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Re: [Qemu-devel] [PATCH v2] qemu-io: add pattern file for write command
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v2] qemu-io: add pattern file for write command |
Date: |
Wed, 29 May 2019 14:28:09 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 |
On 29.05.19 13:46, Denis Plotnikov wrote:
> The patch allows to provide a pattern file for write
> command. There was no similar ability before.
> ---
> 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..148f2ff92a 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);
strerror(errno) would probably be helpful.
> + return NULL;
> + }
> +
> + if (qemuio_misalign) {
> + len += MISALIGN_OFFSET;
> + }
> + buf = blk_blockalign(blk, len);
> + memset(buf, 0, len);
> +
> + if (!fread(buf, sizeof(char), len, f)) {
(1) You should probably check ferror(f),
(2) Currently, on a short read, the rest in buf is unallocated. I think
it would be nicest if the pattern would be repeated to fill the whole
buffer.
> + printf("file '%s' is empty\n", file_name);
> + qemu_vfree(buf);
> + return NULL;
> + }
> +
> + if (qemuio_misalign) {
> + buf += MISALIGN_OFFSET;
This still uses pointer arithmetic on a void * pointer as Vladimir has
said. Making buf a char * pointer should be the simplest way to fix this.
> + }
> + 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;
>
> - 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;
> + file_name = g_strdup(optarg);
> + 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 (sflag && zflag) {
> + printf("-s and -z cannot be specified at the same time\n");
> + }
> +
Well, you also need to return from this function, just printing the
message is not sufficient to abort the operation.
Also, the shorter way would be something like:
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;
}
Max
> 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);
>
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