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
This commit is contained in:
Jilles Tjoelker
parent
e2ee8728ee
commit
364e9ccb9c
@ -28,8 +28,10 @@
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <paths.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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@ -73,6 +75,24 @@ wordexp(const char * __restrict words, wordexp_t * __restrict we, int flags)
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return (0);
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}
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static size_t
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we_read_fully(int fd, char *buffer, size_t len)
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{
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size_t done;
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ssize_t nread;
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done = 0;
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do {
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nread = _read(fd, buffer + done, len - done);
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if (nread == -1 && errno == EINTR)
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continue;
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if (nread <= 0)
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break;
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done += nread;
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} while (done != len);
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return done;
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}
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/*
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* we_askshell --
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* Use the `wordexp' /bin/sh builtin function to do most of the work
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@ -90,20 +110,31 @@ we_askshell(const char *words, wordexp_t *we, int flags)
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size_t sofs; /* Offset into we->we_strings */
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size_t vofs; /* Offset into we->we_wordv */
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pid_t pid; /* Process ID of child */
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pid_t wpid; /* waitpid return value */
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int status; /* Child exit status */
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int error; /* Our return value */
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int serrno; /* errno to return */
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char *ifs; /* IFS env. var. */
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char *np, *p; /* Handy pointers */
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char *nstrings; /* Temporary for realloc() */
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char **nwv; /* Temporary for realloc() */
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sigset_t newsigblock, oldsigblock;
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serrno = errno;
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if ((ifs = getenv("IFS")) == NULL)
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ifs = " \t\n";
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if (pipe(pdes) < 0)
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return (WRDE_NOSPACE); /* XXX */
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(void)sigemptyset(&newsigblock);
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(void)sigaddset(&newsigblock, SIGCHLD);
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(void)_sigprocmask(SIG_BLOCK, &newsigblock, &oldsigblock);
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if ((pid = fork()) < 0) {
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serrno = errno;
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_close(pdes[0]);
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_close(pdes[1]);
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(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
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errno = serrno;
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return (WRDE_NOSPACE); /* XXX */
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}
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else if (pid == 0) {
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@ -114,6 +145,7 @@ we_askshell(const char *words, wordexp_t *we, int flags)
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int devnull;
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char *cmd;
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(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
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_close(pdes[0]);
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if (_dup2(pdes[1], STDOUT_FILENO) < 0)
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_exit(1);
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@ -139,10 +171,11 @@ we_askshell(const char *words, wordexp_t *we, int flags)
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* the expanded words separated by nulls.
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*/
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_close(pdes[1]);
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if (_read(pdes[0], wbuf, 8) != 8 || _read(pdes[0], bbuf, 8) != 8) {
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_close(pdes[0]);
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_waitpid(pid, &status, 0);
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return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
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if (we_read_fully(pdes[0], wbuf, 8) != 8 ||
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we_read_fully(pdes[0], bbuf, 8) != 8) {
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error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX;
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serrno = errno;
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goto cleanup;
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}
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wbuf[8] = bbuf[8] = '\0';
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nwords = strtol(wbuf, NULL, 16);
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@ -162,33 +195,38 @@ we_askshell(const char *words, wordexp_t *we, int flags)
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if ((nwv = realloc(we->we_wordv, (we->we_wordc + 1 +
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(flags & WRDE_DOOFFS ? we->we_offs : 0)) *
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sizeof(char *))) == NULL) {
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_close(pdes[0]);
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_waitpid(pid, &status, 0);
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return (WRDE_NOSPACE);
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error = WRDE_NOSPACE;
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goto cleanup;
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}
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we->we_wordv = nwv;
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if ((nstrings = realloc(we->we_strings, we->we_nbytes)) == NULL) {
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_close(pdes[0]);
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_waitpid(pid, &status, 0);
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return (WRDE_NOSPACE);
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error = WRDE_NOSPACE;
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goto cleanup;
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}
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for (i = 0; i < vofs; i++)
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if (we->we_wordv[i] != NULL)
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we->we_wordv[i] += nstrings - we->we_strings;
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we->we_strings = nstrings;
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if (_read(pdes[0], we->we_strings + sofs, nbytes) != nbytes) {
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_close(pdes[0]);
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_waitpid(pid, &status, 0);
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return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
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if (we_read_fully(pdes[0], we->we_strings + sofs, nbytes) != nbytes) {
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error = flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX;
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serrno = errno;
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goto cleanup;
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}
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if (_waitpid(pid, &status, 0) < 0 || !WIFEXITED(status) ||
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WEXITSTATUS(status) != 0) {
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_close(pdes[0]);
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return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
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}
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error = 0;
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cleanup:
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_close(pdes[0]);
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do
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wpid = _waitpid(pid, &status, 0);
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while (wpid < 0 && errno == EINTR);
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(void)_sigprocmask(SIG_SETMASK, &oldsigblock, NULL);
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if (error != 0) {
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errno = serrno;
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return (error);
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}
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if (wpid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0)
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return (flags & WRDE_UNDEF ? WRDE_BADVAL : WRDE_SYNTAX);
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/*
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* Break the null-terminated expanded word strings out into
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@ -32,17 +32,36 @@
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/wait.h>
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#include <assert.h>
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#include <errno.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <wordexp.h>
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static void
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chld_handler(int x)
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{
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int status, serrno;
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(void)x;
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serrno = errno;
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while (waitpid(-1, &status, WNOHANG) > 0)
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;
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errno = serrno;
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}
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int
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main(int argc, char *argv[])
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{
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struct sigaction sa;
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wordexp_t we;
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int r;
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int i;
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char longdata[6 * 10000 + 1];
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/* Test that the macros are there. */
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(void)(WRDE_APPEND + WRDE_DOOFFS + WRDE_NOCMD + WRDE_REUSE +
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@ -59,6 +78,15 @@ main(int argc, char *argv[])
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assert(we.we_wordv[2] == NULL);
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wordfree(&we);
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/* Long output. */
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for (i = 0; i < 10000; i++)
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snprintf(longdata + 6 * i, 7, "%05d ", i);
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r = wordexp(longdata, &we, 0);
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assert(r == 0);
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assert(we.we_wordc == 10000);
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assert(we.we_wordv[10000] == NULL);
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wordfree(&we);
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/* WRDE_DOOFFS */
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we.we_offs = 3;
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r = wordexp("hello world", &we, WRDE_DOOFFS);
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@ -167,6 +195,20 @@ main(int argc, char *argv[])
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r = wordexp("test } test", &we, 0);
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assert(r == WRDE_BADCHAR);
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/* With a SIGCHLD handler that reaps all zombies. */
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sa.sa_flags = 0;
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sigemptyset(&sa.sa_mask);
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sa.sa_handler = chld_handler;
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r = sigaction(SIGCHLD, &sa, NULL);
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assert(r == 0);
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r = wordexp("hello world", &we, 0);
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assert(r == 0);
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assert(we.we_wordc == 2);
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assert(strcmp(we.we_wordv[0], "hello") == 0);
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assert(strcmp(we.we_wordv[1], "world") == 0);
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assert(we.we_wordv[2] == NULL);
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wordfree(&we);
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printf("PASS wordexp()\n");
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printf("PASS wordfree()\n");
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