bin/68839: [PATCH] gcore hangs on current

Dan Nelson dan at
Thu Jul 8 19:40:22 PDT 2004

>Number:         68839
>Category:       bin
>Synopsis:       [PATCH] gcore hangs on current
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Jul 09 02:40:22 GMT 2004
>Originator:     Dan Nelson
>Release:        FreeBSD 5.2-CURRENT i386
The Allant Group
System: FreeBSD 5.2-CURRENT FreeBSD 5.2-CURRENT #341: Wed Jun 23 23:03:45 CDT 2004 zsh at i386


The 2003/09/29 commit to procfs_map.c added a column to /proc/*/map. 
This breaks gcore, which ends up in an infinite loop trying to parse
the first line of the mapfile over and over and over with the wrong
number of fields.


$ gcore $$
<wait forever>

Parse the new field, and add a sanity check that we scanned a nonzero
number of characters so when someone changes the format of /proc/*/map
again gcore will catch it.  gcore should probably be rewritten to not
use /procfs.

Index: elfcore.c
RCS file: /home/ncvs/src/usr.bin/gcore/elfcore.c,v
retrieving revision 1.16
diff -u -r1.16 elfcore.c
--- elfcore.c	15 Feb 2004 22:48:25 -0000	1.16
+++ elfcore.c	9 Jul 2004 02:16:54 -0000
@@ -504,10 +504,10 @@
 		len = 0;
 		n = sscanf(mapbuf + pos, "%x %x %*d %*d %*x %3[-rwx]"
-		    " %*d %*d %*x %*s %*s %16s%*[\n]%n",
+		    " %*d %*d %*x %*s %*s %16s %*s%*[\n]%n",
 		    &start, &end, prot, type, &len);
-		if (n != 4)
-			errx(1, "ill-formed line in %s", mapname);
+		if (n != 4 || len == 0)
+			errx(1, "ill-formed line in %s starting at character %d", mapname, pos + 1);
 		pos += len;
 		/* Ignore segments of the wrong kind, and unwritable ones */



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