xref: /libuv/src/unix/proctitle.c (revision c2589424)
1 /* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
2  * Permission is hereby granted, free of charge, to any person obtaining a copy
3  * of this software and associated documentation files (the "Software"), to
4  * deal in the Software without restriction, including without limitation the
5  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
6  * sell copies of the Software, and to permit persons to whom the Software is
7  * furnished to do so, subject to the following conditions:
8  *
9  * The above copyright notice and this permission notice shall be included in
10  * all copies or substantial portions of the Software.
11  *
12  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
13  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
14  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
15  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
16  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
17  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
18  * IN THE SOFTWARE.
19  */
20 
21 #include "uv.h"
22 #include "internal.h"
23 
24 #include <stdlib.h>
25 #include <string.h>
26 
27 struct uv__process_title {
28   char* str;
29   size_t len;  /* Length of the current process title. */
30   size_t cap;  /* Maximum capacity. Computed once in uv_setup_args(). */
31 };
32 
33 extern void uv__set_process_title(const char* title);
34 
35 static uv_mutex_t process_title_mutex;
36 static uv_once_t process_title_mutex_once = UV_ONCE_INIT;
37 static struct uv__process_title process_title;
38 static void* args_mem;
39 
40 
init_process_title_mutex_once(void)41 static void init_process_title_mutex_once(void) {
42   uv_mutex_init(&process_title_mutex);
43 }
44 
45 
uv_setup_args(int argc,char ** argv)46 char** uv_setup_args(int argc, char** argv) {
47   struct uv__process_title pt;
48   char** new_argv;
49   size_t size;
50   char* s;
51   int i;
52 
53   if (argc <= 0)
54     return argv;
55 
56   pt.str = argv[0];
57   pt.len = strlen(argv[0]);
58   pt.cap = pt.len + 1;
59 
60   /* Calculate how much memory we need for the argv strings. */
61   size = pt.cap;
62   for (i = 1; i < argc; i++)
63     size += strlen(argv[i]) + 1;
64 
65   /* Add space for the argv pointers. */
66   size += (argc + 1) * sizeof(char*);
67 
68   new_argv = uv__malloc(size);
69   if (new_argv == NULL)
70     return argv;
71 
72   /* Copy over the strings and set up the pointer table. */
73   i = 0;
74   s = (char*) &new_argv[argc + 1];
75   size = pt.cap;
76   goto loop;
77 
78   for (/* empty */; i < argc; i++) {
79     size = strlen(argv[i]) + 1;
80   loop:
81     memcpy(s, argv[i], size);
82     new_argv[i] = s;
83     s += size;
84   }
85   new_argv[i] = NULL;
86 
87   pt.cap = argv[i - 1] + size - argv[0];
88 
89   args_mem = new_argv;
90   process_title = pt;
91 
92   return new_argv;
93 }
94 
95 
uv_set_process_title(const char * title)96 int uv_set_process_title(const char* title) {
97   struct uv__process_title* pt;
98   size_t len;
99 
100   /* If uv_setup_args wasn't called or failed, we can't continue. */
101   if (args_mem == NULL)
102     return UV_ENOBUFS;
103 
104   pt = &process_title;
105   len = strlen(title);
106 
107   uv_once(&process_title_mutex_once, init_process_title_mutex_once);
108   uv_mutex_lock(&process_title_mutex);
109 
110   if (len >= pt->cap) {
111     len = 0;
112     if (pt->cap > 0)
113       len = pt->cap - 1;
114   }
115 
116   memcpy(pt->str, title, len);
117   memset(pt->str + len, '\0', pt->cap - len);
118   pt->len = len;
119   uv__set_process_title(pt->str);
120 
121   uv_mutex_unlock(&process_title_mutex);
122 
123   return 0;
124 }
125 
126 
uv_get_process_title(char * buffer,size_t size)127 int uv_get_process_title(char* buffer, size_t size) {
128   if (buffer == NULL || size == 0)
129     return UV_EINVAL;
130 
131   /* If uv_setup_args wasn't called or failed, we can't continue. */
132   if (args_mem == NULL)
133     return UV_ENOBUFS;
134 
135   uv_once(&process_title_mutex_once, init_process_title_mutex_once);
136   uv_mutex_lock(&process_title_mutex);
137 
138   if (size <= process_title.len) {
139     uv_mutex_unlock(&process_title_mutex);
140     return UV_ENOBUFS;
141   }
142 
143   if (process_title.len != 0)
144     memcpy(buffer, process_title.str, process_title.len + 1);
145 
146   buffer[process_title.len] = '\0';
147 
148   uv_mutex_unlock(&process_title_mutex);
149 
150   return 0;
151 }
152 
153 
uv__process_title_cleanup(void)154 void uv__process_title_cleanup(void) {
155   uv__free(args_mem);  /* Keep valgrind happy. */
156   args_mem = NULL;
157 }
158