From 209df1f20e34620e6d970358b343af10e90800be Mon Sep 17 00:00:00 2001
From: Matthias Andree <matthias.andree@gmx.de>
Date: Mon, 14 Aug 2006 00:58:00 +0000
Subject: Ignore SIGPIPE, EPIPE must suffice as error. Calling longjmp() from a
 signal handler is unsafe.

svn path=/branches/BRANCH_6-3/; revision=4893
---
 NEWS     |  3 +++
 driver.c | 27 +++++----------------------
 2 files changed, 8 insertions(+), 22 deletions(-)

diff --git a/NEWS b/NEWS
index 8a733bae..6d8f922a 100644
--- a/NEWS
+++ b/NEWS
@@ -104,6 +104,9 @@ fetchmail 6.3.5 (not yet released):
   now reported to the TTY where fetchmail was started from.
 * fetchmail now complains and aborts when it cannot properly daemonize itself.
 * fix compilation on systems that don't know struct addrinfo (Solaris 2.6).
+* ignore SIGPIPE signals and rely on functions to return EPIPE instead. This is
+  necessary because the former longjmp() from the signal handler is unsafe and
+  makes the whole fetchmail behavior undefined after the event.
 
 # CHANGES:
 * Rename all fetchmail-internal lock_* functions to fm_lock_*. Obsoletes
diff --git a/driver.c b/driver.c
index c1d38a41..ae4b7e69 100644
--- a/driver.c
+++ b/driver.c
@@ -55,7 +55,6 @@
 
 /* throw types for runtime errors */
 #define THROW_TIMEOUT	1		/* server timed out */
-#define THROW_SIGPIPE	2		/* SIGPIPE on stream socket */
 
 /* magic values for the message length array */
 #define MSGLEN_UNKNOWN	0		/* length unknown (0 is impossible) */
@@ -110,18 +109,14 @@ static RETSIGTYPE timeout_handler (int signal)
     (void)signal;
     if(stage != STAGE_IDLE) {
 	timeoutcount++;
+	/* XXX FIXME: this siglongjmp must die - it's not safe to be
+	 * called from a function handler and breaks, for instance,
+	 * getaddrinfo() */
 	siglongjmp(restart, THROW_TIMEOUT);
     } else
 	idletimeout = 1;
 }
 
-static RETSIGTYPE sigpipe_handler (int signal)
-/* handle SIGPIPE signal indicating a broken stream socket */
-{
-    (void)signal;
-    siglongjmp(restart, THROW_SIGPIPE);
-}
-
 #define CLEANUP_TIMEOUT 60 /* maximum timeout during cleanup */
 
 static int cleanupSockClose (int fd)
@@ -845,7 +840,6 @@ static int do_session(
     int tmperr;
     int deletions = 0, js;
     const char *msg;
-    SIGHANDLERTYPE pipesave;
     SIGHANDLERTYPE alrmsave;
 
     ctl->server.base_protocol = proto;
@@ -859,9 +853,6 @@ static int do_session(
     alrmsave = set_signal_handler(SIGALRM, timeout_handler);
     mytimeout = ctl->server.timeout;
 
-    /* set up the broken-pipe timeout */
-    pipesave = set_signal_handler(SIGPIPE, sigpipe_handler);
-
     if ((js = sigsetjmp(restart,1)))
     {
 	/* exception caught */
@@ -878,14 +869,7 @@ static int do_session(
 	    freeaddrinfo(ai1); ai1 = NULL;
 	}
 	
-	if (js == THROW_SIGPIPE)
-	{
-	    set_signal_handler(SIGPIPE, SIG_IGN);
-	    report(stdout,
-		   GT_("SIGPIPE thrown from an MDA or a stream socket error\n"));
-	    wait(0);
-	}
-	else if (js == THROW_TIMEOUT)
+	if (js == THROW_TIMEOUT)
 	{
 	    if (phase == OPEN_WAIT)
 		report(stdout,
@@ -939,7 +923,7 @@ static int do_session(
     }
     else
     {
-	/* setjmp returned zero -> normal operation */
+	/* sigsetjmp returned zero -> normal operation */
 	char buf[MSGBUFSIZE+1], *realhost;
 	int count, newm, bytes;
 	int fetches, dispatches, oldphase;
@@ -1581,7 +1565,6 @@ closeUp:
 
     set_timeout(0); /* cancel any pending alarm */
     set_signal_handler(SIGALRM, alrmsave);
-    set_signal_handler(SIGPIPE, pipesave);
     return(err);
 }
 
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