1 /* Guts of POSIX spawn interface. Generic POSIX.1 version.
2 Copyright (C) 2000-2006, 2008-2020 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/>. */
22 #include "spawn_int.h"
29 # define O_LARGEFILE 0
32 #if _LIBC || HAVE_PATHS_H
35 # define _PATH_BSHELL BOURNE_SHELL
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
81 /* The Unix standard contains a long explanation of the way to signal
82 an error after the fork() was successful. Since no new wait status
83 was wanted there is no way to signal an error using one of the
84 available methods. The committee chose to signal an error by a
85 normal program exit with the exit code 127. */
86 #define SPAWN_ERROR 127
89 #if defined _WIN32 && ! defined __CYGWIN__
91 /* Native Windows API. */
93 __spawni (pid_t
*pid
, const char *file
,
94 const posix_spawn_file_actions_t
*file_actions
,
95 const posix_spawnattr_t
*attrp
, const char *const argv
[],
96 const char *const envp
[], int use_path
)
98 /* Not yet implemented. */
105 /* Spawn a new process executing PATH with the attributes describes in *ATTRP.
106 Before running the process perform the actions described in FILE-ACTIONS. */
108 __spawni (pid_t
*pid
, const char *file
,
109 const posix_spawn_file_actions_t
*file_actions
,
110 const posix_spawnattr_t
*attrp
, const char *const argv
[],
111 const char *const envp
[], int use_path
)
114 char *path
, *p
, *name
;
119 short int flags
= attrp
== NULL
? 0 : attrp
->_flags
;
122 "variable 'flags' might be clobbered by 'longjmp' or 'vfork'" */
125 /* Generate the new process. */
127 if ((flags
& POSIX_SPAWN_USEVFORK
) != 0
128 /* If no major work is done, allow using vfork. Note that we
129 might perform the path searching. But this would be done by
130 a call to execvp(), too, and such a call must be OK according
132 || ((flags
& (POSIX_SPAWN_SETSIGMASK
| POSIX_SPAWN_SETSIGDEF
133 | POSIX_SPAWN_SETSCHEDPARAM
| POSIX_SPAWN_SETSCHEDULER
134 | POSIX_SPAWN_SETPGROUP
| POSIX_SPAWN_RESETIDS
)) == 0
135 && file_actions
== NULL
))
146 /* The call was successful. Store the PID if necessary. */
153 /* Set signal mask. */
154 if ((flags
& POSIX_SPAWN_SETSIGMASK
) != 0
155 && sigprocmask (SIG_SETMASK
, &attrp
->_ss
, NULL
) != 0)
158 /* Set signal default action. */
159 if ((flags
& POSIX_SPAWN_SETSIGDEF
) != 0)
161 /* We have to iterate over all signals. This could possibly be
162 done better but it requires system specific solutions since
163 the sigset_t data type can be very different on different
168 memset (&sa
, '\0', sizeof (sa
));
169 sa
.sa_handler
= SIG_DFL
;
171 for (sig
= 1; sig
<= NSIG
; ++sig
)
172 if (sigismember (&attrp
->_sd
, sig
) != 0
173 && sigaction (sig
, &sa
, NULL
) != 0)
178 #if (_LIBC ? defined _POSIX_PRIORITY_SCHEDULING : HAVE_SCHED_SETPARAM && HAVE_SCHED_SETSCHEDULER)
179 /* Set the scheduling algorithm and parameters. */
180 if ((flags
& (POSIX_SPAWN_SETSCHEDPARAM
| POSIX_SPAWN_SETSCHEDULER
))
181 == POSIX_SPAWN_SETSCHEDPARAM
)
183 if (sched_setparam (0, &attrp
->_sp
) == -1)
186 else if ((flags
& POSIX_SPAWN_SETSCHEDULER
) != 0)
188 if (sched_setscheduler (0, attrp
->_policy
,
189 (flags
& POSIX_SPAWN_SETSCHEDPARAM
) != 0
190 ? &attrp
->_sp
: NULL
) == -1)
195 /* Set the process group ID. */
196 if ((flags
& POSIX_SPAWN_SETPGROUP
) != 0
197 && setpgid (0, attrp
->_pgrp
) != 0)
200 /* Set the effective user and group IDs. */
201 if ((flags
& POSIX_SPAWN_RESETIDS
) != 0
202 && (local_seteuid (getuid ()) != 0
203 || local_setegid (getgid ()) != 0))
206 /* Execute the file actions. */
207 if (file_actions
!= NULL
)
211 for (cnt
= 0; cnt
< file_actions
->_used
; ++cnt
)
213 struct __spawn_action
*action
= &file_actions
->_actions
[cnt
];
218 if (close_not_cancel (action
->action
.close_action
.fd
) != 0)
219 /* Signal the error. */
225 int new_fd
= open_not_cancel (action
->action
.open_action
.path
,
226 action
->action
.open_action
.oflag
228 action
->action
.open_action
.mode
);
231 /* The 'open' call failed. */
234 /* Make sure the desired file descriptor is used. */
235 if (new_fd
!= action
->action
.open_action
.fd
)
237 if (dup2 (new_fd
, action
->action
.open_action
.fd
)
238 != action
->action
.open_action
.fd
)
239 /* The 'dup2' call failed. */
242 if (close_not_cancel (new_fd
) != 0)
243 /* The 'close' call failed. */
250 if (dup2 (action
->action
.dup2_action
.fd
,
251 action
->action
.dup2_action
.newfd
)
252 != action
->action
.dup2_action
.newfd
)
253 /* The 'dup2' call failed. */
258 if (chdir (action
->action
.chdir_action
.path
) < 0)
259 /* The 'chdir' call failed. */
263 case spawn_do_fchdir
:
264 if (fchdir (action
->action
.fchdir_action
.fd
) < 0)
265 /* The 'fchdir' call failed. */
272 if (! use_path
|| strchr (file
, '/') != NULL
)
274 /* The FILE parameter is actually a path. */
275 execve (file
, (char * const *) argv
, (char * const *) envp
);
277 /* Oh, oh. 'execve' returns. This is bad. */
281 /* We have to search for FILE on the path. */
282 path
= getenv ("PATH");
286 /* There is no 'PATH' in the environment.
287 The default search path is the current directory
288 followed by the path 'confstr' returns for '_CS_PATH'. */
289 len
= confstr (_CS_PATH
, (char *) NULL
, 0);
290 path
= (char *) alloca (1 + len
);
292 (void) confstr (_CS_PATH
, path
+ 1, len
);
294 /* Pretend that the PATH contains only the current directory. */
299 len
= strlen (file
) + 1;
300 pathlen
= strlen (path
);
301 name
= alloca (pathlen
+ len
+ 1);
302 /* Copy the file name at the top. */
303 name
= (char *) memcpy (name
+ pathlen
+ 1, file
, len
);
304 /* And add the slash. */
313 p
= strchrnul (path
, ':');
316 /* Two adjacent colons, or a colon at the beginning or the end
317 of 'PATH' means to search the current directory. */
320 startp
= (char *) memcpy (name
- (p
- path
), path
, p
- path
);
322 /* Try to execute this name. If it works, execv will not return. */
323 execve (startp
, (char * const *) argv
, (char * const *) envp
);
331 /* Those errors indicate the file is missing or not executable
332 by us, in which case we want to just try the next path
337 /* Some other error means we found an executable file, but
338 something went wrong executing it; return the error to our
343 while (*p
++ != '\0');
345 /* Return with an error. */