Use faccessat, not access, when checking file permissions.

* .bzrignore: Add lib/fcntl.h.
* configure.ac (euidaccess): Remove check; gnulib does this for us now.
(gl_FCNTL_O_FLAGS): Define a dummy version.
* lib/at-func.c, lib/euidaccess.c, lib/faccessat.c, lib/fcntl.in.h:
* lib/getgroups.c, lib/group-member.c, lib/root-uid.h:
* lib/xalloc-oversized.h, m4/euidaccess.m4, m4/faccessat.m4:
* m4/fcntl_h.m4, m4/getgroups.m4, m4/group-member.m4:
New files, from gnulib.
* lib/gnulib.mk, m4/gnulib-comp.m4: Regenerate.
* admin/merge-gnulib (GNULIB_MODULES): Add faccessat.
(GNULIB_TOOL_FLAGS): Avoid at-internal, fchdir, malloc-posix,
openat-die, openat-h, save-cwd.  Do not avoid fcntl-h.
Omit gnulib's m4/fcntl-o.m4.
* nt/inc/ms-w32.h (AT_FDCWD, AT_EACCESS): New symbols.
(access): Remove.
(faccessat): New macro.
* src/Makefile.in (LIB_EACCESS): New macro.
(LIBES): Use it.
* src/callproc.c (init_callproc):
* src/charset.c (init_charset):
* src/fileio.c (check_existing, check_executable):
* src/lread.c (openp, load_path_check):
* src/process.c (allocate_pty):
* src/xrdb.c (file_p):
Use faccessat, not access or euidaccess.  Use symbolic names
instead of integers for the flags, as they're portable now.
* src/charset.c, src/xrdb.c: Include <fcntl.h>, for the new flags used.
* src/fileio.c (Ffile_readable_p):
Use faccessat, not stat + open + close.
(file_directory_p): New function, which uses 'stat' on most places
but 'access' (for efficiency) if WINDOWSNT.
* src/fileio.c (Ffile_directory_p, Fset_file_times):
* src/xrdb.c (file_p): Use file_directory_p.
* src/lisp.h (file_directory_p): New decl.
* src/lread.c (openp): When opening a file, use fstat rather than
stat, as that avoids a permissions race.  When not opening a file,
use file_directory_p rather than stat.
* src/process.c, src/sysdep.c, src/term.c: All uses of '#ifdef O_NONBLOCK'
changed to '#if O_NONBLOCK', to accommodate gnulib O_* tyle.
* src/w32.c (sys_faccessat): Rename from sys_access and switch to
faccessat's API.  All uses changed.

Fixes: debbugs:12632

1 files changed, 18 insertions, 18 deletions

diff --git a/src/process.c b/src/process.c
index 307e82819d6..572ab83de09 100644
--- a/src/process.c
+++ b/src/process.c
@@ -204,7 +204,7 @@ static EMACS_INT update_tick;
 #ifndef NON_BLOCKING_CONNECT
 #ifdef HAVE_SELECT
 #if defined (HAVE_GETPEERNAME) || defined (GNU_LINUX)
-#if defined (O_NONBLOCK) || defined (O_NDELAY)
+#if O_NONBLOCK || O_NDELAY
 #if defined (EWOULDBLOCK) || defined (EINPROGRESS)
 #define NON_BLOCKING_CONNECT
 #endif /* EWOULDBLOCK || EINPROGRESS */
@@ -651,7 +651,7 @@ allocate_pty (void)
         PTY_OPEN;
 #else /* no PTY_OPEN */
         {
-#  ifdef O_NONBLOCK
+#  if O_NONBLOCK
           fd = emacs_open (pty_name, O_RDWR | O_NONBLOCK, 0);
 #  else
           fd = emacs_open (pty_name, O_RDWR | O_NDELAY, 0);
@@ -668,7 +668,7 @@ allocate_pty (void)
 #else
             sprintf (pty_name, "/dev/tty%c%x", c, i);
 #endif /* no PTY_TTY_NAME_SPRINTF */
-            if (access (pty_name, 6) != 0)
+            if (faccessat (AT_FDCWD, pty_name, R_OK | W_OK, AT_EACCESS) != 0)
               {
                 emacs_close (fd);
 # ifndef __sgi
@@ -1621,7 +1621,7 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
 #if ! defined (USG) || defined (USG_SUBTTY_WORKS)
       /* On most USG systems it does not work to open the pty's tty here,
          then close it and reopen it in the child.  */
-#ifdef O_NOCTTY
+#if O_NOCTTY
       /* Don't let this terminal become our controlling terminal
          (in case we don't have one).  */
       forkout = forkin = emacs_open (pty_name, O_RDWR | O_NOCTTY, 0);
@@ -1675,11 +1675,11 @@ create_process (Lisp_Object process, char **new_argv, Lisp_Object current_dir)
     }
 #endif
 
-#ifdef O_NONBLOCK
+#if O_NONBLOCK
   fcntl (inchannel, F_SETFL, O_NONBLOCK);
   fcntl (outchannel, F_SETFL, O_NONBLOCK);
 #else
-#ifdef O_NDELAY
+#if O_NDELAY
   fcntl (inchannel, F_SETFL, O_NDELAY);
   fcntl (outchannel, F_SETFL, O_NDELAY);
 #endif
@@ -1967,7 +1967,7 @@ create_pty (Lisp_Object process)
 #if ! defined (USG) || defined (USG_SUBTTY_WORKS)
       /* On most USG systems it does not work to open the pty's tty here,
          then close it and reopen it in the child.  */
-#ifdef O_NOCTTY
+#if O_NOCTTY
       /* Don't let this terminal become our controlling terminal
          (in case we don't have one).  */
       int forkout = emacs_open (pty_name, O_RDWR | O_NOCTTY, 0);
@@ -1987,11 +1987,11 @@ create_pty (Lisp_Object process)
     }
 #endif /* HAVE_PTYS */
 
-#ifdef O_NONBLOCK
+#if O_NONBLOCK
   fcntl (inchannel, F_SETFL, O_NONBLOCK);
   fcntl (outchannel, F_SETFL, O_NONBLOCK);
 #else
-#ifdef O_NDELAY
+#if O_NDELAY
   fcntl (inchannel, F_SETFL, O_NDELAY);
   fcntl (outchannel, F_SETFL, O_NDELAY);
 #endif
@@ -2951,7 +2951,7 @@ usage: (make-network-process &rest ARGS)  */)
     {
       /* Don't support network sockets when non-blocking mode is
          not available, since a blocked Emacs is not useful.  */
-#if !defined (O_NONBLOCK) && !defined (O_NDELAY)
+#if !O_NONBLOCK && !O_NDELAY
       error ("Network servers not supported");
 #else
       is_server = 1;
@@ -3217,7 +3217,7 @@ usage: (make-network-process &rest ARGS)  */)
 #ifdef NON_BLOCKING_CONNECT
       if (is_non_blocking_client)
         {
-#ifdef O_NONBLOCK
+#if O_NONBLOCK
           ret = fcntl (s, F_SETFL, O_NONBLOCK);
 #else
           ret = fcntl (s, F_SETFL, O_NDELAY);
@@ -3434,10 +3434,10 @@ usage: (make-network-process &rest ARGS)  */)
 
   chan_process[inch] = proc;
 
-#ifdef O_NONBLOCK
+#if O_NONBLOCK
   fcntl (inch, F_SETFL, O_NONBLOCK);
 #else
-#ifdef O_NDELAY
+#if O_NDELAY
   fcntl (inch, F_SETFL, O_NDELAY);
 #endif
 #endif
@@ -4169,10 +4169,10 @@ server_accept_connection (Lisp_Object server, int channel)
 
   chan_process[s] = proc;
 
-#ifdef O_NONBLOCK
+#if O_NONBLOCK
   fcntl (s, F_SETFL, O_NONBLOCK);
 #else
-#ifdef O_NDELAY
+#if O_NDELAY
   fcntl (s, F_SETFL, O_NDELAY);
 #endif
 #endif
@@ -4873,11 +4873,11 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd,
 #endif
               /* ISC 4.1 defines both EWOULDBLOCK and O_NONBLOCK,
                  and Emacs uses O_NONBLOCK, so what we get is EAGAIN.  */
-#ifdef O_NONBLOCK
+#if O_NONBLOCK
               else if (nread == -1 && errno == EAGAIN)
                 ;
 #else
-#ifdef O_NDELAY
+#if O_NDELAY
               else if (nread == -1 && errno == EAGAIN)
                 ;
               /* Note that we cannot distinguish between no input
@@ -7363,7 +7363,7 @@ init_process_emacs (void)
 #ifdef HAVE_GETSOCKNAME
    ADD_SUBFEATURE (QCservice, Qt);
 #endif
-#if defined (O_NONBLOCK) || defined (O_NDELAY)
+#if O_NONBLOCK || O_NDELAY
    ADD_SUBFEATURE (QCserver, Qt);
 #endif