1 /* vi: set sw=4 ts=4: */
3 * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
5 * Copyright 1999 George Staikos
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
10 * v1.01 - added -p <preload> to preload values from a file
11 * v1.01.1 - busybox applet aware by <solar@gentoo.org>
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"
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"
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: */
46 #define OPTION_STR "neAapwq"
48 static void sysctl_dots_to_slashes(char *name
)
50 char *cptr
, *last_good
, *end
;
52 /* Convert minimum number of '.' to '/' so that
53 * we end up with existing file's name.
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.
64 * Another bug we later had is that
65 * net.ipv4.conf.eth0.100
66 * (without .mc_forwarding) was mishandled.
68 * To set up testing: modprobe 8021q; vconfig add eth0 100
70 end
= name
+ strlen(name
);
72 *end
= '.'; /* trick the loop into trying full name too */
76 while (cptr
> last_good
) {
79 //bb_error_msg("trying:'%s'", name);
80 if (access(name
, F_OK
) == 0) {
82 //bb_error_msg("replaced:'%s'", name);
93 static int sysctl_act_on_setting(char *setting
)
95 int fd
, retval
= EXIT_SUCCESS
;
97 char *value
= value
; /* for compiler */
99 outname
= xstrdup(setting
);
108 if (option_mask32
& FLAG_WRITE
) {
109 cptr
= strchr(setting
, '=');
111 bb_error_msg("error: '%s' must be of the form name=value",
113 retval
= EXIT_FAILURE
;
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
;
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);
127 fd
= open(setting
, O_RDONLY
);
133 /* Happens for write-only settings, e.g. net.ipv6.route.flush */
136 if (option_mask32
& FLAG_SHOW_KEY_ERRORS
)
137 bb_error_msg("error: '%s' is an unknown key", outname
);
140 bb_perror_msg("error %sing key '%s'",
141 option_mask32
& FLAG_WRITE
?
146 retval
= EXIT_FAILURE
;
150 if (option_mask32
& FLAG_WRITE
) {
151 //TODO: procps 3.2.7 writes "value\n", note trailing "\n"
152 xwrite_str(fd
, value
);
154 if (!(option_mask32
& FLAG_QUIET
)) {
155 if (option_mask32
& FLAG_SHOW_KEYS
)
156 printf("%s = ", outname
);
162 value
= cptr
= xmalloc_read(fd
, NULL
);
165 bb_perror_msg("error reading key '%s'", outname
);
169 /* dev.cdrom.info and sunrpc.transports, for example,
170 * are multi-line. Try "sysctl sunrpc.transports"
172 while ((c
= *cptr
) != '\0') {
173 if (option_mask32
& FLAG_SHOW_KEYS
)
174 printf("%s = ", outname
);
192 static int sysctl_act_recursive(const char *path
)
196 struct dirent
*entry
;
201 if (S_ISDIR(buf
.st_mode
) && !(option_mask32
& FLAG_WRITE
)) {
202 dirp
= opendir(path
);
205 while ((entry
= readdir(dirp
)) != NULL
) {
206 next
= concat_subpath_file(path
, entry
->d_name
);
208 continue; /* d_name is "." or ".." */
209 /* if path was ".", drop "./" prefix: */
210 retval
|= sysctl_act_recursive((next
[0] == '.' && next
[1] == '/') ?
216 char *name
= xstrdup(path
);
217 retval
|= sysctl_act_on_setting(name
);
224 /* Set sysctl's from a conf file. Format example:
225 * # Controls IP packet forwarding
226 * net.ipv4.ip_forward = 0
228 static int sysctl_handle_preload_file(const char *filename
)
233 parser
= config_open(filename
);
234 /* Must do it _after_ config_open(): */
236 /* xchroot("/proc/sys") - if you are paranoid */
238 //TODO: ';' is comment char too
239 //TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
240 // (but _whitespace_ from ends should be trimmed first (and we do it right))
241 //TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
242 // can it be fixed by removing PARSE_COLLAPSE bit?
243 while (config_read(parser
, token
, 2, 2, "# \t=", PARSE_NORMAL
)) {
245 sysctl_dots_to_slashes(token
[0]);
246 tp
= xasprintf("%s=%s", token
[0], token
[1]);
247 sysctl_act_recursive(tp
);
250 if (ENABLE_FEATURE_CLEAN_UP
)
251 config_close(parser
);
255 int sysctl_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
256 int sysctl_main(int argc UNUSED_PARAM
, char **argv
)
261 opt
= getopt32(argv
, "+" OPTION_STR
); /* '+' - stop on first non-option */
263 opt
^= (FLAG_SHOW_KEYS
| FLAG_SHOW_KEY_ERRORS
);
266 if (opt
& FLAG_PRELOAD_FILE
) {
267 option_mask32
|= FLAG_WRITE
;
268 /* xchdir("/proc/sys") is inside */
269 return sysctl_handle_preload_file(*argv
? *argv
: "/etc/sysctl.conf");
272 /* xchroot("/proc/sys") - if you are paranoid */
273 if (opt
& (FLAG_TABLE_FORMAT
| FLAG_SHOW_ALL
)) {
274 return sysctl_act_recursive(".");
279 sysctl_dots_to_slashes(*argv
);
280 retval
|= sysctl_act_recursive(*argv
);