| Message ID | CA+XhMqyzW=ah4Q=OCE9KP6DYpiQN18oQpVWjqFCvzQfH3MvQFA@mail.gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] util/oslib-posix: : qemu_init_exec_dir implementation for Mac | expand |
On Mon, 15 Jun 2020 at 18:06, David CARLIER <devnexen@gmail.com> wrote: > > From dfa1e900dd950f4d3fca17fbf5d3dfb5725c83fa Mon Sep 17 00:00:00 2001 > From: David Carlier <devnexen@gmail.com> > Date: Tue, 26 May 2020 21:35:27 +0100 > Subject: [PATCH] util/oslib-posix : qemu_init_exec_dir implementation for Mac > > Using dyld API to get the full path of the current process. > > Signed-off-by: David Carlier <devnexen@gmail.com> > +#elif defined(__APPLE__) > + { > + uint32_t len = (uint32_t)sizeof(buf); Why do we need the cast? > + if (_NSGetExecutablePath(buf, &len) == 0) { > + buf[len - 1] = 0; > + p = buf; > + } > + } What does this return if you start QEMU with a relative path (eg "./qemu-system-x86_64") ? The documentation suggests that you need to call realpath() to resolve that kind of relative path. Did you try the test I suggested with checking that this actually does return something different from argv[0] ? thanks -- PMM
With this basic program
#include <mach-o/dyld.h>
#include <stdio.h>
int main(void)
{
char buf[4096];
uint32_t bufsize = sizeof(buf);
_NSGetExecutablePath(buf, &bufsize);
printf("%s\n", buf);
return 0;
}
I get
Davids-MacBook-Pro-2:Contribs dcarlier$ ./a.out
/Users/dcarlier/Contribs/./a.out
The cast was to avoid possible warning with pedantic compile flags if used.
On Mon, 15 Jun 2020 at 20:05, Peter Maydell <peter.maydell@linaro.org> wrote:
>
> On Mon, 15 Jun 2020 at 18:06, David CARLIER <devnexen@gmail.com> wrote:
> >
> > From dfa1e900dd950f4d3fca17fbf5d3dfb5725c83fa Mon Sep 17 00:00:00 2001
> > From: David Carlier <devnexen@gmail.com>
> > Date: Tue, 26 May 2020 21:35:27 +0100
> > Subject: [PATCH] util/oslib-posix : qemu_init_exec_dir implementation for Mac
> >
> > Using dyld API to get the full path of the current process.
> >
> > Signed-off-by: David Carlier <devnexen@gmail.com>
>
> > +#elif defined(__APPLE__)
> > + {
> > + uint32_t len = (uint32_t)sizeof(buf);
>
> Why do we need the cast?
>
> > + if (_NSGetExecutablePath(buf, &len) == 0) {
> > + buf[len - 1] = 0;
> > + p = buf;
> > + }
> > + }
>
> What does this return if you start QEMU with a relative
> path (eg "./qemu-system-x86_64") ? The documentation
> suggests that you need to call realpath() to resolve that kind
> of relative path.
>
> Did you try the test I suggested with checking that this
> actually does return something different from argv[0] ?
>
> thanks
> -- PMM
On Mon, 15 Jun 2020 at 20:14, David CARLIER <devnexen@gmail.com> wrote: > > With this basic program > > #include <mach-o/dyld.h> > #include <stdio.h> > > int main(void) > { > char buf[4096]; > uint32_t bufsize = sizeof(buf); > _NSGetExecutablePath(buf, &bufsize); > printf("%s\n", buf); > return 0; > } > > I get > > Davids-MacBook-Pro-2:Contribs dcarlier$ ./a.out > /Users/dcarlier/Contribs/./a.out Hmm. I think we should run that through realpath() just to get rid of the /./ in that. This is similar to how Chromium uses it (though it uses a different API for doing the absolutifying): https://chromium.googlesource.com/chromium/src/base/+/master/base_paths_mac.mm#41 Thanks for the test program, I used it a minor variation of it to confirm that this does do the right thing even when argv[0] has been passed as a different string: $ (exec -a foo /tmp/zz9) _NSGetExecutablePath: /tmp/zz9 argv[0]: foo So _NSGetExecutablePath() is definitely the thing to use here. > The cast was to avoid possible warning with pedantic compile flags if used. We don't compile with -pedantic, so you don't need to guard against using it. thanks -- PMM
diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 916f1be224..0aeaed2fa4 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -57,6 +57,10 @@ #include <lwp.h> #endif +#ifdef __APPLE__ +#include <mach-o/dyld.h> +#endif + #include "qemu/mmap-alloc.h" #ifdef CONFIG_DEBUG_STACK_USAGE @@ -375,6 +379,14 @@ void qemu_init_exec_dir(const char *argv0) p = buf; } } +#elif defined(__APPLE__) + { + uint32_t len = (uint32_t)sizeof(buf); + if (_NSGetExecutablePath(buf, &len) == 0) { + buf[len - 1] = 0; + p = buf; + } + } #endif /* If we don't have any way of figuring out the actual executable location then try argv[0]. */