v4l2-tracer: Fix libv4l2tracer.so loader
Commit Message
From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
The code was still assuming libtools being use, so it didn't work
installed anymore. Also, it didn't work installed if the full
v4l2-tracer path was being passed.
Fix this by always trying next by libv4l2tracer.so loading (using stat()
to validate) and always fallback to the installed path otherwise.
Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
---
Hi - thanks to Nicolas for this patch.
I tested tracing and retracing on both installed and uninstalled
v4l2-tracer including with and without an absolute path and it
all works as expected.
Note that I've got three sets of v4l2-tracer patches outstanding now,
but they all still apply independently of each other:
Tuner patches:
https://lore.kernel.org/linux-media/cover.1684453027.git.deborah.brouwer@collabora.com/
Debug patches:
https://lore.kernel.org/linux-media/cover.1681245372.git.deborah.brouwer@collabora.com/
Thanks,
Deb
utils/v4l2-tracer/v4l2-tracer.cpp | 33 +++++++++++++++++--------------
1 file changed, 18 insertions(+), 15 deletions(-)
Comments
Thanks Deborah,
Le mercredi 24 mai 2023 à 17:20 -0700, Deborah Brouwer a écrit :
> From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
>
> The code was still assuming libtools being use, so it didn't work
> installed anymore. Also, it didn't work installed if the full
> v4l2-tracer path was being passed.
>
> Fix this by always trying next by libv4l2tracer.so loading (using stat()
> to validate) and always fallback to the installed path otherwise.
>
> Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Mind adding you Singed-off-by ?
> ---
> Hi - thanks to Nicolas for this patch.
> I tested tracing and retracing on both installed and uninstalled
> v4l2-tracer including with and without an absolute path and it
> all works as expected.
>
> Note that I've got three sets of v4l2-tracer patches outstanding now,
> but they all still apply independently of each other:
>
> Tuner patches:
> https://lore.kernel.org/linux-media/cover.1684453027.git.deborah.brouwer@collabora.com/
>
> Debug patches:
> https://lore.kernel.org/linux-media/cover.1681245372.git.deborah.brouwer@collabora.com/
>
> Thanks,
> Deb
>
> utils/v4l2-tracer/v4l2-tracer.cpp | 33 +++++++++++++++++--------------
> 1 file changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/utils/v4l2-tracer/v4l2-tracer.cpp b/utils/v4l2-tracer/v4l2-tracer.cpp
> index e3f002a9..7c3662be 100644
> --- a/utils/v4l2-tracer/v4l2-tracer.cpp
> +++ b/utils/v4l2-tracer/v4l2-tracer.cpp
> @@ -5,6 +5,7 @@
>
> #include "retrace.h"
> #include <climits>
> +#include <sys/stat.h>
> #include <sys/wait.h>
> #include <time.h>
>
> @@ -295,24 +296,26 @@ int tracer(int argc, char *argv[], bool retrace)
> fclose(trace_file);
>
> /*
> - * Preload the libv4l2tracer library. If the program is installed, load the library
> - * from its installed location, otherwise load it locally. If it's loaded locally,
> - * use ./configure --disable-dyn-libv4l.
> + * Preload the libv4l2tracer library. The libv4l2tracer is looked up next to
> + * the executable first in order to support uninstalled build.
> */
> std::string libv4l2tracer_path;
> std::string program = argv[0];
> - std::size_t idx = program.rfind("/v4l2-tracer");
> - if (idx != std::string::npos) {
> - libv4l2tracer_path = program.replace(program.begin() + idx + 1, program.end(), ".libs");
> - DIR *directory_pointer = opendir(libv4l2tracer_path.c_str());
> - if (directory_pointer == nullptr)
> - libv4l2tracer_path = program.replace(program.begin() + idx, program.end(), "./.libs");
> - else
> - closedir(directory_pointer);
> - } else {
> - libv4l2tracer_path = LIBTRACER_PATH;
> - }
> - libv4l2tracer_path += "/libv4l2tracer.so";
> + std::size_t idx = program.rfind("/");
> + struct stat sb;
> +
> + if (idx == std::string::npos)
> + idx = 0;
> + else
> + idx++;
> +
> + /* look for libv4l2tracer next to the executable */
> + libv4l2tracer_path = program.replace(program.begin() + idx, program.end(), "libv4l2tracer.so");
> +
> + /* otherwise, use the installation path */
> + if (stat(libv4l2tracer_path.c_str(), &sb) == -1)
> + libv4l2tracer_path = std::string(LIBTRACER_PATH) + "/libv4l2tracer.so";
> +
> if (is_verbose())
> fprintf(stderr, "Loading libv4l2tracer: %s\n", libv4l2tracer_path.c_str());
> setenv("LD_PRELOAD", libv4l2tracer_path.c_str(), 0);
On Thu, May 25, 2023 at 12:45:28PM -0400, Nicolas Dufresne wrote:
> Thanks Deborah,
>
> Le mercredi 24 mai 2023 à 17:20 -0700, Deborah Brouwer a écrit :
> > From: Nicolas Dufresne <nicolas.dufresne@collabora.com>
> >
> > The code was still assuming libtools being use, so it didn't work
> > installed anymore. Also, it didn't work installed if the full
> > v4l2-tracer path was being passed.
> >
> > Fix this by always trying next by libv4l2tracer.so loading (using stat()
> > to validate) and always fallback to the installed path otherwise.
> >
> > Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
>
> Mind adding you Singed-off-by ?
Actually Hans already applied your patch (thanks!) but will do it next
time.
>
> > ---
> > Hi - thanks to Nicolas for this patch.
> > I tested tracing and retracing on both installed and uninstalled
> > v4l2-tracer including with and without an absolute path and it
> > all works as expected.
> >
> > Note that I've got three sets of v4l2-tracer patches outstanding now,
> > but they all still apply independently of each other:
> >
> > Tuner patches:
> > https://lore.kernel.org/linux-media/cover.1684453027.git.deborah.brouwer@collabora.com/
> >
> > Debug patches:
> > https://lore.kernel.org/linux-media/cover.1681245372.git.deborah.brouwer@collabora.com/
> >
> > Thanks,
> > Deb
> >
> > utils/v4l2-tracer/v4l2-tracer.cpp | 33 +++++++++++++++++--------------
> > 1 file changed, 18 insertions(+), 15 deletions(-)
> >
> > diff --git a/utils/v4l2-tracer/v4l2-tracer.cpp b/utils/v4l2-tracer/v4l2-tracer.cpp
> > index e3f002a9..7c3662be 100644
> > --- a/utils/v4l2-tracer/v4l2-tracer.cpp
> > +++ b/utils/v4l2-tracer/v4l2-tracer.cpp
> > @@ -5,6 +5,7 @@
> >
> > #include "retrace.h"
> > #include <climits>
> > +#include <sys/stat.h>
> > #include <sys/wait.h>
> > #include <time.h>
> >
> > @@ -295,24 +296,26 @@ int tracer(int argc, char *argv[], bool retrace)
> > fclose(trace_file);
> >
> > /*
> > - * Preload the libv4l2tracer library. If the program is installed, load the library
> > - * from its installed location, otherwise load it locally. If it's loaded locally,
> > - * use ./configure --disable-dyn-libv4l.
> > + * Preload the libv4l2tracer library. The libv4l2tracer is looked up next to
> > + * the executable first in order to support uninstalled build.
> > */
> > std::string libv4l2tracer_path;
> > std::string program = argv[0];
> > - std::size_t idx = program.rfind("/v4l2-tracer");
> > - if (idx != std::string::npos) {
> > - libv4l2tracer_path = program.replace(program.begin() + idx + 1, program.end(), ".libs");
> > - DIR *directory_pointer = opendir(libv4l2tracer_path.c_str());
> > - if (directory_pointer == nullptr)
> > - libv4l2tracer_path = program.replace(program.begin() + idx, program.end(), "./.libs");
> > - else
> > - closedir(directory_pointer);
> > - } else {
> > - libv4l2tracer_path = LIBTRACER_PATH;
> > - }
> > - libv4l2tracer_path += "/libv4l2tracer.so";
> > + std::size_t idx = program.rfind("/");
> > + struct stat sb;
> > +
> > + if (idx == std::string::npos)
> > + idx = 0;
> > + else
> > + idx++;
> > +
> > + /* look for libv4l2tracer next to the executable */
> > + libv4l2tracer_path = program.replace(program.begin() + idx, program.end(), "libv4l2tracer.so");
> > +
> > + /* otherwise, use the installation path */
> > + if (stat(libv4l2tracer_path.c_str(), &sb) == -1)
> > + libv4l2tracer_path = std::string(LIBTRACER_PATH) + "/libv4l2tracer.so";
> > +
> > if (is_verbose())
> > fprintf(stderr, "Loading libv4l2tracer: %s\n", libv4l2tracer_path.c_str());
> > setenv("LD_PRELOAD", libv4l2tracer_path.c_str(), 0);
>
@@ -5,6 +5,7 @@
#include "retrace.h"
#include <climits>
+#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
@@ -295,24 +296,26 @@ int tracer(int argc, char *argv[], bool retrace)
fclose(trace_file);
/*
- * Preload the libv4l2tracer library. If the program is installed, load the library
- * from its installed location, otherwise load it locally. If it's loaded locally,
- * use ./configure --disable-dyn-libv4l.
+ * Preload the libv4l2tracer library. The libv4l2tracer is looked up next to
+ * the executable first in order to support uninstalled build.
*/
std::string libv4l2tracer_path;
std::string program = argv[0];
- std::size_t idx = program.rfind("/v4l2-tracer");
- if (idx != std::string::npos) {
- libv4l2tracer_path = program.replace(program.begin() + idx + 1, program.end(), ".libs");
- DIR *directory_pointer = opendir(libv4l2tracer_path.c_str());
- if (directory_pointer == nullptr)
- libv4l2tracer_path = program.replace(program.begin() + idx, program.end(), "./.libs");
- else
- closedir(directory_pointer);
- } else {
- libv4l2tracer_path = LIBTRACER_PATH;
- }
- libv4l2tracer_path += "/libv4l2tracer.so";
+ std::size_t idx = program.rfind("/");
+ struct stat sb;
+
+ if (idx == std::string::npos)
+ idx = 0;
+ else
+ idx++;
+
+ /* look for libv4l2tracer next to the executable */
+ libv4l2tracer_path = program.replace(program.begin() + idx, program.end(), "libv4l2tracer.so");
+
+ /* otherwise, use the installation path */
+ if (stat(libv4l2tracer_path.c_str(), &sb) == -1)
+ libv4l2tracer_path = std::string(LIBTRACER_PATH) + "/libv4l2tracer.so";
+
if (is_verbose())
fprintf(stderr, "Loading libv4l2tracer: %s\n", libv4l2tracer_path.c_str());
setenv("LD_PRELOAD", libv4l2tracer_path.c_str(), 0);