Re: [libvirt] [PATCH] host-validate: Improve CPU flags processing

Instead of relying on substring search, tokenize the input and process each CPU flag separately. This ensures CPU flag detection will continue to work correctly even if we start looking for CPU flags whose name might appear as part of other CPU flags' names. The result of processing is stored in a virBitmap, which means we don't have to parse /proc/cpuinfo in its entirety for each single CPU flag we want to check. Moreover, use of the newly-introduced virHostValidateCPUFlag enumeration ensures we don't go looking for random CPU flags which might actually be simple typos. --- The concern was raised by John in https://www.redhat.com/archives/libvir-list/2016-March/msg01301.html when discussing a new check on the "sie" CPU flag. tools/virt-host-validate-common.c | 50 +++++++++++++++++++++++++++++---------- tools/virt-host-validate-common.h | 13 +++++++++- tools/virt-host-validate-qemu.c | 12 ++++++++-- 3 files changed, 60 insertions(+), 15 deletions(-) diff --git a/tools/virt-host-validate-common.c b/tools/virt-host-validate-common.c index 8ebf73e..57fa332 100644 --- a/tools/virt-host-validate-common.c +++ b/tools/virt-host-validate-common.c

@@ -188,29 +191,47 @@ int virHostValidateNamespace(const char *hvname, } -bool virHostValidateHasCPUFlag(const char *name) +virBitmapPtr virHostValidateGetCPUFlags(void) { - FILE *fp = fopen("/proc/cpuinfo", "r"); - bool ret = false; + FILE *fp; + virBitmapPtr flags; - if (!fp) - return false; + if (!(fp = fopen("/proc/cpuinfo", "r"))) + return NULL; + + if (!(flags = virBitmapNewQuiet(VIR_HOST_VALIDATE_CPU_FLAG_LAST)))

+ return NULL; do { char line[1024]; + char *saveptr; + char *token; if (!fgets(line, sizeof(line), fp)) break; - if (strstr(line, name)) { - ret = true; - break; + if (!(token = strtok_r(line, " \t\n", &saveptr)))

+ continue; + + /* The line we're interested in is marked either as "flags" or + * as "Features" depending on the architecture, so check both + * prefixes. It's very unlikely that there will be no whitespace + * between the line name and the colon, but handle that as well */ + if (strcmp(token, "flags") && strcmp(token, "flags:") &&