1 | /* Copyright (C) 1993-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Written by Per Bothner <bothner@cygnus.com>. |
4 | |
5 | The GNU C Library is free software; you can redistribute it and/or |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either |
8 | version 2.1 of the License, or (at your option) any later version. |
9 | |
10 | The GNU C Library 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 GNU |
13 | Lesser General Public License for more details. |
14 | |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see |
17 | <http://www.gnu.org/licenses/>. |
18 | |
19 | As a special exception, if you link the code in this file with |
20 | files compiled with a GNU compiler to produce an executable, |
21 | that does not cause the resulting executable to be covered by |
22 | the GNU Lesser General Public License. This exception does not |
23 | however invalidate any other reasons why the executable file |
24 | might be covered by the GNU Lesser General Public License. |
25 | This exception applies to code released by its copyright holders |
26 | in files containing the exception. */ |
27 | |
28 | #ifndef _POSIX_SOURCE |
29 | # define _POSIX_SOURCE |
30 | #endif |
31 | #include "libioP.h" |
32 | #include <fcntl.h> |
33 | #include <signal.h> |
34 | #include <unistd.h> |
35 | #include <stdlib.h> |
36 | #ifdef _LIBC |
37 | # include <shlib-compat.h> |
38 | # include <not-cancel.h> |
39 | #endif |
40 | #include <sys/types.h> |
41 | #include <sys/wait.h> |
42 | #include <kernel-features.h> |
43 | |
44 | #ifndef _IO_fork |
45 | #ifdef _LIBC |
46 | #define _IO_fork __fork |
47 | #else |
48 | #define _IO_fork fork /* defined in libiberty, if needed */ |
49 | #endif |
50 | extern _IO_pid_t _IO_fork (void) __THROW; |
51 | #endif |
52 | |
53 | #ifndef _IO_dup2 |
54 | #ifdef _LIBC |
55 | #define _IO_dup2 __dup2 |
56 | #else |
57 | #define _IO_dup2 dup2 |
58 | #endif |
59 | extern int _IO_dup2 (int fd, int fd2) __THROW; |
60 | #endif |
61 | |
62 | #ifndef _IO_waitpid |
63 | #ifdef _LIBC |
64 | #define _IO_waitpid waitpid_not_cancel |
65 | #else |
66 | #define _IO_waitpid waitpid |
67 | #endif |
68 | #endif |
69 | |
70 | #ifndef _IO_execl |
71 | #define _IO_execl execl |
72 | #endif |
73 | #ifndef _IO__exit |
74 | #define _IO__exit _exit |
75 | #endif |
76 | |
77 | #ifndef _IO_close |
78 | #ifdef _LIBC |
79 | #define _IO_close close_not_cancel |
80 | #else |
81 | #define _IO_close close |
82 | #endif |
83 | #endif |
84 | |
85 | struct _IO_proc_file |
86 | { |
87 | struct _IO_FILE_plus file; |
88 | /* Following fields must match those in class procbuf (procbuf.h) */ |
89 | _IO_pid_t pid; |
90 | struct _IO_proc_file *next; |
91 | }; |
92 | typedef struct _IO_proc_file _IO_proc_file; |
93 | |
94 | static const struct _IO_jump_t _IO_proc_jumps; |
95 | |
96 | static struct _IO_proc_file *proc_file_chain; |
97 | |
98 | #ifdef _IO_MTSAFE_IO |
99 | static _IO_lock_t proc_file_chain_lock = _IO_lock_initializer; |
100 | |
101 | static void |
102 | unlock (void *not_used) |
103 | { |
104 | _IO_lock_unlock (proc_file_chain_lock); |
105 | } |
106 | #endif |
107 | |
108 | _IO_FILE * |
109 | _IO_new_proc_open (_IO_FILE *fp, const char *command, const char *mode) |
110 | { |
111 | int read_or_write; |
112 | int parent_end, child_end; |
113 | int pipe_fds[2]; |
114 | _IO_pid_t child_pid; |
115 | |
116 | int do_read = 0; |
117 | int do_write = 0; |
118 | int do_cloexec = 0; |
119 | while (*mode != '\0') |
120 | switch (*mode++) |
121 | { |
122 | case 'r': |
123 | do_read = 1; |
124 | break; |
125 | case 'w': |
126 | do_write = 1; |
127 | break; |
128 | case 'e': |
129 | do_cloexec = 1; |
130 | break; |
131 | default: |
132 | errout: |
133 | __set_errno (EINVAL); |
134 | return NULL; |
135 | } |
136 | |
137 | if ((do_read ^ do_write) == 0) |
138 | goto errout; |
139 | |
140 | if (_IO_file_is_open (fp)) |
141 | return NULL; |
142 | |
143 | /* Atomically set the O_CLOEXEC flag for the pipe end used by the |
144 | child process (to avoid leaking the file descriptor in case of a |
145 | concurrent fork). This is later reverted in the child process. |
146 | When popen returns, the parent pipe end can be O_CLOEXEC or not, |
147 | depending on the 'e' open mode, but there is only one flag which |
148 | controls both descriptors. The parent end is adjusted below, |
149 | after creating the child process. (In the child process, the |
150 | parent end should be closed on execve, so O_CLOEXEC remains set |
151 | there.) */ |
152 | if (__pipe2 (pipe_fds, O_CLOEXEC) < 0) |
153 | return NULL; |
154 | |
155 | if (do_read) |
156 | { |
157 | parent_end = pipe_fds[0]; |
158 | child_end = pipe_fds[1]; |
159 | read_or_write = _IO_NO_WRITES; |
160 | } |
161 | else |
162 | { |
163 | parent_end = pipe_fds[1]; |
164 | child_end = pipe_fds[0]; |
165 | read_or_write = _IO_NO_READS; |
166 | } |
167 | |
168 | ((_IO_proc_file *) fp)->pid = child_pid = _IO_fork (); |
169 | if (child_pid == 0) |
170 | { |
171 | int child_std_end = do_read ? 1 : 0; |
172 | struct _IO_proc_file *p; |
173 | |
174 | if (child_end != child_std_end) |
175 | _IO_dup2 (child_end, child_std_end); |
176 | else |
177 | /* The descriptor is already the one we will use. But it must |
178 | not be marked close-on-exec. Undo the effects. */ |
179 | __fcntl (child_end, F_SETFD, 0); |
180 | /* POSIX.2: "popen() shall ensure that any streams from previous |
181 | popen() calls that remain open in the parent process are closed |
182 | in the new child process." */ |
183 | for (p = proc_file_chain; p; p = p->next) |
184 | { |
185 | int fd = _IO_fileno ((_IO_FILE *) p); |
186 | |
187 | /* If any stream from previous popen() calls has fileno |
188 | child_std_end, it has been already closed by the dup2 syscall |
189 | above. */ |
190 | if (fd != child_std_end) |
191 | _IO_close (fd); |
192 | } |
193 | |
194 | _IO_execl ("/bin/sh" , "sh" , "-c" , command, (char *) 0); |
195 | _IO__exit (127); |
196 | } |
197 | _IO_close (child_end); |
198 | if (child_pid < 0) |
199 | { |
200 | _IO_close (parent_end); |
201 | return NULL; |
202 | } |
203 | |
204 | if (!do_cloexec) |
205 | /* Undo the effects of the pipe2 call which set the |
206 | close-on-exec flag. */ |
207 | __fcntl (parent_end, F_SETFD, 0); |
208 | |
209 | _IO_fileno (fp) = parent_end; |
210 | |
211 | /* Link into proc_file_chain. */ |
212 | #ifdef _IO_MTSAFE_IO |
213 | _IO_cleanup_region_start_noarg (unlock); |
214 | _IO_lock_lock (proc_file_chain_lock); |
215 | #endif |
216 | ((_IO_proc_file *) fp)->next = proc_file_chain; |
217 | proc_file_chain = (_IO_proc_file *) fp; |
218 | #ifdef _IO_MTSAFE_IO |
219 | _IO_lock_unlock (proc_file_chain_lock); |
220 | _IO_cleanup_region_end (0); |
221 | #endif |
222 | |
223 | _IO_mask_flags (fp, read_or_write, _IO_NO_READS|_IO_NO_WRITES); |
224 | return fp; |
225 | } |
226 | |
227 | _IO_FILE * |
228 | _IO_new_popen (const char *command, const char *mode) |
229 | { |
230 | struct locked_FILE |
231 | { |
232 | struct _IO_proc_file fpx; |
233 | #ifdef _IO_MTSAFE_IO |
234 | _IO_lock_t lock; |
235 | #endif |
236 | } *new_f; |
237 | _IO_FILE *fp; |
238 | |
239 | new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE)); |
240 | if (new_f == NULL) |
241 | return NULL; |
242 | #ifdef _IO_MTSAFE_IO |
243 | new_f->fpx.file.file._lock = &new_f->lock; |
244 | #endif |
245 | fp = &new_f->fpx.file.file; |
246 | _IO_init_internal (fp, 0); |
247 | _IO_JUMPS (&new_f->fpx.file) = &_IO_proc_jumps; |
248 | _IO_new_file_init_internal (&new_f->fpx.file); |
249 | #if !_IO_UNIFIED_JUMPTABLES |
250 | new_f->fpx.file.vtable = NULL; |
251 | #endif |
252 | if (_IO_new_proc_open (fp, command, mode) != NULL) |
253 | return (_IO_FILE *) &new_f->fpx.file; |
254 | _IO_un_link (&new_f->fpx.file); |
255 | free (new_f); |
256 | return NULL; |
257 | } |
258 | |
259 | int |
260 | _IO_new_proc_close (_IO_FILE *fp) |
261 | { |
262 | /* This is not name-space clean. FIXME! */ |
263 | int wstatus; |
264 | _IO_proc_file **ptr = &proc_file_chain; |
265 | _IO_pid_t wait_pid; |
266 | int status = -1; |
267 | |
268 | /* Unlink from proc_file_chain. */ |
269 | #ifdef _IO_MTSAFE_IO |
270 | _IO_cleanup_region_start_noarg (unlock); |
271 | _IO_lock_lock (proc_file_chain_lock); |
272 | #endif |
273 | for ( ; *ptr != NULL; ptr = &(*ptr)->next) |
274 | { |
275 | if (*ptr == (_IO_proc_file *) fp) |
276 | { |
277 | *ptr = (*ptr)->next; |
278 | status = 0; |
279 | break; |
280 | } |
281 | } |
282 | #ifdef _IO_MTSAFE_IO |
283 | _IO_lock_unlock (proc_file_chain_lock); |
284 | _IO_cleanup_region_end (0); |
285 | #endif |
286 | |
287 | if (status < 0 || _IO_close (_IO_fileno(fp)) < 0) |
288 | return -1; |
289 | /* POSIX.2 Rationale: "Some historical implementations either block |
290 | or ignore the signals SIGINT, SIGQUIT, and SIGHUP while waiting |
291 | for the child process to terminate. Since this behavior is not |
292 | described in POSIX.2, such implementations are not conforming." */ |
293 | do |
294 | { |
295 | wait_pid = _IO_waitpid (((_IO_proc_file *) fp)->pid, &wstatus, 0); |
296 | } |
297 | while (wait_pid == -1 && errno == EINTR); |
298 | if (wait_pid == -1) |
299 | return -1; |
300 | return wstatus; |
301 | } |
302 | |
303 | static const struct _IO_jump_t _IO_proc_jumps libio_vtable = { |
304 | JUMP_INIT_DUMMY, |
305 | JUMP_INIT(finish, _IO_new_file_finish), |
306 | JUMP_INIT(overflow, _IO_new_file_overflow), |
307 | JUMP_INIT(underflow, _IO_new_file_underflow), |
308 | JUMP_INIT(uflow, _IO_default_uflow), |
309 | JUMP_INIT(pbackfail, _IO_default_pbackfail), |
310 | JUMP_INIT(xsputn, _IO_new_file_xsputn), |
311 | JUMP_INIT(xsgetn, _IO_default_xsgetn), |
312 | JUMP_INIT(seekoff, _IO_new_file_seekoff), |
313 | JUMP_INIT(seekpos, _IO_default_seekpos), |
314 | JUMP_INIT(setbuf, _IO_new_file_setbuf), |
315 | JUMP_INIT(sync, _IO_new_file_sync), |
316 | JUMP_INIT(doallocate, _IO_file_doallocate), |
317 | JUMP_INIT(read, _IO_file_read), |
318 | JUMP_INIT(write, _IO_new_file_write), |
319 | JUMP_INIT(seek, _IO_file_seek), |
320 | JUMP_INIT(close, _IO_new_proc_close), |
321 | JUMP_INIT(stat, _IO_file_stat), |
322 | JUMP_INIT(showmanyc, _IO_default_showmanyc), |
323 | JUMP_INIT(imbue, _IO_default_imbue) |
324 | }; |
325 | |
326 | strong_alias (_IO_new_popen, __new_popen) |
327 | versioned_symbol (libc, _IO_new_popen, _IO_popen, GLIBC_2_1); |
328 | versioned_symbol (libc, __new_popen, popen, GLIBC_2_1); |
329 | versioned_symbol (libc, _IO_new_proc_open, _IO_proc_open, GLIBC_2_1); |
330 | versioned_symbol (libc, _IO_new_proc_close, _IO_proc_close, GLIBC_2_1); |
331 | |