| Message ID | 20160402105716.GA10998@var.jdll.illyse.net |
|---|---|
| State | New |
| Headers | show |
On 02 Apr 2016 12:57, Samuel Thibault wrote: > Systems without HAVE_AUX_VECTOR have GLRO(dl_auxv) == NULL, and > getauxval would thus crash. assuming this is for GNU/hurd > --- a/misc/getauxval.c > +++ b/misc/getauxval.c > @@ -30,9 +30,10 @@ __getauxval (unsigned long int type) > else if (type == AT_HWCAP2) > return GLRO(dl_hwcap2); > > - for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++) > - if (p->a_type == type) > - return p->a_un.a_val; > + if (GLRO(dl_auxv) != NULL) > + for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++) > + if (p->a_type == type) > + return p->a_un.a_val; should this just be under HAVE_AUX_VECTOR ? seems like we shouldn't even bother defining/exporting dl_auxv at all if it's disabled. then we wouldn't run into more latent problems like this at run time -- it would be a build failure. in looking at other uses of dl_auxv, why isn't _dl_sysdep_start an issue too ? rtld.c:_dl_start_final always calls that, and that func always walks GLRO(dl_auxv). -mike
> On 02 Apr 2016 12:57, Samuel Thibault wrote: > > Systems without HAVE_AUX_VECTOR have GLRO(dl_auxv) == NULL, and > > getauxval would thus crash. > > assuming this is for GNU/hurd Yes. > should this just be under HAVE_AUX_VECTOR ? seems like we shouldn't > even bother defining/exporting dl_auxv at all if it's disabled. then > we wouldn't run into more latent problems like this at run time -- it > would be a build failure. Agreed. > in looking at other uses of dl_auxv, why isn't _dl_sysdep_start an > issue too ? rtld.c:_dl_start_final always calls that, and that func > always walks GLRO(dl_auxv). You are looking at elf/dl-sysdep.c, not sysdeps/mach/hurd/dl-sysdep.c.
On 2016.04.02 at 12:57 +0200, Samuel Thibault wrote: > Systems without HAVE_AUX_VECTOR have GLRO(dl_auxv) == NULL, and > getauxval would thus crash. Your commit 0cdc5e930a breaks the build for me: In file included from ../sysdeps/x86_64/ldsodefs.h:54:0, from ../sysdeps/gnu/ldsodefs.h:46, from ../sysdeps/unix/sysv/linux/ldsodefs.h:22, from getauxval.c:20: getauxval.c: In function ‘__getauxval’: ../sysdeps/generic/ldsodefs.h:439:21: error: ‘_dl_auxv’ undeclared (first use in this function) # define GLRO(name) _##name ^ getauxval.c:34:12: note: in expansion of macro ‘GLRO’ for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++) ^~~~ ../sysdeps/generic/ldsodefs.h:439:21: note: each undeclared identifier is reported only once for each function it appears in # define GLRO(name) _##name ^ getauxval.c:34:12: note: in expansion of macro ‘GLRO’ for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++) ^~~~ ../o-iterator.mk:9: recipe for target '/var/tmp/glibc-build/misc/getauxval.o' failed
Hello, Markus Trippelsdorf, on Mon 11 Apr 2016 09:55:12 +0200, wrote: > On 2016.04.02 at 12:57 +0200, Samuel Thibault wrote: > > Systems without HAVE_AUX_VECTOR have GLRO(dl_auxv) == NULL, and > > getauxval would thus crash. > > Your commit 0cdc5e930a breaks the build for me: Ah, sorry, part of the commit was missing indeed, now fixed. Samuel
diff --git a/misc/getauxval.c b/misc/getauxval.c index e48f40f..7ba0598 100644 --- a/misc/getauxval.c +++ b/misc/getauxval.c @@ -30,9 +30,10 @@ __getauxval (unsigned long int type) else if (type == AT_HWCAP2) return GLRO(dl_hwcap2); - for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++) - if (p->a_type == type) - return p->a_un.a_val; + if (GLRO(dl_auxv) != NULL) + for (p = GLRO(dl_auxv); p->a_type != AT_NULL; p++) + if (p->a_type == type) + return p->a_un.a_val; __set_errno (ENOENT); return 0;