Adding upstream version 2.11.2.upstream/2.11.2upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 255 insertions, 0 deletions

diff --git a/gl/lib/renameatu.c b/gl/lib/renameatu.c
new file mode 100644
index 0000000..7ba186c
--- /dev/null
+++ b/gl/lib/renameatu.c
@@ -0,0 +1,255 @@
+/* Rename a file relative to open directories.
+   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 and Paul Eggert */
+
+#include <config.h>
+
+#include "renameatu.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#ifdef __linux__
+# include <sys/syscall.h>
+#endif
+
+static int
+errno_fail (int e)
+{
+  errno = e;
+  return -1;
+}
+
+#if HAVE_RENAMEAT
+
+# include <stdbool.h>
+# include <stdlib.h>
+# include <string.h>
+
+# include "dirname.h"
+# include "openat.h"
+
+#else
+# include "openat-priv.h"
+
+static int
+rename_noreplace (char const *src, char const *dst)
+{
+  /* This has a race between the call to lstat and the call to rename.  */
+  struct stat st;
+  return (lstat (dst, &st) == 0 || errno == EOVERFLOW ? errno_fail (EEXIST)
+          : errno == ENOENT ? rename (src, dst)
+          : -1);
+}
+#endif
+
+#undef renameat
+
+#if HAVE_RENAMEAT
+
+/* Act like renameat (FD1, SRC, FD2, DST), except fail with EEXIST if
+   FLAGS is nonzero and it is easy to fail atomically if DST already exists.
+   This lets renameatu be atomic when it can be implemented in terms
+   of renameatx_np.  */
+static int
+renameat2ish (int fd1, char const *src, int fd2, char const *dst,
+              unsigned int flags)
+{
+# ifdef RENAME_EXCL
+  if (flags)
+    {
+      int r = renameatx_np (fd1, src, fd2, dst, RENAME_EXCL);
+      if (r == 0 || errno != ENOTSUP)
+        return r;
+    }
+# endif
+
+  return renameat (fd1, src, fd2, dst);
+}
+#endif
+
+/* Rename FILE1, in the directory open on descriptor FD1, to FILE2, in
+   the directory open on descriptor FD2.  If possible, do it without
+   changing the working directory.  Otherwise, resort to using
+   save_cwd/fchdir, then rename/restore_cwd.  If either the save_cwd or
+   the restore_cwd fails, then give a diagnostic and exit nonzero.
+
+   Obey FLAGS when doing the renaming.  If FLAGS is zero, this
+   function is equivalent to renameat (FD1, SRC, FD2, DST).
+   Otherwise, attempt to implement FLAGS even if the implementation is
+   not atomic; this differs from the GNU/Linux native renameat2,
+   which fails if it cannot guarantee atomicity.  */
+
+int
+renameatu (int fd1, char const *src, int fd2, char const *dst,
+           unsigned int flags)
+{
+  int ret_val = -1;
+  int err = EINVAL;
+
+#ifdef HAVE_RENAMEAT2
+  ret_val = renameat2 (fd1, src, fd2, dst, flags);
+  err = errno;
+#elif defined SYS_renameat2
+  ret_val = syscall (SYS_renameat2, fd1, src, fd2, dst, flags);
+  err = errno;
+#endif
+
+  if (! (ret_val < 0 && (err == EINVAL || err == ENOSYS || err == ENOTSUP)))
+    return ret_val;
+
+#if HAVE_RENAMEAT
+  {
+  size_t src_len;
+  size_t dst_len;
+  char *src_temp = (char *) src;
+  char *dst_temp = (char *) dst;
+  bool src_slash;
+  bool dst_slash;
+  int rename_errno = ENOTDIR;
+  struct stat src_st;
+  struct stat dst_st;
+  bool dst_found_nonexistent = false;
+
+  switch (flags)
+    {
+    case 0:
+      break;
+
+    case RENAME_NOREPLACE:
+      /* This has a race between the call to fstatat and the calls to
+         renameat below.  This fstatat is needed even if RENAME_EXCL
+         is defined, because RENAME_EXCL is buggy on macOS 11.2:
+         renameatx_np (fd, "X", fd, "X", RENAME_EXCL) incorrectly
+         succeeds when X exists.  */
+      if (fstatat (fd2, dst, &dst_st, AT_SYMLINK_NOFOLLOW) == 0
+          || errno == EOVERFLOW)
+        return errno_fail (EEXIST);
+      if (errno != ENOENT)
+        return -1;
+      dst_found_nonexistent = true;
+      break;
+
+    default:
+      return errno_fail (ENOTSUP);
+    }
+
+  /* Let strace see any ENOENT failure.  */
+  src_len = strlen (src);
+  dst_len = strlen (dst);
+  if (!src_len || !dst_len)
+    return renameat2ish (fd1, src, fd2, dst, flags);
+
+  src_slash = src[src_len - 1] == '/';
+  dst_slash = dst[dst_len - 1] == '/';
+  if (!src_slash && !dst_slash)
+    return renameat2ish (fd1, src, fd2, dst, flags);
+
+  /* Presence of a trailing slash requires directory semantics.  If
+     the source does not exist, or if the destination cannot be turned
+     into a directory, give up now.  Otherwise, strip trailing slashes
+     before calling rename.  */
+  if (fstatat (fd1, src, &src_st, AT_SYMLINK_NOFOLLOW))
+    return -1;
+  if (dst_found_nonexistent)
+    {
+      if (!S_ISDIR (src_st.st_mode))
+        return errno_fail (ENOENT);
+    }
+  else if (fstatat (fd2, dst, &dst_st, AT_SYMLINK_NOFOLLOW))
+    {
+      if (errno != ENOENT || !S_ISDIR (src_st.st_mode))
+        return -1;
+    }
+  else if (!S_ISDIR (dst_st.st_mode))
+    return errno_fail (ENOTDIR);
+  else if (!S_ISDIR (src_st.st_mode))
+    return errno_fail (EISDIR);
+
+# if RENAME_TRAILING_SLASH_SOURCE_BUG
+  /* See the lengthy comment in rename.c why Solaris 9 is forced to
+     GNU behavior, while Solaris 10 is left with POSIX behavior,
+     regarding symlinks with trailing slash.  */
+  ret_val = -1;
+  if (src_slash)
+    {
+      src_temp = strdup (src);
+      if (!src_temp)
+        {
+          /* Rather than rely on strdup-posix, we set errno ourselves.  */
+          rename_errno = ENOMEM;
+          goto out;
+        }
+      strip_trailing_slashes (src_temp);
+      if (fstatat (fd1, src_temp, &src_st, AT_SYMLINK_NOFOLLOW))
+        {
+          rename_errno = errno;
+          goto out;
+        }
+      if (S_ISLNK (src_st.st_mode))
+        goto out;
+    }
+  if (dst_slash)
+    {
+      dst_temp = strdup (dst);
+      if (!dst_temp)
+        {
+          rename_errno = ENOMEM;
+          goto out;
+        }
+      strip_trailing_slashes (dst_temp);
+      char readlink_buf[1];
+      if (readlinkat (fd2, dst_temp, readlink_buf, sizeof readlink_buf) < 0)
+        {
+          if (errno != ENOENT && errno != EINVAL)
+            {
+              rename_errno = errno;
+              goto out;
+            }
+        }
+      else
+        goto out;
+    }
+# endif /* RENAME_TRAILING_SLASH_SOURCE_BUG */
+
+  /* renameat does not honor trailing / on Solaris 10.  Solve it in a
+     similar manner to rename.  No need to worry about bugs not present
+     on Solaris, since all other systems either lack renameat or honor
+     trailing slash correctly.  */
+
+  ret_val = renameat2ish (fd1, src_temp, fd2, dst_temp, flags);
+  rename_errno = errno;
+  goto out;
+ out:
+  if (src_temp != src)
+    free (src_temp);
+  if (dst_temp != dst)
+    free (dst_temp);
+  errno = rename_errno;
+  return ret_val;
+  }
+#else /* !HAVE_RENAMEAT */
+
+  /* RENAME_NOREPLACE is the only flag currently supported.  */
+  if (flags & ~RENAME_NOREPLACE)
+    return errno_fail (ENOTSUP);
+  return at_func2 (fd1, src, fd2, dst, flags ? rename_noreplace : rename);
+
+#endif /* !HAVE_RENAMEAT */
+}