Re: [Qemu-devel] [PATCH v2] fw_cfg: Use g_file_get_contents instead of multiple fread() calls

[Anthony Liguori <anthony@codemonkey.ws>]

On 10/24/2011 06:31 AM, Pavel Borzenkov wrote:
> Signed-off-by: Pavel Borzenkov<pavel.borzenkov@gmail.com>

Applied.  Thanks.

Regards,

Anthony Liguori

> ---
>   hw/fw_cfg.c |  102 ++++++++++++++++++++++-------------------------------------
>   1 files changed, 38 insertions(+), 64 deletions(-)
>
> diff --git a/hw/fw_cfg.c b/hw/fw_cfg.c
> index 8df265c..dbcb888 100644
> --- a/hw/fw_cfg.c
> +++ b/hw/fw_cfg.c
> @@ -60,71 +60,55 @@ struct FWCfgState {
>   #define JPG_FILE 0
>   #define BMP_FILE 1
>
> -static FILE *probe_splashfile(char *filename, int *file_sizep, int *file_typep)
> +static char *read_splashfile(char *filename, int *file_sizep, int *file_typep)
>   {
> -    FILE *fp = NULL;
> -    int fop_ret;
> -    int file_size;
> +    GError *err = NULL;
> +    gboolean res;
> +    gchar *content;
>       int file_type = -1;
> -    unsigned char buf[2] = {0, 0};
> -    unsigned int filehead_value = 0;
> +    unsigned int filehead = 0;
>       int bmp_bpp;
>
> -    fp = fopen(filename, "rb");
> -    if (fp == NULL) {
> -        error_report("failed to open file '%s'.", filename);
> -        return fp;
> +    res = g_file_get_contents(filename,&content, (gsize *)file_sizep,&err);
> +    if (res == FALSE) {
> +        error_report("failed to read splash file '%s'", filename);
> +        g_error_free(err);
> +        return NULL;
>       }
> +
>       /* check file size */
> -    fseek(fp, 0L, SEEK_END);
> -    file_size = ftell(fp);
> -    if (file_size<  2) {
> -        error_report("file size is less than 2 bytes '%s'.", filename);
> -        fclose(fp);
> -        fp = NULL;
> -        return fp;
> +    if (*file_sizep<  30) {
> +        goto error;
>       }
> +
>       /* check magic ID */
> -    fseek(fp, 0L, SEEK_SET);
> -    fop_ret = fread(buf, 1, 2, fp);
> -    if (fop_ret != 2) {
> -        error_report("Could not read header from '%s': %s",
> -                     filename, strerror(errno));
> -        fclose(fp);
> -        fp = NULL;
> -        return fp;
> -    }
> -    filehead_value = (buf[0] + (buf[1]<<  8))&  0xffff;
> -    if (filehead_value == 0xd8ff) {
> +    filehead = ((content[0]&  0xff) + (content[1]<<  8))&  0xffff;
> +    if (filehead == 0xd8ff) {
>           file_type = JPG_FILE;
> +    } else if (filehead == 0x4d42) {
> +        file_type = BMP_FILE;
>       } else {
> -        if (filehead_value == 0x4d42) {
> -            file_type = BMP_FILE;
> -        }
> -    }
> -    if (file_type<  0) {
> -        error_report("'%s' not jpg/bmp file,head:0x%x.",
> -                         filename, filehead_value);
> -        fclose(fp);
> -        fp = NULL;
> -        return fp;
> +        goto error;
>       }
> +
>       /* check BMP bpp */
>       if (file_type == BMP_FILE) {
> -        fseek(fp, 28, SEEK_SET);
> -        fop_ret = fread(buf, 1, 2, fp);
> -        bmp_bpp = (buf[0] + (buf[1]<<  8))&  0xffff;
> +        bmp_bpp = (content[28] + (content[29]<<  8))&  0xffff;
>           if (bmp_bpp != 24) {
> -            error_report("only 24bpp bmp file is supported.");
> -            fclose(fp);
> -            fp = NULL;
> -            return fp;
> +            goto error;
>           }
>       }
> +
>       /* return values */
> -    *file_sizep = file_size;
>       *file_typep = file_type;
> -    return fp;
> +
> +    return content;
> +
> +error:
> +    error_report("splash file '%s' format not recognized; must be JPEG "
> +                 "or 24 bit BMP", filename);
> +    g_free(content);
> +    return NULL;
>   }
>
>   static void fw_cfg_bootsplash(FWCfgState *s)
> @@ -132,9 +116,7 @@ static void fw_cfg_bootsplash(FWCfgState *s)
>       int boot_splash_time = -1;
>       const char *boot_splash_filename = NULL;
>       char *p;
> -    char *filename;
> -    FILE *fp;
> -    int fop_ret;
> +    char *filename, *file_data;
>       int file_size;
>       int file_type = -1;
>       const char *temp;
> @@ -174,27 +156,19 @@ static void fw_cfg_bootsplash(FWCfgState *s)
>               error_report("failed to find file '%s'.", boot_splash_filename);
>               return;
>           }
> -        /* probing the file */
> -        fp = probe_splashfile(filename,&file_size,&file_type);
> -        if (fp == NULL) {
> +
> +        /* loading file data */
> +        file_data = read_splashfile(filename,&file_size,&file_type);
> +        if (file_data == NULL) {
>               g_free(filename);
>               return;
>           }
> -        /* loading file data */
>           if (boot_splash_filedata != NULL) {
>               g_free(boot_splash_filedata);
>           }
> -        boot_splash_filedata = g_malloc(file_size);
> +        boot_splash_filedata = (uint8_t *)file_data;
>           boot_splash_filedata_size = file_size;
> -        fseek(fp, 0L, SEEK_SET);
> -        fop_ret = fread(boot_splash_filedata, 1, file_size, fp);
> -        if (fop_ret != file_size) {
> -            error_report("failed to read data from '%s'.",
> -                         boot_splash_filename);
> -            fclose(fp);
> -            return;
> -        }
> -        fclose(fp);
> +
>           /* insert data */
>           if (file_type == JPG_FILE) {
>               fw_cfg_add_file(s, "bootsplash.jpg",