1 files changed, 383 insertions, 0 deletions
diff --git a/gnulib-tests/test-linkat.c b/gnulib-tests/test-linkat.c
new file mode 100644
index 0000000..1b4eee4
--- /dev/null
+++ b/gnulib-tests/test-linkat.c
@@ -0,0 +1,383 @@
+/* Tests of linkat.
+   Copyright (C) 2009-2022 Free Software Foundation, Inc.
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Written by Eric Blake <ebb9@byu.net>, 2009.  */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include "signature.h"
+SIGNATURE_CHECK (linkat, int, (int, char const *, int, char const *, int));
+
+#include <fcntl.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include "areadlink.h"
+#include "filenamecat.h"
+#include "same-inode.h"
+#include "ignore-value.h"
+#include "macros.h"
+
+#define BASE "test-linkat.t"
+
+#include "test-link.h"
+
+static int dfd1 = AT_FDCWD;
+static int dfd2 = AT_FDCWD;
+static int flag = AT_SYMLINK_FOLLOW;
+
+/* Wrapper to test linkat like link.  */
+static int
+do_link (char const *name1, char const *name2)
+{
+  return linkat (dfd1, name1, dfd2, name2, flag);
+}
+
+/* Can we expect that link() and linkat(), when called on a symlink,
+   increment the link count of that symlink?  */
+#if LINK_FOLLOWS_SYMLINKS == 0
+# define EXPECT_LINK_HARDLINKS_SYMLINKS 1
+#elif LINK_FOLLOWS_SYMLINKS == -1
+extern int __xpg4;
+# define EXPECT_LINK_HARDLINKS_SYMLINKS (__xpg4 == 0)
+#else
+# define EXPECT_LINK_HARDLINKS_SYMLINKS 0
+#endif
+
+/* Wrapper to see if two symlinks act the same.  */
+static void
+check_same_link (char const *name1, char const *name2)
+{
+  struct stat st1;
+  struct stat st2;
+  char *contents1;
+  char *contents2;
+  ASSERT (lstat (name1, &st1) == 0);
+  ASSERT (lstat (name2, &st2) == 0);
+  contents1 = areadlink_with_size (name1, st1.st_size);
+  contents2 = areadlink_with_size (name2, st2.st_size);
+  ASSERT (contents1);
+  ASSERT (contents2);
+  ASSERT (strcmp (contents1, contents2) == 0);
+  if (EXPECT_LINK_HARDLINKS_SYMLINKS)
+    ASSERT (SAME_INODE (st1, st2));
+  free (contents1);
+  free (contents2);
+}
+
+int
+main (void)
+{
+  int i;
+  int dfd;
+  char *cwd;
+  int result;
+
+  /* Clean up any trash from prior testsuite runs.  */
+  ignore_value (system ("rm -rf " BASE "*"));
+
+  /* Test behaviour for invalid file descriptors.  */
+  {
+    errno = 0;
+    ASSERT (linkat (-1, "foo", AT_FDCWD, "bar", 0) == -1);
+    ASSERT (errno == EBADF);
+  }
+  {
+    close (99);
+    errno = 0;
+    ASSERT (linkat (99, "foo", AT_FDCWD, "bar", 0) == -1);
+    ASSERT (errno == EBADF);
+  }
+  ASSERT (close (creat (BASE "oo", 0600)) == 0);
+  {
+    errno = 0;
+    ASSERT (linkat (AT_FDCWD, BASE "oo", -1, "bar", 0) == -1);
+    ASSERT (errno == EBADF);
+  }
+  {
+    errno = 0;
+    ASSERT (linkat (AT_FDCWD, BASE "oo", 99, "bar", 0) == -1);
+    ASSERT (errno == EBADF);
+  }
+  ASSERT (unlink (BASE "oo") == 0);
+
+  /* Test basic link functionality, without mentioning symlinks.  */
+  result = test_link (do_link, true);
+  dfd1 = open (".", O_RDONLY);
+  ASSERT (0 <= dfd1);
+  ASSERT (test_link (do_link, false) == result);
+  dfd2 = dfd1;
+  ASSERT (test_link (do_link, false) == result);
+  dfd1 = AT_FDCWD;
+  ASSERT (test_link (do_link, false) == result);
+  flag = 0;
+  ASSERT (test_link (do_link, false) == result);
+  dfd1 = dfd2;
+  ASSERT (test_link (do_link, false) == result);
+  dfd2 = AT_FDCWD;
+  ASSERT (test_link (do_link, false) == result);
+  ASSERT (close (dfd1) == 0);
+  dfd1 = AT_FDCWD;
+  ASSERT (test_link (do_link, false) == result);
+
+  /* Create locations to manipulate.  */
+  ASSERT (mkdir (BASE "sub1", 0700) == 0);
+  ASSERT (mkdir (BASE "sub2", 0700) == 0);
+  ASSERT (close (creat (BASE "00", 0600)) == 0);
+  cwd = getcwd (NULL, 0);
+  ASSERT (cwd);
+
+  dfd = open (BASE "sub1", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (chdir (BASE "sub2") == 0);
+
+  /* There are 16 possible scenarios, based on whether an fd is
+     AT_FDCWD or real, whether a file is absolute or relative, coupled
+     with whether flag is set for 32 iterations.
+
+     To ensure that we test all of the code paths (rather than
+     triggering early normalization optimizations), we use a loop to
+     repeatedly rename a file in the parent directory, use an fd open
+     on subdirectory 1, all while executing in subdirectory 2; all
+     relative names are thus given with a leading "../".  Finally, the
+     last scenario (two relative paths given, neither one AT_FDCWD)
+     has two paths, based on whether the two fds are equivalent, so we
+     do the other variant after the loop.  */
+  for (i = 0; i < 32; i++)
+    {
+      int fd1 = (i & 8) ? dfd : AT_FDCWD;
+      char *file1 = mfile_name_concat ((i & 4) ? ".." : cwd, BASE "xx", NULL);
+      int fd2 = (i & 2) ? dfd : AT_FDCWD;
+      char *file2 = mfile_name_concat ((i & 1) ? ".." : cwd, BASE "xx", NULL);
+      ASSERT (file1);
+      ASSERT (file2);
+      flag = (i & 0x10 ? AT_SYMLINK_FOLLOW : 0);
+
+      ASSERT (sprintf (strchr (file1, '\0') - 2, "%02d", i) == 2);
+      ASSERT (sprintf (strchr (file2, '\0') - 2, "%02d", i + 1) == 2);
+      ASSERT (linkat (fd1, file1, fd2, file2, flag) == 0);
+      ASSERT (unlinkat (fd1, file1, 0) == 0);
+      free (file1);
+      free (file2);
+    }
+  dfd2 = open ("..", O_RDONLY);
+  ASSERT (0 <= dfd2);
+  ASSERT (linkat (dfd, "../" BASE "32", dfd2, BASE "33", 0) == 0);
+  ASSERT (linkat (dfd, "../" BASE "33", dfd2, BASE "34",
+                  AT_SYMLINK_FOLLOW) == 0);
+  ASSERT (close (dfd2) == 0);
+
+  /* Now we change back to the parent directory, and set dfd to ".",
+     in order to test behavior on symlinks.  */
+  ASSERT (chdir ("..") == 0);
+  ASSERT (close (dfd) == 0);
+  if (symlink (BASE "sub1", BASE "link1"))
+    {
+      ASSERT (unlink (BASE "32") == 0);
+      ASSERT (unlink (BASE "33") == 0);
+      ASSERT (unlink (BASE "34") == 0);
+      ASSERT (rmdir (BASE "sub1") == 0);
+      ASSERT (rmdir (BASE "sub2") == 0);
+      free (cwd);
+      if (!result)
+        fputs ("skipping test: symlinks not supported on this file system\n",
+               stderr);
+      return result;
+    }
+  dfd = open (".", O_RDONLY);
+  ASSERT (0 <= dfd);
+  ASSERT (symlink (BASE "34", BASE "link2") == 0);
+  ASSERT (symlink (BASE "link3", BASE "link3") == 0);
+  ASSERT (symlink (BASE "nowhere", BASE "link4") == 0);
+
+  /* Link cannot overwrite existing files.  */
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "sub1", 0) == -1);
+  ASSERT (errno == EEXIST);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1/", dfd, BASE "sub1", 0) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "sub1/", 0) == -1);
+  ASSERT (errno == EEXIST || errno == ENOTDIR);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "sub1",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1/", dfd, BASE "sub1",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES
+          || errno == EINVAL);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "sub1/",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES
+          || errno == EINVAL);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link2", 0) == -1);
+  ASSERT (errno == EEXIST);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link2",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link3", 0) == -1);
+  ASSERT (errno == EEXIST || errno == ELOOP);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link3",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES
+          || errno == ELOOP);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link2", dfd, BASE "link3", 0) == -1);
+  ASSERT (errno == EEXIST || errno == ELOOP);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link2", dfd, BASE "link3",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == ELOOP);
+
+  /* AT_SYMLINK_FOLLOW only follows first argument, not second.  */
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link4", 0) == -1);
+  ASSERT (errno == EEXIST);
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link4",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST || errno == EPERM || errno == EACCES);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "34", dfd, BASE "link4", 0) == -1);
+  ASSERT (errno == EEXIST);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "34", dfd, BASE "link4", AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EEXIST);
+
+  /* Trailing slash handling.  */
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link2/", dfd, BASE "link5", 0) == -1);
+  ASSERT (errno == ENOTDIR);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link2/", dfd, BASE "link5",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ENOTDIR || errno == EINVAL);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link3/", dfd, BASE "link5", 0) == -1);
+  ASSERT (errno == ELOOP);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link3/", dfd, BASE "link5",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ELOOP || errno == EINVAL);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link4/", dfd, BASE "link5", 0) == -1);
+  ASSERT (errno == ENOENT);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link4/", dfd, BASE "link5",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ENOENT || errno == EINVAL);
+
+  /* Check for hard links to symlinks.  */
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link5", 0) == 0);
+  check_same_link (BASE "link1", BASE "link5");
+  ASSERT (unlink (BASE "link5") == 0);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link1", dfd, BASE "link5",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == EPERM || errno == EACCES);
+  ASSERT (linkat (dfd, BASE "link2", dfd, BASE "link5", 0) == 0);
+  check_same_link (BASE "link2", BASE "link5");
+  ASSERT (unlink (BASE "link5") == 0);
+  ASSERT (linkat (dfd, BASE "link2", dfd, BASE "file", AT_SYMLINK_FOLLOW) == 0);
+  errno = 0;
+  ASSERT (areadlink (BASE "file") == NULL);
+  ASSERT (errno == EINVAL);
+  ASSERT (unlink (BASE "file") == 0);
+  ASSERT (linkat (dfd, BASE "link3", dfd, BASE "link5", 0) == 0);
+  check_same_link (BASE "link3", BASE "link5");
+  ASSERT (unlink (BASE "link5") == 0);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link3", dfd, BASE "link5",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ELOOP);
+  ASSERT (linkat (dfd, BASE "link4", dfd, BASE "link5", 0) == 0);
+  check_same_link (BASE "link4", BASE "link5");
+  ASSERT (unlink (BASE "link5") == 0);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link4", dfd, BASE "link5",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ENOENT);
+
+  /* Check that symlink to symlink to file is followed all the way.  */
+  ASSERT (symlink (BASE "link2", BASE "link5") == 0);
+  ASSERT (linkat (dfd, BASE "link5", dfd, BASE "link6", 0) == 0);
+  check_same_link (BASE "link5", BASE "link6");
+  ASSERT (unlink (BASE "link6") == 0);
+  ASSERT (linkat (dfd, BASE "link5", dfd, BASE "file", AT_SYMLINK_FOLLOW) == 0);
+  errno = 0;
+  ASSERT (areadlink (BASE "file") == NULL);
+  ASSERT (errno == EINVAL);
+  ASSERT (unlink (BASE "file") == 0);
+  ASSERT (unlink (BASE "link5") == 0);
+  ASSERT (symlink (BASE "link3", BASE "link5") == 0);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link5", dfd, BASE "file",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ELOOP);
+  ASSERT (unlink (BASE "link5") == 0);
+  ASSERT (symlink (BASE "link4", BASE "link5") == 0);
+  errno = 0;
+  ASSERT (linkat (dfd, BASE "link5", dfd, BASE "file",
+                  AT_SYMLINK_FOLLOW) == -1);
+  ASSERT (errno == ENOENT);
+
+  /* Now for some real fun with directory crossing.  */
+  ASSERT (symlink (cwd, BASE "sub1/link") == 0);
+  ASSERT (symlink (".././/" BASE "sub1/link/" BASE "link2",
+                   BASE "sub2/link") == 0);
+  ASSERT (close (dfd) == 0);
+  dfd = open (BASE "sub1", O_RDONLY);
+  ASSERT (0 <= dfd);
+  dfd2 = open (BASE "sub2", O_RDONLY);
+  ASSERT (0 < dfd2);
+  ASSERT (linkat (dfd, "../" BASE "sub2/link", dfd2, "./..//" BASE "sub1/file",
+              AT_SYMLINK_FOLLOW) == 0);
+  errno = 0;
+  ASSERT (areadlink (BASE "sub1/file") == NULL);
+  ASSERT (errno == EINVAL);
+
+  /* Cleanup.  */
+  ASSERT (close (dfd) == 0);
+  ASSERT (close (dfd2) == 0);
+  ASSERT (unlink (BASE "sub1/file") == 0);
+  ASSERT (unlink (BASE "sub1/link") == 0);
+  ASSERT (unlink (BASE "sub2/link") == 0);
+  ASSERT (unlink (BASE "32") == 0);
+  ASSERT (unlink (BASE "33") == 0);
+  ASSERT (unlink (BASE "34") == 0);
+  ASSERT (rmdir (BASE "sub1") == 0);
+  ASSERT (rmdir (BASE "sub2") == 0);
+  ASSERT (unlink (BASE "link1") == 0);
+  ASSERT (unlink (BASE "link2") == 0);
+  ASSERT (unlink (BASE "link3") == 0);
+  ASSERT (unlink (BASE "link4") == 0);
+  ASSERT (unlink (BASE "link5") == 0);
+  free (cwd);
+  return result;
+}