Message ID | 20171201224909.9373-1-klim.kireev@virtuozzo.com |
---|---|
State | New |
Headers | show |
Series | [v2] qemu-img: add the simplest format recognition | expand |
On 12/01/2017 04:49 PM, Klim Kireev wrote: > Now, if you type something like > > qemu-img create disk.qcow2 1G > or > qemu-img dd if=/dev/sda of=disk.qcow2 > > it creates a raw image and if you need you should > manually specify an image format with -f qcow2. It would > be more convenient if it could be detected from an extension. > > This patch adds a simple heuristic to recognize the image format > for qcow, qcow2, vmdk, vhdx, vdi > > It warns users about guessed format and informs them about '-f' option. > > Signed-off-by: Klim Kireev <klim.kireev@virtuozzo.com> > --- > qemu-img.c | 21 +++++++++++++++++++-- > 1 file changed, 19 insertions(+), 2 deletions(-) > > diff --git a/qemu-img.c b/qemu-img.c > index 02a6e27beb..ac1adf1582 100644 > --- a/qemu-img.c > +++ b/qemu-img.c > @@ -421,11 +421,22 @@ static int64_t cvtnum(const char *s) > return value; > } > > +static const char *get_format(const char *filename) > +{ > + const char *fmt = strrchr(filename, '.'); > + if (fmt == NULL || bdrv_find_format(++fmt) == NULL) { > + fmt = "raw"; > + } > + printf("!!! %s format was detected.\n" Assumed, not detected. (We didn't read the file, because we're creating it; we're assuming a format based on the file name, not its contents, and detection tends to imply a contents-based check). > + "!!! If you meant another format, specify it with -f.\n", fmt); Not our usual error reporting style; the !!! is yelling at the user, and we tend to avoid trailing '.'. printf() goes to stdout, but the message should go to stderr(); you really want to use warn_report(). I suggest: warn_report("No format specified with -f, assuming %s.", fmt);
diff --git a/qemu-img.c b/qemu-img.c index 02a6e27beb..ac1adf1582 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -421,11 +421,22 @@ static int64_t cvtnum(const char *s) return value; } +static const char *get_format(const char *filename) +{ + const char *fmt = strrchr(filename, '.'); + if (fmt == NULL || bdrv_find_format(++fmt) == NULL) { + fmt = "raw"; + } + printf("!!! %s format was detected.\n" + "!!! If you meant another format, specify it with -f.\n", fmt); + return fmt; +} + static int img_create(int argc, char **argv) { int c; uint64_t img_size = -1; - const char *fmt = "raw"; + const char *fmt = NULL; const char *base_fmt = NULL; const char *filename; const char *base_filename = NULL; @@ -496,6 +507,9 @@ static int img_create(int argc, char **argv) /* Get the filename */ filename = (optind < argc) ? argv[optind] : NULL; + if (fmt == NULL) { + fmt = get_format(filename); + } if (options && has_help_option(options)) { g_free(options); return print_block_option_help(filename, fmt); @@ -4181,7 +4195,7 @@ static int img_dd(int argc, char **argv) Error *local_err = NULL; bool image_opts = false; int c, i; - const char *out_fmt = "raw"; + const char *out_fmt = NULL; const char *fmt = NULL; int64_t size = 0; int64_t block_count = 0, out_pos, in_pos; @@ -4308,6 +4322,9 @@ static int img_dd(int argc, char **argv) goto out; } + if (out_fmt == NULL) { + out_fmt = get_format(out.filename); + } drv = bdrv_find_format(out_fmt); if (!drv) { error_report("Unknown file format");
Now, if you type something like qemu-img create disk.qcow2 1G or qemu-img dd if=/dev/sda of=disk.qcow2 it creates a raw image and if you need you should manually specify an image format with -f qcow2. It would be more convenient if it could be detected from an extension. This patch adds a simple heuristic to recognize the image format for qcow, qcow2, vmdk, vhdx, vdi It warns users about guessed format and informs them about '-f' option. Signed-off-by: Klim Kireev <klim.kireev@virtuozzo.com> --- qemu-img.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)