Author: jilles
Date: Fri Oct 23 14:50:11 2009
New Revision: 198406
URL: http://svn.freebsd.org/changeset/base/198406
Log:
wordexp(3): fix some bugs with signals and long outputs
* retry various system calls on EINTR
* retry the rest after a short read (common if there is more than about 1K
of output)
* block SIGCHLD like system(3) does (note that this does not and cannot
work fully in threaded programs, they will need to be careful with wait
functions)
PR: 90580
MFC after: 1 month
Modified:
head/lib/libc/gen/wordexp.c
head/tools/regression/lib/libc/gen/test-wordexp.c
Modified: head/lib/libc/gen/wordexp.c
==============================================================================
--- head/lib/libc/gen/wordexp.c Fri Oct 23 14:43:17 2009 (r198405)
+++ head/lib/libc/gen/wordexp.c Fri Oct 23 14:50:11 2009 (r198406)
@@ -28,8 +28,10 @@
#include <sys/cdefs.h>
#include <sys/types.h>
#include <sys/wait.h>
+#include <errno.h>
#include <fcntl.h>
#include <paths.h>
+#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@@ -73,6 +75,24 @@ wordexp(const char * __restrict words, w
return (0);
}
+static size_t
+we_read_fully(int fd, char *buffer, size_t len)
+{
+ size_t done;
+ ssize_t nread;
+
+ done = 0;
+ do {
+ nread = _read(fd, buffer + done, len - done);
+ if (nread == -1 && errno == EINTR)
+ continue;
+ if (nread <= 0)
+ break;
+ done += nread;
+ } while (done != len);
+ return done;
+}
+
/*
* we_askshell --
* Use the `wordexp' /bin/sh builtin function to do most of the work
@@ -90,20 +110,31 @@ we_askshell(const char *words, wordexp_t
size_t sofs; /* Offset into we->we_strings */
size_t vofs; /* Offset into we->we_wordv */
pid_t pid; /* Process ID of child */
+ pid_t wpid; /* waitpid return value */
int status; /* Child exit status */
+ int error; /* Our return value */
+ int serrno; /* errno to return */
char *ifs; /* IFS env. var. */
char *np, *p; /* Handy pointers */
char *nstrings; /* Temporary for realloc() */
char **nwv; /* Temporary for realloc() */
+ sigset_t newsigblock, oldsigblock;
+ serrno = errno;
if ((ifs = getenv("IFS")) == NULL)
ifs = " \t\n";
if (pipe(pdes) < 0)
return (WRDE_NOSPACE); /* XXX */
+ (void)sigemptyset(&newsigblock);
+ (void)sigaddset(&newsigblock, SIGCHLD);
+ (void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
if ((pid = fork()) < 0) {
+ serrno = errno;
_close(pdes[0]);
_close(pdes[1]);
+ (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+ errno = serrno;
return (WRDE_NOSPACE); /* XXX */
}
else if (pid == 0) {
@@ -114,6 +145,7 @@ we_askshell(const char *words, wordexp_t
int devnull;
char *cmd;
+ (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
_close(pdes[0]);
if (_dup2(pdes[1], STDOUT_FILENO) < 0)
_exit(1);
@@ -139,10 +171,11 @@ we_askshell(const char *words, wordexp_t
* the expanded words separated by nulls.
*/
_close(pdes[1]);
- if (_read(pdes[0], wbuf, 8) != 8 || _read(pdes[0], bbuf, 8) != 8) {
- _close(pdes[0]);
- _waitpid(pid, &status, 0);
- return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
+ if (we_read_fully(pdes[0], wbuf, 8) != 8 ||
+ we_read_fully(pdes[0], bbuf, 8) != 8) {
+ error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX;
+ serrno = errno;
+ goto cleanup;
}
wbuf[8] = bbuf[8] = '\0';
nwords = strtol(wbuf, NULL, 16);
@@ -162,33 +195,38 @@ we_askshell(const char *words, wordexp_t
if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 +
(flags & WRDE_DOOFFS ? we->we_offs : 0)) *
sizeof(char *))) == NULL) {
- _close(pdes[0]);
- _waitpid(pid, &status, 0);
- return (WRDE_NOSPACE);
+ error = WRDE_NOSPACE;
+ goto cleanup;
}
we->we_wordv = nwv;
if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) {
- _close(pdes[0]);
- _waitpid(pid, &status, 0);
- return (WRDE_NOSPACE);
+ error = WRDE_NOSPACE;
+ goto cleanup;
}
for (i = 0; i < vofs; i++)
if (we->we_wordv[i] != NULL)
we->we_wordv[i] += nstrings - we->we_strings;
we->we_strings = nstrings;
- if (_read(pdes[0], we->we_strings + sofs, nbytes) != nbytes) {
- _close(pdes[0]);
- _waitpid(pid, &status, 0);
- return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
+ if (we_read_fully(pdes[0], we->we_strings + sofs, nbytes) != nbytes) {
+ error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX;
+ serrno = errno;
+ goto cleanup;
}
- if (_waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) ||
- WEXITSTATUS(status) != 0) {
- _close(pdes[0]);
- return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
- }
+ error = 0;
+cleanup:
_close(pdes[0]);
+ do
+ wpid = _waitpid(pid, &status, 0);
+ while (wpid < 0 && errno == EINTR);
+ (void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
+ if (error != 0) {
+ errno = serrno;
+ return (error);
+ }
+ if (wpid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0)
+ return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
/*
* Break the null-terminated expanded word strings out into
Modified: head/tools/regression/lib/libc/gen/test-wordexp.c
==============================================================================
--- head/tools/regression/lib/libc/gen/test-wordexp.c Fri Oct 23 14:43:17
2009 (r198405)
+++ head/tools/regression/lib/libc/gen/test-wordexp.c Fri Oct 23 14:50:11
2009 (r198406)
@@ -32,17 +32,36 @@
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
+#include <sys/wait.h>
+
#include <assert.h>
+#include <errno.h>
+#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <wordexp.h>
+static void
+chld_handler(int x)
+{
+ int status, serrno;
+
+ (void)x;
+ serrno = errno;
+ while (waitpid(-1, &status, WNOHANG) > 0)
+ ;
+ errno = serrno;
+}
+
int
main(int argc, char *argv[])
{
+ struct sigaction sa;
wordexp_t we;
int r;
+ int i;
+ char longdata[6 * 10000 + 1];
/* Test that the macros are there. */
(void)(WRDE_APPEND + WRDE_DOOFFS + WRDE_NOCMD + WRDE_REUSE +
@@ -59,6 +78,15 @@ main(int argc, char *argv[])
assert(we.we_wordv[2] == NULL);
wordfree(&we);
+ /* Long output. */
+ for (i = 0; i < 10000; i++)
+ snprintf(longdata + 6 * i, 7, "%05d ", i);
+ r = wordexp(longdata, &we, 0);
+ assert(r == 0);
+ assert(we.we_wordc == 10000);
+ assert(we.we_wordv[10000] == NULL);
+ wordfree(&we);
+
/* WRDE_DOOFFS */
we.we_offs = 3;
r = wordexp("hello world", &we, WRDE_DOOFFS);
@@ -167,6 +195,20 @@ main(int argc, char *argv[])
r = wordexp("test } test", &we, 0);
assert(r == WRDE_BADCHAR);
+ /* With a SIGCHLD handler that reaps all zombies. */
+ sa.sa_flags = 0;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_handler = chld_handler;
+ r = sigaction(SIGCHLD, &sa, NULL);
+ assert(r == 0);
+ r = wordexp("hello world", &we, 0);
+ assert(r == 0);
+ assert(we.we_wordc == 2);
+ assert(strcmp(we.we_wordv[0], "hello") == 0);
+ assert(strcmp(we.we_wordv[1], "world") == 0);
+ assert(we.we_wordv[2] == NULL);
+ wordfree(&we);
+
printf("PASS wordexp()\n");
printf("PASS wordfree()\n");
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