blob: fe70bfd3bb60bf4455fdd135db033bfb88625f53
1 | /* vi: set sw=4 ts=4: */ |
2 | /* |
3 | * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters |
4 | * |
5 | * Copyright 1999 George Staikos |
6 | * |
7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree. |
8 | * |
9 | * Changelog: |
10 | * v1.01 - added -p <preload> to preload values from a file |
11 | * v1.01.1 - busybox applet aware by <solar@gentoo.org> |
12 | */ |
13 | |
14 | //usage:#define sysctl_trivial_usage |
15 | //usage: "[OPTIONS] [KEY[=VALUE]]..." |
16 | //usage:#define sysctl_full_usage "\n\n" |
17 | //usage: "Show/set kernel parameters\n" |
18 | //usage: "\n -e Don't warn about unknown keys" |
19 | //usage: "\n -n Don't show key names" |
20 | //usage: "\n -a Show all values" |
21 | /* Same as -a, no need to show it */ |
22 | /* //usage: "\n -A Show all values in table form" */ |
23 | //usage: "\n -w Set values" |
24 | //usage: "\n -p FILE Set values from FILE (default /etc/sysctl.conf)" |
25 | //usage: "\n -q Set values silently" |
26 | //usage: |
27 | //usage:#define sysctl_example_usage |
28 | //usage: "sysctl [-n] [-e] variable...\n" |
29 | //usage: "sysctl [-n] [-e] [-q] -w variable=value...\n" |
30 | //usage: "sysctl [-n] [-e] -a\n" |
31 | //usage: "sysctl [-n] [-e] [-q] -p file (default /etc/sysctl.conf)\n" |
32 | //usage: "sysctl [-n] [-e] -A\n" |
33 | |
34 | #include "libbb.h" |
35 | |
36 | enum { |
37 | FLAG_SHOW_KEYS = 1 << 0, |
38 | FLAG_SHOW_KEY_ERRORS = 1 << 1, |
39 | FLAG_TABLE_FORMAT = 1 << 2, /* not implemented */ |
40 | FLAG_SHOW_ALL = 1 << 3, |
41 | FLAG_PRELOAD_FILE = 1 << 4, |
42 | /* TODO: procps 3.2.8 seems to not require -w for KEY=VAL to work: */ |
43 | FLAG_WRITE = 1 << 5, |
44 | FLAG_QUIET = 1 << 6, |
45 | }; |
46 | #define OPTION_STR "neAapwq" |
47 | |
48 | static void sysctl_dots_to_slashes(char *name) |
49 | { |
50 | char *cptr, *last_good, *end; |
51 | |
52 | /* Convert minimum number of '.' to '/' so that |
53 | * we end up with existing file's name. |
54 | * |
55 | * Example from bug 3894: |
56 | * net.ipv4.conf.eth0.100.mc_forwarding -> |
57 | * net/ipv4/conf/eth0.100/mc_forwarding |
58 | * NB: net/ipv4/conf/eth0/mc_forwarding *also exists*, |
59 | * therefore we must start from the end, and if |
60 | * we replaced even one . -> /, start over again, |
61 | * but never replace dots before the position |
62 | * where last replacement occurred. |
63 | * |
64 | * Another bug we later had is that |
65 | * net.ipv4.conf.eth0.100 |
66 | * (without .mc_forwarding) was mishandled. |
67 | * |
68 | * To set up testing: modprobe 8021q; vconfig add eth0 100 |
69 | */ |
70 | end = name + strlen(name); |
71 | last_good = name - 1; |
72 | *end = '.'; /* trick the loop into trying full name too */ |
73 | |
74 | again: |
75 | cptr = end; |
76 | while (cptr > last_good) { |
77 | if (*cptr == '.') { |
78 | *cptr = '\0'; |
79 | //bb_error_msg("trying:'%s'", name); |
80 | if (access(name, F_OK) == 0) { |
81 | *cptr = '/'; |
82 | //bb_error_msg("replaced:'%s'", name); |
83 | last_good = cptr; |
84 | goto again; |
85 | } |
86 | *cptr = '.'; |
87 | } |
88 | cptr--; |
89 | } |
90 | *end = '\0'; |
91 | } |
92 | |
93 | static int sysctl_act_on_setting(char *setting) |
94 | { |
95 | int fd, retval = EXIT_SUCCESS; |
96 | char *cptr, *outname; |
97 | char *value = NULL; |
98 | |
99 | outname = xstrdup(setting); |
100 | |
101 | cptr = outname; |
102 | while (*cptr) { |
103 | if (*cptr == '/') |
104 | *cptr = '.'; |
105 | cptr++; |
106 | } |
107 | |
108 | if (option_mask32 & FLAG_WRITE) { |
109 | cptr = strchr(setting, '='); |
110 | if (cptr == NULL) { |
111 | bb_error_msg("error: '%s' must be of the form name=value", |
112 | outname); |
113 | retval = EXIT_FAILURE; |
114 | goto end; |
115 | } |
116 | value = cptr + 1; /* point to the value in name=value */ |
117 | if (setting == cptr || !*value) { |
118 | bb_error_msg("error: malformed setting '%s'", outname); |
119 | retval = EXIT_FAILURE; |
120 | goto end; |
121 | } |
122 | *cptr = '\0'; |
123 | outname[cptr - setting] = '\0'; |
124 | /* procps 3.2.7 actually uses these flags */ |
125 | fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666); |
126 | } else { |
127 | fd = open(setting, O_RDONLY); |
128 | } |
129 | |
130 | if (fd < 0) { |
131 | switch (errno) { |
132 | case ENOENT: |
133 | if (option_mask32 & FLAG_SHOW_KEY_ERRORS) |
134 | bb_error_msg("error: '%s' is an unknown key", outname); |
135 | break; |
136 | default: |
137 | bb_perror_msg("error %sing key '%s'", |
138 | option_mask32 & FLAG_WRITE ? |
139 | "sett" : "read", |
140 | outname); |
141 | break; |
142 | } |
143 | retval = EXIT_FAILURE; |
144 | goto end; |
145 | } |
146 | |
147 | if (option_mask32 & FLAG_WRITE) { |
148 | //TODO: procps 3.2.7 writes "value\n", note trailing "\n" |
149 | xwrite_str(fd, value); |
150 | close(fd); |
151 | if (!(option_mask32 & FLAG_QUIET)) { |
152 | if (option_mask32 & FLAG_SHOW_KEYS) |
153 | printf("%s = ", outname); |
154 | puts(value); |
155 | } |
156 | } else { |
157 | char c; |
158 | |
159 | value = cptr = xmalloc_read(fd, NULL); |
160 | close(fd); |
161 | if (value == NULL) { |
162 | bb_perror_msg("error reading key '%s'", outname); |
163 | goto end; |
164 | } |
165 | |
166 | /* dev.cdrom.info and sunrpc.transports, for example, |
167 | * are multi-line. Try "sysctl sunrpc.transports" |
168 | */ |
169 | while ((c = *cptr) != '\0') { |
170 | if (option_mask32 & FLAG_SHOW_KEYS) |
171 | printf("%s = ", outname); |
172 | while (1) { |
173 | fputc(c, stdout); |
174 | cptr++; |
175 | if (c == '\n') |
176 | break; |
177 | c = *cptr; |
178 | if (c == '\0') |
179 | break; |
180 | } |
181 | } |
182 | free(value); |
183 | } |
184 | end: |
185 | free(outname); |
186 | return retval; |
187 | } |
188 | |
189 | static int sysctl_act_recursive(const char *path) |
190 | { |
191 | DIR *dirp; |
192 | struct stat buf; |
193 | struct dirent *entry; |
194 | char *next; |
195 | int retval = 0; |
196 | |
197 | stat(path, &buf); |
198 | if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) { |
199 | dirp = opendir(path); |
200 | if (dirp == NULL) |
201 | return -1; |
202 | while ((entry = readdir(dirp)) != NULL) { |
203 | next = concat_subpath_file(path, entry->d_name); |
204 | if (next == NULL) |
205 | continue; /* d_name is "." or ".." */ |
206 | /* if path was ".", drop "./" prefix: */ |
207 | retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ? |
208 | next + 2 : next); |
209 | free(next); |
210 | } |
211 | closedir(dirp); |
212 | } else { |
213 | char *name = xstrdup(path); |
214 | retval |= sysctl_act_on_setting(name); |
215 | free(name); |
216 | } |
217 | |
218 | return retval; |
219 | } |
220 | |
221 | /* Set sysctl's from a conf file. Format example: |
222 | * # Controls IP packet forwarding |
223 | * net.ipv4.ip_forward = 0 |
224 | */ |
225 | static int sysctl_handle_preload_file(const char *filename) |
226 | { |
227 | char *token[2]; |
228 | parser_t *parser; |
229 | |
230 | parser = config_open(filename); |
231 | /* Must do it _after_ config_open(): */ |
232 | xchdir("/proc/sys"); |
233 | /* xchroot("/proc/sys") - if you are paranoid */ |
234 | |
235 | //TODO: ';' is comment char too |
236 | //TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value |
237 | // (but _whitespace_ from ends should be trimmed first (and we do it right)) |
238 | //TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1") |
239 | // can it be fixed by removing PARSE_COLLAPSE bit? |
240 | while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) { |
241 | char *tp; |
242 | sysctl_dots_to_slashes(token[0]); |
243 | tp = xasprintf("%s=%s", token[0], token[1]); |
244 | sysctl_act_recursive(tp); |
245 | free(tp); |
246 | } |
247 | if (ENABLE_FEATURE_CLEAN_UP) |
248 | config_close(parser); |
249 | return 0; |
250 | } |
251 | |
252 | int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; |
253 | int sysctl_main(int argc UNUSED_PARAM, char **argv) |
254 | { |
255 | int retval; |
256 | int opt; |
257 | |
258 | opt = getopt32(argv, "+" OPTION_STR); /* '+' - stop on first non-option */ |
259 | argv += optind; |
260 | opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS); |
261 | option_mask32 = opt; |
262 | |
263 | if (opt & FLAG_PRELOAD_FILE) { |
264 | option_mask32 |= FLAG_WRITE; |
265 | /* xchdir("/proc/sys") is inside */ |
266 | return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf"); |
267 | } |
268 | xchdir("/proc/sys"); |
269 | /* xchroot("/proc/sys") - if you are paranoid */ |
270 | if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) { |
271 | return sysctl_act_recursive("."); |
272 | } |
273 | |
274 | retval = 0; |
275 | while (*argv) { |
276 | sysctl_dots_to_slashes(*argv); |
277 | retval |= sysctl_act_recursive(*argv); |
278 | argv++; |
279 | } |
280 | |
281 | return retval; |
282 | } |
283 |