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fix and refactor child reaping logic in wordexp

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loop condition was incorrect and confusing and caused an infinite loop
when (broken) applications reaped the pid from a signal handler or
another thread before wordexp's call to waitpid could do so.
This commit is contained in:
Rich Felker 2013-11-22 16:29:31 -05:00
commit aeea71dc04
1 changed files with 16 additions and 6 deletions
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22
src/misc/wordexp.c
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@ -11,6 +11,18 @@
#include <fcntl.h> #include <fcntl.h>
#include "pthread_impl.h" #include "pthread_impl.h"
static void reap(pid_t pid)
{
int status;
for (;;) {
if (waitpid(pid, &status, 0) < 0) {
if (errno != EINTR) return;
} else {
if (WIFEXITED(status)) return;
}
}
}
static char *getword(FILE *f) static char *getword(FILE *f)
{ {
char *s = 0; char *s = 0;
@ -24,7 +36,7 @@ static int do_wordexp(const char *s, wordexp_t *we, int flags)
size_t np=0; size_t np=0;
char *w, **tmp; char *w, **tmp;
char *redir = (flags & WRDE_SHOWERR) ? "" : "2>/dev/null"; char *redir = (flags & WRDE_SHOWERR) ? "" : "2>/dev/null";
int err = 0, status; int err = 0;
FILE *f; FILE *f;
size_t wc = 0; size_t wc = 0;
char **wv = 0; char **wv = 0;
@ -112,7 +124,7 @@ static int do_wordexp(const char *s, wordexp_t *we, int flags)
if (!f) { if (!f) {
close(p[0]); close(p[0]);
kill(pid, SIGKILL); kill(pid, SIGKILL);
waitpid(pid, &status, 0); reap(pid);
goto nospace; goto nospace;
} }
@ -121,8 +133,7 @@ static int do_wordexp(const char *s, wordexp_t *we, int flags)
free(getword(f)); free(getword(f));
if (feof(f)) { if (feof(f)) {
fclose(f); fclose(f);
while ((waitpid(pid, &status, 0) < 0 && errno == EINTR) reap(pid);
|| !WIFEXITED(status));
return WRDE_SYNTAX; return WRDE_SYNTAX;
} }
@ -139,8 +150,7 @@ static int do_wordexp(const char *s, wordexp_t *we, int flags)
if (!feof(f)) err = WRDE_NOSPACE; if (!feof(f)) err = WRDE_NOSPACE;
fclose(f); fclose(f);
while ((waitpid(pid, &status, 0) < 0 && errno == EINTR) reap(pid);
|| !WIFEXITED(status));
if (!wv) wv = calloc(i+1, sizeof *wv); if (!wv) wv = calloc(i+1, sizeof *wv);