|author||Rich Felker <email@example.com>||2020-08-08 20:59:26 -0400|
|committer||Rich Felker <firstname.lastname@example.org>||2020-08-08 20:59:26 -0400|
prefer new socket syscalls, fallback to SYS_socketcall only if needed
a number of users performing seccomp filtering have requested use of the new individual syscall numbers for socket syscalls, rather than the legacy multiplexed socketcall, since the latter has the arguments all in memory where they can't participate in filter decisions. previously, some archs used the multiplexed socketcall if it was historically all that was available, while other archs used the separate syscalls. the intent was that the latter set only include archs that have "always" had separate socket syscalls, at least going back to linux 2.6.0. however, at least powerpc, powerpc64, and sh were wrongly included in this set, and thus socket operations completely failed on old kernels for these archs. with the changes made here, the separate syscalls are always preferred, but fallback code is compiled for archs that also define SYS_socketcall. two such archs, mips (plain o32) and microblaze, define SYS_socketcall despite never having needed it, so it's now undefined by their versions of syscall_arch.h to prevent inclusion of useless fallback code. some archs, where the separate syscalls were only added after the addition of SYS_accept4, lack SYS_accept. because socket calls are always made with zeros in the unused argument positions, it suffices to just use SYS_accept4 to provide a definition of SYS_accept, and this is done to make happy the macro machinery that concatenates the socket call name onto __SC_ and SYS_.
Diffstat (limited to 'src/setjmp/x32')
0 files changed, 0 insertions, 0 deletions