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>
17 FLAG_SHOW_KEYS
= 1 << 0,
18 FLAG_SHOW_KEY_ERRORS
= 1 << 1,
19 FLAG_TABLE_FORMAT
= 1 << 2, /* not implemented */
20 FLAG_SHOW_ALL
= 1 << 3,
21 FLAG_PRELOAD_FILE
= 1 << 4,
24 #define OPTION_STR "neAapw"
26 static void sysctl_dots_to_slashes(char *name
)
28 char *cptr
, *last_good
, *end
;
30 /* Convert minimum number of '.' to '/' so that
31 * we end up with existing file's name.
33 * Example from bug 3894:
34 * net.ipv4.conf.eth0.100.mc_forwarding ->
35 * net/ipv4/conf/eth0.100/mc_forwarding
36 * NB: net/ipv4/conf/eth0/mc_forwarding *also exists*,
37 * therefore we must start from the end, and if
38 * we replaced even one . -> /, start over again,
39 * but never replace dots before the position
40 * where last replacement occurred.
42 * Another bug we later had is that
43 * net.ipv4.conf.eth0.100
44 * (without .mc_forwarding) was mishandled.
46 * To set up testing: modprobe 8021q; vconfig add eth0 100
48 end
= name
+ strlen(name
);
50 *end
= '.'; /* trick the loop into trying full name too */
54 while (cptr
> last_good
) {
57 //bb_error_msg("trying:'%s'", name);
58 if (access(name
, F_OK
) == 0) {
60 //bb_error_msg("replaced:'%s'", name);
71 static int sysctl_act_on_setting(char *setting
)
73 int fd
, retval
= EXIT_SUCCESS
;
75 char *value
= value
; /* for compiler */
77 outname
= xstrdup(setting
);
86 if (option_mask32
& FLAG_WRITE
) {
87 cptr
= strchr(setting
, '=');
89 bb_error_msg("error: '%s' must be of the form name=value",
91 retval
= EXIT_FAILURE
;
94 value
= cptr
+ 1; /* point to the value in name=value */
95 if (setting
== cptr
|| !*value
) {
96 bb_error_msg("error: malformed setting '%s'", outname
);
97 retval
= EXIT_FAILURE
;
101 outname
[cptr
- setting
] = '\0';
102 /* procps 3.2.7 actually uses these flags */
103 fd
= open(setting
, O_WRONLY
|O_CREAT
|O_TRUNC
, 0666);
105 fd
= open(setting
, O_RDONLY
);
111 if (option_mask32
& FLAG_SHOW_KEY_ERRORS
)
112 bb_error_msg("error: '%s' is an unknown key", outname
);
115 bb_perror_msg("error %sing key '%s'",
116 option_mask32
& FLAG_WRITE
?
121 retval
= EXIT_FAILURE
;
125 if (option_mask32
& FLAG_WRITE
) {
126 //TODO: procps 3.2.7 writes "value\n", note trailing "\n"
127 xwrite_str(fd
, value
);
129 if (option_mask32
& FLAG_SHOW_KEYS
)
130 printf("%s = ", outname
);
135 value
= cptr
= xmalloc_read(fd
, NULL
);
138 bb_perror_msg("error reading key '%s'", outname
);
142 /* dev.cdrom.info and sunrpc.transports, for example,
143 * are multi-line. Try "sysctl sunrpc.transports"
145 while ((c
= *cptr
) != '\0') {
146 if (option_mask32
& FLAG_SHOW_KEYS
)
147 printf("%s = ", outname
);
165 static int sysctl_act_recursive(const char *path
)
169 struct dirent
*entry
;
174 if (S_ISDIR(buf
.st_mode
) && !(option_mask32
& FLAG_WRITE
)) {
175 dirp
= opendir(path
);
178 while ((entry
= readdir(dirp
)) != NULL
) {
179 next
= concat_subpath_file(path
, entry
->d_name
);
181 continue; /* d_name is "." or ".." */
182 /* if path was ".", drop "./" prefix: */
183 retval
|= sysctl_act_recursive((next
[0] == '.' && next
[1] == '/') ?
189 char *name
= xstrdup(path
);
190 retval
|= sysctl_act_on_setting(name
);
197 /* Set sysctl's from a conf file. Format example:
198 * # Controls IP packet forwarding
199 * net.ipv4.ip_forward = 0
201 static int sysctl_handle_preload_file(const char *filename
)
206 parser
= config_open(filename
);
207 /* Must do it _after_ config_open(): */
209 /* xchroot(".") - if you are paranoid */
211 //TODO: ';' is comment char too
212 //TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
213 // (but _whitespace_ from ends should be trimmed first (and we do it right))
214 //TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
215 // can it be fixed by removing PARSE_COLLAPSE bit?
216 while (config_read(parser
, token
, 2, 2, "# \t=", PARSE_NORMAL
)) {
218 sysctl_dots_to_slashes(token
[0]);
219 tp
= xasprintf("%s=%s", token
[0], token
[1]);
220 sysctl_act_recursive(tp
);
223 if (ENABLE_FEATURE_CLEAN_UP
)
224 config_close(parser
);
228 int sysctl_main(int argc
, char **argv
) MAIN_EXTERNALLY_VISIBLE
;
229 int sysctl_main(int argc UNUSED_PARAM
, char **argv
)
234 opt
= getopt32(argv
, "+" OPTION_STR
); /* '+' - stop on first non-option */
236 opt
^= (FLAG_SHOW_KEYS
| FLAG_SHOW_KEY_ERRORS
);
239 if (opt
& FLAG_PRELOAD_FILE
) {
240 option_mask32
|= FLAG_WRITE
;
241 /* xchdir("/proc/sys") is inside */
242 return sysctl_handle_preload_file(*argv
? *argv
: "/etc/sysctl.conf");
245 /* xchroot(".") - if you are paranoid */
246 if (opt
& (FLAG_TABLE_FORMAT
| FLAG_SHOW_ALL
)) {
247 return sysctl_act_recursive(".");
252 sysctl_dots_to_slashes(*argv
);
253 retval
|= sysctl_act_recursive(*argv
);