Date: Mon, 24 Mar 2003 18:54:47 +0000
From: "Richard Dawe" <rich AT phekda DOT freeserve DOT co DOT uk>
Sender: rich AT phekda DOT freeserve DOT co DOT uk
To: djgpp-workers AT delorie DOT com
X-Mailer: Emacs 21.3.50 (via feedmail 8.3.emacs20_6 I) and Blat ver 1.8.6
Subject: open(), symlinks and O_CREAT|O_EXCL
Message-Id: <E18xX2Q-00017i-00@phekda.freeserve.co.uk>
Reply-To: djgpp-workers AT delorie DOT com

Hello.

I think that open() on symlinks does not honour O_CREAT|O_EXCL
in the way required by POSIX:

"If O_EXCL and O_CREAT are set, and path names a symbolic link,
open( ) shall fail and set errno to [EEXIST], regardless of the contents
of the symbolic link."

(This is taken from the pages for open() in draft 7 of new POSIX.)

Example: Create a symlink 'test3' pointing to 'doesnotexist', which
does not exist. Now open() 'test3'. I think this open call should fail
with errno == EEXIST, as described above.

Below is a diff to add this test case.

Is my interpretation correct?

Bye, Rich =]

Index: tests/libc/posix/fcntl/open.c
===================================================================
RCS file: /cvs/djgpp/djgpp/tests/libc/posix/fcntl/open.c,v
retrieving revision 1.4
diff -p -u -3 -r1.4 open.c
--- tests/libc/posix/fcntl/open.c	11 Mar 2001 05:22:18 -0000	1.4
+++ tests/libc/posix/fcntl/open.c	24 Mar 2003 18:45:25 -0000
@@ -45,28 +45,58 @@ static int testnum;
 int main(void)
 {
    int fd;
+
    if (!__file_exists("file1") || !__file_exists("test1") || 
        !__file_exists("test2") || !__file_exists("dir/file1"))
    {
       fprintf(stderr, "Required data file is missing\n");
       exit(1);
    }
+
+   if (__file_exists("doesnotexist"))
+   {
+      fprintf(stderr,
+	      "File 'doesnotexist' is in the way - "
+	      "please remove it!\n");
+      exit(1);
+   }
+
    test_success("test1", O_RDONLY, "file1");
    test_success("test1", O_RDONLY | O_NOLINK, "!<symlink>");
    test_success("test2/file1", O_RDONLY | O_NOFOLLOW, "file1");
+
    ++testnum;
    fd = open("test2/test1", O_RDONLY | O_NOFOLLOW);
    if (fd != -1)
    {
-      fprintf(stderr, "Test 4 failed - unexpected open() success.\n");
+      fprintf(stderr, "Test %d failed - unexpected open() success.\n",
+	      testnum);
       exit(1);
    }
    if (errno != ELOOP)
    { 
-      perror("Test 4 failed - wrong errno returned ");
+      fprintf(stderr, "Test %d failed - wrong errno returned: %s\n",
+	      testnum, strerror(errno));
+      exit(1);
+   }
+   printf("Test %d passed\n", testnum);
+
+   ++testnum;
+   fd = open("test3", O_RDONLY | O_CREAT | O_EXCL);
+   if (fd != -1)
+   {
+      fprintf(stderr, "Test %d failed - unexpected open() success.\n",
+	      testnum);
+      exit(1);
+   }
+   if (errno != EEXIST)
+   { 
+      fprintf(stderr, "Test %d failed - wrong errno returned: %s\n",
+	      testnum, strerror(errno));
       exit(1);
    }
-   printf("Test 4 passed\n");
+   printf("Test %d passed\n", testnum);
+
    test_success("test2/test1", O_RDONLY | O_NOLINK, "!<symlink>");
    test_success("dir/test2", O_RDONLY, "tstlink2");
    test_o_temporary();
--- /dev/null	2003-03-24 18:49:41.000000000 +0000
+++ tests/libc/posix/fcntl/test3	2003-03-24 17:25:02.000000000 +0000
@@ -0,0 +1,2 @@
+!<symlink>doesnotexist
+This is just a text to force symlink file to be 510 bytes long. Do not delete it nor spaces following it.                                                                                                                                                                                                                                                                                                                                                                                              
\ No newline at end of file