*-map tests: Fix compilation error.
[gnulib.git] / lib / spawni.c
blob39e99a0b43f2eec5758fca50761b7edbba691aab
1 /* Guts of POSIX spawn interface. Generic POSIX.1 version.
2 Copyright (C) 2000-2006, 2008-2019 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 <https://www.gnu.org/licenses/>. */
18 #include <config.h>
20 /* Specification. */
21 #include <spawn.h>
22 #include "spawn_int.h"
24 #include <alloca.h>
25 #include <errno.h>
27 #include <fcntl.h>
28 #ifndef O_LARGEFILE
29 # define O_LARGEFILE 0
30 #endif
32 #if _LIBC || HAVE_PATHS_H
33 # include <paths.h>
34 #else
35 # define _PATH_BSHELL BOURNE_SHELL
36 #endif
38 #include <signal.h>
39 #include <stdlib.h>
40 #include <string.h>
41 #include <unistd.h>
43 #if _LIBC
44 # include <not-cancel.h>
45 #else
46 # define close_not_cancel close
47 # define open_not_cancel open
48 #endif
50 #if _LIBC
51 # include <local-setxid.h>
52 #else
53 # if !HAVE_SETEUID
54 # define seteuid(id) setresuid (-1, id, -1)
55 # endif
56 # if !HAVE_SETEGID
57 # define setegid(id) setresgid (-1, id, -1)
58 # endif
59 # define local_seteuid(id) seteuid (id)
60 # define local_setegid(id) setegid (id)
61 #endif
63 #if _LIBC
64 # define alloca __alloca
65 # define execve __execve
66 # define dup2 __dup2
67 # define fork __fork
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
78 #else
79 # undef internal_function
80 # define internal_function /* empty */
81 #endif
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 #if defined _WIN32 && ! defined __CYGWIN__
94 /* Native Windows API. */
95 int
96 __spawni (pid_t *pid, const char *file,
97 const posix_spawn_file_actions_t *file_actions,
98 const posix_spawnattr_t *attrp, char *const argv[],
99 char *const envp[], int use_path)
101 /* Not yet implemented. */
102 return ENOSYS;
105 #else
108 /* The file is accessible but it is not an executable file. Invoke
109 the shell to interpret it as a script. */
110 static void
111 internal_function
112 script_execute (const char *file, char *const argv[], char *const envp[])
114 /* Count the arguments. */
115 int argc = 0;
116 while (argv[argc++])
119 /* Construct an argument list for the shell. */
121 char **new_argv = (char **) alloca ((argc + 1) * sizeof (char *));
122 new_argv[0] = (char *) _PATH_BSHELL;
123 new_argv[1] = (char *) file;
124 while (argc > 1)
126 new_argv[argc] = argv[argc - 1];
127 --argc;
130 /* Execute the shell. */
131 execve (new_argv[0], new_argv, envp);
136 /* Spawn a new process executing PATH with the attributes describes in *ATTRP.
137 Before running the process perform the actions described in FILE-ACTIONS. */
139 __spawni (pid_t *pid, const char *file,
140 const posix_spawn_file_actions_t *file_actions,
141 const posix_spawnattr_t *attrp, char *const argv[],
142 char *const envp[], int use_path)
144 pid_t new_pid;
145 char *path, *p, *name;
146 size_t len;
147 size_t pathlen;
149 /* Do this once. */
150 short int flags = attrp == NULL ? 0 : attrp->_flags;
152 /* Avoid gcc warning
153 "variable 'flags' might be clobbered by 'longjmp' or 'vfork'" */
154 (void) &flags;
156 /* Generate the new process. */
157 #if HAVE_VFORK
158 if ((flags & POSIX_SPAWN_USEVFORK) != 0
159 /* If no major work is done, allow using vfork. Note that we
160 might perform the path searching. But this would be done by
161 a call to execvp(), too, and such a call must be OK according
162 to POSIX. */
163 || ((flags & (POSIX_SPAWN_SETSIGMASK | POSIX_SPAWN_SETSIGDEF
164 | POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER
165 | POSIX_SPAWN_SETPGROUP | POSIX_SPAWN_RESETIDS)) == 0
166 && file_actions == NULL))
167 new_pid = vfork ();
168 else
169 #endif
170 new_pid = fork ();
172 if (new_pid != 0)
174 if (new_pid < 0)
175 return errno;
177 /* The call was successful. Store the PID if necessary. */
178 if (pid != NULL)
179 *pid = new_pid;
181 return 0;
184 /* Set signal mask. */
185 if ((flags & POSIX_SPAWN_SETSIGMASK) != 0
186 && sigprocmask (SIG_SETMASK, &attrp->_ss, NULL) != 0)
187 _exit (SPAWN_ERROR);
189 /* Set signal default action. */
190 if ((flags & POSIX_SPAWN_SETSIGDEF) != 0)
192 /* We have to iterate over all signals. This could possibly be
193 done better but it requires system specific solutions since
194 the sigset_t data type can be very different on different
195 architectures. */
196 int sig;
197 struct sigaction sa;
199 memset (&sa, '\0', sizeof (sa));
200 sa.sa_handler = SIG_DFL;
202 for (sig = 1; sig <= NSIG; ++sig)
203 if (sigismember (&attrp->_sd, sig) != 0
204 && sigaction (sig, &sa, NULL) != 0)
205 _exit (SPAWN_ERROR);
209 #if (_LIBC ? defined _POSIX_PRIORITY_SCHEDULING : HAVE_SCHED_SETPARAM && HAVE_SCHED_SETSCHEDULER)
210 /* Set the scheduling algorithm and parameters. */
211 if ((flags & (POSIX_SPAWN_SETSCHEDPARAM | POSIX_SPAWN_SETSCHEDULER))
212 == POSIX_SPAWN_SETSCHEDPARAM)
214 if (sched_setparam (0, &attrp->_sp) == -1)
215 _exit (SPAWN_ERROR);
217 else if ((flags & POSIX_SPAWN_SETSCHEDULER) != 0)
219 if (sched_setscheduler (0, attrp->_policy,
220 (flags & POSIX_SPAWN_SETSCHEDPARAM) != 0
221 ? &attrp->_sp : NULL) == -1)
222 _exit (SPAWN_ERROR);
224 #endif
226 /* Set the process group ID. */
227 if ((flags & POSIX_SPAWN_SETPGROUP) != 0
228 && setpgid (0, attrp->_pgrp) != 0)
229 _exit (SPAWN_ERROR);
231 /* Set the effective user and group IDs. */
232 if ((flags & POSIX_SPAWN_RESETIDS) != 0
233 && (local_seteuid (getuid ()) != 0
234 || local_setegid (getgid ()) != 0))
235 _exit (SPAWN_ERROR);
237 /* Execute the file actions. */
238 if (file_actions != NULL)
240 int cnt;
242 for (cnt = 0; cnt < file_actions->_used; ++cnt)
244 struct __spawn_action *action = &file_actions->_actions[cnt];
246 switch (action->tag)
248 case spawn_do_close:
249 if (close_not_cancel (action->action.close_action.fd) != 0)
250 /* Signal the error. */
251 _exit (SPAWN_ERROR);
252 break;
254 case spawn_do_open:
256 int new_fd = open_not_cancel (action->action.open_action.path,
257 action->action.open_action.oflag
258 | O_LARGEFILE,
259 action->action.open_action.mode);
261 if (new_fd == -1)
262 /* The 'open' call failed. */
263 _exit (SPAWN_ERROR);
265 /* Make sure the desired file descriptor is used. */
266 if (new_fd != action->action.open_action.fd)
268 if (dup2 (new_fd, action->action.open_action.fd)
269 != action->action.open_action.fd)
270 /* The 'dup2' call failed. */
271 _exit (SPAWN_ERROR);
273 if (close_not_cancel (new_fd) != 0)
274 /* The 'close' call failed. */
275 _exit (SPAWN_ERROR);
278 break;
280 case spawn_do_dup2:
281 if (dup2 (action->action.dup2_action.fd,
282 action->action.dup2_action.newfd)
283 != action->action.dup2_action.newfd)
284 /* The 'dup2' call failed. */
285 _exit (SPAWN_ERROR);
286 break;
288 case spawn_do_chdir:
289 if (chdir (action->action.chdir_action.path) < 0)
290 /* The 'chdir' call failed. */
291 _exit (SPAWN_ERROR);
292 break;
297 if (! use_path || strchr (file, '/') != NULL)
299 /* The FILE parameter is actually a path. */
300 execve (file, argv, envp);
302 if (errno == ENOEXEC)
303 script_execute (file, argv, envp);
305 /* Oh, oh. 'execve' returns. This is bad. */
306 _exit (SPAWN_ERROR);
309 /* We have to search for FILE on the path. */
310 path = getenv ("PATH");
311 if (path == NULL)
313 #if HAVE_CONFSTR
314 /* There is no 'PATH' in the environment.
315 The default search path is the current directory
316 followed by the path 'confstr' returns for '_CS_PATH'. */
317 len = confstr (_CS_PATH, (char *) NULL, 0);
318 path = (char *) alloca (1 + len);
319 path[0] = ':';
320 (void) confstr (_CS_PATH, path + 1, len);
321 #else
322 /* Pretend that the PATH contains only the current directory. */
323 path = "";
324 #endif
327 len = strlen (file) + 1;
328 pathlen = strlen (path);
329 name = alloca (pathlen + len + 1);
330 /* Copy the file name at the top. */
331 name = (char *) memcpy (name + pathlen + 1, file, len);
332 /* And add the slash. */
333 *--name = '/';
335 p = path;
338 char *startp;
340 path = p;
341 p = strchrnul (path, ':');
343 if (p == path)
344 /* Two adjacent colons, or a colon at the beginning or the end
345 of 'PATH' means to search the current directory. */
346 startp = name + 1;
347 else
348 startp = (char *) memcpy (name - (p - path), path, p - path);
350 /* Try to execute this name. If it works, execv will not return. */
351 execve (startp, argv, envp);
353 if (errno == ENOEXEC)
354 script_execute (startp, argv, envp);
356 switch (errno)
358 case EACCES:
359 case ENOENT:
360 case ESTALE:
361 case ENOTDIR:
362 /* Those errors indicate the file is missing or not executable
363 by us, in which case we want to just try the next path
364 directory. */
365 break;
367 default:
368 /* Some other error means we found an executable file, but
369 something went wrong executing it; return the error to our
370 caller. */
371 _exit (SPAWN_ERROR);
374 while (*p++ != '\0');
376 /* Return with an error. */
377 _exit (SPAWN_ERROR);
380 #endif