[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v7] qemu-io: add pattern file for write command
From: |
Max Reitz |
Subject: |
Re: [Qemu-devel] [PATCH v7] qemu-io: add pattern file for write command |
Date: |
Fri, 2 Aug 2019 18:05:22 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 |
On 05.07.19 12:21, 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>
> ---
> v7:
> * fix variable naming
> * make code more readable
> * extend help for write command
>
> 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 | 86 ++++++++++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 80 insertions(+), 6 deletions(-)
>
> diff --git a/qemu-io-cmds.c b/qemu-io-cmds.c
> index 09750a23ce..495170380a 100644
> --- a/qemu-io-cmds.c
> +++ b/qemu-io-cmds.c
> @@ -343,6 +343,66 @@ 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)
Wouldn’t a const char * suffice?
> +{
> + char *buf, *buf_origin;
> + FILE *f = fopen(file_name, "r");
> + int pattern_len;
> +
> + if (!f) {
> + printf("'%s': %s\n", file_name, strerror(errno));
(1) Why stdout and not stderr?
(2) Why not just perror()?
> + return NULL;
> + }
> +
> + if (qemuio_misalign) {
> + len += MISALIGN_OFFSET;
> + }
> +
> + buf_origin = buf = blk_blockalign(blk, len);
> +
> + pattern_len = fread(buf, sizeof(char), len, f);
I know I pointed out already that the C standard defines sizeof(char) to
be 1, but I just want to add that “sizeof(char)” does not appear
anywhere in qemu so far.
That doesn’t make it wrong, but here it looks a bit weird...
> +
> + if (ferror(f)) {
> + printf("'%s': %s\n", file_name, strerror(errno));
> + goto error;
> + }
> +
> + if (pattern_len == 0) {
> + printf("'%s' is empty\n", file_name);
> + goto error;
> + }
> +
> + fclose(f);
> +
> + if (len > pattern_len) {
> + char *file_buf = g_malloc(sizeof(char) * pattern_len);
...and here you’d actually have to check that the multiplication doesn’t
overflow if you actually consider it a possibility that
sizeof(char) != 1.
But actually, this allocation is just unnecessary altogether, as
Vladimir has said for v6. You can drop this line,...
> + memcpy(file_buf, buf, pattern_len);
...this line,...
> + len -= pattern_len;
> + buf += pattern_len;
> +
> + while (len > 0) {
> + size_t len_to_copy = MIN(pattern_len, len);
> +
> + memcpy(buf, file_buf, len_to_copy);
...make this a memcpy(buf, buf_origin, len_to_copy);,...
> +
> + len -= len_to_copy;
> + buf += len_to_copy;
> + }
> + qemu_vfree(file_buf);
...and drop this line, too.
> + }
> +
> + if (qemuio_misalign) {
> + buf_origin += MISALIGN_OFFSET;
This will change the pattern, though, because now you’re skipping the
first MISALIGN_OFFSET bytes. Should the fread() above read to
buf_origin + MISALIGN_OFFSET in that case?
[...]
> @@ -983,8 +1044,9 @@ 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 +1082,10 @@ static int write_f(BlockBackend *blk, int argc, char
> **argv)
> case 'z':
> zflag = true;
> break;
> + case 's':
> + sflag = true;
> + file_name = g_strdup(optarg);
Why does file_name need to be a char * and duplicated here? (optarg
always points into argv, so as long as that doesn’t change, the optarg
pointer stays valid.)
Max
> + break;
> default:
> qemuio_command_usage(&write_cmd);
> return -EINVAL;
signature.asc
Description: OpenPGP digital signature
[Prev in Thread] |
Current Thread |
[Next in Thread] |
- Re: [Qemu-devel] [PATCH v7] qemu-io: add pattern file for write command,
Max Reitz <=