From: Andreas Schwab <schwab@suse.de>
Date: Sat, 19 Jan 2013 16:18:47 +0000 (+0100)
Subject: Avoid busy loop in wordexp when substituted command closed its stdout
X-Git-Tag: upstream/2.30~9593
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ab087e0aa4bd9f12a73ca0b248f02d8a22d49e46;p=external%2Fglibc.git

Avoid busy loop in wordexp when substituted command closed its stdout
---

diff --git a/ChangeLog b/ChangeLog
index 3bf3949..9b53463 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2013-01-21  Andreas Schwab  <schwab@suse.de>
+
+	[BZ #15020]
+	* posix/wordexp.c (exec_comm): Avoid busy loop when command has
+	closed its stdout.
+
 2013-01-20  Andreas Schwab  <schwab@linux-m68k.org>
 
 	* sysdeps/powerpc/powerpc32/power4/fpu/mpa.c: Don't include
diff --git a/NEWS b/NEWS
index cf6191b..abbbbae 100644
--- a/NEWS
+++ b/NEWS
@@ -10,7 +10,7 @@ Version 2.18
 * The following bugs are resolved with this release:
 
   13951, 14200, 14317, 14327, 14496, 14964, 14981, 14982, 14985, 14994,
-  14996, 15003, 15023.
+  14996, 15003, 15020, 15023.
 
 
 Version 2.17
diff --git a/posix/wordexp.c b/posix/wordexp.c
index bf49baa..96ce8a4 100644
--- a/posix/wordexp.c
+++ b/posix/wordexp.c
@@ -953,7 +953,12 @@ exec_comm (char *comm, char **word, size_t *word_length, size_t *max_length,
 	  if ((buflen = TEMP_FAILURE_RETRY (__read (fildes[0], buffer,
 						    bufsize))) < 1)
 	    {
-	      if (TEMP_FAILURE_RETRY (__waitpid (pid, &status, WNOHANG)) == 0)
+	      /* If read returned 0 then the process has closed its
+		 stdout.  Don't use WNOHANG in that case to avoid busy
+		 looping until the process eventually exits.  */
+	      if (TEMP_FAILURE_RETRY (__waitpid (pid, &status,
+						 buflen == 0 ? 0 : WNOHANG))
+		  == 0)
 		continue;
 	      if ((buflen = TEMP_FAILURE_RETRY (__read (fildes[0], buffer,
 							bufsize))) < 1)
@@ -983,7 +988,12 @@ exec_comm (char *comm, char **word, size_t *word_length, size_t *max_length,
 	  if ((buflen = TEMP_FAILURE_RETRY (__read (fildes[0], buffer,
 						    bufsize))) < 1)
 	    {
-	      if (TEMP_FAILURE_RETRY (__waitpid (pid, &status, WNOHANG)) == 0)
+	      /* If read returned 0 then the process has closed its
+		 stdout.  Don't use WNOHANG in that case to avoid busy
+		 looping until the process eventually exits.  */
+	      if (TEMP_FAILURE_RETRY (__waitpid (pid, &status,
+						 buflen == 0 ? 0 : WNOHANG))
+		  == 0)
 		continue;
 	      if ((buflen = TEMP_FAILURE_RETRY (__read (fildes[0], buffer,
 							bufsize))) < 1)