On 07/17/2018 08:42 PM, John Ferlan wrote:
On 07/04/2018 05:23 AM, Michal Privoznik wrote:
Firstly, we can utilize virCommandSetOutputBuffer() API which will collect the command output for us. Secondly, sscanf()-ing through each line is easier to understand (and more robust) than jumping over a string with strchr().
Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/util/viriscsi.c | 85 +++++++++++++++++++++-------------------------------- 1 file changed, 34 insertions(+), 51 deletions(-)
diff --git a/src/util/viriscsi.c b/src/util/viriscsi.c index 01b5b4be68..1ddf00aa4c 100644 --- a/src/util/viriscsi.c +++ b/src/util/viriscsi.c @@ -108,7 +108,6 @@ virISCSIGetSession(const char *devpath,
-#define LINE_SIZE 4096 #define IQN_FOUND 1 #define IQN_MISSING 0 #define IQN_ERROR -1 @@ -117,71 +116,56 @@ static int virStorageBackendIQNFound(const char *initiatoriqn, char **ifacename) { - int ret = IQN_ERROR, fd = -1; - char ebuf[64]; - FILE *fp = NULL; - char *line = NULL, *newline = NULL, *iqn = NULL, *token = NULL; + int ret = IQN_ERROR; + char *outbuf = NULL; + char *line = NULL; + char *iface = NULL; + char *iqn = NULL; virCommandPtr cmd = virCommandNewArgList(ISCSIADM, "--mode", "iface", NULL);
*ifacename = NULL;
- if (VIR_ALLOC_N(line, LINE_SIZE) != 0) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("Could not allocate memory for output of '%s'"), - ISCSIADM); + virCommandSetOutputBuffer(cmd, &outbuf); + if (virCommandRun(cmd, NULL) < 0) goto cleanup; - }
- memset(line, 0, LINE_SIZE); + /* Example of data we are dealing with: + * default tcp,<empty>,<empty>,<empty>,<empty> + * iser iser,<empty>,<empty>,<empty>,<empty> + * libvirt-iface-253db048 tcp,<empty>,<empty>,<empty>,iqn.2017-03.com.user:client + */
- virCommandSetOutputFD(cmd, &fd); - if (virCommandRunAsync(cmd, NULL) < 0) - goto cleanup; + line = outbuf; + while (line && *line) { + char *newline; + int num;
- if ((fp = VIR_FDOPEN(fd, "r")) == NULL) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("Failed to open stream for file descriptor " - "when reading output from '%s': '%s'"), - ISCSIADM, virStrerror(errno, ebuf, sizeof(ebuf))); - goto cleanup; - } + if (!(newline = strchr(line, '\n'))) + break;
The next hunk is is going to pick up a non libvirt generated initiator.iqn, is that something we want? Or should we :
if (!STRPREFIX(line, "libvirt-iface-")) continue;
I don't think we need this. Firstly, the code as is now doesn't care about that either. Secondly, even though we currently call the function only to learn about libvirt-iface-* it is generic enough to be called over any interface.
where "libvirt-iface-" could be made into a #define constant for usage by both this and virStorageBackendCreateIfaceIQN
- while (fgets(line, LINE_SIZE, fp) != NULL) { - newline = strrchr(line, '\n'); - if (newline == NULL) { - virReportError(VIR_ERR_INTERNAL_ERROR, - _("Unexpected line > %d characters " - "when parsing output of '%s'"), - LINE_SIZE, ISCSIADM); - goto cleanup; - } *newline = '\0';
- iqn = strrchr(line, ','); - if (iqn == NULL) - continue; - iqn++; + VIR_FREE(iface); + VIR_FREE(iqn); + num = sscanf(line, "%ms %*[^,],%*[^,],%*[^,],%*[^,],%ms", &iface, &iqn);
Reading up on sscanf, the '%ms' seems to imply a GNU lib C mechanism vs. a C standard mechanism. So the query/concern being all our various build environments acceptance of the 'm' qualifier (at least coverity didn't choke on it ;-)).
Not really. From sscanf(3): The use of the letter a for this purpose was problematic, since a is also specified by the ISO C standard as a synonym for f (floating-point input). POSIX.1-2008 instead specifies the m modifier for assignment allocation (as documented in DESCRIPTION, above). So it's mandated by POSIX which should be good enough for us to use.
Reviewed-by: John Ferlan <jferlan@redhat.com>
Thanks, Michal