open: detect FreeBSD bug

open("link-to-file/", O_RDONLY) mistakenly succeeds.  The previous
patch was enough to fix utimens when no fd is involved, but this is
necessary for futimens to pass.

* m4/open.m4 (gl_FUNC_OPEN): Also detect FreeBSD bug with slash on
symlink.
* doc/posix-functions/open.texi (open): Document the bug.
* doc/posix-functions/utimes.texi (utimes): Likewise.
* tests/test-open.h (test_open): Add parameters, and test symlink
handling.
* tests/test-open.c (main): Adjust caller.
* tests/test-fcntl-safer.c (main): Likewise.
* modules/open-tests (Depends-on): Add stdbool, symlink.
* modules/fcntl-safer-tests (Depends-on): Likewise.
* tests/test-openat.c (main): Add test-open tests.

Signed-off-by: Eric Blake <ebb9@byu.net>

4 files changed, 111 insertions, 39 deletions

diff --git a/tests/test-fcntl-safer.c b/tests/test-fcntl-safer.c
index 33c7c2cd8a..15f6e2ca6c 100644
--- a/tests/test-fcntl-safer.c
+++ b/tests/test-fcntl-safer.c
@@ -20,6 +20,24 @@
 
 #include "fcntl--.h"
 
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+  do                                                                         \
+    {                                                                        \
+      if (!(expr))                                                           \
+        {                                                                    \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+          fflush (stderr);                                                   \
+          abort ();                                                          \
+        }                                                                    \
+    }                                                                        \
+  while (0)
+
 #define BASE "test-fcntl-safer.t"
 
 #include "test-open.h"
@@ -27,5 +45,5 @@
 int
 main (void)
 {
-  return test_open ();
+  return test_open (open, true);
 }
diff --git a/tests/test-open.c b/tests/test-open.c
index 738934e124..37109a58a1 100644
--- a/tests/test-open.c
+++ b/tests/test-open.c
@@ -20,6 +20,24 @@
 
 #include <fcntl.h>
 
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#define ASSERT(expr) \
+  do                                                                         \
+    {                                                                        \
+      if (!(expr))                                                           \
+        {                                                                    \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+          fflush (stderr);                                                   \
+          abort ();                                                          \
+        }                                                                    \
+    }                                                                        \
+  while (0)
+
 #define BASE "test-open.t"
 
 #include "test-open.h"
@@ -27,5 +45,5 @@
 int
 main (void)
 {
-  return test_open ();
+  return test_open (open, true);
 }
diff --git a/tests/test-open.h b/tests/test-open.h
index 4dba767087..9b43945825 100644
--- a/tests/test-open.h
+++ b/tests/test-open.h
@@ -16,29 +16,14 @@
 
 /* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
 
-/* Include <config.h> and a form of <fcntl.h> first.  */
-
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#define ASSERT(expr) \
-  do									     \
-    {									     \
-      if (!(expr))							     \
-        {								     \
-          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
-          fflush (stderr);						     \
-          abort ();							     \
-        }								     \
-    }									     \
-  while (0)
-
-/* Test fopen.  Assumes BASE is defined.  */
+/* This file is designed to test both open(n,buf[,mode]) and
+   openat(AT_FDCWD,n,buf[,mode]).  FUNC is the function to test.
+   Assumes that BASE and ASSERT are already defined, and that
+   appropriate headers are already included.  If PRINT, warn before
+   skipping symlink tests with status 77.  */
 
 static int
-test_open (void)
+test_open (int (*func) (char const *, int, ...), bool print)
 {
   int fd;
   /* Remove anything from prior partial run.  */
@@ -46,40 +31,57 @@ test_open (void)
 
   /* Cannot create directory.  */
   errno = 0;
-  ASSERT (open ("nonexist.ent/", O_CREAT | O_RDONLY, 0600) == -1);
+  ASSERT (func ("nonexist.ent/", O_CREAT | O_RDONLY, 0600) == -1);
   ASSERT (errno == ENOTDIR || errno == EISDIR || errno == ENOENT
           || errno == EINVAL);
 
   /* Create a regular file.  */
-  fd = open (BASE "file", O_CREAT | O_RDONLY, 0600);
+  fd = func (BASE "file", O_CREAT | O_RDONLY, 0600);
   ASSERT (0 <= fd);
   ASSERT (close (fd) == 0);
 
   /* Trailing slash handling.  */
   errno = 0;
-  ASSERT (open (BASE "file/", O_RDONLY) == -1);
+  ASSERT (func (BASE "file/", O_RDONLY) == -1);
   ASSERT (errno == ENOTDIR || errno == EISDIR || errno == EINVAL);
 
   /* Directories cannot be opened for writing.  */
   errno = 0;
-  ASSERT (open (".", O_WRONLY) == -1);
+  ASSERT (func (".", O_WRONLY) == -1);
   ASSERT (errno == EISDIR || errno == EACCES);
 
   /* /dev/null must exist, and be writable.  */
-  fd = open ("/dev/null", O_RDONLY);
+  fd = func ("/dev/null", O_RDONLY);
   ASSERT (0 <= fd);
   {
     char c;
     ASSERT (read (fd, &c, 1) == 0);
   }
   ASSERT (close (fd) == 0);
-  fd = open ("/dev/null", O_WRONLY);
+  fd = func ("/dev/null", O_WRONLY);
   ASSERT (0 <= fd);
   ASSERT (write (fd, "c", 1) == 1);
   ASSERT (close (fd) == 0);
 
+  /* Symlink handling, where supported.  */
+  if (symlink (BASE "file", BASE "link") != 0)
+    {
+      ASSERT (unlink (BASE "file") == 0);
+      if (print)
+        fputs ("skipping test: symlinks not supported on this file system\n",
+               stderr);
+      return 77;
+    }
+  errno = 0;
+  ASSERT (func (BASE "link/", O_RDONLY) == -1);
+  ASSERT (errno == ENOTDIR);
+  fd = func (BASE "link", O_RDONLY);
+  ASSERT (0 <= fd);
+  ASSERT (close (fd) == 0);
+
   /* Cleanup.  */
   ASSERT (unlink (BASE "file") == 0);
+  ASSERT (unlink (BASE "link") == 0);
 
   return 0;
 }
diff --git a/tests/test-openat.c b/tests/test-openat.c
index 6e5c5199cb..77185cc45a 100644
--- a/tests/test-openat.c
+++ b/tests/test-openat.c
@@ -20,6 +20,9 @@
 
 #include <fcntl.h>
 
+#include <errno.h>
+#include <stdarg.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
@@ -28,20 +31,51 @@
   do                                                                         \
     {                                                                        \
       if (!(expr))                                                           \
-	{                                                                    \
-	  fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
-	  fflush (stderr);                                                   \
-	  abort ();                                                          \
-	}                                                                    \
+        {                                                                    \
+          fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
+          fflush (stderr);                                                   \
+          abort ();                                                          \
+        }                                                                    \
     }                                                                        \
   while (0)
 
+#define BASE "test-openat.t"
+
+#include "test-open.h"
+
+static int dfd = AT_FDCWD;
+
+/* Wrapper around openat to test open behavior.  */
+static int
+do_open (char const *name, int flags, ...)
+{
+  if (flags & O_CREAT)
+    {
+      mode_t mode = 0;
+      va_list arg;
+      va_start (arg, flags);
+
+      /* We have to use PROMOTED_MODE_T instead of mode_t, otherwise GCC 4
+         creates crashing code when 'mode_t' is smaller than 'int'.  */
+      mode = va_arg (arg, PROMOTED_MODE_T);
+
+      va_end (arg);
+      return openat (dfd, name, flags, mode);
+    }
+  return openat (dfd, name, flags);
+}
+
 int
 main (void)
 {
-  /* FIXME - add more tests.  For example, share /dev/null and
-     trailing slash tests with test-open, and do more checks for
-     proper fd handling.  */
+  int result;
+
+  /* Basic checks.  */
+  result = test_open (do_open, false);
+  dfd = open (".", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (test_open (do_open, false) == result);
+  ASSERT (close (dfd) == 0);
 
   /* Check that even when *-safer modules are in use, plain openat can
      land in fd 0.  Do this test last, since it is destructive to
@@ -49,12 +83,12 @@ main (void)
   ASSERT (close (STDIN_FILENO) == 0);
   ASSERT (openat (AT_FDCWD, ".", O_RDONLY) == STDIN_FILENO);
   {
-    int dfd = open (".", O_RDONLY);
+    dfd = open (".", O_RDONLY);
     ASSERT (STDIN_FILENO < dfd);
     ASSERT (chdir ("..") == 0);
     ASSERT (close (STDIN_FILENO) == 0);
     ASSERT (openat (dfd, ".", O_RDONLY) == STDIN_FILENO);
     ASSERT (close (dfd) == 0);
   }
-  return 0;
+  return result;
 }