The linux-user syscall emulation layer currently supports the openat family of syscalls via two mechanisms: simply calling the corresponding libc functions, and making direct syscalls. Since glibc has supported these functions since at least glibc 2.5, there's no real need to retain the (essentially untested) direct syscall fallback code, so this patchset simply deletes it.
This allows us to remove some ifdeffery that was attempting to disable provision of some of the syscalls if the host didn't seem to support them, which in some cases was actually wrong. For example where there are several flavours of the syscall, we only need one of them, not necessarily the exact one the guest has, as with the fstatat* calls. And if the guest needs the futimesat() syscall we can provide it via glibc, even if that syscall is deprecated or not provided in the host (because the host implements utimensat instead). AArch64 in particular hits the last of these, which resulted in a compile failure due to an unused function, because the syscall implementation's ifdef was inconsistent with the ifdef used to define the sys_futimesat() function. Basically, removing the ugly direct syscall access seemed nicer than trying to fix up and render consistent the broken ifdefs :-) [RHEL5 has glibc2.5 and provides these functions. RHEL4 did not but we don't build on RHEL4 anyhow because its glib is too old. uClibc provides these functions.] Peter Maydell (2): linux-user: Drop direct use of openat etc syscalls configure: Drop CONFIG_ATFILE test configure | 26 ------ linux-user/syscall.c | 218 ++++++-------------------------------------------- 2 files changed, 24 insertions(+), 220 deletions(-) -- 1.7.9.5
