gui: Combine open_stat_pipe() and para_open_stat_pipe().
[paraslash.git] / exec.c
1 /*
2 * Copyright (C) 2003-2010 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file exec.c Helper functions for spawning new processes. */
8
9 #include <regex.h>
10 #include <dirent.h>
11
12 #include "para.h"
13 #include "close_on_fork.h"
14 #include "error.h"
15 #include "fd.h"
16 #include "string.h"
17
18 /**
19 * Spawn a new process and redirect fd 0, 1, and 2.
20 *
21 * \param pid Will hold the pid of the created process upon return.
22 * \param file Path of the executable to execute.
23 * \param args The argument array for the command.
24 * \param fds a Pointer to a value-result array.
25 *
26 * \return Standard.
27 *
28 * \sa null(4), pipe(2), dup2(2), fork(2), exec(3).
29 */
30 static int para_exec(pid_t *pid, const char *file, char *const *const args, int *fds)
31 {
32 int ret, in[2] = {-1, -1}, out[2] = {-1, -1}, err[2] = {-1, -1},
33 null = -1; /* ;) */
34
35 ret = -E_DUP_PIPE;
36 if (fds[0] > 0 && pipe(in) < 0)
37 goto err_out;
38 if (fds[1] > 0 && pipe(out) < 0)
39 goto err_out;
40 if (fds[2] > 0 && pipe(err) < 0)
41 goto err_out;
42 if (!fds[0] || !fds[1] || !fds[2]) {
43 ret = para_open("/dev/null", O_RDWR, 42);
44 if (ret < 0)
45 goto err_out;
46 null = ret;
47 }
48 ret = fork();
49 if (ret < 0) {
50 ret = -ERRNO_TO_PARA_ERROR(errno);
51 goto err_out;
52 }
53 *pid = ret;
54 if (!(*pid)) { /* child */
55 if (fds[0] >= 0) {
56 if (fds[0]) {
57 close(in[1]);
58 if (in[0] != STDIN_FILENO)
59 dup2(in[0], STDIN_FILENO);
60 } else
61 dup2(null, STDIN_FILENO);
62 }
63 if (fds[1] >= 0) {
64 if (fds[1]) {
65 close(out[0]);
66 if (out[1] != STDOUT_FILENO)
67 dup2(out[1], STDOUT_FILENO);
68 } else
69 dup2(null, STDOUT_FILENO);
70 }
71 if (fds[2] >= 0) {
72 if (fds[2]) {
73 close(err[0]);
74 if (err[1] != STDERR_FILENO)
75 dup2(err[1], STDERR_FILENO);
76 } else
77 dup2(null, STDERR_FILENO);
78 }
79 if (null >= 0)
80 close(null);
81 execvp(file, args);
82 _exit(EXIT_FAILURE);
83 }
84 if (fds[0] > 0) {
85 close(in[0]);
86 *fds = in[1];
87 }
88 if (fds[1] > 0) {
89 close(out[1]);
90 *(fds + 1) = out[0];
91 }
92 if (fds[2] > 0) {
93 close(err[1]);
94 *(fds + 2) = err[0];
95 }
96 if (null >= 0)
97 close(null);
98 return 1;
99 err_out:
100 if (err[0] >= 0)
101 close(err[0]);
102 if (err[1] >= 0)
103 close(err[1]);
104 if (out[0] >= 0)
105 close(out[0]);
106 if (out[1] >= 0)
107 close(out[1]);
108 if (in[0] >= 0)
109 close(in[0]);
110 if (in[1] >= 0)
111 close(in[1]);
112 if (null >= 0)
113 close(null);
114 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
115 return ret;
116 }
117
118 /**
119 * Exec the given command.
120 *
121 * \param pid Will hold the pid of the created process upon return.
122 * \param cmdline Holds the command and its arguments, seperated by spaces.
123 * \param fds A pointer to a value-result array.
124 *
125 * This function uses fork/exec to create a new process. \a fds must be a
126 * pointer to three integers, corresponding to stdin, stdout and stderr
127 * respectively. It specifies how to deal with fd 0, 1, 2 in the child. The
128 * contents of \a fds are interpreted as follows:
129 *
130 * - fd[i] < 0: leave fd \a i alone.
131 * - fd[i] = 0: dup fd \a i to \p /dev/null.
132 * - fd[i] > 0: create a pipe and dup i to one end of that pipe.
133 * Upon return, fd[i] contains the file descriptor of the pipe.
134 *
135 * In any case, all unneeded filedescriptors are closed.
136 *
137 * \return Standard.
138 */
139 int para_exec_cmdline_pid(pid_t *pid, const char *cmdline, int *fds)
140 {
141 int ret;
142 char **argv;
143
144 ret = create_argv(cmdline, " \t", &argv);
145 if (ret < 0)
146 return ret;
147 ret = para_exec(pid, argv[0], argv, fds);
148 free_argv(argv);
149 return ret;
150 }