From 9338b244572e07bbff314b3570228e8cf43f1300 Mon Sep 17 00:00:00 2001

From: Kamil Dudka <kdudka@redhat.com>

Date: Tue, 6 Sep 2016 17:38:26 +0200

Subject: [PATCH] ls: allow interruption when reading slow directories

Postpone installation of signal handlers until they're needed.

That is right before the first escape sequence is printed.

* src/ls.c (signal_setup): A new function refactored from main()

to set and restore signal handlers.

(main): Move signal handler setup to put_indicator()

so that the default signal handling is untouched as long as possible.

Adjusted condition for restoring signal handlers to reflect the change.

(put_indicator): Install signal handlers if called for the very first

time.  It uses the same code that was in main() prior to this commit.

* NEWS: Mention the improvement.

See https://bugzilla.redhat.com/1365933

Fixes http://bugs.gnu.org/24232

Upstream-commit: 5445f7811ff945ea13aa2a0fd797eb4c0a0e4db0

Signed-off-by: Kamil Dudka <kdudka@redhat.com>

---

 src/ls.c | 161 ++++++++++++++++++++++++++++++++++++---------------------------

 1 file changed, 93 insertions(+), 68 deletions(-)

diff --git a/src/ls.c b/src/ls.c

index d976036..66df307 100644

--- a/src/ls.c

+++ b/src/ls.c

@@ -1244,13 +1244,12 @@ process_signals (void)

     }

 }

-int

-main (int argc, char **argv)

-{

-  int i;

-  struct pending *thispend;

-  int n_files;

+/* Setup signal handlers if INIT is true,

+   otherwise restore to the default.  */

+static void

+signal_setup (bool init)

+{

   /* The signals that are trapped, and the number of such signals.  */

   static int const sig[] =

     {

@@ -1278,8 +1277,77 @@ main (int argc, char **argv)

   enum { nsigs = ARRAY_CARDINALITY (sig) };

 #if ! SA_NOCLDSTOP

-  bool caught_sig[nsigs];

+  static bool caught_sig[nsigs];

+#endif

+

+  int j;

+

+  if (init)

+    {

+#if SA_NOCLDSTOP

+      struct sigaction act;

+

+      sigemptyset (&caught_signals);

+      for (j = 0; j < nsigs; j++)

+        {

+          sigaction (sig[j], NULL, &act;;

+          if (act.sa_handler != SIG_IGN)

+            sigaddset (&caught_signals, sig[j]);

+        }

+

+      act.sa_mask = caught_signals;

+      act.sa_flags = SA_RESTART;

+

+      for (j = 0; j < nsigs; j++)

+        if (sigismember (&caught_signals, sig[j]))

+          {

+            act.sa_handler = sig[j] == SIGTSTP ? stophandler : sighandler;

+            sigaction (sig[j], &act, NULL);

+          }

+#else

+      for (j = 0; j < nsigs; j++)

+        {

+          caught_sig[j] = (signal (sig[j], SIG_IGN) != SIG_IGN);

+          if (caught_sig[j])

+            {

+              signal (sig[j], sig[j] == SIGTSTP ? stophandler : sighandler);

+              siginterrupt (sig[j], 0);

+            }

+        }

 #endif

+    }

+  else /* restore.  */

+    {

+#if SA_NOCLDSTOP

+      for (j = 0; j < nsigs; j++)

+        if (sigismember (&caught_signals, sig[j]))

+          signal (sig[j], SIG_DFL);

+#else

+      for (j = 0; j < nsigs; j++)

+        if (caught_sig[j])

+          signal (sig[j], SIG_DFL);

+#endif

+    }

+}

+

+static inline void

+signal_init (void)

+{

+  signal_setup (true);

+}

+

+static inline void

+signal_restore (void)

+{

+  signal_setup (false);

+}

+

+int

+main (int argc, char **argv)

+{

+  int i;

+  struct pending *thispend;

+  int n_files;

   initialize_main (&argc, &argv);

   set_program_name (argv[0]);

@@ -1314,46 +1382,6 @@ main (int argc, char **argv)

           || (is_colored (C_EXEC) && color_symlink_as_referent)

           || (is_colored (C_MISSING) && format == long_format))

         check_symlink_color = true;

-

-      /* If the standard output is a controlling terminal, watch out

-         for signals, so that the colors can be restored to the

-         default state if "ls" is suspended or interrupted.  */

-

-      if (0 <= tcgetpgrp (STDOUT_FILENO))

-        {

-          int j;

-#if SA_NOCLDSTOP

-          struct sigaction act;

-

-          sigemptyset (&caught_signals);

-          for (j = 0; j < nsigs; j++)

-            {

-              sigaction (sig[j], NULL, &act;;

-              if (act.sa_handler != SIG_IGN)

-                sigaddset (&caught_signals, sig[j]);

-            }

-

-          act.sa_mask = caught_signals;

-          act.sa_flags = SA_RESTART;

-

-          for (j = 0; j < nsigs; j++)

-            if (sigismember (&caught_signals, sig[j]))

-              {

-                act.sa_handler = sig[j] == SIGTSTP ? stophandler : sighandler;

-                sigaction (sig[j], &act, NULL);

-              }

-#else

-          for (j = 0; j < nsigs; j++)

-            {

-              caught_sig[j] = (signal (sig[j], SIG_IGN) != SIG_IGN);

-              if (caught_sig[j])

-                {

-                  signal (sig[j], sig[j] == SIGTSTP ? stophandler : sighandler);

-                  siginterrupt (sig[j], 0);

-                }

-            }

-#endif

-        }

     }

   if (dereference == DEREF_UNDEFINED)

@@ -1466,32 +1494,21 @@ main (int argc, char **argv)

       print_dir_name = true;

     }

-  if (print_with_color)

+  if (print_with_color && used_color)

     {

       int j;

-      if (used_color)

-        {

-          /* Skip the restore when it would be a no-op, i.e.,

-             when left is "\033[" and right is "m".  */

-          if (!(color_indicator[C_LEFT].len == 2

-                && memcmp (color_indicator[C_LEFT].string, "\033[", 2) == 0

-                && color_indicator[C_RIGHT].len == 1

-                && color_indicator[C_RIGHT].string[0] == 'm'))

-            restore_default_color ();

-        }

+      /* Skip the restore when it would be a no-op, i.e.,

+         when left is "\033[" and right is "m".  */

+      if (!(color_indicator[C_LEFT].len == 2

+            && memcmp (color_indicator[C_LEFT].string, "\033[", 2) == 0

+            && color_indicator[C_RIGHT].len == 1

+            && color_indicator[C_RIGHT].string[0] == 'm'))

+        restore_default_color ();

+

       fflush (stdout);

-      /* Restore the default signal handling.  */

-#if SA_NOCLDSTOP

-      for (j = 0; j < nsigs; j++)

-        if (sigismember (&caught_signals, sig[j]))

-          signal (sig[j], SIG_DFL);

-#else

-      for (j = 0; j < nsigs; j++)

-        if (caught_sig[j])

-          signal (sig[j], SIG_DFL);

-#endif

+      signal_restore ();

       /* Act on any signals that arrived before the default was restored.

          This can process signals out of order, but there doesn't seem to

@@ -4482,6 +4499,14 @@ put_indicator (const struct bin_str *ind)

   if (! used_color)

     {

       used_color = true;

+

+      /* If the standard output is a controlling terminal, watch out

+         for signals, so that the colors can be restored to the

+         default state if "ls" is suspended or interrupted.  */

+

+      if (0 <= tcgetpgrp (STDOUT_FILENO))

+        signal_init ();

+

       prep_non_filename_text ();

     }

-- 

2.7.4