. */
        XFREE(MTYPE_VTY_HIST, vty->hist[vty->hindex]);
        vty->hist[vty->hindex] = XSTRDUP(MTYPE_VTY_HIST, vty->buf);

        /* History index rotation. */
        vty->hindex++;
        if (vty->hindex == VTY_MAXHIST)
                vty->hindex = 0;

        vty->hp = vty->hindex;
}

/* #define TELNET_OPTION_DEBUG */

/* Get telnet window size. */
static int vty_telnet_option(struct vty *vty, unsigned char *buf, int nbytes)
{
#ifdef TELNET_OPTION_DEBUG
        int i;

        for (i = 0; i < nbytes; i++) {
                switch (buf[i]) {
                case IAC:
                        vty_out(vty, "IAC ");
                        break;
                case WILL:
                        vty_out(vty, "WILL ");
                        break;
                case WONT:
                        vty_out(vty, "WONT ");
                        break;
                case DO:
                        vty_out(vty, "DO ");
                        break;
                case DONT:
                        vty_out(vty, "DONT ");
                        break;
                case SB:
                        vty_out(vty, "SB ");
                        break;
                case SE:
                        vty_out(vty, "SE ");
                        break;
                case TELOPT_ECHO:
                        vty_out(vty, "TELOPT_ECHO \n");
                        break;
                case TELOPT_SGA:
                        vty_out(vty, "TELOPT_SGA \n");
                        break;
                case TELOPT_NAWS:
                        vty_out(vty, "TELOPT_NAWS \n");
                        break;
                default:
                        vty_out(vty, "%x ", buf[i]);
                        break;
                }
        }
        vty_out(vty, "\n");

#endif /* TELNET_OPTION_DEBUG */

        switch (buf[0]) {
        case SB:
                vty->sb_len = 0;
                vty->iac_sb_in_progress = 1;
                return 0;
                break;
        case SE: {
                if (!vty->iac_sb_in_progress)
                        return 0;

                if ((vty->sb_len == 0) || (vty->sb_buf[0] == '\0')) {
                        vty->iac_sb_in_progress = 0;
                        return 0;
                }
                switch (vty->sb_buf[0]) {
                case TELOPT_NAWS:
                        if (vty->sb_len != TELNET_NAWS_SB_LEN)
                                flog_err(
                                        EC_LIB_SYSTEM_CALL,
                                        "RFC 1073 violation detected: telnet NAWS option "
                                        "should send %d characters, but we received %lu",
                                        TELNET_NAWS_SB_LEN,
                                        (unsigned long)vty->sb_len);
                        else if (sizeof(vty->sb_buf) < TELNET_NAWS_SB_LEN)
                                flog_err(
                                        EC_LIB_DEVELOPMENT,
                                        "Bug detected: sizeof(vty->sb_buf) %lu < %d, too small to handle the telnet NAWS option",
                                        (unsigned long)sizeof(vty->sb_buf),
                                        TELNET_NAWS_SB_LEN);
                        else {
                                vty->width = ((vty->sb_buf[1] << 8)
                                              | vty->sb_buf[2]);
                                vty->height = ((vty->sb_buf[3] << 8)
                                               | vty->sb_buf[4]);
#ifdef TELNET_OPTION_DEBUG
                                vty_out(vty,
                                        "TELNET NAWS window size negotiation completed: "
                                        "width %d, height %d\n",
                                        vty->width, vty->height);
#endif
                        }
                        break;
                }
                vty->iac_sb_in_progress = 0;
                return 0;
                break;
        }
        default:
                break;
        }
        return 1;
}

/* Execute current command line. */
static int vty_execute(struct vty *vty)
{
        int ret;

        ret = CMD_SUCCESS;

        switch (vty->node) {
        case AUTH_NODE:
        case AUTH_ENABLE_NODE:
                vty_auth(vty, vty->buf);
                break;
        default:
                ret = vty_command(vty, vty->buf);
                if (vty->type == VTY_TERM)
                        vty_hist_add(vty);
                break;
        }

        /* Clear command line buffer. */
        vty->cp = vty->length = 0;
        vty_clear_buf(vty);

        if (vty->status != VTY_CLOSE)
                vty_prompt(vty);

        return ret;
}

#define CONTROL(X)  ((X) - '@')
#define VTY_NORMAL     0
#define VTY_PRE_ESCAPE 1
#define VTY_ESCAPE     2

/* Escape character command map. */
static void vty_escape_map(unsigned char c, struct vty *vty)
{
        switch (c) {
        case ('A'):
                vty_previous_line(vty);
                break;
        case ('B'):
                vty_next_line(vty);
                break;
        case ('C'):
                vty_forward_char(vty);
                break;
        case ('D'):
                vty_backward_char(vty);
                break;
        default:
                break;
        }

        /* Go back to normal mode. */
        vty->escape = VTY_NORMAL;
}

/* Quit print out to the buffer. */
static void vty_buffer_reset(struct vty *vty)
{
        buffer_reset(vty->obuf);
        buffer_reset(vty->lbuf);
        vty_prompt(vty);
        vty_redraw_line(vty);
}

/* Read data via vty socket. */
static int vty_read(struct thread *thread)
{
        int i;
        int nbytes;
        unsigned char buf[VTY_READ_BUFSIZ];

        int vty_sock = THREAD_FD(thread);
        struct vty *vty = THREAD_ARG(thread);

        /* Read raw data from socket */
        if ((nbytes = read(vty->fd, buf, VTY_READ_BUFSIZ)) <= 0) {
                if (nbytes < 0) {
                        if (ERRNO_IO_RETRY(errno)) {
                                vty_event(VTY_READ, vty_sock, vty);
                                return 0;
                        }
                        vty->monitor = 0; /* disable monitoring to avoid
                                             infinite recursion */
                        flog_err(
                                EC_LIB_SOCKET,
                                "%s: read error on vty client fd %d, closing: %s",
                                __func__, vty->fd, safe_strerror(errno));
                        buffer_reset(vty->obuf);
                        buffer_reset(vty->lbuf);
                }
                vty->status = VTY_CLOSE;
        }

        for (i = 0; i < nbytes; i++) {
                if (buf[i] == IAC) {
                        if (!vty->iac) {
                                vty->iac = 1;
                                continue;
                        } else {
                                vty->iac = 0;
                        }
                }

                if (vty->iac_sb_in_progress && !vty->iac) {
                        if (vty->sb_len < sizeof(vty->sb_buf))
                                vty->sb_buf[vty->sb_len] = buf[i];
                        vty->sb_len++;
                        continue;
                }

                if (vty->iac) {
                        /* In case of telnet command */
                        int ret = 0;
                        ret = vty_telnet_option(vty, buf + i, nbytes - i);
                        vty->iac = 0;
                        i += ret;
                        continue;
                }


                if (vty->status == VTY_MORE) {
                        switch (buf[i]) {
                        case CONTROL('C'):
                        case 'q':
                        case 'Q':
                                vty_buffer_reset(vty);
                                break;
#if 0 /* More line does not work for "show ip bgp".  */
            case '\n':
            case '\r':
              vty->status = VTY_MORELINE;
              break;
#endif
                        default:
                                break;
                        }
                        continue;
                }

                /* Escape character. */
                if (vty->escape == VTY_ESCAPE) {
                        vty_escape_map(buf[i], vty);
                        continue;
                }

                /* Pre-escape status. */
                if (vty->escape == VTY_PRE_ESCAPE) {
                        switch (buf[i]) {
                        case '[':
                                vty->escape = VTY_ESCAPE;
                                break;
                        case 'b':
                                vty_backward_word(vty);
                                vty->escape = VTY_NORMAL;
                                break;
                        case 'f':
                                vty_forward_word(vty);
                                vty->escape = VTY_NORMAL;
                                break;
                        case 'd':
                                vty_forward_kill_word(vty);
                                vty->escape = VTY_NORMAL;
                                break;
                        case CONTROL('H'):
                        case 0x7f:
                                vty_backward_kill_word(vty);
                                vty->escape = VTY_NORMAL;
                                break;
                        default:
                                vty->escape = VTY_NORMAL;
                                break;
                        }
                        continue;
                }

                switch (buf[i]) {
                case CONTROL('A'):
                        vty_beginning_of_line(vty);
                        break;
                case CONTROL('B'):
                        vty_backward_char(vty);
                        break;
                case CONTROL('C'):
                        vty_stop_input(vty);
                        break;
                case CONTROL('D'):
                        vty_delete_char(vty);
                        break;
                case CONTROL('E'):
                        vty_end_of_line(vty);
                        break;
                case CONTROL('F'):
                        vty_forward_char(vty);
                        break;
                case CONTROL('H'):
                case 0x7f:
                        vty_delete_backward_char(vty);
                        break;
                case CONTROL('K'):
                        vty_kill_line(vty);
                        break;
                case CONTROL('N'):
                        vty_next_line(vty);
                        break;
                case CONTROL('P'):
                        vty_previous_line(vty);
                        break;
                case CONTROL('T'):
                        vty_transpose_chars(vty);
                        break;
                case CONTROL('U'):
                        vty_kill_line_from_beginning(vty);
                        break;
                case CONTROL('W'):
                        vty_backward_kill_word(vty);
                        break;
                case CONTROL('Z'):
                        vty_end_config(vty);
                        break;
                case '\n':
                case '\r':
                        vty_out(vty, "\n");
                        vty_execute(vty);
                        break;
                case '\t':
                        vty_complete_command(vty);
                        break;
                case '?':
                        if (vty->node == AUTH_NODE
                            || vty->node == AUTH_ENABLE_NODE)
                                vty_self_insert(vty, buf[i]);
                        else
                                vty_describe_command(vty);
                        break;
                case '\033':
                        if (i + 1 < nbytes && buf[i + 1] == '[') {
                                vty->escape = VTY_ESCAPE;
                                i++;
                        } else
                                vty->escape = VTY_PRE_ESCAPE;
                        break;
                default:
                        if (buf[i] > 31 && buf[i] < 127)
                                vty_self_insert(vty, buf[i]);
                        break;
                }
        }

        /* Check status. */
        if (vty->status == VTY_CLOSE)
                vty_close(vty);
        else {
                vty_event(VTY_WRITE, vty->wfd, vty);
                vty_event(VTY_READ, vty_sock, vty);
        }
        return 0;
}

/* Flush buffer to the vty. */
static int vty_flush(struct thread *thread)
{
        int erase;
        buffer_status_t flushrc;
        int vty_sock = THREAD_FD(thread);
        struct vty *vty = THREAD_ARG(thread);

        /* Tempolary disable read thread. */
        if (vty->lines == 0)
                THREAD_OFF(vty->t_read);

        /* Function execution continue. */
        erase = ((vty->status == VTY_MORE || vty->status == VTY_MORELINE));

        /* N.B. if width is 0, that means we don't know the window size. */
        if ((vty->lines == 0) || (vty->width == 0) || (vty->height == 0))
                flushrc = buffer_flush_available(vty->obuf, vty_sock);
        else if (vty->status == VTY_MORELINE)
                flushrc = buffer_flush_window(vty->obuf, vty_sock, vty->width,
                                              1, erase, 0);
        else
                flushrc = buffer_flush_window(
                        vty->obuf, vty_sock, vty->width,
                        vty->lines >= 0 ? vty->lines : vty->height, erase, 0);
        switch (flushrc) {
        case BUFFER_ERROR:
                vty->monitor =
                        0; /* disable monitoring to avoid infinite recursion */
                zlog_info("buffer_flush failed on vty client fd %d, closing",
                          vty->fd);
                buffer_reset(vty->lbuf);
                buffer_reset(vty->obuf);
                vty_close(vty);
                return 0;
        case BUFFER_EMPTY:
                if (vty->status == VTY_CLOSE)
                        vty_close(vty);
                else {
                        vty->status = VTY_NORMAL;
                        if (vty->lines == 0)
                                vty_event(VTY_READ, vty_sock, vty);
                }
                break;
        case BUFFER_PENDING:
                /* There is more data waiting to be written. */
                vty->status = VTY_MORE;
                if (vty->lines == 0)
                        vty_event(VTY_WRITE, vty_sock, vty);
                break;
        }

        return 0;
}

/* Allocate new vty struct. */
struct vty *vty_new(void)
{
        struct vty *new = XCALLOC(MTYPE_VTY, sizeof(struct vty));

        new->fd = new->wfd = -1;
        new->of = stdout;
        new->lbuf = buffer_new(0);
        new->obuf = buffer_new(0); /* Use default buffer size. */
        new->buf = XCALLOC(MTYPE_VTY, VTY_BUFSIZ);
        new->max = VTY_BUFSIZ;

        return new;
}


/* allocate and initialise vty */
static struct vty *vty_new_init(int vty_sock)
{
        struct vty *vty;

        vty = vty_new();
        vty->fd = vty_sock;
        vty->wfd = vty_sock;
        vty->type = VTY_TERM;
        vty->node = AUTH_NODE;
        vty->fail = 0;
        vty->cp = 0;
        vty_clear_buf(vty);
        vty->length = 0;
        memset(vty->hist, 0, sizeof(vty->hist));
        vty->hp = 0;
        vty->hindex = 0;
        vty->xpath_index = 0;
        memset(vty->xpath, 0, sizeof(vty->xpath));
        vty->private_config = false;
        vty->candidate_config = vty_shared_candidate_config;
        vector_set_index(vtyvec, vty_sock, vty);
        vty->status = VTY_NORMAL;
        vty->lines = -1;
        vty->iac = 0;
        vty->iac_sb_in_progress = 0;
        vty->sb_len = 0;

        return vty;
}

/* Create new vty structure. */
static struct vty *vty_create(int vty_sock, union sockunion *su)
{
        char buf[SU_ADDRSTRLEN];
        struct vty *vty;

        sockunion2str(su, buf, SU_ADDRSTRLEN);

        /* Allocate new vty structure and set up default values. */
        vty = vty_new_init(vty_sock);

        /* configurable parameters not part of basic init */
        vty->v_timeout = vty_timeout_val;
        strlcpy(vty->address, buf, sizeof(vty->address));
        if (no_password_check) {
                if (host.advanced)
                        vty->node = ENABLE_NODE;
                else
                        vty->node = VIEW_NODE;
        }
        if (host.lines >= 0)
                vty->lines = host.lines;

        if (!no_password_check) {
                /* Vty is not available if password isn't set. */
                if (host.password == NULL && host.password_encrypt == NULL) {
                        vty_out(vty, "Vty password is not set.\n");
                        vty->status = VTY_CLOSE;
                        vty_close(vty);
                        return NULL;
                }
        }

        /* Say hello to the world. */
        vty_hello(vty);
        if (!no_password_check)
                vty_out(vty, "\nUser Access Verification\n\n");

        /* Setting up terminal. */
        vty_will_echo(vty);
        vty_will_suppress_go_ahead(vty);

        vty_dont_linemode(vty);
        vty_do_window_size(vty);
        /* vty_dont_lflow_ahead (vty); */

        vty_prompt(vty);

        /* Add read/write thread. */
        vty_event(VTY_WRITE, vty_sock, vty);
        vty_event(VTY_READ, vty_sock, vty);

        return vty;
}

/* create vty for stdio */
static struct termios stdio_orig_termios;
static struct vty *stdio_vty = NULL;
static bool stdio_termios = false;
static void (*stdio_vty_atclose)(int isexit);

static void vty_stdio_reset(int isexit)
{
        if (stdio_vty) {
                if (stdio_termios)
                        tcsetattr(0, TCSANOW, &stdio_orig_termios);
                stdio_termios = false;

                stdio_vty = NULL;

                if (stdio_vty_atclose)
                        stdio_vty_atclose(isexit);
                stdio_vty_atclose = NULL;
        }
}

static void vty_stdio_atexit(void)
{
        vty_stdio_reset(1);
}

void vty_stdio_suspend(void)
{
        if (!stdio_vty)
                return;

        THREAD_OFF(stdio_vty->t_write);
        THREAD_OFF(stdio_vty->t_read);
        THREAD_OFF(stdio_vty->t_timeout);

        if (stdio_termios)
                tcsetattr(0, TCSANOW, &stdio_orig_termios);
        stdio_termios = false;
}

void vty_stdio_resume(void)
{
        if (!stdio_vty)
                return;

        if (!tcgetattr(0, &stdio_orig_termios)) {
                struct termios termios;

                termios = stdio_orig_termios;
                termios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR
                                     | IGNCR | ICRNL | IXON);
                termios.c_oflag &= ~OPOST;
                termios.c_lflag &= ~(ECHO | ECHONL | ICANON | IEXTEN);
                termios.c_cflag &= ~(CSIZE | PARENB);
                termios.c_cflag |= CS8;
                tcsetattr(0, TCSANOW, &termios);
                stdio_termios = true;
        }

        vty_prompt(stdio_vty);

        /* Add read/write thread. */
        vty_event(VTY_WRITE, 1, stdio_vty);
        vty_event(VTY_READ, 0, stdio_vty);
}

void vty_stdio_close(void)
{
        if (!stdio_vty)
                return;
        vty_close(stdio_vty);
}

struct vty *vty_stdio(void (*atclose)(int isexit))
{
        struct vty *vty;

        /* refuse creating two vtys on stdio */
        if (stdio_vty)
                return NULL;

        vty = stdio_vty = vty_new_init(0);
        stdio_vty_atclose = atclose;
        vty->wfd = 1;

        /* always have stdio vty in a known _unchangeable_ state, don't want
         * config
         * to have any effect here to make sure scripting this works as intended
         */
        vty->node = ENABLE_NODE;
        vty->v_timeout = 0;
        strlcpy(vty->address, "console", sizeof(vty->address));

        vty_stdio_resume();
        return vty;
}

/* Accept connection from the network. */
static int vty_accept(struct thread *thread)
{
        int vty_sock;
        union sockunion su;
        int ret;
        unsigned int on;
        int accept_sock;
        struct prefix p;
        struct access_list *acl = NULL;
        char buf[SU_ADDRSTRLEN];

        accept_sock = THREAD_FD(thread);

        /* We continue hearing vty socket. */
        vty_event(VTY_SERV, accept_sock, NULL);

        memset(&su, 0, sizeof(union sockunion));

        /* We can handle IPv4 or IPv6 socket. */
        vty_sock = sockunion_accept(accept_sock, &su);
        if (vty_sock < 0) {
                flog_err(EC_LIB_SOCKET, "can't accept vty socket : %s",
                         safe_strerror(errno));
                return -1;
        }
        set_nonblocking(vty_sock);
        set_cloexec(vty_sock);

        sockunion2hostprefix(&su, &p);

        /* VTY's accesslist apply. */
        if (p.family == AF_INET && vty_accesslist_name) {
                if ((acl = access_list_lookup(AFI_IP, vty_accesslist_name))
                    && (access_list_apply(acl, &p) == FILTER_DENY)) {
                        zlog_info("Vty connection refused from %s",
                                  sockunion2str(&su, buf, SU_ADDRSTRLEN));
                        close(vty_sock);

                        /* continue accepting connections */
                        vty_event(VTY_SERV, accept_sock, NULL);

                        return 0;
                }
        }

        /* VTY's ipv6 accesslist apply. */
        if (p.family == AF_INET6 && vty_ipv6_accesslist_name) {
                if ((acl = access_list_lookup(AFI_IP6,
                                              vty_ipv6_accesslist_name))
                    && (access_list_apply(acl, &p) == FILTER_DENY)) {
                        zlog_info("Vty connection refused from %s",
                                  sockunion2str(&su, buf, SU_ADDRSTRLEN));
                        close(vty_sock);

                        /* continue accepting connections */
                        vty_event(VTY_SERV, accept_sock, NULL);

                        return 0;
                }
        }

        on = 1;
        ret = setsockopt(vty_sock, IPPROTO_TCP, TCP_NODELAY, (char *)&on,
                         sizeof(on));
        if (ret < 0)
                zlog_info("can't set sockopt to vty_sock : %s",
                          safe_strerror(errno));

        zlog_info("Vty connection from %s",
                  sockunion2str(&su, buf, SU_ADDRSTRLEN));

        vty_create(vty_sock, &su);

        return 0;
}

static void vty_serv_sock_addrinfo(const char *hostname, unsigned short port)
{
        int ret;
        struct addrinfo req;
        struct addrinfo *ainfo;
        struct addrinfo *ainfo_save;
        int sock;
        char port_str[BUFSIZ];

        memset(&req, 0, sizeof(struct addrinfo));
        req.ai_flags = AI_PASSIVE;
        req.ai_family = AF_UNSPEC;
        req.ai_socktype = SOCK_STREAM;
        sprintf(port_str, "%d", port);
        port_str[sizeof(port_str) - 1] = '\0';

        ret = getaddrinfo(hostname, port_str, &req, &ainfo);

        if (ret != 0) {
                flog_err_sys(EC_LIB_SYSTEM_CALL, "getaddrinfo failed: %s",
                             gai_strerror(ret));
                exit(1);
        }

        ainfo_save = ainfo;

        do {
                if (ainfo->ai_family != AF_INET && ainfo->ai_family != AF_INET6)
                        continue;

                sock = socket(ainfo->ai_family, ainfo->ai_socktype,
                              ainfo->ai_protocol);
                if (sock < 0)
                        continue;

                sockopt_v6only(ainfo->ai_family, sock);
                sockopt_reuseaddr(sock);
                sockopt_reuseport(sock);
                set_cloexec(sock);

                ret = bind(sock, ainfo->ai_addr, ainfo->ai_addrlen);
                if (ret < 0) {
                        close(sock); /* Avoid sd leak. */
                        continue;
                }

                ret = listen(sock, 3);
                if (ret < 0) {
                        close(sock); /* Avoid sd leak. */
                        continue;
                }

                vty_event(VTY_SERV, sock, NULL);
        } while ((ainfo = ainfo->ai_next) != NULL);

        freeaddrinfo(ainfo_save);
}

#ifdef VTYSH
/* For sockaddr_un. */
#include <sys/un.h>

/* VTY shell UNIX domain socket. */
static void vty_serv_un(const char *path)
{
        int ret;
        int sock, len;
        struct sockaddr_un serv;
        mode_t old_mask;
        struct zprivs_ids_t ids;

        /* First of all, unlink existing socket */
        unlink(path);

        /* Set umask */
        old_mask = umask(0007);

        /* Make UNIX domain socket. */
        sock = socket(AF_UNIX, SOCK_STREAM, 0);
        if (sock < 0) {
                flog_err_sys(EC_LIB_SOCKET,
                             "Cannot create unix stream socket: %s",
                             safe_strerror(errno));
                return;
        }

        /* Make server socket. */
        memset(&serv, 0, sizeof(struct sockaddr_un));
        serv.sun_family = AF_UNIX;
        strlcpy(serv.sun_path, path, sizeof(serv.sun_path));
#ifdef HAVE_STRUCT_SOCKADDR_UN_SUN_LEN
        len = serv.sun_len = SUN_LEN(&serv);
#else
        len = sizeof(serv.sun_family) + strlen(serv.sun_path);
#endif /* HAVE_STRUCT_SOCKADDR_UN_SUN_LEN */

        set_cloexec(sock);

        ret = bind(sock, (struct sockaddr *)&serv, len);
        if (ret < 0) {
                flog_err_sys(EC_LIB_SOCKET, "Cannot bind path %s: %s", path,
                             safe_strerror(errno));
                close(sock); /* Avoid sd leak. */
                return;
        }

        ret = listen(sock, 5);
        if (ret < 0) {
                flog_err_sys(EC_LIB_SOCKET, "listen(fd %d) failed: %s", sock,
                             safe_strerror(errno));
                close(sock); /* Avoid sd leak. */
                return;
        }

        umask(old_mask);

        zprivs_get_ids(&ids);

        /* Hack: ids.gid_vty is actually a uint, but we stored -1 in it
           earlier for the case when we don't need to chown the file
           type casting it here to make a compare */
        if ((int)ids.gid_vty > 0) {
                /* set group of socket */
                if (chown(path, -1, ids.gid_vty)) {
                        flog_err_sys(EC_LIB_SYSTEM_CALL,
                                     "vty_serv_un: could chown socket, %s",
                                     safe_strerror(errno));
                }
        }

        vty_event(VTYSH_SERV, sock, NULL);
}

/* #define VTYSH_DEBUG 1 */

static int vtysh_accept(struct thread *thread)
{
        int accept_sock;
        int sock;
        int client_len;
        struct sockaddr_un client;
        struct vty *vty;

        accept_sock = THREAD_FD(thread);

        vty_event(VTYSH_SERV, accept_sock, NULL);

        memset(&client, 0, sizeof(struct sockaddr_un));
        client_len = sizeof(struct sockaddr_un);

        sock = accept(accept_sock, (struct sockaddr *)&client,
                      (socklen_t *)&client_len);

        if (sock < 0) {
                flog_err(EC_LIB_SOCKET, "can't accept vty socket : %s",
                         safe_strerror(errno));
                return -1;
        }

        if (set_nonblocking(sock) < 0) {
                flog_err(
                        EC_LIB_SOCKET,
                        "vtysh_accept: could not set vty socket %d to non-blocking, %s, closing",
                        sock, safe_strerror(errno));
                close(sock);
                return -1;
        }
        set_cloexec(sock);

#ifdef VTYSH_DEBUG
        printf("VTY shell accept\n");
#endif /* VTYSH_DEBUG */

        vty = vty_new();
        vty->fd = sock;
        vty->wfd = sock;
        vty->type = VTY_SHELL_SERV;
        vty->node = VIEW_NODE;

        vty_event(VTYSH_READ, sock, vty);

        return 0;
}

static int vtysh_flush(struct vty *vty)
{
        switch (buffer_flush_available(vty->obuf, vty->wfd)) {
        case BUFFER_PENDING:
                vty_event(VTYSH_WRITE, vty->wfd, vty);
                break;
        case BUFFER_ERROR:
                vty->monitor =
                        0; /* disable monitoring to avoid infinite recursion */
                flog_err(EC_LIB_SOCKET, "%s: write error to fd %d, closing",
                         __func__, vty->fd);
                buffer_reset(vty->lbuf);
                buffer_reset(vty->obuf);
                vty_close(vty);
                return -1;
                break;
        case BUFFER_EMPTY:
                break;
        }
        return 0;
}

static int vtysh_read(struct thread *thread)
{
        int ret;
        int sock;
        int nbytes;
        struct vty *vty;
        unsigned char buf[VTY_READ_BUFSIZ];
        unsigned char *p;
        uint8_t header[4] = {0, 0, 0, 0};

        sock = THREAD_FD(thread);
        vty = THREAD_ARG(thread);

        if ((nbytes = read(sock, buf, VTY_READ_BUFSIZ)) <= 0) {
                if (nbytes < 0) {
                        if (ERRNO_IO_RETRY(errno)) {
                                vty_event(VTYSH_READ, sock, vty);
                                return 0;
                        }
                        vty->monitor = 0; /* disable monitoring to avoid
                                             infinite recursion */
                        flog_err(
                                EC_LIB_SOCKET,
                                "%s: read failed on vtysh client fd %d, closing: %s",
                                __func__, sock, safe_strerror(errno));
                }
                buffer_reset(vty->lbuf);
                buffer_reset(vty->obuf);
                vty_close(vty);
#ifdef VTYSH_DEBUG
                printf("close vtysh\n");
#endif /* VTYSH_DEBUG */
                return 0;
        }

#ifdef VTYSH_DEBUG
        printf("line: %.*s\n", nbytes, buf);
#endif /* VTYSH_DEBUG */

        if (vty->length + nbytes >= VTY_BUFSIZ) {
                /* Clear command line buffer. */
                vty->cp = vty->length = 0;
                vty_clear_buf(vty);
                vty_out(vty, "%% Command is too long.\n");
        } else {
                for (p = buf; p < buf + nbytes; p++) {
                        vty->buf[vty->length++] = *p;
                        if (*p == '\0') {
                                /* Pass this line to parser. */
                                ret = vty_execute(vty);
/* Note that vty_execute clears the command buffer and resets
   vty->length to 0. */

/* Return result. */
#ifdef VTYSH_DEBUG
                                printf("result: %d\n", ret);
                                printf("vtysh node: %d\n", vty->node);
#endif /* VTYSH_DEBUG */

                                /* hack for asynchronous "write integrated"
                                 * - other commands in "buf" will be ditched
                                 * - input during pending config-write is
                                 * "unsupported" */
                                if (ret == CMD_SUSPEND)
                                        break;

                                /* warning: watchfrr hardcodes this result write
                                 */
                                header[3] = ret;
                                buffer_put(vty->obuf, header, 4);

                                if (!vty->t_write && (vtysh_flush(vty) < 0))
                                        /* Try to flush results; exit if a write
                                         * error occurs. */
                                        return 0;
                        }
                }
        }

        if (vty->status == VTY_CLOSE)
                vty_close(vty);
        else
                vty_event(VTYSH_READ, sock, vty);

        return 0;
}

static int vtysh_write(struct thread *thread)
{
        struct vty *vty = THREAD_ARG(thread);

        vtysh_flush(vty);
        return 0;
}

#endif /* VTYSH */

/* Determine address family to bind. */
void vty_serv_sock(const char *addr, unsigned short port, const char *path)
{
        /* If port is set to 0, do not listen on TCP/IP at all! */
        if (port)
                vty_serv_sock_addrinfo(addr, port);

#ifdef VTYSH
        vty_serv_un(path);
#endif /* VTYSH */
}

static void vty_error_delete(void *arg)
{
        struct vty_error *ve = arg;

        XFREE(MTYPE_TMP, ve);
}

/* Close vty interface.  Warning: call this only from functions that
   will be careful not to access the vty afterwards (since it has
   now been freed).  This is safest from top-level functions (called
   directly by the thread dispatcher). */
void vty_close(struct vty *vty)
{
        int i;
        bool was_stdio = false;

        /* Cancel threads.*/
        THREAD_OFF(vty->t_read);
        THREAD_OFF(vty->t_write);
        THREAD_OFF(vty->t_timeout);

        /* Flush buffer. */
        buffer_flush_all(vty->obuf, vty->wfd);

        /* Free input buffer. */
        buffer_free(vty->obuf);
        buffer_free(vty->lbuf);

        /* Free command history. */
        for (i = 0; i < VTY_MAXHIST; i++) {
                XFREE(MTYPE_VTY_HIST, vty->hist[i]);
        }

        /* Unset vector. */
        if (vty->fd != -1)
                vector_unset(vtyvec, vty->fd);

        if (vty->wfd > 0 && vty->type == VTY_FILE)
                fsync(vty->wfd);

        /* Close socket.
         * note check is for fd > STDERR_FILENO, not fd != -1.
         * We never close stdin/stdout/stderr here, because we may be
         * running in foreground mode with logging to stdout.  Also,
         * additionally, we'd need to replace these fds with /dev/null. */
        if (vty->wfd > STDERR_FILENO && vty->wfd != vty->fd)
                close(vty->wfd);
        if (vty->fd > STDERR_FILENO)
                close(vty->fd);
        if (vty->fd == STDIN_FILENO)
                was_stdio = true;

        XFREE(MTYPE_VTY, vty->buf);

        if (vty->error) {
                vty->error->del = vty_error_delete;
                list_delete(&vty->error);
        }

        /* Check configure. */
        vty_config_exit(vty);

        /* OK free vty. */
        XFREE(MTYPE_VTY, vty);

        if (was_stdio)
                vty_stdio_reset(0);
}

/* When time out occur output message then close connection. */
static int vty_timeout(struct thread *thread)
{
        struct vty *vty;

        vty = THREAD_ARG(thread);
        vty->v_timeout = 0;

        /* Clear buffer*/
        buffer_reset(vty->lbuf);
        buffer_reset(vty->obuf);
        vty_out(vty, "\nVty connection is timed out.\n");

        /* Close connection. */
        vty->status = VTY_CLOSE;
        vty_close(vty);

        return 0;
}

/* Read up configuration file from file_name. */
static void vty_read_file(struct nb_config *config, FILE *confp)
{
        int ret;
        struct vty *vty;
        struct vty_error *ve;
        struct listnode *node;
        unsigned int line_num = 0;

        vty = vty_new();
        /* vty_close won't close stderr;  if some config command prints
         * something it'll end up there.  (not ideal; it'd be beter if output
         * from a file-load went to logging instead.  Also note that if this
         * function is called after daemonizing, stderr will be /dev/null.)
         *
         * vty->fd will be -1 from vty_new()
         */
        vty->wfd = STDERR_FILENO;
        vty->type = VTY_FILE;
        vty->node = CONFIG_NODE;
        vty->config = true;
        if (config)
                vty->candidate_config = config;
        else {
                vty->private_config = true;
                vty->candidate_config = nb_config_new(NULL);
        }

        /* Execute configuration file */
        ret = config_from_file(vty, confp, &line_num);

        /* Flush any previous errors before printing messages below */
        buffer_flush_all(vty->obuf, vty->wfd);

        if (!((ret == CMD_SUCCESS) || (ret == CMD_ERR_NOTHING_TODO))) {
                const char *message = NULL;
                char *nl;

                switch (ret) {
                case CMD_ERR_AMBIGUOUS:
                        message = "Ambiguous command";
                        break;
                case CMD_ERR_NO_MATCH:
                        message = "No such command";
                        break;
                case CMD_WARNING:
                        message = "Command returned Warning";
                        break;
                case CMD_WARNING_CONFIG_FAILED:
                        message = "Command returned Warning Config Failed";
                        break;
                case CMD_ERR_INCOMPLETE:
                        message = "Command returned Incomplete";
                        break;
                case CMD_ERR_EXEED_ARGC_MAX:
                        message =
                                "Command exceeded maximum number of Arguments";
                        break;
                default:
                        message = "Command returned unhandled error message";
                        break;
                }

                for (ALL_LIST_ELEMENTS_RO(vty->error, node, ve)) {
                        nl = strchr(ve->error_buf, '\n');
                        if (nl)
                                *nl = '\0';
                        flog_err(EC_LIB_VTY, "ERROR: %s on config line %u: %s",
                                 message, ve->line_num, ve->error_buf);
                }
        }

        /*
         * Automatically commit the candidate configuration after
         * reading the configuration file.
         */
        if (config == NULL && vty->candidate_config
            && frr_get_cli_mode() == FRR_CLI_TRANSACTIONAL) {
                ret = nb_candidate_commit(vty->candidate_config, NB_CLIENT_CLI,
                                          vty, true, "Read configuration file",
                                          NULL);
                if (ret != NB_OK && ret != NB_ERR_NO_CHANGES)
                        zlog_err("%s: failed to read configuration file.",
                                 __func__);
        }

        vty_close(vty);
}

static FILE *vty_use_backup_config(const char *fullpath)
{
        char *fullpath_sav, *fullpath_tmp;
        FILE *ret = NULL;
        int tmp, sav;
        int c;
        char buffer[512];

        size_t fullpath_sav_sz = strlen(fullpath) + strlen(CONF_BACKUP_EXT) + 1;
        fullpath_sav = malloc(fullpath_sav_sz);
        strlcpy(fullpath_sav, fullpath, fullpath_sav_sz);
        strlcat(fullpath_sav, CONF_BACKUP_EXT, fullpath_sav_sz);

        sav = open(fullpath_sav, O_RDONLY);
        if (sav < 0) {
                free(fullpath_sav);
                return NULL;
        }

        fullpath_tmp = malloc(strlen(fullpath) + 8);
        sprintf(fullpath_tmp, "%s.XXXXXX", fullpath);

        /* Open file to configuration write. */
        tmp = mkstemp(fullpath_tmp);
        if (tmp < 0)
                goto out_close_sav;

        if (fchmod(tmp, CONFIGFILE_MASK) != 0)
                goto out_close;

        while ((c = read(sav, buffer, 512)) > 0) {
                if (write(tmp, buffer, c) <= 0)
                        goto out_close;
        }
        close(sav);
        close(tmp);

        if (rename(fullpath_tmp, fullpath) == 0)
                ret = fopen(fullpath, "r");
        else
                unlink(fullpath_tmp);

        if (0) {
        out_close:
                close(tmp);
                unlink(fullpath_tmp);
        out_close_sav:
                close(sav);
        }

        free(fullpath_sav);
        free(fullpath_tmp);
        return ret;
}

/* Read up configuration file from file_name. */
bool vty_read_config(struct nb_config *config, const char *config_file,
                     char *config_default_dir)
{
        char cwd[MAXPATHLEN];
        FILE *confp = NULL;
        const char *fullpath;
        char *tmp = NULL;
        bool read_success = false;

        /* If -f flag specified. */
        if (config_file != NULL) {
                if (!IS_DIRECTORY_SEP(config_file[0])) {
                        if (getcwd(cwd, MAXPATHLEN) == NULL) {
                                flog_err_sys(
                                        EC_LIB_SYSTEM_CALL,
                                        "%s: failure to determine Current Working Directory %d!",
                                        __func__, errno);
                                goto tmp_free_and_out;
                        }
                        tmp = XMALLOC(MTYPE_TMP,
                                      strlen(cwd) + strlen(config_file) + 2);
                        sprintf(tmp, "%s/%s", cwd, config_file);
                        fullpath = tmp;
                } else
                        fullpath = config_file;

                confp = fopen(fullpath, "r");

                if (confp == NULL) {
                        flog_warn(
                                EC_LIB_BACKUP_CONFIG,
                                "%s: failed to open configuration file %s: %s, checking backup",
                                __func__, fullpath, safe_strerror(errno));

                        confp = vty_use_backup_config(fullpath);
                        if (confp)
                                flog_warn(
                                        EC_LIB_BACKUP_CONFIG,
                                        "WARNING: using backup configuration file!");
                        else {
                                flog_err(
                                        EC_LIB_VTY,
                                        "%s: can't open configuration file [%s]",
                                        __func__, config_file);
                                goto tmp_free_and_out;
                        }
                }
        } else {

                host_config_set(config_default_dir);

#ifdef VTYSH
                int ret;
                struct stat conf_stat;

                /* !!!!PLEASE LEAVE!!!!
                 * This is NEEDED for use with vtysh -b, or else you can get
                 * a real configuration food fight with a lot garbage in the
                 * merged configuration file it creates coming from the per
                 * daemon configuration files.  This also allows the daemons
                 * to start if there default configuration file is not
                 * present or ignore them, as needed when using vtysh -b to
                 * configure the daemons at boot - MAG
                 */

                /* Stat for vtysh Zebra.conf, if found startup and wait for
                 * boot configuration
                 */

                if (strstr(config_default_dir, "vtysh") == NULL) {
                        ret = stat(integrate_default, &conf_stat);
                        if (ret >= 0) {
                                read_success = true;
                                goto tmp_free_and_out;
                        }
                }
#endif /* VTYSH */
                confp = fopen(config_default_dir, "r");
                if (confp == NULL) {
                        flog_err(
                                EC_LIB_SYSTEM_CALL,
                                "%s: failed to open configuration file %s: %s, checking backup",
                                __func__, config_default_dir,
                                safe_strerror(errno));

                        confp = vty_use_backup_config(config_default_dir);
                        if (confp) {
                                flog_warn(
                                        EC_LIB_BACKUP_CONFIG,
                                        "WARNING: using backup configuration file!");
                                fullpath = config_default_dir;
                        } else {
                                flog_err(EC_LIB_VTY,
                                         "can't open configuration file [%s]",
                                         config_default_dir);
                                goto tmp_free_and_out;
                        }
                } else
                        fullpath = config_default_dir;
        }

        vty_read_file(config, confp);
        read_success = true;

        fclose(confp);

        host_config_set(fullpath);

tmp_free_and_out:
        XFREE(MTYPE_TMP, tmp);

        return read_success;
}

/* Small utility function which output log to the VTY. */
void vty_log(const char *level, const char *proto_str, const char *msg,
             struct timestamp_control *ctl)
{
        unsigned int i;
        struct vty *vty;

        if (!vtyvec)
                return;

        for (i = 0; i < vector_active(vtyvec); i++)
                if ((vty = vector_slot(vtyvec, i)) != NULL)
                        if (vty->monitor)
                                vty_log_out(vty, level, proto_str, msg, ctl);
}

/* Async-signal-safe version of vty_log for fixed strings. */
void vty_log_fixed(char *buf, size_t len)
{
        unsigned int i;
        struct iovec iov[2];
        char crlf[4] = "\r\n";

        /* vty may not have been initialised */
        if (!vtyvec)
                return;

        iov[0].iov_base = buf;
        iov[0].iov_len = len;
        iov[1].iov_base = crlf;
        iov[1].iov_len = 2;

        for (i = 0; i < vector_active(vtyvec); i++) {
                struct vty *vty;
                if (((vty = vector_slot(vtyvec, i)) != NULL) && vty->monitor)
                        /* N.B. We don't care about the return code, since
                           process is
                           most likely just about to die anyway. */
                        if (writev(vty->wfd, iov, 2) == -1) {
                                fprintf(stderr, "Failure to writev: %d\n",
                                        errno);
                                exit(-1);
                        }
        }
}

int vty_config_enter(struct vty *vty, bool private_config, bool exclusive)
{
        if (exclusive && nb_running_lock(NB_CLIENT_CLI, vty)) {
                vty_out(vty, "%% Configuration is locked by other client\n");
                return CMD_WARNING;
        }

        vty->node = CONFIG_NODE;
        vty->config = true;
        vty->private_config = private_config;
        vty->xpath_index = 0;

        pthread_rwlock_rdlock(&running_config->lock);
        {
                if (private_config) {
                        vty->candidate_config = nb_config_dup(running_config);
                        vty->candidate_config_base =
                                nb_config_dup(running_config);
                        vty_out(vty,
                                "Warning: uncommitted changes will be discarded on exit.\n\n");
                } else {
                        vty->candidate_config = vty_shared_candidate_config;
                        if (frr_get_cli_mode() == FRR_CLI_TRANSACTIONAL)
                                vty->candidate_config_base =
                                        nb_config_dup(running_config);
                }
        }
        pthread_rwlock_unlock(&running_config->lock);

        return CMD_SUCCESS;
}

void vty_config_exit(struct vty *vty)
{
        /* Check if there's a pending confirmed commit. */
        if (vty->t_confirmed_commit_timeout) {
                vty_out(vty,
                        "WARNING: exiting with a pending confirmed commit. Rolling back to previous configuration.\n\n");
                nb_cli_confirmed_commit_rollback(vty);
                nb_cli_confirmed_commit_clean(vty);
        }

        (void)nb_running_unlock(NB_CLIENT_CLI, vty);

        if (vty->candidate_config) {
                if (vty->private_config)
                        nb_config_free(vty->candidate_config);
                vty->candidate_config = NULL;
        }
        if (vty->candidate_config_base) {
                nb_config_free(vty->candidate_config_base);
                vty->candidate_config_base = NULL;
        }

        vty->config = false;
}

/* Master of the threads. */
static struct thread_master *vty_master;

static void vty_event(enum event event, int sock, struct vty *vty)
{
        struct thread *vty_serv_thread = NULL;

        switch (event) {
        case VTY_SERV:
                vty_serv_thread = thread_add_read(vty_master, vty_accept, vty,
                                                  sock, NULL);
                vector_set_index(Vvty_serv_thread, sock, vty_serv_thread);
                break;
#ifdef VTYSH
        case VTYSH_SERV:
                vty_serv_thread = thread_add_read(vty_master, vtysh_accept, vty,
                                                  sock, NULL);
                vector_set_index(Vvty_serv_thread, sock, vty_serv_thread);
                break;
        case VTYSH_READ:
                thread_add_read(vty_master, vtysh_read, vty, sock,
                                &vty->t_read);
                break;
        case VTYSH_WRITE:
                thread_add_write(vty_master, vtysh_write, vty, sock,
                                 &vty->t_write);
                break;
#endif /* VTYSH */
        case VTY_READ:
                thread_add_read(vty_master, vty_read, vty, sock, &vty->t_read);

                /* Time out treatment. */
                if (vty->v_timeout) {
                        THREAD_OFF(vty->t_timeout);
                        thread_add_timer(vty_master, vty_timeout, vty,
                                         vty->v_timeout, &vty->t_timeout);
                }
                break;
        case VTY_WRITE:
                thread_add_write(vty_master, vty_flush, vty, sock,
                                 &vty->t_write);
                break;
        case VTY_TIMEOUT_RESET:
                THREAD_OFF(vty->t_timeout);
                if (vty->v_timeout)
                        thread_add_timer(vty_master, vty_timeout, vty,
                                         vty->v_timeout, &vty->t_timeout);
                break;
        }
}

DEFUN_NOSH (config_who,
       config_who_cmd,
       "who",
       "Display who is on vty\n")
{
        unsigned int i;
        struct vty *v;

        for (i = 0; i < vector_active(vtyvec); i++)
                if ((v = vector_slot(vtyvec, i)) != NULL)
                        vty_out(vty, "%svty[%d] connected from %s.\n",
                                v->config ? "*" : " ", i, v->address);
        return CMD_SUCCESS;
}

/* Move to vty configuration mode. */
DEFUN_NOSH (line_vty,
       line_vty_cmd,
       "line vty",
       "Configure a terminal line\n"
       "Virtual terminal\n")
{
        vty->node = VTY_NODE;
        return CMD_SUCCESS;
}

/* Set time out value. */
static int exec_timeout(struct vty *vty, const char *min_str,
                        const char *sec_str)
{
        unsigned long timeout = 0;

        /* min_str and sec_str are already checked by parser.  So it must be
           all digit string. */
        if (min_str) {
                timeout = strtol(min_str, NULL, 10);
                timeout *= 60;
        }
        if (sec_str)
                timeout += strtol(sec_str, NULL, 10);

        vty_timeout_val = timeout;
        vty->v_timeout = timeout;
        vty_event(VTY_TIMEOUT_RESET, 0, vty);


        return CMD_SUCCESS;
}

DEFUN (exec_timeout_min,
       exec_timeout_min_cmd,
       "exec-timeout (0-35791)",
       "Set timeout value\n"
       "Timeout value in minutes\n")
{
        int idx_number = 1;
        return exec_timeout(vty, argv[idx_number]->arg, NULL);
}

DEFUN (exec_timeout_sec,
       exec_timeout_sec_cmd,
       "exec-timeout (0-35791) (0-2147483)",
       "Set the EXEC timeout\n"
       "Timeout in minutes\n"
       "Timeout in seconds\n")
{
        int idx_number = 1;
        int idx_number_2 = 2;
        return exec_timeout(vty, argv[idx_number]->arg,
                            argv[idx_number_2]->arg);
}

DEFUN (no_exec_timeout,
       no_exec_timeout_cmd,
       "no exec-timeout",
       NO_STR
       "Set the EXEC timeout\n")
{
        return exec_timeout(vty, NULL, NULL);
}

/* Set vty access class. */
DEFUN (vty_access_class,
       vty_access_class_cmd,
       "access-class WORD",
       "Filter connections based on an IP access list\n"
       "IP access list\n")
{
        int idx_word = 1;
        if (vty_accesslist_name)
                XFREE(MTYPE_VTY, vty_accesslist_name);

        vty_accesslist_name = XSTRDUP(MTYPE_VTY, argv[idx_word]->arg);

        return CMD_SUCCESS;
}

/* Clear vty access class. */
DEFUN (no_vty_access_class,
       no_vty_access_class_cmd,
       "no access-class [WORD]",
       NO_STR
       "Filter connections based on an IP access list\n"
       "IP access list\n")
{
        int idx_word = 2;
        const char *accesslist = (argc == 3) ? argv[idx_word]->arg : NULL;
        if (!vty_accesslist_name
            || (argc == 3 && strcmp(vty_accesslist_name, accesslist))) {
                vty_out(vty, "Access-class is not currently applied to vty\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        XFREE(MTYPE_VTY, vty_accesslist_name);

        vty_accesslist_name = NULL;

        return CMD_SUCCESS;
}

/* Set vty access class. */
DEFUN (vty_ipv6_access_class,
       vty_ipv6_access_class_cmd,
       "ipv6 access-class WORD",
       IPV6_STR
       "Filter connections based on an IP access list\n"
       "IPv6 access list\n")
{
        int idx_word = 2;
        if (vty_ipv6_accesslist_name)
                XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);

        vty_ipv6_accesslist_name = XSTRDUP(MTYPE_VTY, argv[idx_word]->arg);

        return CMD_SUCCESS;
}

/* Clear vty access class. */
DEFUN (no_vty_ipv6_access_class,
       no_vty_ipv6_access_class_cmd,
       "no ipv6 access-class [WORD]",
       NO_STR
       IPV6_STR
       "Filter connections based on an IP access list\n"
       "IPv6 access list\n")
{
        int idx_word = 3;
        const char *accesslist = (argc == 4) ? argv[idx_word]->arg : NULL;

        if (!vty_ipv6_accesslist_name
            || (argc == 4 && strcmp(vty_ipv6_accesslist_name, accesslist))) {
                vty_out(vty,
                        "IPv6 access-class is not currently applied to vty\n");
                return CMD_WARNING_CONFIG_FAILED;
        }

        XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);

        vty_ipv6_accesslist_name = NULL;

        return CMD_SUCCESS;
}

/* vty login. */
DEFUN (vty_login,
       vty_login_cmd,
       "login",
       "Enable password checking\n")
{
        no_password_check = 0;
        return CMD_SUCCESS;
}

DEFUN (no_vty_login,
       no_vty_login_cmd,
       "no login",
       NO_STR
       "Enable password checking\n")
{
        no_password_check = 1;
        return CMD_SUCCESS;
}

DEFUN (service_advanced_vty,
       service_advanced_vty_cmd,
       "service advanced-vty",
       "Set up miscellaneous service\n"
       "Enable advanced mode vty interface\n")
{
        host.advanced = 1;
        return CMD_SUCCESS;
}

DEFUN (no_service_advanced_vty,
       no_service_advanced_vty_cmd,
       "no service advanced-vty",
       NO_STR
       "Set up miscellaneous service\n"
       "Enable advanced mode vty interface\n")
{
        host.advanced = 0;
        return CMD_SUCCESS;
}

DEFUN_NOSH (terminal_monitor,
       terminal_monitor_cmd,
       "terminal monitor",
       "Set terminal line parameters\n"
       "Copy debug output to the current terminal line\n")
{
        vty->monitor = 1;
        return CMD_SUCCESS;
}

DEFUN_NOSH (terminal_no_monitor,
       terminal_no_monitor_cmd,
       "terminal no monitor",
       "Set terminal line parameters\n"
       NO_STR
       "Copy debug output to the current terminal line\n")
{
        vty->monitor = 0;
        return CMD_SUCCESS;
}

DEFUN_NOSH (no_terminal_monitor,
       no_terminal_monitor_cmd,
       "no terminal monitor",
       NO_STR
       "Set terminal line parameters\n"
       "Copy debug output to the current terminal line\n")
{
        return terminal_no_monitor(self, vty, argc, argv);
}


DEFUN_NOSH (show_history,
       show_history_cmd,
       "show history",
       SHOW_STR
       "Display the session command history\n")
{
        int index;

        for (index = vty->hindex + 1; index != vty->hindex;) {
                if (index == VTY_MAXHIST) {
                        index = 0;
                        continue;
                }

                if (vty->hist[index] != NULL)
                        vty_out(vty, "  %s\n", vty->hist[index]);

                index++;
        }

        return CMD_SUCCESS;
}

/* vty login. */
DEFPY (log_commands,
       log_commands_cmd,
       "[no] log commands",
       NO_STR
       "Logging control\n"
       "Log all commands\n")
{
        if (no) {
                if (do_log_commands_perm) {
                        vty_out(vty,
                                "Daemon started with permanent logging turned on for commands, ignoring\n");
                        return CMD_WARNING;
                }

                do_log_commands = false;
        } else
                do_log_commands = true;

        return CMD_SUCCESS;
}

/* Display current configuration. */
static int vty_config_write(struct vty *vty)
{
        vty_out(vty, "line vty\n");

        if (vty_accesslist_name)
                vty_out(vty, " access-class %s\n", vty_accesslist_name);

        if (vty_ipv6_accesslist_name)
                vty_out(vty, " ipv6 access-class %s\n",
                        vty_ipv6_accesslist_name);

        /* exec-timeout */
        if (vty_timeout_val != VTY_TIMEOUT_DEFAULT)
                vty_out(vty, " exec-timeout %ld %ld\n", vty_timeout_val / 60,
                        vty_timeout_val % 60);

        /* login */
        if (no_password_check)
                vty_out(vty, " no login\n");

        if (do_log_commands)
                vty_out(vty, "log commands\n");

        vty_out(vty, "!\n");

        return CMD_SUCCESS;
}

struct cmd_node vty_node = {
        VTY_NODE, "%s(config-line)# ", 1,
};

/* Reset all VTY status. */
void vty_reset(void)
{
        unsigned int i;
        struct vty *vty;
        struct thread *vty_serv_thread;

        for (i = 0; i < vector_active(vtyvec); i++)
                if ((vty = vector_slot(vtyvec, i)) != NULL) {
                        buffer_reset(vty->lbuf);
                        buffer_reset(vty->obuf);
                        vty->status = VTY_CLOSE;
                        vty_close(vty);
                }

        for (i = 0; i < vector_active(Vvty_serv_thread); i++)
                if ((vty_serv_thread = vector_slot(Vvty_serv_thread, i))
                    != NULL) {
                        THREAD_OFF(vty_serv_thread);
                        vector_slot(Vvty_serv_thread, i) = NULL;
                        close(i);
                }

        vty_timeout_val = VTY_TIMEOUT_DEFAULT;

        if (vty_accesslist_name) {
                XFREE(MTYPE_VTY, vty_accesslist_name);
                vty_accesslist_name = NULL;
        }

        if (vty_ipv6_accesslist_name) {
                XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);
                vty_ipv6_accesslist_name = NULL;
        }
}

static void vty_save_cwd(void)
{
        char *c;

        c = getcwd(vty_cwd, sizeof(vty_cwd));

        if (!c) {
                /*
                 * At this point if these go wrong, more than likely
                 * the whole world is coming down around us
                 * Hence not worrying about it too much.
                 */
                if (!chdir(SYSCONFDIR)) {
                        flog_err_sys(EC_LIB_SYSTEM_CALL,
                                     "Failure to chdir to %s, errno: %d",
                                     SYSCONFDIR, errno);
                        exit(-1);
                }
                if (getcwd(vty_cwd, sizeof(vty_cwd)) == NULL) {
                        flog_err_sys(EC_LIB_SYSTEM_CALL,
                                     "Failure to getcwd, errno: %d", errno);
                        exit(-1);
                }
        }
}

char *vty_get_cwd(void)
{
        return vty_cwd;
}

int vty_shell(struct vty *vty)
{
        return vty->type == VTY_SHELL ? 1 : 0;
}

int vty_shell_serv(struct vty *vty)
{
        return vty->type == VTY_SHELL_SERV ? 1 : 0;
}

void vty_init_vtysh(void)
{
        vtyvec = vector_init(VECTOR_MIN_SIZE);
}

/* Install vty's own commands like `who' command. */
void vty_init(struct thread_master *master_thread, bool do_command_logging)
{
        /* For further configuration read, preserve current directory. */
        vty_save_cwd();

        vtyvec = vector_init(VECTOR_MIN_SIZE);

        vty_master = master_thread;

        atexit(vty_stdio_atexit);

        /* Initilize server thread vector. */
        Vvty_serv_thread = vector_init(VECTOR_MIN_SIZE);

        /* Install bgp top node. */
        install_node(&vty_node, vty_config_write);

        install_element(VIEW_NODE, &config_who_cmd);
        install_element(VIEW_NODE, &show_history_cmd);
        install_element(CONFIG_NODE, &line_vty_cmd);
        install_element(CONFIG_NODE, &service_advanced_vty_cmd);
        install_element(CONFIG_NODE, &no_service_advanced_vty_cmd);
        install_element(CONFIG_NODE, &show_history_cmd);
        install_element(CONFIG_NODE, &log_commands_cmd);

        if (do_command_logging) {
                do_log_commands = true;
                do_log_commands_perm = true;
        }

        install_element(ENABLE_NODE, &terminal_monitor_cmd);
        install_element(ENABLE_NODE, &terminal_no_monitor_cmd);
        install_element(ENABLE_NODE, &no_terminal_monitor_cmd);

        install_default(VTY_NODE);
        install_element(VTY_NODE, &exec_timeout_min_cmd);
        install_element(VTY_NODE, &exec_timeout_sec_cmd);
        install_element(VTY_NODE, &no_exec_timeout_cmd);
        install_element(VTY_NODE, &vty_access_class_cmd);
        install_element(VTY_NODE, &no_vty_access_class_cmd);
        install_element(VTY_NODE, &vty_login_cmd);
        install_element(VTY_NODE, &no_vty_login_cmd);
        install_element(VTY_NODE, &vty_ipv6_access_class_cmd);
        install_element(VTY_NODE, &no_vty_ipv6_access_class_cmd);
}

void vty_terminate(void)
{
        memset(vty_cwd, 0x00, sizeof(vty_cwd));

        if (vtyvec && Vvty_serv_thread) {
                vty_reset();
                vector_free(vtyvec);
                vector_free(Vvty_serv_thread);
                vtyvec = NULL;
                Vvty_serv_thread = NULL;
        }
}