libc/fts: Use O_CLOEXEC for internal file descriptors

Because fts keeps internal file descriptors open across calls, making such
descriptors close-on-exec helps not only multi-threaded applications but
also single-threaded applications.

In particular, this prevents passing a temporary file descriptor for saving
the current directory to processes created via find -exec.

Taken-from: FreeBSD SVN 241010 (27 SEP 2012)

diff --git a/lib/libc/gen/fts.c b/lib/libc/gen/fts.c
index 3af5487..5f453a5 100644 (file)
--- a/lib/libc/gen/fts.c
+++ b/lib/libc/gen/fts.c
@@ -196,7 +196,8 @@ fts_open(char * const *argv, int options,
         * and ".." are all fairly nasty problems.  Note, if we can't get the
         * descriptor we run anyway, just more slowly.
         */
-       if (!ISSET(FTS_NOCHDIR) && (sp->fts_rfd = _open(".", O_RDONLY, 0)) < 0)
+       if (!ISSET(FTS_NOCHDIR) &&
+           (sp->fts_rfd = _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
                SET(FTS_NOCHDIR);
 
        return (sp);
@@ -321,7 +322,8 @@ fts_read(FTS *sp)
            (p->fts_info == FTS_SL || p->fts_info == FTS_SLNONE)) {
                p->fts_info = fts_stat(sp, p, 1);
                if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
-                       if ((p->fts_symfd = _open(".", O_RDONLY, 0)) < 0) {
+                       if ((p->fts_symfd = _open(".", O_RDONLY | O_CLOEXEC,
+                           0)) < 0) {
                                p->fts_errno = errno;
                                p->fts_info = FTS_ERR;
                        } else
@@ -411,8 +413,8 @@ next:       tmp = p;
                if (p->fts_instr == FTS_FOLLOW) {
                        p->fts_info = fts_stat(sp, p, 1);
                        if (p->fts_info == FTS_D && !ISSET(FTS_NOCHDIR)) {
-                               if ((p->fts_symfd =
-                                   _open(".", O_RDONLY, 0)) < 0) {
+                               if ((p->fts_symfd = _open(".", O_RDONLY | O_CLOEXEC,
+                                   0)) < 0) {
                                        p->fts_errno = errno;
                                        p->fts_info = FTS_ERR;
                                } else
@@ -548,7 +550,7 @@ fts_children(FTS *sp, int instr)
            ISSET(FTS_NOCHDIR))
                return (sp->fts_child = fts_build(sp, instr));
 
-       if ((fd = _open(".", O_RDONLY, 0)) < 0)
+       if ((fd = _open(".", O_RDONLY | O_CLOEXEC, 0)) < 0)
                return (NULL);
        sp->fts_child = fts_build(sp, instr);
        if (fchdir(fd)) {
@@ -1098,7 +1100,7 @@ fts_safe_changedir(FTS *sp, FTSENT *p, int fd, const char *path)
        newfd = fd;
        if (ISSET(FTS_NOCHDIR))
                return (0);
-       if (fd < 0 && (newfd = _open(path, O_RDONLY, 0)) < 0)
+       if (fd < 0 && (newfd = _open(path, O_RDONLY | O_CLOEXEC, 0)) < 0)
                return (-1);
        if (_fstat(newfd, &sb)) {
                ret = -1;