[libvirt] [PATCH 3/5] virStorageBackendIQNFound: Rework iscsiadm output parsing

Michal Prívozník mprivozn at redhat.com
Mon Jul 2 14:26:49 UTC 2018


On 07/02/2018 09:39 AM, Peter Krempa wrote:
> On Fri, Jun 29, 2018 at 17:01:49 +0200, 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 at 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 2e55b3c10b..44788056fd 100644
>> --- a/src/util/viriscsi.c
>> +++ b/src/util/viriscsi.c
> 
> [...]
> 
>> @@ -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) {
> 
> This is severely misleading and makes this loop technically infinite. Or
> just checks that output buffer was not null. Both operations should be
> made explicit. Or you meant *line or line[0]

Okay, how about:

while (line && *line) {

Michal




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