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95c4aff2 DL |
1 | /* |
2 | watchquagga CLI functions. | |
3 | ||
4 | Copyright (C) 2016 David Lamparter for NetDEF, Inc. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
19 | */ | |
20 | ||
21 | #include <zebra.h> | |
22 | #include <sys/wait.h> | |
23 | ||
24 | #include "memory.h" | |
25 | #include "log.h" | |
26 | #include "vty.h" | |
27 | #include "command.h" | |
28 | ||
29 | #include "watchquagga.h" | |
30 | ||
31 | pid_t integrated_write_pid; | |
32 | static int integrated_result_fd; | |
33 | ||
34 | DEFUN (config_write_integrated, | |
35 | config_write_integrated_cmd, | |
36 | "write integrated", | |
37 | "Write running configuration to memory, network, or terminal\n" | |
38 | "Write integrated all-daemon Quagga.conf file\n") | |
39 | { | |
40 | pid_t child; | |
41 | sigset_t oldmask, sigmask; | |
42 | ||
43 | if (integrated_write_pid != -1) { | |
44 | vty_out(vty, "%% configuration write already in progress.%s", | |
45 | VTY_NEWLINE); | |
46 | return CMD_WARNING; | |
47 | } | |
48 | ||
49 | fflush(stdout); | |
50 | fflush(stderr); | |
51 | ||
52 | /* need to temporarily block SIGCHLD because it could arrive between | |
53 | * fork() call and setting the integrated_write_pid variable. This | |
54 | * would mean the completion call gets lost and this hangs forever. | |
55 | */ | |
56 | sigemptyset(&oldmask); | |
57 | sigemptyset(&sigmask); | |
58 | sigaddset(&sigmask, SIGCHLD); | |
59 | sigprocmask(SIG_BLOCK, &sigmask, &oldmask); | |
60 | ||
61 | child = fork(); | |
62 | if (child == -1) { | |
63 | vty_out(vty, "%% configuration write fork() failed: %s.%s", | |
64 | safe_strerror(errno), VTY_NEWLINE); | |
65 | sigprocmask(SIG_SETMASK, &oldmask, NULL); | |
66 | return CMD_WARNING; | |
67 | } | |
68 | if (child != 0) { | |
69 | /* note: the VTY won't write a command return value to vtysh; the | |
70 | * session temporarily enters an intentional "hang" state. This is | |
71 | * to make sure latency in vtysh doing the config write (several | |
72 | * seconds is not rare to see) does not interfere with watchquagga's | |
73 | * supervisor job. | |
74 | * | |
75 | * The fd is duplicated here so we don't need to hold a vty pointer | |
76 | * (which could become invalid in the meantime). | |
77 | */ | |
78 | integrated_write_pid = child; | |
79 | integrated_result_fd = dup(vty->wfd); | |
80 | sigprocmask(SIG_SETMASK, &oldmask, NULL); | |
81 | return CMD_SUSPEND; | |
82 | } | |
83 | ||
84 | /* redirect stdout/stderr to vty session. Note vty->wfd is marked | |
85 | * CLOEXEC, but dup2 will clear that flag. */ | |
86 | dup2(vty->wfd, 1); | |
87 | dup2(vty->wfd, 2); | |
88 | ||
89 | /* don't allow the user to pass parameters, we're root here! | |
90 | * should probably harden vtysh at some point too... */ | |
91 | execl(VTYSH_BIN_PATH, "vtysh", "-w", NULL); | |
92 | ||
93 | /* unbuffered write; we just messed with stdout... */ | |
94 | char msg[512]; | |
95 | snprintf(msg, sizeof(msg), "error executing %s: %s\n", | |
96 | VTYSH_BIN_PATH, safe_strerror(errno)); | |
97 | write(1, msg, strlen(msg)); | |
98 | exit(1); | |
99 | } | |
100 | ||
101 | void integrated_write_sigchld(int status) | |
102 | { | |
103 | uint8_t reply[4] = { 0, 0, 0, CMD_WARNING }; | |
104 | ||
105 | if (WIFEXITED(status)) { | |
106 | zlog_info("configuration write completed with exit code %d", | |
107 | WEXITSTATUS(status)); | |
108 | reply[3] = WEXITSTATUS(status); | |
109 | } else if (WIFSIGNALED(status)) { | |
110 | zlog_warn("configuration write terminated by signal %d", | |
111 | WTERMSIG(status)); | |
112 | } else { | |
113 | zlog_warn("configuration write terminated"); | |
114 | } | |
115 | ||
c10c5926 DL |
116 | if (reply[3] != CMD_SUCCESS) { |
117 | /* failure might be silent in vtysh without this */ | |
118 | static const char msg[] = "% Configuration write failed.\n"; | |
119 | write(integrated_result_fd, msg, strlen(msg)); | |
120 | } | |
121 | ||
95c4aff2 DL |
122 | /* don't care about failures here, if the connection is broken the |
123 | * return value will just be lost. */ | |
124 | write(integrated_result_fd, reply, sizeof(reply)); | |
125 | close(integrated_result_fd); | |
126 | ||
127 | integrated_write_pid = -1; | |
128 | } | |
129 | ||
130 | void watchquagga_vty_init(void) | |
131 | { | |
132 | integrated_write_pid = -1; | |
133 | install_element(ENABLE_NODE, &config_write_integrated_cmd); | |
134 | } |