maint: update copyright

[gnulib.git] / lib / chown.c

diff --git a/lib/chown.c b/lib/chown.c
index cca1d7f..1503841 100644 (file)
--- a/lib/chown.c
+++ b/lib/chown.c
@@ -1,7 +1,7 @@
 /* provide consistent interface to chown for systems that don't interpret
-   an ID of -1 as meaning `don't change the corresponding ID'.
+   an ID of -1 as meaning "don't change the corresponding ID".
 
-   Copyright (C) 1997, 2004-2007, 2009 Free Software Foundation, Inc.
+   Copyright (C) 1997, 2004-2007, 2009-2014 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
@@ -23,44 +23,65 @@
 /* Specification.  */
 #include <unistd.h>
 
+#include <errno.h>
+#include <fcntl.h>
 #include <stdbool.h>
-#include <sys/types.h>
+#include <string.h>
 #include <sys/stat.h>
-#include <fcntl.h>
-#include <errno.h>
+
+#if !HAVE_CHOWN
+
+/* Simple stub that always fails with ENOSYS, for mingw.  */
+int
+chown (const char *file _GL_UNUSED, uid_t uid _GL_UNUSED,
+       gid_t gid _GL_UNUSED)
+{
+  errno = ENOSYS;
+  return -1;
+}
+
+#else /* HAVE_CHOWN */
 
 /* Below we refer to the system's chown().  */
-#undef chown
+# undef chown
 
 /* The results of open() in this file are not used with fchdir,
    therefore save some unnecessary work in fchdir.c.  */
-#undef open
-#undef close
+# undef open
+# undef close
 
 /* Provide a more-closely POSIX-conforming version of chown on
    systems with one or both of the following problems:
    - chown doesn't treat an ID of -1 as meaning
-   `don't change the corresponding ID'.
+   "don't change the corresponding ID".
    - chown doesn't dereference symlinks.  */
 
 int
 rpl_chown (const char *file, uid_t uid, gid_t gid)
 {
-#if HAVE_CHOWN
+  struct stat st;
+  bool stat_valid = false;
+  int result;
+
+# if CHOWN_CHANGE_TIME_BUG
+  if (gid != (gid_t) -1 || uid != (uid_t) -1)
+    {
+      if (stat (file, &st))
+        return -1;
+      stat_valid = true;
+    }
+# endif
+
 # if CHOWN_FAILS_TO_HONOR_ID_OF_NEGATIVE_ONE
   if (gid == (gid_t) -1 || uid == (uid_t) -1)
     {
-      struct stat file_stats;
-
       /* Stat file to get id(s) that should remain unchanged.  */
-      if (stat (file, &file_stats))
-       return -1;
-
+      if (!stat_valid && stat (file, &st))
+        return -1;
       if (gid == (gid_t) -1)
-       gid = file_stats.st_gid;
-
+        gid = st.st_gid;
       if (uid == (uid_t) -1)
-       uid = file_stats.st_uid;
+        uid = st.st_uid;
     }
 # endif
 
@@ -74,36 +95,62 @@ rpl_chown (const char *file, uid_t uid, gid_t gid)
     int open_flags = O_NONBLOCK | O_NOCTTY;
     int fd = open (file, O_RDONLY | open_flags);
     if (0 <= fd
-       || (errno == EACCES
-           && 0 <= (fd = open (file, O_WRONLY | open_flags))))
+        || (errno == EACCES
+            && 0 <= (fd = open (file, O_WRONLY | open_flags))))
       {
-       int result = fchown (fd, uid, gid);
-       int saved_errno = errno;
-
-       /* POSIX says fchown can fail with errno == EINVAL on sockets,
-          so fall back on chown in that case.  */
-       struct stat sb;
-       bool fchown_socket_failure =
-         (result != 0 && saved_errno == EINVAL
-          && fstat (fd, &sb) == 0 && S_ISFIFO (sb.st_mode));
-
-       close (fd);
-
-       if (! fchown_socket_failure)
-         {
-           errno = saved_errno;
-           return result;
-         }
+        int saved_errno;
+        bool fchown_socket_failure;
+
+        result = fchown (fd, uid, gid);
+        saved_errno = errno;
+
+        /* POSIX says fchown can fail with errno == EINVAL on sockets
+           and pipes, so fall back on chown in that case.  */
+        fchown_socket_failure =
+          (result != 0 && saved_errno == EINVAL
+           && fstat (fd, &st) == 0
+           && (S_ISFIFO (st.st_mode) || S_ISSOCK (st.st_mode)));
+
+        close (fd);
+
+        if (! fchown_socket_failure)
+          {
+            errno = saved_errno;
+            return result;
+          }
       }
     else if (errno != EACCES)
       return -1;
   }
 # endif
 
-  return chown (file, uid, gid);
+# if CHOWN_TRAILING_SLASH_BUG
+  if (!stat_valid)
+    {
+      size_t len = strlen (file);
+      if (len && file[len - 1] == '/' && stat (file, &st))
+        return -1;
+    }
+# endif
+
+  result = chown (file, uid, gid);
 
-#else /* !HAVE_CHOWN */
-  errno = EOPNOTSUPP;
-  return -1;
-#endif
+# if CHOWN_CHANGE_TIME_BUG
+  if (result == 0 && stat_valid
+      && (uid == st.st_uid || uid == (uid_t) -1)
+      && (gid == st.st_gid || gid == (gid_t) -1))
+    {
+      /* No change in ownership, but at least one argument was not -1,
+         so we are required to update ctime.  Since chown succeeded,
+         we assume that chmod will do likewise.  Fortunately, on all
+         known systems where a 'no-op' chown skips the ctime update, a
+         'no-op' chmod still does the trick.  */
+      result = chmod (file, st.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO
+                                          | S_ISUID | S_ISGID | S_ISVTX));
+    }
+# endif
+
+  return result;
 }
+
+#endif /* HAVE_CHOWN */