[Pkg-shadow-commits] r276 - trunk/debian/patches

[Alexander Gattin]

Author: xrgtn-guest
Date: 2005-06-20 08:30:38 +0000 (Mon, 20 Jun 2005)
New Revision: 276

Added:
   trunk/debian/patches/356_su-stop_cont-proxy
Modified:
   trunk/debian/patches/series
Log:
added "stop/cont proxy" patch for bug #314727


Added: trunk/debian/patches/356_su-stop_cont-proxy
===================================================================
--- trunk/debian/patches/356_su-stop_cont-proxy	2005-06-20 00:16:30 UTC (rev 275)
+++ trunk/debian/patches/356_su-stop_cont-proxy	2005-06-20 08:30:38 UTC (rev 276)
@@ -0,0 +1,61 @@
+Goal:	When su process sits between parent and child shells, it should
+	pass STOPs from child to parent and CONTs from parent to child.
+
+Status wrt upstream: Will possibly be accepted upstream, in 4.0.11.
+
+Notes:	SIGCHLD is handled implicitly by waitpid() when WUNTRACED flag is
+	specified.
+	
+	SIGCONT just resumes execution of "su" right after the point where
+	it was stopped -- i.e. starting from the next command after
+	kill(SIGSTOP), which has been processed synchronously.
+	
+	Thus there's no need to set signal handlers for either SIGCHLD or
+	SIGCONT, and code is much cleaner with this.
+	
+	Because waitpid() is now placed inside a loop, here are some comments
+	about when the loop is broken:
+	1. (wpid != pid && errno != EINTR) -- waitpid(pid, ...) error like
+	   wrong pid, options, but excluding interrupted by signal case
+	2. WIFEXITED
+	3. WIFSIGNALED
+	4. WCOREDUMP
+	This _differs_ with Tomasz's in EINTR handling -- Tomasz's su will
+	_exit_ on EINTR. This code won't. I suspect that it's not possible
+	to be inerrupted _that way_ with e.g. SIGCHLD, but who knows...
+
+	Closes: 314727
+	(suspend command from su shell fails to return to parent shell)
+
+Index: shadow-4.0.3/src/su.c
+===================================================================
+--- shadow-4.0.3.orig/src/su.c	2005-06-20 11:15:03.000000000 +0300
++++ shadow-4.0.3/src/su.c	2005-06-20 11:35:27.000000000 +0300
+@@ -737,7 +737,7 @@
+ 	   around to close sessions */
+ 	if (getdef_bool("CLOSE_SESSIONS")) {
+ 		pid_t pid;
+-		int status;
++		int status, wpid;
+ 
+ 		signal(SIGINT, SIG_IGN);
+ 		pid = fork();
+@@ -754,7 +754,17 @@
+ 			signal(SIGINT, SIG_DFL);
+ 			break;
+ 		default: /* parent */
+-			waitpid(pid, &status, 0);
++			do {
++				errno = 0;
++				wpid = waitpid(pid, &status, WUNTRACED);
++				if (wpid == pid && WIFSTOPPED(status)) {
++					/* stop when child stops */
++					raise(SIGSTOP);
++					/* wake child when resumed */
++					kill(pid, SIGCONT);
++				}
++			} while (wpid == pid && WIFSTOPPED(status)
++					|| wpid != pid && errno == EINTR);
+ 			/* now we are done using PAM */
+ 			pam_setcred(pamh, PAM_DELETE_CRED);
+ 			ret = pam_close_session(pamh, 0);

Modified: trunk/debian/patches/series
===================================================================
--- trunk/debian/patches/series	2005-06-20 00:16:30 UTC (rev 275)
+++ trunk/debian/patches/series	2005-06-20 08:30:38 UTC (rev 276)
@@ -120,3 +120,4 @@
 421_login.1_pishing
 422_getdate.c_generated_file
 010_more-i18ned-messages
+356_su-stop_cont-proxy