view src/os/unix/ngx_linux_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 d620f497c50f
children adba26ff70b5
line wrap: on
line source


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


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


u_char  ngx_linux_kern_ostype[50];
u_char  ngx_linux_kern_osrelease[50];

int     ngx_linux_rtsig_max;


static ngx_os_io_t ngx_linux_io = {
    ngx_unix_recv,
    ngx_readv_chain,
    ngx_udp_unix_recv,
    ngx_unix_send,
#if (NGX_HAVE_SENDFILE)
    ngx_linux_sendfile_chain,
    NGX_IO_SENDFILE
#else
    ngx_writev_chain,
    0
#endif
};


ngx_int_t
ngx_os_specific_init(ngx_log_t *log)
{
    struct utsname  u;

    if (uname(&u) == -1) {
        ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "uname() failed");
        return NGX_ERROR;
    }

    (void) ngx_cpystrn(ngx_linux_kern_ostype, (u_char *) u.sysname,
                       sizeof(ngx_linux_kern_ostype));

    (void) ngx_cpystrn(ngx_linux_kern_osrelease, (u_char *) u.release,
                       sizeof(ngx_linux_kern_osrelease));

#if (NGX_HAVE_RTSIG)
    {
    int        name[2];
    size_t     len;
    ngx_err_t  err;

    name[0] = CTL_KERN;
    name[1] = KERN_RTSIGMAX;
    len = sizeof(ngx_linux_rtsig_max);

    if (sysctl(name, 2, &ngx_linux_rtsig_max, &len, NULL, 0) == -1) {
        err = ngx_errno;

        if (err != NGX_ENOTDIR && err != NGX_ENOSYS) {
            ngx_log_error(NGX_LOG_ALERT, log, err,
                          "sysctl(KERN_RTSIGMAX) failed");

            return NGX_ERROR;
        }

        ngx_linux_rtsig_max = 0;
    }

    }
#endif

    ngx_os_io = ngx_linux_io;

    return NGX_OK;
}


void
ngx_os_specific_status(ngx_log_t *log)
{
    ngx_log_error(NGX_LOG_NOTICE, log, 0, "OS: %s %s",
                  ngx_linux_kern_ostype, ngx_linux_kern_osrelease);

#if (NGX_HAVE_RTSIG)
    ngx_log_error(NGX_LOG_NOTICE, log, 0, "sysctl(KERN_RTSIGMAX): %d",
                  ngx_linux_rtsig_max);
#endif
}