]> Dogcows Code - chaz/tar/blobdiff - src/compare.c
tar: --atime-preserve fixes for races etc.
[chaz/tar] / src / compare.c
index 70d72513aaef6ea80e0e35ae99ba2002758f4e5c..6a873d7b131949bbc05fcb9634e78f90179fef5f 100644 (file)
@@ -1,13 +1,13 @@
 /* Diff files from a tar archive.
 
    Copyright (C) 1988, 1992, 1993, 1994, 1996, 1997, 1999, 2000, 2001,
-   2003, 2004, 2005 Free Software Foundation, Inc.
+   2003, 2004, 2005, 2006, 2007, 2009, 2010 Free Software Foundation, Inc.
 
    Written by John Gilmore, on 1987-04-30.
 
    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 2, or (at your option) any later
+   Free Software Foundation; either version 3, or (at your option) any later
    version.
 
    This program is distributed in the hope that it will be useful, but
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
 
 #include <system.h>
+#include <system-ioctl.h>
 
 #if HAVE_LINUX_FD_H
 # include <linux/fd.h>
 #endif
 
-#include <quotearg.h>
-#include <utimens.h>
-
 #include "common.h"
+#include <quotearg.h>
 #include <rmt.h>
 #include <stdarg.h>
 
@@ -54,22 +53,20 @@ diff_init (void)
 /* Sigh about something that differs by writing a MESSAGE to stdlis,
    given MESSAGE is nonzero.  Also set the exit status if not already.  */
 void
-report_difference (struct tar_stat_info *st __attribute__ ((unused)),
-                  const char *fmt, ...)
+report_difference (struct tar_stat_info *st, const char *fmt, ...)
 {
   if (fmt)
     {
       va_list ap;
 
-      fprintf (stdlis, "%s: ", quotearg_colon (current_stat_info.file_name));
+      fprintf (stdlis, "%s: ", quotearg_colon (st->file_name));
       va_start (ap, fmt);
       vfprintf (stdlis, fmt, ap);
       va_end (ap);
       fprintf (stdlis, "\n");
     }
 
-  if (exit_status == TAREXIT_SUCCESS)
-    exit_status = TAREXIT_DIFFERS;
+  set_exit_status (TAREXIT_DIFFERS);
 }
 
 /* Take a buffer returned by read_and_process and do nothing with it.  */
@@ -112,36 +109,20 @@ process_rawdata (size_t bytes, char *buffer)
   return 1;
 }
 
-/* Directory contents, only for GNUTYPE_DUMPDIR.  */
-
-static char *dumpdir_cursor;
-
-static int
-process_dumpdir (size_t bytes, char *buffer)
-{
-  if (memcmp (buffer, dumpdir_cursor, bytes))
-    {
-      report_difference (&current_stat_info, _("Contents differ"));
-      return 0;
-    }
-
-  dumpdir_cursor += bytes;
-  return 1;
-}
-
 /* Some other routine wants SIZE bytes in the archive.  For each chunk
    of the archive, call PROCESSOR with the size of the chunk, and the
    address of the chunk it can work with.  The PROCESSOR should return
-   nonzero for success.  It it return error once, continue skipping
+   nonzero for success.  Once it returns error, continue skipping
    without calling PROCESSOR anymore.  */
+
 static void
-read_and_process (off_t size, int (*processor) (size_t, char *))
+read_and_process (struct tar_stat_info *st, int (*processor) (size_t, char *))
 {
   union block *data_block;
   size_t data_size;
+  off_t size = st->stat.st_size;
 
-  if (multi_volume_option)
-    save_sizeleft = size;
+  mv_begin_read (st);
   while (size)
     {
       data_block = find_next_block ();
@@ -159,9 +140,9 @@ read_and_process (off_t size, int (*processor) (size_t, char *))
       set_next_block_after ((union block *)
                            (data_block->buffer + data_size - 1));
       size -= data_size;
-      if (multi_volume_option)
-       save_sizeleft -= data_size;
+      mv_size_left (size);
     }
+  mv_end ();
 }
 
 /* Call either stat or lstat over STAT_DATA, depending on
@@ -204,9 +185,10 @@ diff_dir (void)
 static void
 diff_file (void)
 {
+  char const *file_name = current_stat_info.file_name;
   struct stat stat_data;
 
-  if (!get_stat_data (current_stat_info.file_name, &stat_data))
+  if (!get_stat_data (file_name, &stat_data))
     skip_member ();
   else if (!S_ISREG (stat_data.st_mode))
     {
@@ -224,21 +206,29 @@ diff_file (void)
       if (!sys_compare_gid (&stat_data, &current_stat_info.stat))
        report_difference (&current_stat_info, _("Gid differs"));
 
-      if (timespec_cmp (get_stat_mtime (&stat_data), current_stat_info.mtime))
+      if (tar_timespec_cmp (get_stat_mtime (&stat_data),
+                            current_stat_info.mtime))
        report_difference (&current_stat_info, _("Mod time differs"));
-      if (current_header->header.typeflag != GNUTYPE_SPARSE &&
-         stat_data.st_size != current_stat_info.stat.st_size)
+      if (current_header->header.typeflag != GNUTYPE_SPARSE
+         && stat_data.st_size != current_stat_info.stat.st_size)
        {
          report_difference (&current_stat_info, _("Size differs"));
          skip_member ();
        }
       else
        {
-         diff_handle = open (current_stat_info.file_name, O_RDONLY | O_BINARY);
+         int atime_flag =
+           (atime_preserve_option == system_atime_preserve
+            ? O_NOATIME
+            : 0);
+
+         diff_handle = open (file_name,
+                             (O_RDONLY | O_BINARY | O_CLOEXEC | O_NOCTTY
+                              | O_NONBLOCK | atime_flag));
 
          if (diff_handle < 0)
            {
-             open_error (current_stat_info.file_name);
+             open_error (file_name);
              skip_member ();
              report_difference (&current_stat_info, NULL);
            }
@@ -249,34 +239,18 @@ diff_file (void)
              if (current_stat_info.is_sparse)
                sparse_diff_file (diff_handle, &current_stat_info);
              else
+               read_and_process (&current_stat_info, process_rawdata);
+
+             if (atime_preserve_option == replace_atime_preserve)
                {
-                 if (multi_volume_option)
-                   {
-                     assign_string (&save_name,
-                                     current_stat_info.orig_file_name);
-                     save_totsize = current_stat_info.stat.st_size;
-                     /* save_sizeleft is set in read_and_process.  */
-                   }
-
-                 read_and_process (current_stat_info.stat.st_size,
-                                   process_rawdata);
-
-                 if (multi_volume_option)
-                   assign_string (&save_name, 0);
+                 struct timespec atime = get_stat_atime (&stat_data);
+                 if (set_file_atime (diff_handle, file_name, atime, 0) != 0)
+                   utime_error (file_name);
                }
 
              status = close (diff_handle);
              if (status != 0)
-               close_error (current_stat_info.file_name);
-
-             if (atime_preserve_option)
-               {
-                 struct timespec ts[2];
-                 ts[0] = get_stat_atime (&stat_data);
-                 ts[1] = get_stat_mtime (&stat_data);
-                 if (utimens (current_stat_info.file_name, ts) != 0)
-                   utime_error (current_stat_info.file_name);
-               }
+               close_error (file_name);
            }
        }
     }
@@ -353,14 +327,49 @@ diff_special (void)
     report_difference (&current_stat_info, _("Mode differs"));
 }
 
+static int
+dumpdir_cmp (const char *a, const char *b)
+{
+  size_t len;
+
+  while (*a)
+    switch (*a)
+      {
+      case 'Y':
+      case 'N':
+       if (!strchr ("YN", *b))
+         return 1;
+       if (strcmp(a + 1, b + 1))
+         return 1;
+       len = strlen (a) + 1;
+       a += len;
+       b += len;
+       break;
+
+      case 'D':
+       if (strcmp(a, b))
+         return 1;
+       len = strlen (a) + 1;
+       a += len;
+       b += len;
+       break;
+
+      case 'R':
+      case 'T':
+      case 'X':
+       return *b;
+      }
+  return *b;
+}
+
 static void
 diff_dumpdir (void)
 {
-  char *dumpdir_buffer;
+  const char *dumpdir_buffer;
   dev_t dev = 0;
-  struct stat stat;
+  struct stat stat_data;
 
-  if (deref_stat (true, current_stat_info.file_name, &stat))
+  if (deref_stat (true, current_stat_info.file_name, &stat_data))
     {
       if (errno == ENOENT)
        stat_warn (current_stat_info.file_name);
@@ -368,28 +377,17 @@ diff_dumpdir (void)
        stat_error (current_stat_info.file_name);
     }
   else
-    dev = stat.st_dev;
-      
-  dumpdir_buffer = get_directory_contents (current_stat_info.file_name, dev);
+    dev = stat_data.st_dev;
 
-  if (multi_volume_option)
-    {
-      assign_string (&save_name, current_stat_info.orig_file_name);
-      save_totsize = current_stat_info.stat.st_size;
-      /* save_sizeleft is set in read_and_process.  */
-    }
+  dumpdir_buffer = directory_contents (scan_directory (&current_stat_info));
 
   if (dumpdir_buffer)
     {
-      dumpdir_cursor = dumpdir_buffer;
-      read_and_process (current_stat_info.stat.st_size, process_dumpdir);
-      free (dumpdir_buffer);
+      if (dumpdir_cmp (current_stat_info.dumpdir, dumpdir_buffer))
+       report_difference (&current_stat_info, _("Contents differ"));
     }
   else
-    read_and_process (current_stat_info.stat.st_size, process_noop);
-
-  if (multi_volume_option)
-    assign_string (&save_name, 0);
+    read_and_process (&current_stat_info, process_noop);
 }
 
 static void
@@ -398,6 +396,10 @@ diff_multivol (void)
   struct stat stat_data;
   int fd, status;
   off_t offset;
+  int atime_flag =
+    (atime_preserve_option == system_atime_preserve
+     ? O_NOATIME
+     : 0);
 
   if (current_stat_info.had_trailing_slash)
     {
@@ -423,7 +425,10 @@ diff_multivol (void)
       return;
     }
 
-  fd = open (current_stat_info.file_name, O_RDONLY | O_BINARY);
+
+  fd = open (current_stat_info.file_name,
+            (O_RDONLY | O_BINARY | O_CLOEXEC | O_NOCTTY | O_NONBLOCK
+             | atime_flag));
 
   if (fd < 0)
     {
@@ -440,17 +445,7 @@ diff_multivol (void)
       return;
     }
 
-  if (multi_volume_option)
-    {
-      assign_string (&save_name, current_stat_info.orig_file_name);
-      save_totsize = stat_data.st_size;
-      /* save_sizeleft is set in read_and_process.  */
-    }
-
-  read_and_process (current_stat_info.stat.st_size, process_rawdata);
-
-  if (multi_volume_option)
-    assign_string (&save_name, 0);
+  read_and_process (&current_stat_info, process_rawdata);
 
   status = close (fd);
   if (status != 0)
@@ -463,7 +458,6 @@ diff_archive (void)
 {
 
   set_next_block_after (current_header);
-  decode_header (current_header, &current_stat_info, &current_format, 1);
 
   /* Print the block from current_header and current_stat_info.  */
 
@@ -471,7 +465,7 @@ diff_archive (void)
     {
       if (now_verifying)
        fprintf (stdlis, _("Verify "));
-      print_header (&current_stat_info, -1);
+      print_header (&current_stat_info, current_header, -1);
     }
 
   switch (current_header->header.typeflag)
@@ -512,10 +506,9 @@ diff_archive (void)
       break;
 
     case GNUTYPE_DUMPDIR:
-      diff_dumpdir ();
-      /* Fall through.  */
-
     case DIRTYPE:
+      if (is_dumpdir (&current_stat_info))
+       diff_dumpdir ();
       diff_dir ();
       break;
 
@@ -590,7 +583,9 @@ verify_volume (void)
   flush_read ();
   while (1)
     {
-      enum read_header status = read_header (false);
+      enum read_header status = read_header (&current_header,
+                                             &current_stat_info,
+                                             read_header_auto);
 
       if (status == HEADER_FAILURE)
        {
@@ -600,7 +595,8 @@ verify_volume (void)
            {
              counter++;
              set_next_block_after (current_header);
-             status = read_header (false);
+             status = read_header (&current_header, &current_stat_info,
+                                   read_header_auto);
            }
          while (status == HEADER_FAILURE);
 
@@ -609,12 +605,27 @@ verify_volume (void)
                            "VERIFY FAILURE: %d invalid headers detected",
                            counter), counter));
        }
-      if (status == HEADER_ZERO_BLOCK || status == HEADER_END_OF_FILE)
+      if (status == HEADER_END_OF_FILE)
        break;
+      if (status == HEADER_ZERO_BLOCK)
+       {
+         set_next_block_after (current_header);
+          if (!ignore_zeros_option)
+            {
+             char buf[UINTMAX_STRSIZE_BOUND];
+
+             status = read_header (&current_header, &current_stat_info,
+                                   read_header_auto);
+             if (status == HEADER_ZERO_BLOCK)
+               break;
+             WARNOPT (WARN_ALONE_ZERO_BLOCK,
+                      (0, 0, _("A lone zero block at %s"),
+                       STRINGIFY_BIGINT (current_block_ordinal (), buf)));
+            }
+       }
 
       diff_archive ();
       tar_stat_destroy (&current_stat_info);
-      xheader_destroy (&extended_header);
     }
 
   access_mode = ACCESS_WRITE;
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