view src/os/unix/ngx_time.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
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


/*
 * FreeBSD does not test /etc/localtime change, however, we can workaround it
 * by calling tzset() with TZ and then without TZ to update timezone.
 * The trick should work since FreeBSD 2.1.0.
 *
 * Linux does not test /etc/localtime change in localtime(),
 * but may stat("/etc/localtime") several times in every strftime(),
 * therefore we use it to update timezone.
 *
 * Solaris does not test /etc/TIMEZONE change too and no workaround available.
 */

void
ngx_timezone_update(void)
{
#if (NGX_FREEBSD)

    if (getenv("TZ")) {
        return;
    }

    putenv("TZ=UTC");

    tzset();

    unsetenv("TZ");

    tzset();

#elif (NGX_LINUX)
    time_t      s;
    struct tm  *t;
    char        buf[4];

    s = time(0);

    t = localtime(&s);

    strftime(buf, 4, "%H", t);

#endif
}


void
ngx_localtime(time_t s, ngx_tm_t *tm)
{
#if (NGX_HAVE_LOCALTIME_R)
    (void) localtime_r(&s, tm);

#else
    ngx_tm_t  *t;

    t = localtime(&s);
    *tm = *t;

#endif

    tm->ngx_tm_mon++;
    tm->ngx_tm_year += 1900;
}


void
ngx_libc_localtime(time_t s, struct tm *tm)
{
#if (NGX_HAVE_LOCALTIME_R)
    (void) localtime_r(&s, tm);

#else
    struct tm  *t;

    t = localtime(&s);
    *tm = *t;

#endif
}


void
ngx_libc_gmtime(time_t s, struct tm *tm)
{
#if (NGX_HAVE_LOCALTIME_R)
    (void) gmtime_r(&s, tm);

#else
    struct tm  *t;

    t = gmtime(&s);
    *tm = *t;

#endif
}