svn commit: r230874 - head/usr.bin/sockstat

[Mikolaj Golub]

Author: trociny
Date: Wed Feb  1 18:03:21 2012
New Revision: 230874
URL: http://svn.freebsd.org/changeset/base/230874

Log:
  Try to avoid ambiguity when sysctl returns ENOMEM additionally
  checking the returned oldlen: when ENOMEM is due to the supplied
  buffer being too short the return oldlen is equal to buffer size.
  
  Without this additional check sockstat gets stuck in loop leaking the
  memory if the returned ENOMEM was due the exceeded memorylocked
  limit. This is easily can be observed running `limits -l 1k sockstat'.
  
  Submitted by:	Andrey Zonov <andrey zonov org>
  MFC after:	1 week

Modified:
  head/usr.bin/sockstat/sockstat.c

Modified: head/usr.bin/sockstat/sockstat.c
==============================================================================
--- head/usr.bin/sockstat/sockstat.c	Wed Feb  1 18:02:13 2012	(r230873)
+++ head/usr.bin/sockstat/sockstat.c	Wed Feb  1 18:03:21 2012	(r230874)
@@ -296,7 +296,7 @@ gather_inet(int proto)
 				break;
 			if (errno == ENOENT)
 				goto out;
-			if (errno != ENOMEM)
+			if (errno != ENOMEM || len != bufsize)
 				err(1, "sysctlbyname()");
 			bufsize *= 2;
 		}
@@ -424,7 +424,7 @@ gather_unix(int proto)
 			len = bufsize;
 			if (sysctlbyname(varname, buf, &len, NULL, 0) == 0)
 				break;
-			if (errno != ENOMEM)
+			if (errno != ENOMEM || len != bufsize)
 				err(1, "sysctlbyname()");
 			bufsize *= 2;
 		}
@@ -476,14 +476,15 @@ out:
 static void
 getfiles(void)
 {
-	size_t len;
+	size_t len, olen;
 
-	if ((xfiles = malloc(len = sizeof *xfiles)) == NULL)
+	olen = len = sizeof *xfiles;
+	if ((xfiles = malloc(len)) == NULL)
 		err(1, "malloc()");
 	while (sysctlbyname("kern.file", xfiles, &len, 0, 0) == -1) {
-		if (errno != ENOMEM)
+		if (errno != ENOMEM || len != olen)
 			err(1, "sysctlbyname()");
-		len *= 2;
+		olen = len *= 2;
 		if ((xfiles = realloc(xfiles, len)) == NULL)
 			err(1, "realloc()");
 	}