Re: [Qemu-devel] [PATCH v0] qemu-io: add pattern file for write command

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

29.05.2019 9:48, Denis Plotnikov wrote:
> The patch allows to provide a pattern file for write
> command. There was no similar ability before.
> 
> Signed-off-by: Denis Plotnikov <dplotnikov@virtuozzo.com>
> ---
>   qemu-io-cmds.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++----
>   1 file changed, 54 insertions(+), 4 deletions(-)
> 
> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
> index 09750a23ce..b93955116f 100644
> --- a/qemu-io-cmds.c
> +++ b/qemu-io-cmds.c
> @@ -21,6 +21,7 @@
>   #include "qemu/option.h"
>   #include "qemu/timer.h"
>   #include "qemu/cutils.h"
> +#include "string.h"
>   
>   #define CMD_NOFILE_OK   0x01
>   
> @@ -343,6 +344,35 @@ static void *qemu_io_alloc(BlockBackend *blk, size_t len, int pattern)
>       return buf;
>   }
>   
> +static void *qemu_io_alloc_from_file(BlockBackend *blk, size_t len,
> +                                     char *file_name)
> +{
> +    void *buf;
> +    FILE *f = fopen(file_name, "r");
> +
> +    if (!f) {
> +        printf("cannot open file '%s'\n", file_name);

I see, printf fro errors is preexisting in qemu-io-cmds.c, but error_report is used here too,
I think it's better to use error_report.

> +        return NULL;
> +    }
> +
> +    if (qemuio_misalign) {
> +        len += MISALIGN_OFFSET;
> +    }
> +    buf = blk_blockalign(blk, len);
> +    memset(buf, 0, len);
> +
> +    if (!fread(buf, sizeof(char), len, f)) {
> +        printf("file '%s' is empty\n", file_name);
> +        free(buf);
> +        return NULL;
> +    }
> +
> +    if (qemuio_misalign) {
> +        buf += MISALIGN_OFFSET;

hmm, preexisting in qemu_io_alloc and qemu_io_free, but If I remember correctly, pointer arithmetic
on void* is not guaranteed to work as expected here..

> +    }
> +    return buf;
> +}
> +
>   static void qemu_io_free(void *p)
>   {
>       if (qemuio_misalign) {
> @@ -965,7 +995,7 @@ static const cmdinfo_t write_cmd = {
>       .perm       = BLK_PERM_WRITE,
>       .argmin     = 2,
>       .argmax     = -1,
> -    .args       = "[-bcCfnquz] [-P pattern] off len",
> +    .args       = "[-bcCfnquz] [-P pattern | -s source_file] off len",
>       .oneline    = "writes a number of bytes at a specified offset",
>       .help       = write_help,
>   };
> @@ -974,7 +1004,7 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
>   {
>       struct timeval t1, t2;
>       bool Cflag = false, qflag = false, bflag = false;
> -    bool Pflag = false, zflag = false, cflag = false;
> +    bool Pflag = false, zflag = false, cflag = false, sflag = false;
>       int flags = 0;
>       int c, cnt, ret;
>       char *buf = NULL;
> @@ -983,8 +1013,9 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
>       /* Some compilers get confused and warn if this is not initialized.  */
>       int64_t total = 0;
>       int pattern = 0xcd;
> +    char file_name[255] = { 0 };
>   
> -    while ((c = getopt(argc, argv, "bcCfnpP:quz")) != -1) {
> +    while ((c = getopt(argc, argv, "bcCfnpP:quzs:")) != -1) {
>           switch (c) {
>           case 'b':
>               bflag = true;
> @@ -1020,6 +1051,10 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
>           case 'z':
>               zflag = true;
>               break;
> +        case 's':
> +            sflag = true;
> +            strncpy(file_name, optarg, sizeof(file_name) - 1);

Maybe, g_strdup and don't care about file_name length?

> +            break;
>           default:
>               qemuio_command_usage(&write_cmd);
>               return -EINVAL;
> @@ -1056,6 +1091,14 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
>           return -EINVAL;
>       }
>   
> +    if (sflag && Pflag) {
> +        printf("-s and -P cannot be specified at the same time\n");
> +    }
> +
> +    if (zflag && Pflag) {
> +        printf("-z and -P cannot be specified at the same time\n");
> +    }

strange, that you add this last check.. I see it in master branch already.

> +
>       offset = cvtnum(argv[optind]);
>       if (offset < 0) {
>           print_cvtnum_err(offset, argv[optind]);
> @@ -1088,7 +1131,14 @@ static int write_f(BlockBackend *blk, int argc, char **argv)
>       }
>   
>       if (!zflag) {
> -        buf = qemu_io_alloc(blk, count, pattern);
> +        if (sflag) {
> +            buf = qemu_io_alloc_from_file(blk, count, file_name);
> +            if (!buf) {
> +                return -EINVAL;
> +            }
> +        } else {
> +            buf = qemu_io_alloc(blk, count, pattern);
> +        }
>       }
>   
>       gettimeofday(&t1, NULL);
> 


-- 
Best regards,
Vladimir