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author | benno <benno@FreeBSD.org> | 2014-09-04 03:31:48 +0000 |
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committer | benno <benno@FreeBSD.org> | 2014-09-04 03:31:48 +0000 |
commit | 420e85e546db714ae4f711b4a7affb378325545f (patch) | |
tree | ff85432eb8515df786908895d9c8fd8dd45748f2 /lib/libgeom | |
parent | a5645731d20064ece00afd48686fde8cf720f5f0 (diff) | |
download | FreeBSD-src-420e85e546db714ae4f711b4a7affb378325545f.zip FreeBSD-src-420e85e546db714ae4f711b4a7affb378325545f.tar.gz |
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.ferris@isilon.com>
Reviewed by: mlaier, ngie
Sponsored by: EMC Isilon Storage Division
Diffstat (limited to 'lib/libgeom')
-rw-r--r-- | lib/libgeom/geom_getxml.c | 41 |
1 files changed, 34 insertions, 7 deletions
diff --git a/lib/libgeom/geom_getxml.c b/lib/libgeom/geom_getxml.c index 17e0476..3fe1e72 100644 --- a/lib/libgeom/geom_getxml.c +++ b/lib/libgeom/geom_getxml.c @@ -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); } |