| Message ID | 1449674087-19122-1-git-send-email-sakari.ailus@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Sakari, Thank you for the patch. On Wednesday 09 December 2015 17:14:47 Sakari Ailus wrote: > The length of the string was ignored, making it possible for the > conversion to fail due to extra characters in the string. I'm not sure to follow you there. Is the issue that passing a string such as "SBGGR10" would match "SBGGR10_DPCM8" if it was listed before "SBGGR10" ? If that's the case I'd write the commit message as Any character beyond the fist `length' characters in the mbus_formats strings are ignored, causing incorrect matches if the format entry starts with but isn't equal to the passed format. > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > --- > This patch should be applied before the set "[v4l-utils PATCH v2 0/3] List > supported formats in libv4l2subdev": > > <URL:http://www.spinics.net/lists/linux-media/msg95377.html> > > utils/media-ctl/libv4l2subdev.c | 10 ++++------ > 1 file changed, 4 insertions(+), 6 deletions(-) > > diff --git a/utils/media-ctl/libv4l2subdev.c > b/utils/media-ctl/libv4l2subdev.c index 33c1ee6..cce527d 100644 > --- a/utils/media-ctl/libv4l2subdev.c > +++ b/utils/media-ctl/libv4l2subdev.c > @@ -769,14 +769,12 @@ enum v4l2_mbus_pixelcode > v4l2_subdev_string_to_pixelcode(const char *string, unsigned int i; > > for (i = 0; i < ARRAY_SIZE(mbus_formats); ++i) { > - if (strncmp(mbus_formats[i].name, string, length) == 0) > - break; > + if (strncmp(mbus_formats[i].name, string, length) == 0 > + && strlen(mbus_formats[i].name) == length) How about mbus_formats[i].name[length] == '\0' instead ? That should be more efficient. I also wonder whether we shouldn't just get rid of the length argument and force the passed format string to be zero-terminated. > + return mbus_formats[i].code; > } > > - if (i == ARRAY_SIZE(mbus_formats)) > - return (enum v4l2_mbus_pixelcode)-1; > - > - return mbus_formats[i].code; > + return (enum v4l2_mbus_pixelcode)-1; > } > > static struct {
Hi Laurent, On Sun, Dec 13, 2015 at 11:33:45PM +0200, Laurent Pinchart wrote: > Hi Sakari, > > Thank you for the patch. > > On Wednesday 09 December 2015 17:14:47 Sakari Ailus wrote: > > The length of the string was ignored, making it possible for the > > conversion to fail due to extra characters in the string. > > I'm not sure to follow you there. Is the issue that passing a string such as > "SBGGR10" would match "SBGGR10_DPCM8" if it was listed before "SBGGR10" ? If > that's the case I'd write the commit message as Yes, that's the problem. > > Any character beyond the fist `length' characters in the mbus_formats strings > are ignored, causing incorrect matches if the format entry starts with but > isn't equal to the passed format. I'll use this commit message then. > > > Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > > --- > > This patch should be applied before the set "[v4l-utils PATCH v2 0/3] List > > supported formats in libv4l2subdev": > > > > <URL:http://www.spinics.net/lists/linux-media/msg95377.html> > > > > utils/media-ctl/libv4l2subdev.c | 10 ++++------ > > 1 file changed, 4 insertions(+), 6 deletions(-) > > > > diff --git a/utils/media-ctl/libv4l2subdev.c > > b/utils/media-ctl/libv4l2subdev.c index 33c1ee6..cce527d 100644 > > --- a/utils/media-ctl/libv4l2subdev.c > > +++ b/utils/media-ctl/libv4l2subdev.c > > @@ -769,14 +769,12 @@ enum v4l2_mbus_pixelcode > > v4l2_subdev_string_to_pixelcode(const char *string, unsigned int i; > > > > for (i = 0; i < ARRAY_SIZE(mbus_formats); ++i) { > > - if (strncmp(mbus_formats[i].name, string, length) == 0) > > - break; > > + if (strncmp(mbus_formats[i].name, string, length) == 0 > > + && strlen(mbus_formats[i].name) == length) > > How about mbus_formats[i].name[length] == '\0' instead ? That should be more > efficient. Fine for me. > > I also wonder whether we shouldn't just get rid of the length argument and > force the passed format string to be zero-terminated. I believe the reason is that the current user (media-ctl test program) parses the user input and passes a portion of that to this function to convert the string to a numeric value. That'd be a bit more cumbersome as we'd either require copying the string elsewhere or changing the input by the program. I wouldn't change the behaviour, at least not now. > > > + return mbus_formats[i].code; > > } > > > > - if (i == ARRAY_SIZE(mbus_formats)) > > - return (enum v4l2_mbus_pixelcode)-1; > > - > > - return mbus_formats[i].code; > > + return (enum v4l2_mbus_pixelcode)-1; > > } > > > > static struct { >
Hi Sakari, On Monday 25 January 2016 13:39:10 Sakari Ailus wrote: > On Sun, Dec 13, 2015 at 11:33:45PM +0200, Laurent Pinchart wrote: > > On Wednesday 09 December 2015 17:14:47 Sakari Ailus wrote: > >> The length of the string was ignored, making it possible for the > >> conversion to fail due to extra characters in the string. > > > > I'm not sure to follow you there. Is the issue that passing a string such > > as "SBGGR10" would match "SBGGR10_DPCM8" if it was listed before > > "SBGGR10" ? If that's the case I'd write the commit message as > > Yes, that's the problem. > > > Any character beyond the fist `length' characters in the mbus_formats > > strings are ignored, causing incorrect matches if the format entry starts > > with but isn't equal to the passed format. > > I'll use this commit message then. > > >> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > >> --- > >> This patch should be applied before the set "[v4l-utils PATCH v2 0/3] > >> List supported formats in libv4l2subdev": > >> > >> <URL:http://www.spinics.net/lists/linux-media/msg95377.html> > >> > >> utils/media-ctl/libv4l2subdev.c | 10 ++++------ > >> 1 file changed, 4 insertions(+), 6 deletions(-) > >> > >> diff --git a/utils/media-ctl/libv4l2subdev.c > >> b/utils/media-ctl/libv4l2subdev.c index 33c1ee6..cce527d 100644 > >> --- a/utils/media-ctl/libv4l2subdev.c > >> +++ b/utils/media-ctl/libv4l2subdev.c > >> @@ -769,14 +769,12 @@ enum v4l2_mbus_pixelcode > >> v4l2_subdev_string_to_pixelcode(const char *string, > >> unsigned int i; > >> > >> for (i = 0; i < ARRAY_SIZE(mbus_formats); ++i) { > >> - if (strncmp(mbus_formats[i].name, string, length) == 0) > >> - break; > >> + if (strncmp(mbus_formats[i].name, string, length) == 0 > >> + && strlen(mbus_formats[i].name) == length) > > > > How about mbus_formats[i].name[length] == '\0' instead ? That should be > > more efficient. > > Fine for me. > > > I also wonder whether we shouldn't just get rid of the length argument and > > force the passed format string to be zero-terminated. > > I believe the reason is that the current user (media-ctl test program) > parses the user input and passes a portion of that to this function to > convert the string to a numeric value. That'd be a bit more cumbersome as > we'd either require copying the string elsewhere or changing the input by > the program. I wouldn't change the behaviour, at least not now. Yes that's the reason, and I think it's an API design mistake (or just a lack of proper API design :-)). Wouldn't it be better to copy the string in the caller ? > >> + return mbus_formats[i].code; > >> } > >> > >> - if (i == ARRAY_SIZE(mbus_formats)) > >> - return (enum v4l2_mbus_pixelcode)-1; > >> - > >> - return mbus_formats[i].code; > >> + return (enum v4l2_mbus_pixelcode)-1; > >> } > >> > >> static struct {
Hi Laurent, On Mon, Jan 25, 2016 at 09:41:12PM +0200, Laurent Pinchart wrote: > Hi Sakari, > > On Monday 25 January 2016 13:39:10 Sakari Ailus wrote: > > On Sun, Dec 13, 2015 at 11:33:45PM +0200, Laurent Pinchart wrote: > > > On Wednesday 09 December 2015 17:14:47 Sakari Ailus wrote: > > >> The length of the string was ignored, making it possible for the > > >> conversion to fail due to extra characters in the string. > > > > > > I'm not sure to follow you there. Is the issue that passing a string such > > > as "SBGGR10" would match "SBGGR10_DPCM8" if it was listed before > > > "SBGGR10" ? If that's the case I'd write the commit message as > > > > Yes, that's the problem. > > > > > Any character beyond the fist `length' characters in the mbus_formats > > > strings are ignored, causing incorrect matches if the format entry starts > > > with but isn't equal to the passed format. > > > > I'll use this commit message then. > > > > >> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > > >> --- > > >> This patch should be applied before the set "[v4l-utils PATCH v2 0/3] > > >> List supported formats in libv4l2subdev": > > >> > > >> <URL:http://www.spinics.net/lists/linux-media/msg95377.html> > > >> > > >> utils/media-ctl/libv4l2subdev.c | 10 ++++------ > > >> 1 file changed, 4 insertions(+), 6 deletions(-) > > >> > > >> diff --git a/utils/media-ctl/libv4l2subdev.c > > >> b/utils/media-ctl/libv4l2subdev.c index 33c1ee6..cce527d 100644 > > >> --- a/utils/media-ctl/libv4l2subdev.c > > >> +++ b/utils/media-ctl/libv4l2subdev.c > > >> @@ -769,14 +769,12 @@ enum v4l2_mbus_pixelcode > > >> v4l2_subdev_string_to_pixelcode(const char *string, > > >> unsigned int i; > > >> > > >> for (i = 0; i < ARRAY_SIZE(mbus_formats); ++i) { > > >> - if (strncmp(mbus_formats[i].name, string, length) == 0) > > >> - break; > > >> + if (strncmp(mbus_formats[i].name, string, length) == 0 > > >> + && strlen(mbus_formats[i].name) == length) > > > > > > How about mbus_formats[i].name[length] == '\0' instead ? That should be > > > more efficient. > > > > Fine for me. > > > > > I also wonder whether we shouldn't just get rid of the length argument and > > > force the passed format string to be zero-terminated. > > > > I believe the reason is that the current user (media-ctl test program) > > parses the user input and passes a portion of that to this function to > > convert the string to a numeric value. That'd be a bit more cumbersome as > > we'd either require copying the string elsewhere or changing the input by > > the program. I wouldn't change the behaviour, at least not now. > > Yes that's the reason, and I think it's an API design mistake (or just a lack > of proper API design :-)). Wouldn't it be better to copy the string in the > caller ? From the API point of view, I don't disagree. But I do think this should be done in a separate patch, not in this one --- this is a bugfix, really. I'll submit one more patch for that. > > >> + return mbus_formats[i].code; > > >> } > > >> > > >> - if (i == ARRAY_SIZE(mbus_formats)) > > >> - return (enum v4l2_mbus_pixelcode)-1; > > >> - > > >> - return mbus_formats[i].code; > > >> + return (enum v4l2_mbus_pixelcode)-1; > > >> } > > >> > > >> static struct { >
Hi Sakari, On Monday 25 January 2016 22:47:07 Sakari Ailus wrote: > On Mon, Jan 25, 2016 at 09:41:12PM +0200, Laurent Pinchart wrote: > > On Monday 25 January 2016 13:39:10 Sakari Ailus wrote: > > > On Sun, Dec 13, 2015 at 11:33:45PM +0200, Laurent Pinchart wrote: > > > > On Wednesday 09 December 2015 17:14:47 Sakari Ailus wrote: > > > >> The length of the string was ignored, making it possible for the > > > >> conversion to fail due to extra characters in the string. > > > > > > > > I'm not sure to follow you there. Is the issue that passing a string > > > > such as "SBGGR10" would match "SBGGR10_DPCM8" if it was listed before > > > > "SBGGR10" ? If that's the case I'd write the commit message as > > > > > > Yes, that's the problem. > > > > > > > Any character beyond the fist `length' characters in the mbus_formats > > > > strings are ignored, causing incorrect matches if the format entry > > > > starts > > > > with but isn't equal to the passed format. > > > > > > I'll use this commit message then. > > > > > > >> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > > > >> --- > > > >> This patch should be applied before the set "[v4l-utils PATCH v2 0/3] > > > >> List supported formats in libv4l2subdev": > > > >> > > > >> <URL:http://www.spinics.net/lists/linux-media/msg95377.html> > > > >> > > > >> utils/media-ctl/libv4l2subdev.c | 10 ++++------ > > > >> 1 file changed, 4 insertions(+), 6 deletions(-) > > > >> > > > >> diff --git a/utils/media-ctl/libv4l2subdev.c > > > >> b/utils/media-ctl/libv4l2subdev.c index 33c1ee6..cce527d 100644 > > > >> --- a/utils/media-ctl/libv4l2subdev.c > > > >> +++ b/utils/media-ctl/libv4l2subdev.c > > > >> @@ -769,14 +769,12 @@ enum v4l2_mbus_pixelcode > > > >> v4l2_subdev_string_to_pixelcode(const char *string, > > > >> > > > >> unsigned int i; > > > >> > > > >> for (i = 0; i < ARRAY_SIZE(mbus_formats); ++i) { > > > >> > > > >> - if (strncmp(mbus_formats[i].name, string, length) == 0) > > > >> - break; > > > >> + if (strncmp(mbus_formats[i].name, string, length) == 0 > > > >> + && strlen(mbus_formats[i].name) == length) > > > > > > > > How about mbus_formats[i].name[length] == '\0' instead ? That should > > > > be more efficient. > > > > > > Fine for me. > > > > > > > I also wonder whether we shouldn't just get rid of the length argument > > > > and force the passed format string to be zero-terminated. > > > > > > I believe the reason is that the current user (media-ctl test program) > > > parses the user input and passes a portion of that to this function to > > > convert the string to a numeric value. That'd be a bit more cumbersome > > > as we'd either require copying the string elsewhere or changing the > > > input by the program. I wouldn't change the behaviour, at least not now. > > > > Yes that's the reason, and I think it's an API design mistake (or just a > > lack of proper API design :-)). Wouldn't it be better to copy the string > > in the caller ? > > From the API point of view, I don't disagree. But I do think this should be > done in a separate patch, not in this one --- this is a bugfix, really. Sure, I agree with that. > I'll submit one more patch for that. Thank you. > > > >> + return mbus_formats[i].code; > > > >> > > > >> } > > > >> > > > >> - if (i == ARRAY_SIZE(mbus_formats)) > > > >> - return (enum v4l2_mbus_pixelcode)-1; > > > >> - > > > >> - return mbus_formats[i].code; > > > >> + return (enum v4l2_mbus_pixelcode)-1; > > > >> > > > >> } > > > >> > > > >> static struct {
diff --git a/utils/media-ctl/libv4l2subdev.c b/utils/media-ctl/libv4l2subdev.c index 33c1ee6..cce527d 100644 --- a/utils/media-ctl/libv4l2subdev.c +++ b/utils/media-ctl/libv4l2subdev.c @@ -769,14 +769,12 @@ enum v4l2_mbus_pixelcode v4l2_subdev_string_to_pixelcode(const char *string, unsigned int i; for (i = 0; i < ARRAY_SIZE(mbus_formats); ++i) { - if (strncmp(mbus_formats[i].name, string, length) == 0) - break; + if (strncmp(mbus_formats[i].name, string, length) == 0 + && strlen(mbus_formats[i].name) == length) + return mbus_formats[i].code; } - if (i == ARRAY_SIZE(mbus_formats)) - return (enum v4l2_mbus_pixelcode)-1; - - return mbus_formats[i].code; + return (enum v4l2_mbus_pixelcode)-1; } static struct {
The length of the string was ignored, making it possible for the conversion to fail due to extra characters in the string. Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> --- This patch should be applied before the set "[v4l-utils PATCH v2 0/3] List supported formats in libv4l2subdev": <URL:http://www.spinics.net/lists/linux-media/msg95377.html> utils/media-ctl/libv4l2subdev.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)