release/src/router/nginx/src/os/unix/ngx_setproctitle.c

   1
   2 /*
   3  * Copyright (C) Igor Sysoev
   4  * Copyright (C) Nginx, Inc.
   5  */
   6
   7
   8 #include <ngx_config.h>
   9 #include <ngx_core.h>
  10
  11
  12 #if (NGX_SETPROCTITLE_USES_ENV)
  13
  14 /*
  15  * To change the process title in Linux and Solaris we have to set argv[1]
  16  * to NULL and to copy the title to the same place where the argv[0] points to.
  17  * However, argv[0] may be too small to hold a new title.  Fortunately, Linux
  18  * and Solaris store argv[] and environ[] one after another.  So we should
  19  * ensure that is the continuous memory and then we allocate the new memory
  20  * for environ[] and copy it.  After this we could use the memory starting
  21  * from argv[0] for our process title.
  22  *
  23  * The Solaris's standard /bin/ps does not show the changed process title.
  24  * You have to use "/usr/ucb/ps -w" instead.  Besides, the UCB ps does not
  25  * show a new title if its length less than the origin command line length.
  26  * To avoid it we append to a new title the origin command line in the
  27  * parenthesis.
  28  */
  29
  30 extern char **environ;
  31
  32 static char *ngx_os_argv_last;
  33
  34 ngx_int_t
  35 ngx_init_setproctitle(ngx_log_t *log)
  36 {
  37     u_char      *p;
  38     size_t       size;
  39     ngx_uint_t   i;
  40
  41     size = 0;
  42
  43     for (i = 0; environ[i]; i++) {
  44         size += ngx_strlen(environ[i]) + 1;
  45     }
  46
  47     p = ngx_alloc(size, log);
  48     if (p == NULL) {
  49         return NGX_ERROR;
  50     }
  51
  52     ngx_os_argv_last = ngx_os_argv[0];
  53
  54     for (i = 0; ngx_os_argv[i]; i++) {
  55         if (ngx_os_argv_last == ngx_os_argv[i]) {
  56             ngx_os_argv_last = ngx_os_argv[i] + ngx_strlen(ngx_os_argv[i]) + 1;
  57         }
  58     }
  59
  60     for (i = 0; environ[i]; i++) {
  61         if (ngx_os_argv_last == environ[i]) {
  62
  63             size = ngx_strlen(environ[i]) + 1;
  64             ngx_os_argv_last = environ[i] + size;
  65
  66             ngx_cpystrn(p, (u_char *) environ[i], size);
  67             environ[i] = (char *) p;
  68             p += size;
  69         }
  70     }
  71
  72     ngx_os_argv_last--;
  73
  74     return NGX_OK;
  75 }
  76
  77
  78 void
  79 ngx_setproctitle(char *title)
  80 {
  81     u_char     *p;
  82
  83 #if (NGX_SOLARIS)
  84
  85     ngx_int_t   i;
  86     size_t      size;
  87
  88 #endif
  89
  90     ngx_os_argv[1] = NULL;
  91
  92     p = ngx_cpystrn((u_char *) ngx_os_argv[0], (u_char *) "nginx: ",
  93                     ngx_os_argv_last - ngx_os_argv[0]);
  94
  95     p = ngx_cpystrn(p, (u_char *) title, ngx_os_argv_last - (char *) p);
  96
  97 #if (NGX_SOLARIS)
  98
  99     size = 0;
 100
 101     for (i = 0; i < ngx_argc; i++) {
 102         size += ngx_strlen(ngx_argv[i]) + 1;
 103     }
 104
 105     if (size > (size_t) ((char *) p - ngx_os_argv[0])) {
 106
 107         /*
 108          * ngx_setproctitle() is too rare operation so we use
 109          * the non-optimized copies
 110          */
 111
 112         p = ngx_cpystrn(p, (u_char *) " (", ngx_os_argv_last - (char *) p);
 113
 114         for (i = 0; i < ngx_argc; i++) {
 115             p = ngx_cpystrn(p, (u_char *) ngx_argv[i],
 116                             ngx_os_argv_last - (char *) p);
 117             p = ngx_cpystrn(p, (u_char *) " ", ngx_os_argv_last - (char *) p);
 118         }
 119
 120         if (*(p - 1) == ' ') {
 121             *(p - 1) = ')';
 122         }
 123     }
 124
 125 #endif
 126
 127     if (ngx_os_argv_last - (char *) p) {
 128         ngx_memset(p, NGX_SETPROCTITLE_PAD, ngx_os_argv_last - (char *) p);
 129     }
 130
 131     ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
 132                    "setproctitle: \"%s\"", ngx_os_argv[0]);
 133 }
 134
 135 #endif /* NGX_SETPROCTITLE_USES_ENV */