Control: reassign -1 src:libc6 On Vi, 06 dec 13, 07:33:39, Vincent Danjean wrote: > Source: libc6 > Version: 2.17-97 > Severity: wishlist > Tags: upstream > > Hi, > > I'm using ifunc functions but I would like to read the environment in order > to select the runtime function. > A small program easily shows that the libc 'environ' variable (nor "_environ" > nor "__environ") is not yet initialized (so the 'getenv' function does not > work either). > > Is there a way I did not find to access to the environment of the program > at the point where ifunc functions are resolved? > > Looking at the sources, the environment is read way before by ld.so itself > (looking for LD_... envvar). However, the pointer to the initial environment > is not exported by ld.so (at least I did not find it). It is given to the > libc, but too late (in ./csu/init-first.c if I read the sources correctly). > > Would it be possible to export the initial environment (ie the __environ > variable used by ld.so with another name, not the __environ of the libc)? > Or can the call to the ifunc resolver function have a (char**envp) parameter > (it would be backward binary compatible but programs requiring this > behavior would need to depends on recent version of libc)? > Or would it be possible to initialize the libc __environ variable more > quickly? > I'm willing to prepare and test patches if you tell me which solution > I should implement. > > Regards, > Vincent > > PS: I attach a small program showing the environ is not yet initialized. > PPS: I already post my question on stackoverflow without any useful answer > http://stackoverflow.com/questions/20353246/reading-the-environment-when-executing-elf-ifunc-dispatch-functions > > -- System Information: > Debian Release: jessie/sid > APT prefers stable-updates > APT policy: (500, 'stable-updates'), (500, 'unstable'), (500, 'testing'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental') > Architecture: amd64 (x86_64) > Foreign Architectures: i386 > armel > mipsel > > Kernel: Linux 3.12-rc7-amd64 (SMP w/8 CPU cores) > Locale: LANG=fr_FR.utf8, LC_CTYPE=fr_FR.utf8 (charmap=UTF-8) > Shell: /bin/sh linked to /bin/dash -- http://wiki.debian.org/FAQsFromDebianUser Offtopic discussions among Debian users and developers: http://lists.alioth.debian.org/mailman/listinfo/d-community-offtopic http://nuvreauspam.ro/gpg-transition.txt
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