1 /*-
2 * Copyright (c) 2013-2018 Devin Teske <dteske@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <sys/cdefs.h>
28 #include <err.h>
29 #include <limits.h>
30 #include <spawn.h>
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <unistd.h>
34
35 #include "util.h"
36
37 extern char **environ;
38 static char cmdbuf[CMDBUFMAX] = "";
39 static char shellcmd[PATH_MAX] = PATH_SHELL;
40 static char *shellcmd_argv[6] = {
41 shellcmd,
42 __DECONST(char *, "-c"),
43 cmdbuf,
44 __DECONST(char *, "--"),
45 shellcmd,
46 NULL,
47 };
48
49 /*
50 * Spawn a sh(1) command. Writes the resulting process ID to the pid_t pointed
51 * at by `pid'. Returns a file descriptor (int) suitable for writing data to
52 * the spawned command (data written to file descriptor is seen as standard-in
53 * by the spawned sh(1) command). Returns `-1' if unable to spawn command.
54 *
55 * If cmd contains a single "%s" sequence, replace it with label if non-NULL.
56 */
57 int
shell_spawn_pipecmd(const char * cmd,const char * label,pid_t * pid)58 shell_spawn_pipecmd(const char *cmd, const char *label, pid_t *pid)
59 {
60 int error;
61 int len;
62 posix_spawn_file_actions_t action;
63 #if SHELL_SPAWN_DEBUG
64 unsigned int i;
65 #endif
66 int stdin_pipe[2] = { -1, -1 };
67
68 /* Populate argument array */
69 if (label != NULL && fmtcheck(cmd, "%s") == cmd)
70 len = snprintf(cmdbuf, CMDBUFMAX, cmd, label);
71 else
72 len = snprintf(cmdbuf, CMDBUFMAX, "%s", cmd);
73 if (len >= CMDBUFMAX) {
74 warnx("%s:%d:%s: cmdbuf[%u] too small to hold cmd argument",
75 __FILE__, __LINE__, __func__, CMDBUFMAX);
76 return (-1);
77 }
78
79 /* Open a pipe to communicate with [X]dialog(1) */
80 if (pipe(stdin_pipe) < 0)
81 err(EXIT_FAILURE, "%s: pipe(2)", __func__);
82
83 /* Fork sh(1) process */
84 #if SHELL_SPAWN_DEBUG
85 fprintf(stderr, "%s: spawning `", __func__);
86 for (i = 0; shellcmd_argv[i] != NULL; i++) {
87 if (i == 0)
88 fprintf(stderr, "%s", shellcmd_argv[i]);
89 else if (i == 2)
90 fprintf(stderr, " '%s'", shellcmd_argv[i]);
91 else
92 fprintf(stderr, " %s", shellcmd_argv[i]);
93 }
94 fprintf(stderr, "'\n");
95 #endif
96 posix_spawn_file_actions_init(&action);
97 posix_spawn_file_actions_adddup2(&action, stdin_pipe[0], STDIN_FILENO);
98 posix_spawn_file_actions_addclose(&action, stdin_pipe[1]);
99 error = posix_spawnp(pid, shellcmd, &action,
100 (const posix_spawnattr_t *)NULL, shellcmd_argv, environ);
101 if (error != 0) err(EXIT_FAILURE, "%s", shellcmd);
102
103 return stdin_pipe[1];
104 }
105