view src/os/unix/ngx_setproctitle.c @ 6949:ff0c8e11edbc

Simplified and improved sendfile() code on Linux. The ngx_linux_sendfile() function is now used for both normal sendfile() and sendfile in threads. The ngx_linux_sendfile_thread() function was modified to use the same interface as ngx_linux_sendfile(), and is simply called from ngx_linux_sendfile() when threads are enabled. Special return code NGX_DONE is used to indicate that a thread task was posted and no further actions are needed. If number of bytes sent is less that what we were sending, we now always retry sending. This is needed for sendfile() in threads as the number of bytes we are sending might have been changed since the thread task was posted. And this is also needed for Linux 4.3+, as sendfile() might be interrupted at any time and provides no indication if it was interrupted or not (ticket #1174).
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 28 Mar 2017 18:15:39 +0300
parents 67653855682e
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


#if (NGX_SETPROCTITLE_USES_ENV)

/*
 * To change the process title in Linux and Solaris we have to set argv[1]
 * to NULL and to copy the title to the same place where the argv[0] points to.
 * However, argv[0] may be too small to hold a new title.  Fortunately, Linux
 * and Solaris store argv[] and environ[] one after another.  So we should
 * ensure that is the continuous memory and then we allocate the new memory
 * for environ[] and copy it.  After this we could use the memory starting
 * from argv[0] for our process title.
 *
 * The Solaris's standard /bin/ps does not show the changed process title.
 * You have to use "/usr/ucb/ps -w" instead.  Besides, the UCB ps does not
 * show a new title if its length less than the origin command line length.
 * To avoid it we append to a new title the origin command line in the
 * parenthesis.
 */

extern char **environ;

static char *ngx_os_argv_last;

ngx_int_t
ngx_init_setproctitle(ngx_log_t *log)
{
    u_char      *p;
    size_t       size;
    ngx_uint_t   i;

    size = 0;

    for (i = 0; environ[i]; i++) {
        size += ngx_strlen(environ[i]) + 1;
    }

    p = ngx_alloc(size, log);
    if (p == NULL) {
        return NGX_ERROR;
    }

    ngx_os_argv_last = ngx_os_argv[0];

    for (i = 0; ngx_os_argv[i]; i++) {
        if (ngx_os_argv_last == ngx_os_argv[i]) {
            ngx_os_argv_last = ngx_os_argv[i] + ngx_strlen(ngx_os_argv[i]) + 1;
        }
    }

    for (i = 0; environ[i]; i++) {
        if (ngx_os_argv_last == environ[i]) {

            size = ngx_strlen(environ[i]) + 1;
            ngx_os_argv_last = environ[i] + size;

            ngx_cpystrn(p, (u_char *) environ[i], size);
            environ[i] = (char *) p;
            p += size;
        }
    }

    ngx_os_argv_last--;

    return NGX_OK;
}


void
ngx_setproctitle(char *title)
{
    u_char     *p;

#if (NGX_SOLARIS)

    ngx_int_t   i;
    size_t      size;

#endif

    ngx_os_argv[1] = NULL;

    p = ngx_cpystrn((u_char *) ngx_os_argv[0], (u_char *) "nginx: ",
                    ngx_os_argv_last - ngx_os_argv[0]);

    p = ngx_cpystrn(p, (u_char *) title, ngx_os_argv_last - (char *) p);

#if (NGX_SOLARIS)

    size = 0;

    for (i = 0; i < ngx_argc; i++) {
        size += ngx_strlen(ngx_argv[i]) + 1;
    }

    if (size > (size_t) ((char *) p - ngx_os_argv[0])) {

        /*
         * ngx_setproctitle() is too rare operation so we use
         * the non-optimized copies
         */

        p = ngx_cpystrn(p, (u_char *) " (", ngx_os_argv_last - (char *) p);

        for (i = 0; i < ngx_argc; i++) {
            p = ngx_cpystrn(p, (u_char *) ngx_argv[i],
                            ngx_os_argv_last - (char *) p);
            p = ngx_cpystrn(p, (u_char *) " ", ngx_os_argv_last - (char *) p);
        }

        if (*(p - 1) == ' ') {
            *(p - 1) = ')';
        }
    }

#endif

    if (ngx_os_argv_last - (char *) p) {
        ngx_memset(p, NGX_SETPROCTITLE_PAD, ngx_os_argv_last - (char *) p);
    }

    ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
                   "setproctitle: \"%s\"", ngx_os_argv[0]);
}

#endif /* NGX_SETPROCTITLE_USES_ENV */