fts, getcwd, glob: audit for dirfd returning -1

* lib/fts.c (opendir): Remove #define; no longer used.
(opendirat): New arg PDIR_FD.  All callers changed.
(fts_build, _opendir2): Use new opendirat to avoid the need for
dirfd, or for checking whether dirfd returns a negative value.
Don't use opendir; always use openat followed by fdopendir.
* lib/getcwd.c (__getcwd): Don't reset fd; fdopendir no longer clobbers
it.
* lib/glob.c (link_exists_p): Add comment explaining why dirfd never
returns -1 here.
* modules/fts (Depends-on): Remove dirfd.
* modules/getcwd (Depends-on): Likewise.

6 files changed, 31 insertions, 17 deletions

diff --git a/ChangeLog b/ChangeLog
index 76fdacb1e5..a9cb9769d6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+2010-09-13  Paul Eggert  <eggert@cs.ucla.edu>
+
+	fts, getcwd, glob: audit for dirfd returning -1
+	* lib/fts.c (opendir): Remove #define; no longer used.
+	(opendirat): New arg PDIR_FD.  All callers changed.
+	(fts_build, _opendir2): Use new opendirat to avoid the need for
+	dirfd, or for checking whether dirfd returns a negative value.
+	Don't use opendir; always use openat followed by fdopendir.
+	* lib/getcwd.c (__getcwd): Don't reset fd; fdopendir no longer clobbers
+	it.
+	* lib/glob.c (link_exists_p): Add comment explaining why dirfd never
+	returns -1 here.
+	* modules/fts (Depends-on): Remove dirfd.
+	* modules/getcwd (Depends-on): Likewise.
+
 2010-09-13  Eric Blake  <eblake@redhat.com>
 
 	float: fix broken MirBSD header
diff --git a/lib/fts.c b/lib/fts.c
index 1daf69c305..2c1e0ecdc1 100644
--- a/lib/fts.c
+++ b/lib/fts.c
@@ -160,8 +160,6 @@ enum Fts_stat
 # define fchdir __fchdir
 # undef open
 # define open __open
-# undef opendir
-# define opendir __opendir
 # undef readdir
 # define readdir __readdir
 #else
@@ -290,7 +288,7 @@ fts_set_stat_required (FTSENT *p, bool required)
 /* FIXME: if others need this function, move it into lib/openat.c */
 static inline DIR *
 internal_function
-opendirat (int fd, char const *dir, int extra_flags)
+opendirat (int fd, char const *dir, int extra_flags, int *pdir_fd)
 {
   int new_fd = openat (fd, dir,
                        (O_RDONLY | O_DIRECTORY | O_NOCTTY | O_NONBLOCK
@@ -301,7 +299,9 @@ opendirat (int fd, char const *dir, int extra_flags)
     return NULL;
   set_cloexec_flag (new_fd, true);
   dirp = fdopendir (new_fd);
-  if (dirp == NULL)
+  if (dirp)
+    *pdir_fd = new_fd;
+  else
     {
       int saved_errno = errno;
       close (new_fd);
@@ -1222,6 +1222,7 @@ fts_build (register FTS *sp, int type)
         bool nostat;
         size_t len, maxlen, new_len;
         char *cp;
+        int dir_fd;
 
         /* Set current node pointer. */
         cur = sp->fts_cur;
@@ -1237,13 +1238,14 @@ fts_build (register FTS *sp, int type)
                 oflag = DTF_HIDEW|DTF_NODUP|DTF_REWIND;
 #else
 # define __opendir2(file, flag) \
-        ( ! ISSET(FTS_NOCHDIR) && ISSET(FTS_CWDFD) \
-          ? opendirat(sp->fts_cwd_fd, file,        \
-                      ((ISSET(FTS_PHYSICAL)                   \
-                        && ! (cur->fts_level == FTS_ROOTLEVEL \
-                              && ISSET(FTS_COMFOLLOW)))       \
-                       ? O_NOFOLLOW : 0))                     \
-          : opendir(file))
+        opendirat((! ISSET(FTS_NOCHDIR) && ISSET(FTS_CWDFD)     \
+                   ? sp->fts_cwd_fd : AT_FDCWD),                \
+                  file,                                         \
+                  ((ISSET(FTS_PHYSICAL)                         \
+                    && ! (ISSET(FTS_COMFOLLOW)                  \
+                          && cur->fts_level == FTS_ROOTLEVEL))  \
+                   ? O_NOFOLLOW : 0),                           \
+                  &dir_fd)
 #endif
        if ((dirp = __opendir2(cur->fts_accpath, oflag)) == NULL) {
                 if (type == BREAD) {
@@ -1306,8 +1308,7 @@ fts_build (register FTS *sp, int type)
          * checking FTS_NS on the returned nodes.
          */
         if (nlinks || type == BREAD) {
-                int dir_fd = dirfd(dirp);
-                if (ISSET(FTS_CWDFD) && 0 <= dir_fd)
+                if (ISSET(FTS_CWDFD))
                   {
                     dir_fd = dup (dir_fd);
                     if (0 <= dir_fd)
diff --git a/lib/getcwd.c b/lib/getcwd.c
index 7d47072101..26e47f7456 100644
--- a/lib/getcwd.c
+++ b/lib/getcwd.c
@@ -247,8 +247,6 @@ __getcwd (char *buf, size_t size)
       dirstream = fdopendir (fd);
       if (dirstream == NULL)
         goto lose;
-      /* Reset fd.  It may have been closed by fdopendir.  */
-      fd = dirfd (dirstream);
       fd_needs_closing = false;
 #else
       dirstream = __opendir (dotlist);
diff --git a/lib/glob.c b/lib/glob.c
index 03b55df28d..5be8c32117 100644
--- a/lib/glob.c
+++ b/lib/glob.c
@@ -1282,6 +1282,8 @@ link_exists_p (int dfd, const char *dir, size_t dirlen, const char *fname,
     return link_exists2_p (dir, dirlen, fname, pglob);
   else
     {
+      /* dfd cannot be -1 here, because dirfd never returns -1 on
+         glibc, or on hosts that have fstatat.  */
       struct_stat64 st64;
       return __fxstatat64 (_STAT_VER, dfd, fname, &st64, 0) == 0;
     }
diff --git a/modules/fts b/modules/fts
index ba8cd573a2..0414ea1080 100644
--- a/modules/fts
+++ b/modules/fts
@@ -13,7 +13,6 @@ cycle-check
 d-ino
 d-type
 dirent-safer
-dirfd
 fchdir
 fcntl-h
 fcntl-safer
diff --git a/modules/getcwd b/modules/getcwd
index c1544f5e5f..108f14b28a 100644
--- a/modules/getcwd
+++ b/modules/getcwd
@@ -10,7 +10,6 @@ m4/getcwd.m4
 Depends-on:
 mempcpy
 d-ino
-dirfd
 extensions
 memmove
 openat