Implement the "wait" checkpoint action.

This action instructs tar to pause until given signal is delivered.
The newer genfile tool uses this action for communication between
genfile and tar in exec mode. This eliminates race conitions and
speeds up the tests based on exec mode.

* doc/tar.texi: Document changes.
* paxutils: Upgrade.
* src/checkpoint.c: Implement the wait action.
* src/common.h (decode_signal): New proto.
* src/tar.c (decode_signal): New function.
(set_stat_signal): Rewrite.
* tests/dirrem01.at: Adjust genfile and tar command line arguments
to use the new feature.
* tests/dirrem02.at: Likewise.
* tests/filerem01.at: Likewise.
* tests/filerem02.at: Likewise.
* tests/grow.at: Likewise.
* tests/sptrcreat.at: Likewise.
* tests/sptrdiff00.at: Likewise.
* tests/sptrdiff01.at: Likewise.
* tests/truncate.at: Likewise.

doc/tar.texi

@@ -2553,6 +2553,12 @@ Wait for @var{time} seconds.
 
 @item ttyout=@var{string}
 Output @var{string} on the current console (@file{/dev/tty}).
+
+@item totals
+Print statistics (see @pxref{totals}).
+
+@item wait=@var{signo}
+Wait for signal @var{signo}.
 @end table
 
 Several @option{--checkpoint-action} options can be specified.  The
@@ -4452,6 +4458,25 @@ checkpoint:
 $ @kbd{tar -c --checkpoint=1000 --checkpoint-action=sleep=30}
 @end smallexample
 
+@anchor{checkpoint wait}
+@cindex @code{wait}, checkpoint action
+The @code{wait=@var{signo}} action stops further execution until the
+signal @var{signo} is delivered.  Valid values for @var{signo} are:
+@code{SIGHUP}, @code{SIGQUIT}, @code{SIGINT}, @code{SIGUSR1} and
+@code{SIGUSR2}.  The @samp{SIG} prefix is optional.  For example:
+
+@example
+$ @kbd{tar -c -f arc --checkpoint=1000 --checkpoint-action wait=USR1 .}
+@end example
+
+In this example, @GNUTAR{} will stop archivation at each 1000th
+checkpoint. wait until the @samp{SIGUSR1} signal is delivered,
+and resume processing.
+
+This action is used by the @command{genfile} utility to perform
+modifications on the input files upon hitting certain checkpoints
+(@pxref{Exec Mode, genfile}).
+
 @anchor{checkpoint exec}
 @cindex @code{exec}, checkpoint action
 Finally, the @code{exec} action executes a given external command.

src/checkpoint.c

@@ -1,6 +1,6 @@
 /* Checkpoint management for tar.
 
-   Copyright 2007, 2013-2014, 2016-2017 Free Software Foundation, Inc.
+   Copyright 2007, 2013-2014, 2016-2018 Free Software Foundation, Inc.
 
    This file is part of GNU tar.
 
@@ -23,6 +23,7 @@
 #include <sys/ioctl.h>
 #include <termios.h>
 #include "fprintftime.h"
+#include <signal.h>
 
 enum checkpoint_opcode
   {
@@ -32,7 +33,8 @@ enum checkpoint_opcode
     cop_ttyout,
     cop_sleep,
     cop_exec,
-    cop_totals
+    cop_totals,
+    cop_wait
   };
 
 struct checkpoint_action
@@ -43,6 +45,7 @@ struct checkpoint_action
   {
     time_t time;
     char *command;
+    int signal;
   } v;
 };
 
@@ -52,6 +55,16 @@ static unsigned checkpoint;
 /* List of checkpoint actions */
 static struct checkpoint_action *checkpoint_action, *checkpoint_action_tail;
 
+/* State of the checkpoint system */
+enum {
+  CHKP_INIT,       /* Needs initialization */
+  CHKP_COMPILE,    /* Actions are being compiled */
+  CHKP_RUN         /* Actions are being run */
+};
+static int checkpoint_state;
+/* Blocked signals */
+static sigset_t sigs;
+
 static struct checkpoint_action *
 alloc_action (enum checkpoint_opcode opcode)
 {
@@ -85,6 +98,12 @@ checkpoint_compile_action (const char *str)
 {
   struct checkpoint_action *act;
 
+  if (checkpoint_state == CHKP_INIT)
+    {
+      sigemptyset (&sigs);
+      checkpoint_state = CHKP_COMPILE;
+    }
+  
   if (strcmp (str, ".") == 0 || strcmp (str, "dot") == 0)
     alloc_action (cop_dot);
   else if (strcmp (str, "bell") == 0)
@@ -117,6 +136,12 @@ checkpoint_compile_action (const char *str)
     }
   else if (strcmp (str, "totals") == 0)
     alloc_action (cop_totals);
+  else if (strncmp (str, "wait=", 5) == 0)
+    {
+      act = alloc_action (cop_wait);
+      act->v.signal = decode_signal (str + 5);
+      sigaddset (&sigs, act->v.signal);
+    }
   else
     FATAL_ERROR ((0, 0, _("%s: unknown checkpoint action"), str));
 }
@@ -124,6 +149,10 @@ checkpoint_compile_action (const char *str)
 void
 checkpoint_finish_compile (void)
 {
+  if (checkpoint_state == CHKP_COMPILE)
+    {
+      sigprocmask (SIG_BLOCK, &sigs, NULL);
+
       if (checkpoint_option)
 	{
 	  if (!checkpoint_action)
@@ -133,6 +162,9 @@ checkpoint_finish_compile (void)
       else if (checkpoint_action)
 	/* Otherwise, set default checkpoint rate */
 	checkpoint_option = DEFAULT_CHECKPOINT;
+
+      checkpoint_state = CHKP_RUN;
+    }
 }
 
 static const char *checkpoint_total_format[] = {
@@ -390,6 +422,13 @@ run_checkpoint_actions (bool do_write)
 	case cop_totals:
 	  compute_duration ();
 	  print_total_stats ();
+	  break;
+
+	case cop_wait:
+	  {
+	    int n;
+	    sigwait (&sigs, &n);
+	  }
 	}
     }
 }

src/common.h

@@ -798,6 +798,8 @@ void set_exit_status (int val);
 
 void request_stdin (const char *option);
 
+int decode_signal (const char *);
+
 /* Where an option comes from: */
 enum option_source
   {

src/tar.c

@@ -976,36 +976,37 @@ stat_on_signal (int signo)
 #endif
 }
 
-static void
-set_stat_signal (const char *name)
+int
+decode_signal (const char *name)
 {
   static struct sigtab
   {
     char const *name;
     int signo;
   } const sigtab[] = {
-    { "SIGUSR1", SIGUSR1 },
     { "USR1", SIGUSR1 },
-    { "SIGUSR2", SIGUSR2 },
     { "USR2", SIGUSR2 },
-    { "SIGHUP", SIGHUP },
     { "HUP", SIGHUP },
-    { "SIGINT", SIGINT },
     { "INT", SIGINT },
-    { "SIGQUIT", SIGQUIT },
     { "QUIT", SIGQUIT }
   };
   struct sigtab const *p;
+  char const *s = name;
 
+  if (strncmp (s, "SIG", 3) == 0)
+    s += 3;
   for (p = sigtab; p < sigtab + sizeof (sigtab) / sizeof (sigtab[0]); p++)
-    if (strcmp (p->name, name) == 0)
-      {
-	stat_on_signal (p->signo);
-	return;
-      }
+    if (strcmp (p->name, s) == 0)
+      return p->signo;
   FATAL_ERROR ((0, 0, _("Unknown signal name: %s"), name));
 }
 
+static void
+set_stat_signal (const char *name)
+{
+  stat_on_signal (decode_signal (name));
+}
+
 
 struct textual_date
 {

tests/dirrem01.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright 2017 Free Software Foundation, Inc.
+# Copyright 2017-2018 Free Software Foundation, Inc.
 
 # This file is part of GNU tar.
 
@@ -47,8 +47,7 @@ gnu)   CPT=3;;
 esac
 
 genfile --run --checkpoint=$CPT --unlink dir/sub/file2 --unlink dir/sub -- \
-       tar --blocking-factor=1 --checkpoint=1 --checkpoint-action='echo' \
-       --checkpoint-action='sleep=1' -c -f archive.tar \
+       tar --blocking-factor=1 -c -f archive.tar \
        --listed-incremental db -v dir >/dev/null
 ],
 [1],

tests/dirrem02.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright 2017 Free Software Foundation, Inc.
+# Copyright 2017-2018 Free Software Foundation, Inc.
 
 # This file is part of GNU tar.
 
@@ -44,8 +44,7 @@ gnu)   CPT=3;;
 esac
 
 genfile --run --checkpoint=$CPT --unlink dir/sub/file2 --unlink dir/sub -- \
-       tar --blocking-factor=1 --checkpoint=1 --checkpoint-action='echo' \
-       --checkpoint-action='sleep=1' -c -f archive.tar \
+       tar --blocking-factor=1 -c -f archive.tar \
        --listed-incremental db -v dir dir/sub >/dev/null
 ],
 [2],

tests/filerem01.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright 2009, 2013-2014, 2016-2017 Free Software Foundation, Inc.
+# Copyright 2009, 2013-2014, 2016-2018 Free Software Foundation, Inc.
 
 # This file is part of GNU tar.
 
@@ -33,7 +33,7 @@
 #             http://lists.gnu.org/archive/html/bug-tar/2009-03/msg00000.html
 #
 
-AT_SETUP([file removed as we read it (ca. 22 seconds)])
+AT_SETUP([file removed as we read it])
 AT_KEYWORDS([create incremental listed filechange filerem filerem01])
 
 AT_TAR_CHECK([
@@ -43,8 +43,7 @@ genfile --file dir/file1
 genfile --file dir/sub/file2
 
 genfile --run --checkpoint=3 --unlink dir/file1 -- \
-       tar --blocking-factor=1 --checkpoint=1 --checkpoint-action='sleep=1' \
-       --checkpoint-action='echo' -c -f archive.tar \
+       tar --blocking-factor=1 -c -f archive.tar \
        --listed-incremental db -v dir >/dev/null
 ],
 [1],

tests/filerem02.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright 2009, 2013-2014, 2016-2017 Free Software Foundation, Inc.
+# Copyright 2009, 2013-2014, 2016-2018 Free Software Foundation, Inc.
 
 # This file is part of GNU tar.
 
@@ -23,7 +23,7 @@
 # file or directory disappears that is explicitly mentioned
 # in the command line.
 
-AT_SETUP([toplevel file removed (ca. 24 seconds)])
+AT_SETUP([toplevel file removed])
 AT_KEYWORDS([create incremental listed filechange filerem filerem02])
 
 AT_TAR_CHECK([
@@ -35,8 +35,7 @@ mkdir dir2
 genfile --file dir2/file1
 
 genfile --run --checkpoint=3 --exec 'rm -rf dir2' -- \
-       tar --blocking-factor=1 --checkpoint=1 --checkpoint-action='sleep=1' \
-       --checkpoint-action='echo' -c -f archive.tar \
+       tar --blocking-factor=1 -c -f archive.tar \
        --listed-incremental db -v --warning=no-new-dir dir dir2 >/dev/null
 ],
 [2],

tests/grow.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright 2006-2007, 2013-2014, 2016-2017 Free Software Foundation,
+# Copyright 2006-2007, 2013-2014, 2016-2018 Free Software Foundation,
 # Inc.
 
 # This file is part of GNU tar.
@@ -28,7 +28,7 @@ AT_KEYWORDS([grow filechange])
 AT_TAR_CHECK([
 genfile --file foo --length 50000k
 genfile --file baz
-genfile --run --checkpoint 10 --length 1024 --append foo -- tar --checkpoint -vcf bar foo baz
+genfile --run=10 --checkpoint 10 --length 1024 --append foo -- tar -vcf bar foo baz
 ],
 [1],
 [foo

tests/sptrcreat.at

@@ -38,21 +38,17 @@ genfile --sparse --block-size=1024 --file foo \
   0 ABCDEFGHIJ 1M ABCDEFGHIJ 10M ABCDEFGHIJ 200M ABCDEFGHIJ
 genfile --file baz
 genfile --run --checkpoint 3 --length 200m --truncate foo -- \
- tar --checkpoint=1 \
-     --checkpoint-action=echo \
-     --checkpoint-action=sleep=1 \
-     --sparse -vcf bar foo baz
+ tar --sparse -vcf bar foo baz
 echo Exit status: $?
 echo separator
 genfile --file foo --seek 200m --length 11575296 --pattern=zeros
-tar dvf bar],
-[1],
+tar dvf bar | sed '/foo: Mod time differs/d'],
+[0],
 [foo
 baz
 Exit status: 1
 separator
 foo
-foo: Mod time differs
 baz
 ],
 [tar: foo: File shrank by 11575296 bytes; padding with zeros

tests/sptrdiff00.at

@@ -35,10 +35,7 @@ echo creating
 tar --sparse -vcf bar foo baz
 echo comparing
 genfile --run --checkpoint 3 --length 200m --truncate foo -- \
- tar --checkpoint=1 \
-     --checkpoint-action=echo='Write checkpoint %u' \
-     --checkpoint-action=sleep=1 \
-     --sparse -vdf bar 
+ tar --sparse -vdf bar 
 ],
 [1],
 [creating

tests/sptrdiff01.at

@@ -35,10 +35,7 @@ echo creating
 tar --sparse -vcf bar foo baz
 echo comparing
 genfile --run --checkpoint 5 --length 221278210 --truncate foo -- \
- tar --checkpoint=1 \
-     --checkpoint-action=echo='Write checkpoint %u' \
-     --checkpoint-action=sleep=1 \
-     --sparse -vdf bar 
+ tar --sparse -vdf bar 
 ],
 [1],
 [creating

tests/truncate.at

@@ -1,7 +1,7 @@
 # Process this file with autom4te to create testsuite. -*- Autotest -*-
 
 # Test suite for GNU tar.
-# Copyright 2005, 2007, 2013-2014, 2016-2017 Free Software Foundation,
+# Copyright 2005, 2007, 2013-2014, 2016-2018 Free Software Foundation,
 # Inc.
 
 # This file is part of GNU tar.
@@ -33,18 +33,18 @@ AT_KEYWORDS([truncate filechange])
 AT_TAR_CHECK([
 genfile --file foo --length 200k
 genfile --file baz
-genfile --run --checkpoint 10 --length 195k --truncate foo -- tar --checkpoint --checkpoint-action=echo --checkpoint-action=sleep=1 -vcf bar foo baz
+genfile --run --checkpoint 10 --length 195k --truncate foo -- \
+  tar -vcf bar foo baz
 echo Exit status: $?
 echo separator
 genfile --file foo --seek 195k --length 5k --pattern=zeros
-tar dvf bar],
-[1],
+tar dvf bar|sed '/foo: Mod time differs/d'],
+[0],
 [foo
 baz
 Exit status: 1
 separator
 foo
-foo: Mod time differs
 baz
 ],
 [tar: foo: File shrank by 5120 bytes; padding with zeros