2 * Copyright (C) 2003-2009 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file exec.c Helper functions for spawning new processes. */
10 #include <sys/types.h>
19 #include "gcc-compat.h"
26 * Spawn a new process and redirect fd 0, 1, and 2.
28 * \param pid Will hold the pid of the created process upon return.
29 * \param file Path of the executable to execute.
30 * \param args The argument array for the command.
31 * \param fds a Pointer to a value-result array.
35 * \sa null(4), pipe(2), dup2(2), fork(2), exec(3).
37 int dss_exec(pid_t *pid, const char *file, char *const *const args, int *fds)
39 int ret, in[2] = {-1, -1}, out[2] = {-1, -1}, err[2] = {-1, -1},
43 if (fds[0] > 0 && pipe(in) < 0)
45 if (fds[1] > 0 && pipe(out) < 0)
47 if (fds[2] > 0 && pipe(err) < 0)
49 if (!fds[0] || !fds[1] || !fds[2]) {
51 null = open("/dev/null", O_RDWR);
55 if ((*pid = fork()) < 0)
57 if (!(*pid)) { /* child */
61 if (in[0] != STDIN_FILENO)
62 dup2(in[0], STDIN_FILENO);
64 dup2(null, STDIN_FILENO);
69 if (out[1] != STDOUT_FILENO)
70 dup2(out[1], STDOUT_FILENO);
72 dup2(null, STDOUT_FILENO);
77 if (err[1] != STDERR_FILENO)
78 dup2(err[1], STDERR_FILENO);
80 dup2(null, STDERR_FILENO);
84 signal(SIGINT, SIG_DFL);
85 signal(SIGTERM, SIG_DFL);
86 signal(SIGCHLD, SIG_DFL);
106 DSS_ERROR_LOG("failed to exec %s\n", file);
126 * Exec the given command.
128 * \param pid Will hold the pid of the created process upon return.
129 * \param cmdline Holds the command and its arguments, seperated by spaces.
130 * \param fds A pointer to a value-result array.
132 * This function uses fork/exec to create a new process. \a fds must be a
133 * pointer to three integers, corresponding to stdin, stdout and stderr
134 * respectively. It specifies how to deal with fd 0, 1, 2 in the child. The
135 * contents of \a fds are interpreted as follows:
137 * - fd[i] < 0: leave fd \a i alone.
138 * - fd[i] = 0: dup fd \a i to \p /dev/null.
139 * - fd[i] > 0: create a pipe and dup i to one end of that pipe.
140 * Upon return, fd[i] contains the file descriptor of the pipe.
142 * In any case, all unneeded filedescriptors are closed.
146 int dss_exec_cmdline_pid(pid_t *pid, const char *cmdline, int *fds)
150 char *tmp = dss_strdup(cmdline);
154 argc = split_args(tmp, &argv, " \t");
155 ret = dss_exec(pid, argv[0], argv, fds);