Re: [libvirt] [PATCH 16/20] xen: Remove PATH_MAX sized stack allocation from block stats code

--- src/xen/block_stats.c | 52 +++++++++++++++++++++++++----------------------- 1 files changed, 27 insertions(+), 25 deletions(-) diff --git a/src/xen/block_stats.c b/src/xen/block_stats.c index e7c80c9..6b4171d 100644 --- a/src/xen/block_stats.c +++ b/src/xen/block_stats.c @@ -113,34 +113,36 @@ read_stat (const char *path) } static int64_t -read_bd_stat (int device, int domid, const char *str) +read_bd_stat(int device, int domid, const char *str) { - char path[PATH_MAX]; + static const char *paths[] = { + "/sys/bus/xen-backend/devices/vbd-%d-%d/statistics/%s", + "/sys/bus/xen-backend/devices/tap-%d-%d/statistics/%s", + "/sys/devices/xen-backend/vbd-%d-%d/statistics/%s", + "/sys/devices/xen-backend/tap-%d-%d/statistics/%s", + NULL + };

+ + int i; + char *path; int64_t r; - snprintf (path, sizeof path, - "/sys/bus/xen-backend/devices/vbd-%d-%d/statistics/%s", - domid, device, str); - r = read_stat (path); - if (r >= 0) return r; - - snprintf (path, sizeof path, - "/sys/bus/xen-backend/devices/tap-%d-%d/statistics/%s", - domid, device, str); - r = read_stat (path); - if (r >= 0) return r; - - snprintf (path, sizeof path, - "/sys/devices/xen-backend/vbd-%d-%d/statistics/%s", - domid, device, str); - r = read_stat (path); - if (r >= 0) return r; - - snprintf (path, sizeof path, - "/sys/devices/xen-backend/tap-%d-%d/statistics/%s", - domid, device, str); - r = read_stat (path); - return r; + for (i = 0; paths[i] != NULL; ++i) {

+ if (virAsprintf(&path, paths[i], domid, device, str) < 0) { + virReportOOMError(); + return -1; + } + + r = read_stat(path); + + VIR_FREE(path); + + if (r >= 0) { + return r; + } + } + + return -1; }