Adding back dri-devel@xxxxxxxxxxxxxxxxxxxxx
On Wed, Jan 18, 2017 at 12:21:23PM +0100, walter harms wrote:
>
>
> Am 18.01.2017 10:02, schrieb Thierry Reding:
> > Allow DRM/KMS devices hosted on USB to be detected by the drmDevice
> > infrastructure.
> >
> > v3:
> > - guard Linux-specific sysfs parsing code with #ifdef __linux__
> >
> > v2:
> > - make sysfs_uevent_get() more flexible using a format string
> >
> > Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxx>
> > ---
> > xf86drm.c | 175 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > xf86drm.h | 13 +++++
> > 2 files changed, 188 insertions(+)
> >
> > diff --git a/xf86drm.c b/xf86drm.c
> > index 7766bfe937db..d83674e638c4 100644
> > --- a/xf86drm.c
> > +++ b/xf86drm.c
> > @@ -2886,6 +2886,50 @@ char *drmGetRenderDeviceNameFromFd(int fd)
> > return drmGetMinorNameForFD(fd, DRM_NODE_RENDER);
> > }
> >
> > +#ifdef __linux__
> > +static char * DRM_PRINTFLIKE(2, 3)
> > +sysfs_uevent_get(const char *path, const char *fmt, ...)
> > +{
> > + char filename[PATH_MAX + 1], *key, *line = NULL, *value = NULL;
> char *filename=NULL, *key, *line = NULL, *value = NULL;
> > + size_t size = 0, len;
> > + ssize_t num;
> > + va_list ap;
> > + FILE *fp;
> > +
> > + va_start(ap, fmt);
> > + num = vasprintf(&key, fmt, ap);
> > + va_end(ap);
> > + len = num;
> > +
> > + snprintf(filename, sizeof(filename), "%s/uevent", path);
>
> since asprintf() is available you could use:
>
> asprintf(&filename,"%s/uevent", path);
>
> same could be done for path below.
I had thought about that, but a stack-allocated string seemed
advantageous for three reasons:
- asprintf() is a GNU extension. That's not much of an issue
because this is already protected by #ifdef __linux__ and
pretty much all C libraries I know support asprintf() and
friends.
- PATH_MAX is the maximum length of a filename, so there's no
need to dynamically allocate, since it should nicely fit into
the stack pretty much everywhere (I think the largest value I
have ever seen for PATH_MAX is 4096 on recent Linux systems).
- Most of the other code in xf86drm.c already uses PATH_MAX, so
the code remains consistent.
Given the added complexity of asprintf() and the need to free the memory
the advantages of the stack-allocated string seemed to outweigh.
Thierry
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