On Sunday 30 December 2018 13:51:10 Walter Harms wrote: > > > > Pali Rohár <[email protected]> hat am 29. Dezember 2018 um 18:45 > > geschrieben: > > > > > > On Monday 26 November 2018 22:17:24 Pali Rohár wrote: > > > Function strtod() sets strtod_error to the pointer of the first invalid > > > character and therefore it does not have to be first character from input. > > > When input is valid then it points to nul byte. Conversion error is > > > indicated by setted errno. Zero-length argument, non-positive DPI or DPI > > > with trailing or leading whitespaces is invalid too. > > > > > > Update also error message about invalid argument. > > > > > > Signed-off-by: Pali Rohár <[email protected]> > > > > > > -- > > > > > > Changes since v1: > > > * Get same error message for `xrandr --dpi ''` and `xrandr --dpi ' '` > > > * Make the check for dpi <= 0 > > > * Do not accept leading whitespaces (trailing were already disallowed) > > > --- > > > xrandr.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/xrandr.c b/xrandr.c > > > index ce3cd91..4baa075 100644 > > > --- a/xrandr.c > > > +++ b/xrandr.c > > > @@ -40,6 +40,7 @@ > > > #include <inttypes.h> > > > #include <stdarg.h> > > > #include <math.h> > > > +#include <ctype.h> > > > > > > #ifdef HAVE_CONFIG_H > > > #include "config.h" > > > @@ -3118,8 +3119,9 @@ main (int argc, char **argv) > > > if (!strcmp ("--dpi", argv[i])) { > > > char *strtod_error; > > > if (++i >= argc) argerr ("%s requires an argument\n", argv[i-1]); > > > + errno = 0; > > > dpi = strtod(argv[i], &strtod_error); > > > - if (argv[i] == strtod_error) > > > + if (!argv[i][0] || isspace(argv[i][0]) || *strtod_error || errno || > > > dpi <= 0) > > > { > > > dpi = 0.0; > > > dpi_output_name = argv[i]; > > > Why spending so much effort ?
Which "much effort"?
This is to ensure that incorrect param or garbage supplied by user is
not interpreted as number.
> Using atoi(argv[i]) and checking for an invalid value seems fine.
atoi does not signal when garbage is on input. And dpi can be
fractional, so atoi cannot be used for it.
> Special cases like NAN do not matter here.
>
> BTW: leading whitespaces are ignored with strtod() (so far i know)
But strtod does not signal that they were ignored. Moreover trailing are
not accepted. So I chose implementation which is consistent for trailing
and leading whitespaces.
> just my 2 cents
> re,
> wh
>
>
>
> > > @@ -3569,7 +3571,7 @@ main (int argc, char **argv)
> > > XRROutputInfo *output_info;
> > > XRRModeInfo *mode_info;
> > > if (!dpi_output)
> > > - fatal ("Cannot find output %s\n", dpi_output_name);
> > > + fatal ("%s is not valid DPI nor valid output\n",
> > > dpi_output_name);
> > > output_info = dpi_output->output_info;
> > > mode_info = dpi_output->mode_info;
> > > if (output_info && mode_info && output_info->mm_height)
> >
> > Hello, can you review this v2 patch?
> >
> > --
> > Pali Rohár
> > [email protected]
> > _______________________________________________
> > [email protected]: X.Org development
> > Archives: http://lists.x.org/archives/xorg-devel
> > Info: https://lists.x.org/mailman/listinfo/xorg-devel
--
Pali Rohár
[email protected]
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