1 /* Guts of POSIX spawn interface. Generic POSIX.1 version.
2 Copyright (C) 2000-2005, 2006, 2008 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "spawn_int.h"
29 # define O_LARGEFILE 0
32 #if _LIBC || HAVE_PATHS_H
35 # define _PATH_BSHELL "/bin/sh"
44 # include <not-cancel.h>
46 # define close_not_cancel close
47 # define open_not_cancel open
51 # include <local-setxid.h>
54 # define seteuid(id) setresuid (-1, id, -1)
57 # define setegid(id) setresgid (-1, id, -1)
59 # define local_seteuid(id) seteuid (id)
60 # define local_setegid(id) setegid (id)
64 # define alloca __alloca
65 # define execve __execve
68 # define getgid __getgid
69 # define getuid __getuid
70 # define sched_setparam __sched_setparam
71 # define sched_setscheduler __sched_setscheduler
72 # define setpgid __setpgid
73 # define sigaction __sigaction
74 # define sigismember __sigismember
75 # define sigprocmask __sigprocmask
76 # define strchrnul __strchrnul
77 # define vfork __vfork
79 # undef internal_function
80 # define internal_function /* empty */
84 /* The Unix standard contains a long explanation of the way to signal
85 an error after the fork() was successful. Since no new wait status
86 was wanted there is no way to signal an error using one of the
87 available methods. The committee chose to signal an error by a
88 normal program exit with the exit code 127. */
89 #define SPAWN_ERROR 127
92 /* The file is accessible but it is not an executable file. Invoke
93 the shell to interpret it as a script. */
96 script_execute (const char *file, char *const argv[], char *const envp[])
98 /* Count the arguments. */
103 /* Construct an argument list for the shell. */
105 char **new_argv = (char **) alloca ((argc + 1) * sizeof (char *));
106 new_argv[0] = (char *) _PATH_BSHELL;
107 new_argv[1] = (char *) file;
110 new_argv[argc] = argv[argc - 1];
114 /* Execute the shell. */
115 execve (new_argv[0], new_argv, envp);
120 /* Spawn a new process executing PATH with the attributes describes in *ATTRP.
121 Before running the process perform the actions described in FILE-ACTIONS. */
123 __spawni (pid_t *pid, const char *file,
124 const posix_spawn_file_actions_t *file_actions,
125 const posix_spawnattr_t *attrp, char *const argv[],
126 char *const envp[], int use_path)
129 char *path, *p, *name;
134 short int flags = attrp == NULL ? 0 : attrp->_flags;
136 /* Generate the new process. */
138 if ((flags & POSIX_SPAWN_USEVFORK) != 0
139 /* If no major work is done, allow using vfork. Note that we
140 might perform the path searching. But this would be done by
141 a call to execvp(), too, and such a call must be OK according
143 || ((flags & (POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF
144 | POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER
145 | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_RESETIDS)) == 0
146 && file_actions == NULL))
157 /* The call was successful. Store the PID if necessary. */
164 /* Set signal mask. */
165 if ((flags & POSIX_SPAWN_SETSIGMASK) != 0
166 && sigprocmask (SIG_SETMASK, &attrp->_ss, NULL) != 0)
169 /* Set signal default action. */
170 if ((flags & POSIX_SPAWN_SETSIGDEF) != 0)
172 /* We have to iterate over all signals. This could possibly be
173 done better but it requires system specific solutions since
174 the sigset_t data type can be very different on different
179 memset (&sa, '\0', sizeof (sa));
180 sa.sa_handler = SIG_DFL;
182 for (sig = 1; sig <= NSIG; ++sig)
183 if (sigismember (&attrp->_sd, sig) != 0
184 && sigaction (sig, &sa, NULL) != 0)
189 #if (_LIBC ? defined _POSIX_PRIORITY_SCHEDULING : HAVE_SCHED_SETPARAM && HAVE_SCHED_SETSCHEDULER)
190 /* Set the scheduling algorithm and parameters. */
191 if ((flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER))
192 == POSIX_SPAWN_SETSCHEDPARAM)
194 if (sched_setparam (0, &attrp->_sp) == -1)
197 else if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0)
199 if (sched_setscheduler (0, attrp->_policy,
200 (flags & POSIX_SPAWN_SETSCHEDPARAM) != 0
201 ? &attrp->_sp : NULL) == -1)
206 /* Set the process group ID. */
207 if ((flags & POSIX_SPAWN_SETPGROUP) != 0
208 && setpgid (0, attrp->_pgrp) != 0)
211 /* Set the effective user and group IDs. */
212 if ((flags & POSIX_SPAWN_RESETIDS) != 0
213 && (local_seteuid (getuid ()) != 0
214 || local_setegid (getgid ()) != 0))
217 /* Execute the file actions. */
218 if (file_actions != NULL)
222 for (cnt = 0; cnt < file_actions->_used; ++cnt)
224 struct __spawn_action *action = &file_actions->_actions[cnt];
229 if (close_not_cancel (action->action.close_action.fd) != 0)
230 /* Signal the error. */
236 int new_fd = open_not_cancel (action->action.open_action.path,
237 action->action.open_action.oflag
239 action->action.open_action.mode);
242 /* The `open' call failed. */
245 /* Make sure the desired file descriptor is used. */
246 if (new_fd != action->action.open_action.fd)
248 if (dup2 (new_fd, action->action.open_action.fd)
249 != action->action.open_action.fd)
250 /* The `dup2' call failed. */
253 if (close_not_cancel (new_fd) != 0)
254 /* The `close' call failed. */
261 if (dup2 (action->action.dup2_action.fd,
262 action->action.dup2_action.newfd)
263 != action->action.dup2_action.newfd)
264 /* The `dup2' call failed. */
271 if (! use_path || strchr (file, '/') != NULL)
273 /* The FILE parameter is actually a path. */
274 execve (file, argv, envp);
276 if (errno == ENOEXEC)
277 script_execute (file, argv, envp);
279 /* Oh, oh. `execve' returns. This is bad. */
283 /* We have to search for FILE on the path. */
284 path = getenv ("PATH");
288 /* There is no `PATH' in the environment.
289 The default search path is the current directory
290 followed by the path `confstr' returns for `_CS_PATH'. */
291 len = confstr (_CS_PATH, (char *) NULL, 0);
292 path = (char *) alloca (1 + len);
294 (void) confstr (_CS_PATH, path + 1, len);
296 /* Pretend that the PATH contains only the current directory. */
301 len = strlen (file) + 1;
302 pathlen = strlen (path);
303 name = alloca (pathlen + len + 1);
304 /* Copy the file name at the top. */
305 name = (char *) memcpy (name + pathlen + 1, file, len);
306 /* And add the slash. */
315 p = strchrnul (path, ':');
318 /* Two adjacent colons, or a colon at the beginning or the end
319 of `PATH' means to search the current directory. */
322 startp = (char *) memcpy (name - (p - path), path, p - path);
324 /* Try to execute this name. If it works, execv will not return. */
325 execve (startp, argv, envp);
327 if (errno == ENOEXEC)
328 script_execute (startp, argv, envp);
336 /* Those errors indicate the file is missing or not executable
337 by us, in which case we want to just try the next path
342 /* Some other error means we found an executable file, but
343 something went wrong executing it; return the error to our
348 while (*p++ != '\0');
350 /* Return with an error. */