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 tarball for details.
11 * - added -p <preload> to preload values from a file
13 * - busybox applet aware by <solar@gentoo.org>
19 static int sysctl_read_setting(const char *setting);
20 static int sysctl_write_setting(const char *setting);
21 static int sysctl_display_all(const char *path);
22 static int sysctl_preload_file_and_exit(const char *filename);
24 static const char ETC_SYSCTL_CONF[] ALIGN1 = "/etc/sysctl.conf";
25 static const char PROC_SYS[] ALIGN1 = "/proc/sys/";
26 enum { strlen_PROC_SYS = sizeof(PROC_SYS) - 1 };
29 static const char ERR_MALFORMED_SETTING[] ALIGN1 =
30 "error: malformed setting '%s'";
31 static const char ERR_NO_EQUALS[] ALIGN1 =
32 "error: '%s' must be of the form name=value";
33 static const char ERR_INVALID_KEY[] ALIGN1 =
34 "error: '%s' is an unknown key";
35 static const char ERR_UNKNOWN_WRITING[] ALIGN1 =
36 "error setting key '%s'";
37 static const char ERR_UNKNOWN_READING[] ALIGN1 =
38 "error reading key '%s'";
39 static const char ERR_PERMISSION_DENIED[] ALIGN1 =
40 "error: permission denied on key '%s'";
41 static const char WARN_BAD_LINE[] ALIGN1 =
42 "warning: %s(%d): invalid syntax, continuing";
45 static void dwrite_str(int fd, const char *buf)
47 write(fd, buf, strlen(buf));
51 FLAG_SHOW_KEYS = 1 << 0,
52 FLAG_SHOW_KEY_ERRORS = 1 << 1,
53 FLAG_TABLE_FORMAT = 1 << 2, /* not implemented */
54 FLAG_SHOW_ALL = 1 << 3,
55 FLAG_PRELOAD_FILE = 1 << 4,
59 int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
60 int sysctl_main(int argc UNUSED_PARAM, char **argv)
65 opt = getopt32(argv, "+neAapw"); /* '+' - stop on first non-option */
67 opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
68 option_mask32 ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
70 if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL))
71 return sysctl_display_all(PROC_SYS);
72 if (opt & FLAG_PRELOAD_FILE)
73 return sysctl_preload_file_and_exit(*argv ? *argv : ETC_SYSCTL_CONF);
78 retval |= sysctl_write_setting(*argv);
80 retval |= sysctl_read_setting(*argv);
85 } /* end sysctl_main() */
88 * preload the sysctl's from a conf file
89 * - we parse the file and then reform it (strip out whitespace)
92 static int sysctl_preload_file_and_exit(const char *filename)
97 parser = config_open(filename);
98 while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) { // TODO: ';' is comment char too
100 // bb_error_msg(WARN_BAD_LINE, filename, parser->lineno);
104 char *s = xasprintf("%s=%s", token[0], token[1]);
105 sysctl_write_setting(s);
107 #else // PLAY_WITH_FIRE for -4 bytes?
108 sprintf(parser->line, "%s=%s", token[0], token[1]); // must have room by definition
109 sysctl_write_setting(parser->line);
113 if (ENABLE_FEATURE_CLEAN_UP)
114 config_close(parser);
116 } /* end sysctl_preload_file_and_exit() */
119 * Write a single sysctl setting
121 static int sysctl_write_setting(const char *setting)
127 char *tmpname, *outname, *cptr;
131 equals = strchr(setting, '=');
133 bb_error_msg(ERR_NO_EQUALS, setting);
137 value = equals + 1; /* point to the value in name=value */
138 if (name == equals || !*value) {
139 bb_error_msg(ERR_MALFORMED_SETTING, setting);
143 tmpname = xasprintf("%s%.*s", PROC_SYS, (int)(equals - name), name);
144 outname = xstrdup(tmpname + strlen_PROC_SYS);
146 while ((cptr = strchr(tmpname, '.')) != NULL)
149 while ((cptr = strchr(outname, '/')) != NULL)
152 fd = open(tmpname, O_WRONLY | O_CREAT | O_TRUNC, 0666);
156 if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
157 bb_error_msg(ERR_INVALID_KEY, outname);
160 bb_perror_msg(ERR_PERMISSION_DENIED, outname);
163 bb_perror_msg(ERR_UNKNOWN_WRITING, outname);
166 retval = EXIT_FAILURE;
168 dwrite_str(fd, value);
170 if (option_mask32 & FLAG_SHOW_KEYS) {
171 printf("%s = ", outname);
174 retval = EXIT_SUCCESS;
180 } /* end sysctl_write_setting() */
183 * Read a sysctl setting
185 static int sysctl_read_setting(const char *name)
188 char *tmpname, *outname, *cptr;
193 if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
194 bb_error_msg(ERR_INVALID_KEY, name);
198 tmpname = concat_path_file(PROC_SYS, name);
199 outname = xstrdup(tmpname + strlen_PROC_SYS);
201 while ((cptr = strchr(tmpname, '.')) != NULL)
203 while ((cptr = strchr(outname, '/')) != NULL)
206 fp = fopen_for_read(tmpname);
210 if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
211 bb_error_msg(ERR_INVALID_KEY, outname);
214 bb_error_msg(ERR_PERMISSION_DENIED, outname);
217 bb_perror_msg(ERR_UNKNOWN_READING, outname);
220 retval = EXIT_FAILURE;
222 while (fgets(inbuf, sizeof(inbuf) - 1, fp)) {
223 if (option_mask32 & FLAG_SHOW_KEYS) {
224 printf("%s = ", outname);
226 fputs(inbuf, stdout);
229 retval = EXIT_SUCCESS;
235 } /* end sysctl_read_setting() */
238 * Display all the sysctl settings
240 static int sysctl_display_all(const char *path)
252 while ((de = readdir(dp)) != NULL) {
253 tmpdir = concat_subpath_file(path, de->d_name);
255 continue; /* . or .. */
256 if (stat(tmpdir, &ts) != 0) {
257 bb_perror_msg(tmpdir);
258 } else if (S_ISDIR(ts.st_mode)) {
259 retval |= sysctl_display_all(tmpdir);
261 retval |= sysctl_read_setting(tmpdir + strlen_PROC_SYS);
268 } /* end sysctl_display_all() */