Message ID | 20171201200515.9938-1-klim.kireev@virtuozzo.com |
---|---|
State | New |
Headers | show |
Series | qemu-img: add the simplest format recognition | expand |
On 12/01/2017 02:05 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 > > Signed-off-by: Klim Kireev <klim.kireev@virtuozzo.com> > Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> > --- > qemu-img.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) Is it also worth warning the user that we guessed, and that they should specify -f if our guess was wrong? > @@ -496,6 +510,9 @@ static int img_create(int argc, char **argv) > > /* Get the filename */ > filename = (optind < argc) ? argv[optind] : NULL; > + if (fmt == NULL) { > + fmt = get_format(filename); Particularly if fmt == "raw", because the user typed something like 'foo.img' instead of 'foo.qcow2'. I suspect another common mis-guess would be users that type .qcow but want qcow2. The idea makes sense to me, though.
diff --git a/qemu-img.c b/qemu-img.c index 02a6e27beb..0a659d2257 100644 --- a/qemu-img.c +++ b/qemu-img.c @@ -421,11 +421,25 @@ 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) { + return "raw"; + } + fmt++; + if (bdrv_find_format(fmt) != NULL) { + return fmt; + } else { + return "raw"; + } +} + 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 +510,9 @@ 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 +4198,7 @@ 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 +4325,9 @@ 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");