Re: [PATCH v4 1/2] libqos/fw_cfg: refactor file directory iteraton to make it more reusable

[Ani Sinha]

> On 10 Jan 2025, at 1:31 AM, Fabiano Rosas <farosas@suse.de> wrote:
> 
> Ani Sinha <anisinha@redhat.com> writes:
> 
>> fw-cfg file directory iteration code can be used by other functions that may
>> want to implement fw-cfg file operations. Refactor it into a smaller helper
>> so that it can be reused.
>> 
>> No functional change.
>> 
>> Signed-off-by: Ani Sinha <anisinha@redhat.com>
>> ---
>> tests/qtest/libqos/fw_cfg.c | 63 ++++++++++++++++++++++++-------------
>> 1 file changed, 41 insertions(+), 22 deletions(-)
>> 
>> diff --git a/tests/qtest/libqos/fw_cfg.c b/tests/qtest/libqos/fw_cfg.c
>> index 89f053ccac..f1ed4898f7 100644
>> --- a/tests/qtest/libqos/fw_cfg.c
>> +++ b/tests/qtest/libqos/fw_cfg.c
>> @@ -60,6 +60,39 @@ static void mm_fw_cfg_select(QFWCFG *fw_cfg, uint16_t key)
>>     qtest_writew(fw_cfg->qts, fw_cfg->base, key);
>> }
>> 
>> +static bool
>> +find_pdir_entry(QFWCFG *fw_cfg, const char *filename,
>> +                uint16_t *sel, uint32_t *size)
>> +{
>> +    g_autofree unsigned char *filesbuf = NULL;
>> +    uint32_t count;
>> +    size_t dsize;
>> +    FWCfgFile *pdir_entry;
>> +    uint32_t i;
>> +    bool found = false;
>> +
>> +    *size = 0;
>> +    *sel = 0;
>> +
>> +    qfw_cfg_get(fw_cfg, FW_CFG_FILE_DIR, &count, sizeof(count));
>> +    count = be32_to_cpu(count);
>> +    dsize = sizeof(uint32_t) + count * sizeof(struct fw_cfg_file);
>> +    filesbuf = g_malloc(dsize);
>> +    g_assert(filesbuf);
> 
> g_malloc already aborts the program if the allocation fails.

ok good point. Will remove them in the next patch spin-up. 

> 
>> +    qfw_cfg_get(fw_cfg, FW_CFG_FILE_DIR, filesbuf, dsize);
>> +    pdir_entry = (FWCfgFile *)(filesbuf + sizeof(uint32_t));
>> +    for (i = 0; i < count; ++i, ++pdir_entry) {
>> +        if (!strcmp(pdir_entry->name, filename)) {
>> +            *size = be32_to_cpu(pdir_entry->size);
>> +            *sel = be16_to_cpu(pdir_entry->select);
>> +            found = true;
>> +            break;
>> +        }
>> +    }
>> +
>> +    return found;
>> +}
>> +
>> /*
>>  * The caller need check the return value. When the return value is
>>  * nonzero, it means that some bytes have been transferred.
>> @@ -75,32 +108,18 @@ static void mm_fw_cfg_select(QFWCFG *fw_cfg, uint16_t 
>> key)
>> size_t qfw_cfg_get_file(QFWCFG *fw_cfg, const char *filename,
>>                       void *data, size_t buflen)
>> {
>> -    uint32_t count;
>> -    uint32_t i;
>> -    unsigned char *filesbuf = NULL;
>> -    size_t dsize;
>> -    FWCfgFile *pdir_entry;
>>     size_t filesize = 0;
>> +    uint32_t len;
>> +    uint16_t sel;
>> 
>> -    qfw_cfg_get(fw_cfg, FW_CFG_FILE_DIR, &count, sizeof(count));
>> -    count = be32_to_cpu(count);
>> -    dsize = sizeof(uint32_t) + count * sizeof(struct fw_cfg_file);
>> -    filesbuf = g_malloc(dsize);
>> -    qfw_cfg_get(fw_cfg, FW_CFG_FILE_DIR, filesbuf, dsize);
>> -    pdir_entry = (FWCfgFile *)(filesbuf + sizeof(uint32_t));
>> -    for (i = 0; i < count; ++i, ++pdir_entry) {
>> -        if (!strcmp(pdir_entry->name, filename)) {
>> -            uint32_t len = be32_to_cpu(pdir_entry->size);
>> -            uint16_t sel = be16_to_cpu(pdir_entry->select);
>> -            filesize = len;
>> -            if (len > buflen) {
>> -                len = buflen;
>> -            }
>> -            qfw_cfg_get(fw_cfg, sel, data, len);
>> -            break;
>> +    if (find_pdir_entry(fw_cfg, filename, &sel, &len)) {
>> +        filesize = len;
>> +        if (len > buflen) {
>> +            len = buflen;
>>         }
>> +        qfw_cfg_get(fw_cfg, sel, data, len);
>>     }
>> -    g_free(filesbuf);
>> +
>>     return filesize;
>> }