view src/os/unix/ngx_posix_init.c @ 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 4c36e15651f7
children 1209b8a7b077
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <nginx.h>


ngx_int_t   ngx_ncpu;
ngx_int_t   ngx_max_sockets;
ngx_uint_t  ngx_inherited_nonblocking;
ngx_uint_t  ngx_tcp_nodelay_and_tcp_nopush;


struct rlimit  rlmt;


ngx_os_io_t ngx_os_io = {
    ngx_unix_recv,
    ngx_readv_chain,
    ngx_udp_unix_recv,
    ngx_unix_send,
    ngx_writev_chain,
    0
};


ngx_int_t
ngx_os_init(ngx_log_t *log)
{
    ngx_uint_t  n;

#if (NGX_HAVE_OS_SPECIFIC_INIT)
    if (ngx_os_specific_init(log) != NGX_OK) {
        return NGX_ERROR;
    }
#endif

    ngx_init_setproctitle(log);

    ngx_pagesize = getpagesize();
    ngx_cacheline_size = NGX_CPU_CACHE_LINE;

    for (n = ngx_pagesize; n >>= 1; ngx_pagesize_shift++) { /* void */ }

#if (NGX_HAVE_SC_NPROCESSORS_ONLN)
    if (ngx_ncpu == 0) {
        ngx_ncpu = sysconf(_SC_NPROCESSORS_ONLN);
    }
#endif

    if (ngx_ncpu < 1) {
        ngx_ncpu = 1;
    }

    ngx_cpuinfo();

    if (getrlimit(RLIMIT_NOFILE, &rlmt) == -1) {
        ngx_log_error(NGX_LOG_ALERT, log, errno,
                      "getrlimit(RLIMIT_NOFILE) failed)");
        return NGX_ERROR;
    }

    ngx_max_sockets = (ngx_int_t) rlmt.rlim_cur;

#if (NGX_HAVE_INHERITED_NONBLOCK || NGX_HAVE_ACCEPT4)
    ngx_inherited_nonblocking = 1;
#else
    ngx_inherited_nonblocking = 0;
#endif

    srandom(ngx_time());

    return NGX_OK;
}


void
ngx_os_status(ngx_log_t *log)
{
    ngx_log_error(NGX_LOG_NOTICE, log, 0, NGINX_VER);

#ifdef NGX_COMPILER
    ngx_log_error(NGX_LOG_NOTICE, log, 0, "built by " NGX_COMPILER);
#endif

#if (NGX_HAVE_OS_SPECIFIC_INIT)
    ngx_os_specific_status(log);
#endif

    ngx_log_error(NGX_LOG_NOTICE, log, 0,
                  "getrlimit(RLIMIT_NOFILE): %r:%r",
                  rlmt.rlim_cur, rlmt.rlim_max);
}


#if 0

ngx_int_t
ngx_posix_post_conf_init(ngx_log_t *log)
{
    ngx_fd_t  pp[2];

    if (pipe(pp) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "pipe() failed");
        return NGX_ERROR;
    }

    if (dup2(pp[1], STDERR_FILENO) == -1) {
        ngx_log_error(NGX_LOG_EMERG, log, errno, "dup2(STDERR) failed");
        return NGX_ERROR;
    }

    if (pp[1] > STDERR_FILENO) {
        if (close(pp[1]) == -1) {
            ngx_log_error(NGX_LOG_EMERG, log, errno, "close() failed");
            return NGX_ERROR;
        }
    }

    return NGX_OK;
}

#endif