Bug Summary

File:src/gnu/lib/libiberty/src/pex-unix.c
Warning:line 424, column 17
This assignment is prohibited after a successful vfork

Annotated Source Code

Press '?' to see keyboard shortcuts

clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name pex-unix.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/lib/libiberty/obj -resource-dir /usr/local/lib/clang/13.0.0 -D HAVE_CONFIG_H -I /usr/src/gnu/lib/libiberty/src -I /usr/src/gnu/lib/libiberty/include -I /usr/src/gnu/lib/libiberty/obj -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/gnu/lib/libiberty/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/gnu/lib/libiberty/src/pex-unix.c
1/* Utilities to execute a program in a subprocess (possibly linked by pipes
2 with other subprocesses), and wait for it. Generic Unix version
3 (also used for UWIN and VMS).
4 Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2003, 2004, 2005
5 Free Software Foundation, Inc.
6
7This file is part of the libiberty library.
8Libiberty is free software; you can redistribute it and/or
9modify it under the terms of the GNU Library General Public
10License as published by the Free Software Foundation; either
11version 2 of the License, or (at your option) any later version.
12
13Libiberty is distributed in the hope that it will be useful,
14but WITHOUT ANY WARRANTY; without even the implied warranty of
15MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16Library General Public License for more details.
17
18You should have received a copy of the GNU Library General Public
19License along with libiberty; see the file COPYING.LIB. If not,
20write to the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
21Boston, MA 02110-1301, USA. */
22
23#include "config.h"
24#include "libiberty.h"
25#include "pex-common.h"
26
27#include <stdio.h>
28#include <signal.h>
29#include <errno(*__errno()).h>
30#ifdef NEED_DECLARATION_ERRNO
31extern int errno(*__errno());
32#endif
33#ifdef HAVE_STDLIB_H1
34#include <stdlib.h>
35#endif
36#ifdef HAVE_STRING_H1
37#include <string.h>
38#endif
39#ifdef HAVE_UNISTD_H1
40#include <unistd.h>
41#endif
42
43#include <sys/types.h>
44
45#ifdef HAVE_FCNTL_H1
46#include <fcntl.h>
47#endif
48#ifdef HAVE_SYS_WAIT_H1
49#include <sys/wait.h>
50#endif
51#ifdef HAVE_GETRUSAGE1
52#include <sys/time.h>
53#include <sys/resource.h>
54#endif
55#ifdef HAVE_SYS_STAT_H1
56#include <sys/stat.h>
57#endif
58
59
60#ifdef vfork /* Autoconf may define this to fork for us. */
61# define VFORK_STRING"vfork" "fork"
62#else
63# define VFORK_STRING"vfork" "vfork"
64#endif
65#ifdef HAVE_VFORK_H
66#include <vfork.h>
67#endif
68#ifdef VMS
69#define vfork() (decc$$alloc_vfork_blocks() >= 0 ? \
70 lib$get_current_invo_context(decc$$get_vfork_jmpbuf()) : -1)
71#endif /* VMS */
72
73
74/* File mode to use for private and world-readable files. */
75
76#if defined (S_IRUSR0000400) && defined (S_IWUSR0000200) && defined (S_IRGRP0000040) && defined (S_IWGRP0000020) && defined (S_IROTH0000004) && defined (S_IWOTH0000002)
77#define PUBLIC_MODE(0000400 | 0000200 | 0000040 | 0000020 | 0000004 | 0000002) \
78 (S_IRUSR0000400 | S_IWUSR0000200 | S_IRGRP0000040 | S_IWGRP0000020 | S_IROTH0000004 | S_IWOTH0000002)
79#else
80#define PUBLIC_MODE(0000400 | 0000200 | 0000040 | 0000020 | 0000004 | 0000002) 0666
81#endif
82
83/* Get the exit status of a particular process, and optionally get the
84 time that it took. This is simple if we have wait4, slightly
85 harder if we have waitpid, and is a pain if we only have wait. */
86
87static pid_t pex_wait (struct pex_obj *, pid_t, int *, struct pex_time *);
88
89#ifdef HAVE_WAIT41
90
91static pid_t
92pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), pid_t pid, int *status,
93 struct pex_time *time)
94{
95 pid_t ret;
96 struct rusage r;
97
98#ifdef HAVE_WAITPID1
99 if (time == NULL((void*)0))
100 return waitpid (pid, status, 0);
101#endif
102
103 ret = wait4 (pid, status, 0, &r);
104
105 if (time != NULL((void*)0))
106 {
107 time->user_seconds = r.ru_utime.tv_sec;
108 time->user_microseconds= r.ru_utime.tv_usec;
109 time->system_seconds = r.ru_stime.tv_sec;
110 time->system_microseconds= r.ru_stime.tv_usec;
111 }
112
113 return ret;
114}
115
116#else /* ! defined (HAVE_WAIT4) */
117
118#ifdef HAVE_WAITPID1
119
120#ifndef HAVE_GETRUSAGE1
121
122static pid_t
123pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), pid_t pid, int *status,
124 struct pex_time *time)
125{
126 if (time != NULL((void*)0))
127 memset (time, 0, sizeof (struct pex_time));
128 return waitpid (pid, status, 0);
129}
130
131#else /* defined (HAVE_GETRUSAGE) */
132
133static pid_t
134pex_wait (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), pid_t pid, int *status,
135 struct pex_time *time)
136{
137 struct rusage r1, r2;
138 pid_t ret;
139
140 if (time == NULL((void*)0))
141 return waitpid (pid, status, 0);
142
143 getrusage (RUSAGE_CHILDREN(-1), &r1);
144
145 ret = waitpid (pid, status, 0);
146 if (ret < 0)
147 return ret;
148
149 getrusage (RUSAGE_CHILDREN(-1), &r2);
150
151 time->user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
152 time->user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
153 if (r2.ru_utime.tv_usec < r1.ru_utime.tv_usec)
154 {
155 --time->user_seconds;
156 time->user_microseconds += 1000000;
157 }
158
159 time->system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
160 time->system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
161 if (r2.ru_stime.tv_usec < r1.ru_stime.tv_usec)
162 {
163 --time->system_seconds;
164 time->system_microseconds += 1000000;
165 }
166
167 return ret;
168}
169
170#endif /* defined (HAVE_GETRUSAGE) */
171
172#else /* ! defined (HAVE_WAITPID) */
173
174struct status_list
175{
176 struct status_list *next;
177 pid_t pid;
178 int status;
179 struct pex_time time;
180};
181
182static pid_t
183pex_wait (struct pex_obj *obj, pid_t pid, int *status, struct pex_time *time)
184{
185 struct status_list **pp;
186
187 for (pp = (struct status_list **) &obj->sysdep;
188 *pp != NULL((void*)0);
189 pp = &(*pp)->next)
190 {
191 if ((*pp)->pid == pid)
192 {
193 struct status_list *p;
194
195 p = *pp;
196 *status = p->status;
197 if (time != NULL((void*)0))
198 *time = p->time;
199 *pp = p->next;
200 free (p);
201 return pid;
202 }
203 }
204
205 while (1)
206 {
207 pid_t cpid;
208 struct status_list *psl;
209 struct pex_time pt;
210#ifdef HAVE_GETRUSAGE1
211 struct rusage r1, r2;
212#endif
213
214 if (time != NULL((void*)0))
215 {
216#ifdef HAVE_GETRUSAGE1
217 getrusage (RUSAGE_CHILDREN(-1), &r1);
218#else
219 memset (&pt, 0, sizeof (struct pex_time));
220#endif
221 }
222
223 cpid = wait (status);
224
225#ifdef HAVE_GETRUSAGE1
226 if (time != NULL((void*)0) && cpid >= 0)
227 {
228 getrusage (RUSAGE_CHILDREN(-1), &r2);
229
230 pt.user_seconds = r2.ru_utime.tv_sec - r1.ru_utime.tv_sec;
231 pt.user_microseconds = r2.ru_utime.tv_usec - r1.ru_utime.tv_usec;
232 if (pt.user_microseconds < 0)
233 {
234 --pt.user_seconds;
235 pt.user_microseconds += 1000000;
236 }
237
238 pt.system_seconds = r2.ru_stime.tv_sec - r1.ru_stime.tv_sec;
239 pt.system_microseconds = r2.ru_stime.tv_usec - r1.ru_stime.tv_usec;
240 if (pt.system_microseconds < 0)
241 {
242 --pt.system_seconds;
243 pt.system_microseconds += 1000000;
244 }
245 }
246#endif
247
248 if (cpid < 0 || cpid == pid)
249 {
250 if (time != NULL((void*)0))
251 *time = pt;
252 return cpid;
253 }
254
255 psl = XNEW (struct status_list)((struct status_list *) xmalloc (sizeof (struct status_list))
);
256 psl->pid = cpid;
257 psl->status = *status;
258 if (time != NULL((void*)0))
259 psl->time = pt;
260 psl->next = (struct status_list *) obj->sysdep;
261 obj->sysdep = (void *) psl;
262 }
263}
264
265#endif /* ! defined (HAVE_WAITPID) */
266#endif /* ! defined (HAVE_WAIT4) */
267
268static void pex_child_error (struct pex_obj *, const char *, const char *, int)
269 ATTRIBUTE_NORETURN__attribute__ ((__noreturn__));
270static int pex_unix_open_read (struct pex_obj *, const char *, int);
271static int pex_unix_open_write (struct pex_obj *, const char *, int);
272static long pex_unix_exec_child (struct pex_obj *, int, const char *,
273 char * const *, char * const *,
274 int, int, int, int,
275 const char **, int *);
276static int pex_unix_close (struct pex_obj *, int);
277static int pex_unix_wait (struct pex_obj *, long, int *, struct pex_time *,
278 int, const char **, int *);
279static int pex_unix_pipe (struct pex_obj *, int *, int);
280static FILE *pex_unix_fdopenr (struct pex_obj *, int, int);
281static FILE *pex_unix_fdopenw (struct pex_obj *, int, int);
282static void pex_unix_cleanup (struct pex_obj *);
283
284/* The list of functions we pass to the common routines. */
285
286const struct pex_funcs funcs =
287{
288 pex_unix_open_read,
289 pex_unix_open_write,
290 pex_unix_exec_child,
291 pex_unix_close,
292 pex_unix_wait,
293 pex_unix_pipe,
294 pex_unix_fdopenr,
295 pex_unix_fdopenw,
296 pex_unix_cleanup
297};
298
299/* Return a newly initialized pex_obj structure. */
300
301struct pex_obj *
302pex_init (int flags, const char *pname, const char *tempbase)
303{
304 return pex_init_common (flags, pname, tempbase, &funcs);
305}
306
307/* Open a file for reading. */
308
309static int
310pex_unix_open_read (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), const char *name,
311 int binary ATTRIBUTE_UNUSED__attribute__ ((__unused__)))
312{
313 return open (name, O_RDONLY0x0000);
314}
315
316/* Open a file for writing. */
317
318static int
319pex_unix_open_write (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), const char *name,
320 int binary ATTRIBUTE_UNUSED__attribute__ ((__unused__)))
321{
322 /* Note that we can't use O_EXCL here because gcc may have already
323 created the temporary file via make_temp_file. */
324 return open (name, O_WRONLY0x0001 | O_CREAT0x0200 | O_TRUNC0x0400, PUBLIC_MODE(0000400 | 0000200 | 0000040 | 0000020 | 0000004 | 0000002));
325}
326
327/* Close a file. */
328
329static int
330pex_unix_close (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), int fd)
331{
332 return close (fd);
333}
334
335/* Report an error from a child process. We don't use stdio routines,
336 because we might be here due to a vfork call. */
337
338static void
339pex_child_error (struct pex_obj *obj, const char *executable,
340 const char *errmsg, int err)
341{
342#define writeerr(s)write (2, s, strlen (s)) write (STDERR_FILE_NO2, s, strlen (s))
343 writeerr (obj->pname)write (2, obj->pname, strlen (obj->pname));
344 writeerr (": error trying to exec '")write (2, ": error trying to exec '", strlen (": error trying to exec '"
));
345 writeerr (executable)write (2, executable, strlen (executable));
346 writeerr ("': ")write (2, "': ", strlen ("': "));
347 writeerr (errmsg)write (2, errmsg, strlen (errmsg));
348 writeerr (": ")write (2, ": ", strlen (": "));
349 writeerr (xstrerror (err))write (2, xstrerror (err), strlen (xstrerror (err)));
350 writeerr ("\n")write (2, "\n", strlen ("\n"));
351 _exit (-1);
352}
353
354/* Execute a child. */
355
356extern char **environ;
357
358static long
359pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
360 char * const * argv, char * const * env,
361 int in, int out, int errdes,
362 int toclose, const char **errmsg, int *err)
363{
364 pid_t pid;
365
366 /* We declare these to be volatile to avoid warnings from gcc about
367 them being clobbered by vfork. */
368 volatile int sleep_interval;
369 volatile int retries;
370
371 sleep_interval = 1;
372 pid = -1;
373 for (retries = 0; retries < 4; ++retries)
1
Loop condition is true. Entering loop body
→
374 {
375 pid = vfork ();
376 if (pid
1.1
'pid' is >= 0
 >= 0)
2
←
Taking true branch
→
377 break;
3
←
 Execution continues on line 382
→
378 sleep (sleep_interval);
379 sleep_interval *= 2;
380 }
381
382 switch (pid)
4
←
Control jumps to 'case 0:' at line 389
→
383 {
384 case -1:
385 *err = errno(*__errno());
386 *errmsg = VFORK_STRING"vfork";
387 return -1;
388
389 case 0:
390 /* Child process. */
391 if (in != STDIN_FILE_NO0)
5
←
Assuming 'in' is equal to STDIN_FILE_NO
→
6
←
Taking false branch
→
392 {
393 if (dup2 (in, STDIN_FILE_NO0) < 0)
394 pex_child_error (obj, executable, "dup2", errno(*__errno()));
395 if (close (in) < 0)
396 pex_child_error (obj, executable, "close", errno(*__errno()));
397 }
398 if (out != STDOUT_FILE_NO1)
7
←
Assuming 'out' is equal to STDOUT_FILE_NO
→
8
←
Taking false branch
→
399 {
400 if (dup2 (out, STDOUT_FILE_NO1) < 0)
401 pex_child_error (obj, executable, "dup2", errno(*__errno()));
402 if (close (out) < 0)
403 pex_child_error (obj, executable, "close", errno(*__errno()));
404 }
405 if (errdes != STDERR_FILE_NO2)
9
←
Assuming 'errdes' is equal to STDERR_FILE_NO
→
10
←
Taking false branch
→
406 {
407 if (dup2 (errdes, STDERR_FILE_NO2) < 0)
408 pex_child_error (obj, executable, "dup2", errno(*__errno()));
409 if (close (errdes) < 0)
410 pex_child_error (obj, executable, "close", errno(*__errno()));
411 }
412 if (toclose >= 0)
11
←
Assuming 'toclose' is < 0
→
12
←
Taking false branch
→
413 {
414 if (close (toclose) < 0)
415 pex_child_error (obj, executable, "close", errno(*__errno()));
416 }
417 if ((flags & PEX_STDERR_TO_STDOUT0x8) != 0)
13
←
Assuming the condition is false
→
14
←
Taking false branch
→
418 {
419 if (dup2 (STDOUT_FILE_NO1, STDERR_FILE_NO2) < 0)
420 pex_child_error (obj, executable, "dup2", errno(*__errno()));
421 }
422
423 if (env)
15
←
Assuming 'env' is non-null
→
16
←
Taking true branch
→
424 environ = (char**) env;
17
←
This assignment is prohibited after a successful vfork
425
426 if ((flags & PEX_SEARCH0x2) != 0)
427 {
428 execvp (executable, argv);
429 pex_child_error (obj, executable, "execvp", errno(*__errno()));
430 }
431 else
432 {
433 execv (executable, argv);
434 pex_child_error (obj, executable, "execv", errno(*__errno()));
435 }
436
437 /* NOTREACHED */
438 return -1;
439
440 default:
441 /* Parent process. */
442 if (in != STDIN_FILE_NO0)
443 {
444 if (close (in) < 0)
445 {
446 *err = errno(*__errno());
447 *errmsg = "close";
448 return -1;
449 }
450 }
451 if (out != STDOUT_FILE_NO1)
452 {
453 if (close (out) < 0)
454 {
455 *err = errno(*__errno());
456 *errmsg = "close";
457 return -1;
458 }
459 }
460 if (errdes != STDERR_FILE_NO2)
461 {
462 if (close (errdes) < 0)
463 {
464 *err = errno(*__errno());
465 *errmsg = "close";
466 return -1;
467 }
468 }
469
470 return (long) pid;
471 }
472}
473
474/* Wait for a child process to complete. */
475
476static int
477pex_unix_wait (struct pex_obj *obj, long pid, int *status,
478 struct pex_time *time, int done, const char **errmsg,
479 int *err)
480{
481 /* If we are cleaning up when the caller didn't retrieve process
482 status for some reason, encourage the process to go away. */
483 if (done)
484 kill (pid, SIGTERM15);
485
486 if (pex_wait (obj, pid, status, time) < 0)
487 {
488 *err = errno(*__errno());
489 *errmsg = "wait";
490 return -1;
491 }
492
493 return 0;
494}
495
496/* Create a pipe. */
497
498static int
499pex_unix_pipe (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), int *p,
500 int binary ATTRIBUTE_UNUSED__attribute__ ((__unused__)))
501{
502 return pipe (p);
503}
504
505/* Get a FILE pointer to read from a file descriptor. */
506
507static FILE *
508pex_unix_fdopenr (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), int fd,
509 int binary ATTRIBUTE_UNUSED__attribute__ ((__unused__)))
510{
511 return fdopen (fd, "r");
512}
513
514static FILE *
515pex_unix_fdopenw (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)), int fd,
516 int binary ATTRIBUTE_UNUSED__attribute__ ((__unused__)))
517{
518 if (fcntl (fd, F_SETFD2, FD_CLOEXEC1) < 0)
519 return NULL((void*)0);
520 return fdopen (fd, "w");
521}
522
523static void
524pex_unix_cleanup (struct pex_obj *obj ATTRIBUTE_UNUSED__attribute__ ((__unused__)))
525{
526#if !defined (HAVE_WAIT41) && !defined (HAVE_WAITPID1)
527 while (obj->sysdep != NULL((void*)0))
528 {
529 struct status_list *this;
530 struct status_list *next;
531
532 this = (struct status_list *) obj->sysdep;
533 next = this->next;
534 free (this);
535 obj->sysdep = (void *) next;
536 }
537#endif
538}