| Message ID | 5551BE4D.4060308@arm.com |
|---|---|
| State | Committed |
| Headers | show |
Szabolcs Nagy <szabolcs.nagy@arm.com> writes: > Kernel uses int pr_uid, pr_gid, but glibc used unsigned short. > > This is an ABI breaking change so I created a bugzilla ticket, > but I guess glibc elf_prpsinfo is not widely used if this > haven't come up yet. Can you find out where the struct is actually been used? Andreas.
On 12 May 2015 11:49, Andreas Schwab wrote: > Szabolcs Nagy <szabolcs.nagy@arm.com> writes: > > Kernel uses int pr_uid, pr_gid, but glibc used unsigned short. > > > > This is an ABI breaking change so I created a bugzilla ticket, > > but I guess glibc elf_prpsinfo is not widely used if this > > haven't come up yet. > > Can you find out where the struct is actually been used? breakpad uses it, but i wouldn't worry too much about that ... it statically links things in general and should be easy to fix it otherwise, the usual debug culprits like gdb, libunwind, strace, etc... *might* use it. i find these proc headers are fairly uncommon though. maybe github code search would help ? -mike
On 12/05/15 10:49, Andreas Schwab wrote: > Szabolcs Nagy <szabolcs.nagy@arm.com> writes: > >> Kernel uses int pr_uid, pr_gid, but glibc used unsigned short. >> >> This is an ABI breaking change so I created a bugzilla ticket, >> but I guess glibc elf_prpsinfo is not widely used if this >> haven't come up yet. > > Can you find out where the struct is actually been used? > it should be used by things that look at elf core dumps, but i cannot find any use of the glibc struct binutils relies on the struct layout: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=bfd/elfxx-aarch64.c;h=db9d4fa01924342cbc110877d1ac06c7a389debc;hb=HEAD#l526 note that those parts are not changed here (the struct is 8 byte aligned so 2*short -> 2*int does not change the layout for other members) i've seen various packages defining their own prpsinfo struct (uclibc, bionic, musl, google-breakpad, valgrind, binutils, qemu) and some using the kernel definition (undertaker). some of the definitions are broken on various platforms (i haven't seen the pr_uid/pr_gid fields used).
Szabolcs Nagy <szabolcs.nagy@arm.com> writes: > note that those parts are not changed here > (the struct is 8 byte aligned so 2*short -> 2*int > does not change the layout for other members) > (i haven't seen the pr_uid/pr_gid fields used). Given these two statements this change should be pretty safe. Andreas.
On 12 May 2015 at 09:48, Szabolcs Nagy <szabolcs.nagy@arm.com> wrote: > Kernel uses int pr_uid, pr_gid, but glibc used unsigned short. > > This is an ABI breaking change so I created a bugzilla ticket, > but I guess glibc elf_prpsinfo is not widely used if this > haven't come up yet. > > Changelog: > > 2015-05-12 Szabolcs Nagy <szabolcs.nagy@arm.com> > > [BZ #18400] > * sysdeps/unix/sysv/linux/aarch64/sys/procfs.h (struct elf_prpsinfo): > Fix pr_uid and pr_gid members. All of the comments on this thread suggest the change is relatively safe, go ahead and commit it. /Marcus
diff --git a/sysdeps/unix/sysv/linux/aarch64/sys/procfs.h b/sysdeps/unix/sysv/linux/aarch64/sys/procfs.h index cf5e76c..ecc65ab 100644 --- a/sysdeps/unix/sysv/linux/aarch64/sys/procfs.h +++ b/sysdeps/unix/sysv/linux/aarch64/sys/procfs.h @@ -91,8 +91,8 @@ struct elf_prpsinfo char pr_zomb; /* Zombie. */ char pr_nice; /* Nice val. */ unsigned long int pr_flag; /* Flags. */ - unsigned short int pr_uid; - unsigned short int pr_gid; + unsigned int pr_uid; + unsigned int pr_gid; int pr_pid, pr_ppid, pr_pgrp, pr_sid; /* Lots missing */ char pr_fname[16]; /* Filename of executable. */