Re: [Bug-tar] tar doesn't stop after extracting with occurrence parameter

[Sergey Poznyakoff]

address@hidden ha escrit:

>    "tar -xzp --occurrence=1 --ignore-failed-read -C 'target' -f 'tgz'
>    'file'
>    >/dev/null 2>&1"
>    It extracts the file after some seconds but doesn't stop. top shows a
>    gzip process running. After some minutes gzip stops and tar ends.

It is a leftover from preious versions: tar tries to drain the input
pipe in order to avoid subprocess termination via SIGPIPE. Thanks for
reporting the bug. Please try the attached patch.

Regards,
Sergey

Index: src/buffer.c
===================================================================
RCS file: /cvsroot/tar/tar/src/buffer.c,v
retrieving revision 1.124
diff -p -u -r1.124 buffer.c
--- src/buffer.c        3 Nov 2008 19:15:52 -0000       1.124
+++ src/buffer.c        25 Nov 2008 12:14:39 -0000
@@ -848,8 +848,6 @@ close_archive (void)
         flush_archive ();
     }
 
-  sys_drain_input_pipe ();
-
   compute_duration ();
   if (verify_option)
     verify_volume ();
@@ -857,7 +855,7 @@ close_archive (void)
   if (rmtclose (archive) != 0)
     close_error (*archive_name_cursor);
 
-  sys_wait_for_child (child_pid);
+  sys_wait_for_child (child_pid, hit_eof);
 
   tar_stat_destroy (&current_stat_info);
   if (save_name)
Index: src/common.h
===================================================================
RCS file: /cvsroot/tar/tar/src/common.h,v
retrieving revision 1.107
diff -p -u -r1.107 common.h
--- src/common.h        30 Oct 2008 14:13:02 -0000      1.107
+++ src/common.h        25 Nov 2008 12:14:39 -0000
@@ -699,8 +699,7 @@ char *xheader_format_name (struct tar_st
 
 void sys_detect_dev_null_output (void);
 void sys_save_archive_dev_ino (void);
-void sys_drain_input_pipe (void);
-void sys_wait_for_child (pid_t);
+void sys_wait_for_child (pid_t, bool);
 void sys_spawn_shell (void);
 bool sys_compare_uid (struct stat *a, struct stat *b);
 bool sys_compare_gid (struct stat *a, struct stat *b);
Index: src/system.c
===================================================================
RCS file: /cvsroot/tar/tar/src/system.c,v
retrieving revision 1.25
diff -p -u -r1.25 system.c
--- src/system.c        6 Mar 2008 08:17:34 -0000       1.25
+++ src/system.c        25 Nov 2008 12:14:39 -0000
@@ -51,12 +51,7 @@ sys_detect_dev_null_output (void)
 }
 
 void
-sys_drain_input_pipe (void)
-{
-}
-
-void
-sys_wait_for_child (pid_t child_pid)
+sys_wait_for_child (pid_t child_pid, bool eof)
 {
 }
 
@@ -160,26 +155,8 @@ sys_detect_dev_null_output (void)
                         && archive_stat.st_ino == dev_null_stat.st_ino));
 }
 
-/* Manage to fully drain a pipe we might be reading, so to not break it on
-   the producer after the EOF block.  FIXME: one of these days, GNU tar
-   might become clever enough to just stop working, once there is no more
-   work to do, we might have to revise this area in such time.  */
-
-void
-sys_drain_input_pipe (void)
-{
-  size_t r;
-
-  if (access_mode == ACCESS_READ
-      && ! _isrmt (archive)
-      && (S_ISFIFO (archive_stat.st_mode) || S_ISSOCK (archive_stat.st_mode)))
-    while ((r = rmtread (archive, record_start->buffer, record_size)) != 0
-          && r != SAFE_READ_ERROR)
-      continue;
-}
-
 void
-sys_wait_for_child (pid_t child_pid)
+sys_wait_for_child (pid_t child_pid, bool eof)
 {
   if (child_pid)
     {
@@ -193,8 +170,11 @@ sys_wait_for_child (pid_t child_pid)
          }
 
       if (WIFSIGNALED (wait_status))
-       ERROR ((0, 0, _("Child died with signal %d"),
-               WTERMSIG (wait_status)));
+       {
+         int sig = WTERMSIG (wait_status);
+         if (!(!eof && sig == SIGPIPE))
+           ERROR ((0, 0, _("Child died with signal %d"), sig));
+       }
       else if (WEXITSTATUS (wait_status) != 0)
        ERROR ((0, 0, _("Child returned status %d"),
                WEXITSTATUS (wait_status)));