view src/os/unix/ngx_sunpro_amd64.il @ 5356:acd51b0f6fd4

Disable symlinks: use O_PATH to open path components. It was introduced in Linux 2.6.39, glibc 2.14 and allows to obtain file descriptors without actually opening files. Thus made it possible to traverse path with openat() syscalls without the need to have read permissions for path components. It is effectively emulates O_SEARCH which is missing on Linux. O_PATH is used in combination with O_RDONLY. The last one is ignored if O_PATH is used, but it allows nginx to not fail when it was built on modern system (i.e. glibc 2.14+) and run with a kernel older than 2.6.39. Then O_PATH is unknown to the kernel and ignored, while O_RDONLY is used. Sadly, fstat() is not working with O_PATH descriptors till Linux 3.6. As a workaround we fallback to fstatat() with the AT_EMPTY_PATH flag that was introduced at the same time as O_PATH.
author Valentin Bartenev <vbart@nginx.com>
date Mon, 02 Sep 2013 08:07:59 +0400
parents d620f497c50f
children 2cd019520210
line wrap: on
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/
/ Copyright (C) Igor Sysoev
/ Copyright (C) Nginx, Inc.
/

/ ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock,
/     ngx_atomic_uint_t old, ngx_atomic_uint_t set);
/
/ the arguments are passed in %rdi, %rsi, %rdx
/ the result is returned in the %rax

        .inline ngx_atomic_cmp_set,0
        movq      %rsi, %rax
        lock
        cmpxchgq  %rdx, (%rdi)
        setz      %al
        movzbq    %al, %rax
        .end


/ ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value,
/     ngx_atomic_int_t add);
/
/ the arguments are passed in %rdi, %rsi
/ the result is returned in the %rax

        .inline ngx_atomic_fetch_add,0
        movq      %rsi, %rax
        lock
        xaddq     %rax, (%rdi)
        .end


/ ngx_cpu_pause()
/
/ the "rep; nop" is used instead of "pause" to avoid the "[ PAUSE ]" hardware
/ capability added by linker because Solaris/amd64 does not know about it:
/
/ ld.so.1: nginx: fatal: hardware capability unsupported: 0x2000 [ PAUSE ]

       .inline ngx_cpu_pause,0
       rep; nop
       .end