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

[Fabiano Rosas]

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.

> +    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;
>  }