arch/um/drivers/xterm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   4  */
   5
   6 #include <stddef.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <unistd.h>
  10 #include <errno.h>
  11 #include <string.h>
  12 #include <termios.h>
  13 #include "chan_user.h"
  14 #include <os.h>
  15 #include <um_malloc.h>
  16 #include "xterm.h"
  17
  18 struct xterm_chan {
  19         int pid;
  20         int helper_pid;
  21         int chan_fd;
  22         char *title;
  23         int device;
  24         int raw;
  25         struct termios tt;
  26 };
  27
  28 static void *xterm_init(char *str, int device, const struct chan_opts *opts)
  29 {
  30         struct xterm_chan *data;
  31
  32         data = uml_kmalloc(sizeof(*data), UM_GFP_KERNEL);
  33         if (data == NULL)
  34                 return NULL;
  35         *data = ((struct xterm_chan) { .pid             = -1,
  36                                        .helper_pid      = -1,
  37                                        .chan_fd         = -1,
  38                                        .device          = device,
  39                                        .title           = opts->xterm_title,
  40                                        .raw             = opts->raw } );
  41         return data;
  42 }
  43
  44 /* Only changed by xterm_setup, which is a setup */
  45 static char *terminal_emulator = "xterm";
  46 static char *title_switch = "-T";
  47 static char *exec_switch = "-e";
  48
  49 static int __init xterm_setup(char *line, int *add)
  50 {
  51         *add = 0;
  52         terminal_emulator = line;
  53
  54         line = strchr(line, ',');
  55         if (line == NULL)
  56                 return 0;
  57
  58         *line++ = '\0';
  59         if (*line)
  60                 title_switch = line;
  61
  62         line = strchr(line, ',');
  63         if (line == NULL)
  64                 return 0;
  65
  66         *line++ = '\0';
  67         if (*line)
  68                 exec_switch = line;
  69
  70         return 0;
  71 }
  72
  73 __uml_setup("xterm=", xterm_setup,
  74 "xterm=<terminal emulator>,<title switch>,<exec switch>\n"
  75 "    Specifies an alternate terminal emulator to use for the debugger,\n"
  76 "    consoles, and serial lines when they are attached to the xterm channel.\n"
  77 "    The values are the terminal emulator binary, the switch it uses to set\n"
  78 "    its title, and the switch it uses to execute a subprocess,\n"
  79 "    respectively.  The title switch must have the form '<switch> title',\n"
  80 "    not '<switch>=title'.  Similarly, the exec switch must have the form\n"
  81 "    '<switch> command arg1 arg2 ...'.\n"
  82 "    The default values are 'xterm=xterm,-T,-e'.  Values for gnome-terminal\n"
  83 "    are 'xterm=gnome-terminal,-t,-x'.\n\n"
  84 );
  85
  86 static int xterm_open(int input, int output, int primary, void *d,
  87                       char **dev_out)
  88 {
  89         struct xterm_chan *data = d;
  90         int pid, fd, new, err;
  91         char title[256], file[] = "/tmp/xterm-pipeXXXXXX";
  92         char *argv[] = { terminal_emulator, title_switch, title, exec_switch,
  93                          OS_LIB_PATH "/uml/port-helper", "-uml-socket",
  94                          file, NULL };
  95
  96         if (access(argv[4], X_OK) < 0)
  97                 argv[4] = "port-helper";
  98
  99         /*
 100          * Check that DISPLAY is set, this doesn't guarantee the xterm
 101          * will work but w/o it we can be pretty sure it won't.
 102          */
 103         if (getenv("DISPLAY") == NULL) {
 104                 printk(UM_KERN_ERR "xterm_open: $DISPLAY not set.\n");
 105                 return -ENODEV;
 106         }
 107
 108         /*
 109          * This business of getting a descriptor to a temp file,
 110          * deleting the file and closing the descriptor is just to get
 111          * a known-unused name for the Unix socket that we really
 112          * want.
 113          */
 114         fd = mkstemp(file);
 115         if (fd < 0) {
 116                 err = -errno;
 117                 printk(UM_KERN_ERR "xterm_open : mkstemp failed, errno = %d\n",
 118                        errno);
 119                 return err;
 120         }
 121
 122         if (unlink(file)) {
 123                 err = -errno;
 124                 printk(UM_KERN_ERR "xterm_open : unlink failed, errno = %d\n",
 125                        errno);
 126                 close(fd);
 127                 return err;
 128         }
 129         close(fd);
 130
 131         fd = os_create_unix_socket(file, sizeof(file), 1);
 132         if (fd < 0) {
 133                 printk(UM_KERN_ERR "xterm_open : create_unix_socket failed, "
 134                        "errno = %d\n", -fd);
 135                 return fd;
 136         }
 137
 138         sprintf(title, data->title, data->device);
 139         pid = run_helper(NULL, NULL, argv);
 140         if (pid < 0) {
 141                 err = pid;
 142                 printk(UM_KERN_ERR "xterm_open : run_helper failed, "
 143                        "errno = %d\n", -err);
 144                 goto out_close1;
 145         }
 146
 147         err = os_set_fd_block(fd, 0);
 148         if (err < 0) {
 149                 printk(UM_KERN_ERR "xterm_open : failed to set descriptor "
 150                        "non-blocking, err = %d\n", -err);
 151                 goto out_kill;
 152         }
 153
 154         data->chan_fd = fd;
 155         new = xterm_fd(fd, &data->helper_pid);
 156         if (new < 0) {
 157                 err = new;
 158                 printk(UM_KERN_ERR "xterm_open : os_rcv_fd failed, err = %d\n",
 159                        -err);
 160                 goto out_kill;
 161         }
 162
 163         err = os_set_fd_block(new, 0);
 164         if (err) {
 165                 printk(UM_KERN_ERR "xterm_open : failed to set xterm "
 166                        "descriptor non-blocking, err = %d\n", -err);
 167                 goto out_close2;
 168         }
 169
 170         CATCH_EINTR(err = tcgetattr(new, &data->tt));
 171         if (err) {
 172                 new = err;
 173                 goto out_close2;
 174         }
 175
 176         if (data->raw) {
 177                 err = raw(new);
 178                 if (err) {
 179                         new = err;
 180                         goto out_close2;
 181                 }
 182         }
 183
 184         unlink(file);
 185         data->pid = pid;
 186         *dev_out = NULL;
 187
 188         return new;
 189
 190  out_close2:
 191         close(new);
 192  out_kill:
 193         os_kill_process(pid, 1);
 194  out_close1:
 195         close(fd);
 196
 197         return err;
 198 }
 199
 200 static void xterm_close(int fd, void *d)
 201 {
 202         struct xterm_chan *data = d;
 203
 204         if (data->pid != -1)
 205                 os_kill_process(data->pid, 1);
 206         data->pid = -1;
 207
 208         if (data->helper_pid != -1)
 209                 os_kill_process(data->helper_pid, 0);
 210         data->helper_pid = -1;
 211
 212         if (data->chan_fd != -1)
 213                 os_close_file(data->chan_fd);
 214         os_close_file(fd);
 215 }
 216
 217 const struct chan_ops xterm_ops = {
 218         .type           = "xterm",
 219         .init           = xterm_init,
 220         .open           = xterm_open,
 221         .close          = xterm_close,
 222         .read           = generic_read,
 223         .write          = generic_write,
 224         .console_write  = generic_console_write,
 225         .window_size    = generic_window_size,
 226         .free           = generic_free,
 227         .winch          = 1,
 228 };