Re: [Qemu-block] [Qemu-devel] [PATCH v6] qemu-io: add pattern file for write command

[Denis Plotnikov]

On 19.06.2019 13:09, Vladimir Sementsov-Ogievskiy wrote:
> 10.06.2019 16:21, 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 <address@hidden>
>> ---
>> v6:
>>     * the pattern file is read once to reduce io
>>
>> v5:
>>     * file name initiated with null to make compilers happy
>>
>> v4:
>>     * missing signed-off clause added
>>
>> v3:
>>     * missing file closing added
>>     * exclusive flags processing changed
>>     * buffer void* converted to char* to fix pointer arithmetics
>>     * file reading error processing added
>> ---
>>    qemu-io-cmds.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++----
>>    1 file changed, 82 insertions(+), 6 deletions(-)
>>
>> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
>> index 09750a23ce..e27203f747 100644
>> --- a/qemu-io-cmds.c
>> +++ b/qemu-io-cmds.c
>> @@ -343,6 +343,69 @@ 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)
>> +{
>> +    char *buf, *buf_origin;
>> +    FILE *f = fopen(file_name, "r");
>> +    int l;
> 
> should be size_t, and could you get it descriptive name pattern_len or like 
> this?
> 
>> +
>> +    if (!f) {
>> +        printf("'%s': %s\n", file_name, strerror(errno));
>> +        return NULL;
>> +    }
>> +
>> +    if (qemuio_misalign) {
>> +        len += MISALIGN_OFFSET;
>> +    }
>> +    buf_origin = blk_blockalign(blk, len);
>> +    memset(buf_origin, 0, len);
>> +
>> +    buf = buf_origin;
>> +
>> +    l = fread(buf, sizeof(char), len, f);
>> +
>> +    if (ferror(f)) {
>> +        printf("'%s': %s\n", file_name, strerror(errno));
>> +        goto error;
>> +    }
>> +
>> +    if (l == 0) {
>> +        printf("'%s' is empty\n", file_name);
>> +        goto error;
>> +    }
>> +
>> +    if (l < len) {
>> +        char *file_buf = g_malloc(sizeof(char) * l);
>> +        memcpy(file_buf, buf, l);
> 
> I see no reason to copy it, you can just use buf_origin pointer
> instead.
I use buf_origin to save the beginning pointer to return it from the 
function avoiding later calculation of the beginning address since 
pointer of the buf is changed in the loop.
> 
>> +        len -= l;
>> +        buf += l;
>> +
>> +        while (len > 0) {
>> +            size_t len_to_copy = len > l ? l : len;
> 
> you may use MIN(len, l)
> 
>> +
>> +            memcpy(buf, file_buf, len_to_copy);
>> +
>> +            len -= len_to_copy;
>> +            buf += len_to_copy;
>> +        }
>> +        qemu_vfree(file_buf);
>> +    }
>> +
>> +    if (qemuio_misalign) {
>> +        buf_origin += MISALIGN_OFFSET;
>> +    }
>> +
>> +    goto out;
>> +
>> +error:
>> +    qemu_vfree(buf);
>> +    buf_origin = NULL;
>> +out:
>> +    fclose(f);
>> +    return buf_origin;
>> +}
>> +
>>    static void qemu_io_free(void *p)
>>    {
>>        if (qemuio_misalign) {
>> @@ -965,7 +1028,7 @@ 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 +1037,7 @@ 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 +1046,9 @@ 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 = NULL;
>>    
>> -    while ((c = getopt(argc, argv, "bcCfnpP:quz")) != -1) {
>> +    while ((c = getopt(argc, argv, "bcCfnpP:quzs:")) != -1) {
>>            switch (c) {
>>            case 'b':
>>                bflag = true;
>> @@ -1020,6 +1084,10 @@ static int write_f(BlockBackend *blk, int argc, char 
>> **argv)
>>            case 'z':
>>                zflag = true;
>>                break;
>> +        case 's':
>> +            sflag = true;
>> +            file_name = g_strdup(optarg);
>> +            break;
>>            default:
>>                qemuio_command_usage(&write_cmd);
>>                return -EINVAL;
>> @@ -1051,8 +1119,9 @@ static int write_f(BlockBackend *blk, int argc, char 
>> **argv)
>>            return -EINVAL;
>>        }
>>    
>> -    if (zflag && Pflag) {
>> -        printf("-z and -P cannot be specified at the same time\n");
>> +    if ((int)zflag + (int)Pflag + (int)sflag > 1) {
>> +        printf("Only one of -z, -P, and -s"
>> +               "can be specified at the same time\n");
>>            return -EINVAL;
>>        }
>>    
>> @@ -1088,7 +1157,14 @@ 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,
Denis