Mercurial > hg > nginx-quic
annotate src/os/unix/ngx_setproctitle.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 | 67653855682e |
children |
rev | line source |
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452 | 1 |
2 /* | |
3 * Copyright (C) Igor Sysoev | |
4412 | 4 * Copyright (C) Nginx, Inc. |
452 | 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. | |
4572
67653855682e
Fixed spelling in multiline C comments.
Ruslan Ermilov <ru@nginx.com>
parents:
4412
diff
changeset
|
24 * You have to use "/usr/ucb/ps -w" instead. Besides, the UCB ps does not |
452 | 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 | |
493 | 34 ngx_int_t |
35 ngx_init_setproctitle(ngx_log_t *log) | |
452 | 36 { |
493 | 37 u_char *p; |
452 | 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 | |
501 | 47 p = ngx_alloc(size, log); |
48 if (p == NULL) { | |
452 | 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 | |
493 | 66 ngx_cpystrn(p, (u_char *) environ[i], size); |
67 environ[i] = (char *) p; | |
452 | 68 p += size; |
69 } | |
70 } | |
71 | |
72 ngx_os_argv_last--; | |
73 | |
74 return NGX_OK; | |
75 } | |
76 | |
77 | |
493 | 78 void |
79 ngx_setproctitle(char *title) | |
452 | 80 { |
81 u_char *p; | |
82 | |
455 | 83 #if (NGX_SOLARIS) |
452 | 84 |
85 ngx_int_t i; | |
86 size_t size; | |
87 | |
88 #endif | |
89 | |
90 ngx_os_argv[1] = NULL; | |
91 | |
507 | 92 p = ngx_cpystrn((u_char *) ngx_os_argv[0], (u_char *) "nginx: ", |
452 | 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 | |
455 | 97 #if (NGX_SOLARIS) |
452 | 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 | |
509 | 135 #endif /* NGX_SETPROCTITLE_USES_ENV */ |