ngx_setproctitle.c revision e18a033b
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
30extern char **environ;
31
32static char *ngx_os_argv_last;
33
34ngx_int_t
35ngx_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
78void
79ngx_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 */
136