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 __FBSDID("$FreeBSD$"); 29 30 #include <err.h> 31 #include <limits.h> 32 #include <spawn.h> 33 #include <stdio.h> 34 #include <stdlib.h> 35 #include <unistd.h> 36 37 #include "util.h" 38 39 extern char **environ; 40 static char cmdbuf[CMDBUFMAX] = ""; 41 static char shellcmd[PATH_MAX] = PATH_SHELL; 42 static char *shellcmd_argv[6] = { 43 shellcmd, 44 __DECONST(char *, "-c"), 45 cmdbuf, 46 __DECONST(char *, "--"), 47 shellcmd, 48 NULL, 49 }; 50 51 /* 52 * Spawn a sh(1) command. Writes the resulting process ID to the pid_t pointed 53 * at by `pid'. Returns a file descriptor (int) suitable for writing data to 54 * the spawned command (data written to file descriptor is seen as standard-in 55 * by the spawned sh(1) command). Returns `-1' if unable to spawn command. 56 * 57 * If cmd contains a single "%s" sequence, replace it with label if non-NULL. 58 */ 59 int 60 shell_spawn_pipecmd(const char *cmd, const char *label, pid_t *pid) 61 { 62 int error; 63 int len; 64 posix_spawn_file_actions_t action; 65 #if SHELL_SPAWN_DEBUG 66 unsigned int i; 67 #endif 68 int stdin_pipe[2] = { -1, -1 }; 69 70 /* Populate argument array */ 71 if (label != NULL && fmtcheck(cmd, "%s") == cmd) 72 len = snprintf(cmdbuf, CMDBUFMAX, cmd, label); 73 else 74 len = snprintf(cmdbuf, CMDBUFMAX, "%s", cmd); 75 if (len >= CMDBUFMAX) { 76 warnx("%s:%d:%s: cmdbuf[%u] too small to hold cmd argument", 77 __FILE__, __LINE__, __func__, CMDBUFMAX); 78 return (-1); 79 } 80 81 /* Open a pipe to communicate with [X]dialog(1) */ 82 if (pipe(stdin_pipe) < 0) 83 err(EXIT_FAILURE, "%s: pipe(2)", __func__); 84 85 /* Fork sh(1) process */ 86 #if SHELL_SPAWN_DEBUG 87 fprintf(stderr, "%s: spawning `", __func__); 88 for (i = 0; shellcmd_argv[i] != NULL; i++) { 89 if (i == 0) 90 fprintf(stderr, "%s", shellcmd_argv[i]); 91 else if (i == 2) 92 fprintf(stderr, " '%s'", shellcmd_argv[i]); 93 else 94 fprintf(stderr, " %s", shellcmd_argv[i]); 95 } 96 fprintf(stderr, "'\n"); 97 #endif 98 posix_spawn_file_actions_init(&action); 99 posix_spawn_file_actions_adddup2(&action, stdin_pipe[0], STDIN_FILENO); 100 posix_spawn_file_actions_addclose(&action, stdin_pipe[1]); 101 error = posix_spawnp(pid, shellcmd, &action, 102 (const posix_spawnattr_t *)NULL, shellcmd_argv, environ); 103 if (error != 0) err(EXIT_FAILURE, "%s", shellcmd); 104 105 return stdin_pipe[1]; 106 } 107