Author: benno
Date: Thu Sep 4 03:31:48 2014
New Revision: 271085
URL: http://svnweb.freebsd.org/changeset/base/271085
Log:
Systems with lots of geom providers can end up with a kern.geom.confxml
value too large for the buffer allocated. Work around this by retrying
a few times with larger buffer sizes.
Submitted by: Scott Ferris <scott.fer...@isilon.com>
Reviewed by: mlaier, ngie
Sponsored by: EMC Isilon Storage Division
Modified:
head/lib/libgeom/geom_getxml.c
Modified: head/lib/libgeom/geom_getxml.c
==============================================================================
--- head/lib/libgeom/geom_getxml.c Thu Sep 4 03:04:37 2014
(r271084)
+++ head/lib/libgeom/geom_getxml.c Thu Sep 4 03:31:48 2014
(r271085)
@@ -31,10 +31,23 @@
#include <sys/types.h>
#include <sys/sysctl.h>
+#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "libgeom.h"
+/*
+ * Amount of extra space we allocate to try and anticipate the size of
+ * confxml.
+ */
+#define GEOM_GETXML_SLACK 4096
+
+/*
+ * Number of times to retry in the face of the size of confxml exceeding
+ * that of our buffer.
+ */
+#define GEOM_GETXML_RETRIES 4
+
char *
geom_getxml(void)
{
@@ -42,19 +55,33 @@ geom_getxml(void)
size_t l = 0;
int mib[3];
size_t sizep;
+ int retries;
sizep = sizeof(mib) / sizeof(*mib);
if (sysctlnametomib("kern.geom.confxml", mib, &sizep) != 0)
return (NULL);
if (sysctl(mib, sizep, NULL, &l, NULL, 0) != 0)
return (NULL);
- l += 4096;
- p = malloc(l);
- if (p == NULL)
- return (NULL);
- if (sysctl(mib, sizep, p, &l, NULL, 0) != 0) {
+ l += GEOM_GETXML_SLACK;
+
+ for (retries = 0; retries < GEOM_GETXML_RETRIES; retries++) {
+ p = malloc(l);
+ if (p == NULL)
+ return (NULL);
+ if (sysctl(mib, sizep, p, &l, NULL, 0) == 0)
+ return (reallocf(p, strlen(p) + 1));
+
free(p);
- return (NULL);
+
+ if (errno != ENOMEM)
+ return (NULL);
+
+ /*
+ * Our buffer wasn't big enough. Make it bigger and
+ * try again.
+ */
+ l *= 2;
}
- return (reallocf(p, strlen(p) + 1));
+
+ return (NULL);
}
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