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 tarball for details. 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#include "libbb.h" 15 16enum { 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, 22 FLAG_WRITE = 1 << 5, 23}; 24#define OPTION_STR "neAapw" 25 26static void sysctl_dots_to_slashes(char *name) 27{ 28 char *cptr, *last_good, *end; 29 30 /* Convert minimum number of '.' to '/' so that 31 * we end up with existing file's name. 32 * 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. 41 * 42 * Another bug we later had is that 43 * net.ipv4.conf.eth0.100 44 * (without .mc_forwarding) was mishandled. 45 * 46 * To set up testing: modprobe 8021q; vconfig add eth0 100 47 */ 48 end = name + strlen(name); 49 last_good = name - 1; 50 *end = '.'; /* trick the loop into trying full name too */ 51 52 again: 53 cptr = end; 54 while (cptr > last_good) { 55 if (*cptr == '.') { 56 *cptr = '\0'; 57 //bb_error_msg("trying:'%s'", name); 58 if (access(name, F_OK) == 0) { 59 *cptr = '/'; 60 //bb_error_msg("replaced:'%s'", name); 61 last_good = cptr; 62 goto again; 63 } 64 *cptr = '.'; 65 } 66 cptr--; 67 } 68 *end = '\0'; 69} 70 71static int sysctl_act_on_setting(char *setting) 72{ 73 int fd, retval = EXIT_SUCCESS; 74 char *cptr, *outname; 75 char *value = value; /* for compiler */ 76 77 outname = xstrdup(setting); 78 79 cptr = outname; 80 while (*cptr) { 81 if (*cptr == '/') 82 *cptr = '.'; 83 cptr++; 84 } 85 86 if (option_mask32 & FLAG_WRITE) { 87 cptr = strchr(setting, '='); 88 if (cptr == NULL) { 89 bb_error_msg("error: '%s' must be of the form name=value", 90 outname); 91 retval = EXIT_FAILURE; 92 goto end; 93 } 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; 98 goto end; 99 } 100 *cptr = '\0'; 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); 104 } else { 105 fd = open(setting, O_RDONLY); 106 } 107 108 if (fd < 0) { 109 switch (errno) { 110 case ENOENT: 111 if (option_mask32 & FLAG_SHOW_KEY_ERRORS) 112 bb_error_msg("error: '%s' is an unknown key", outname); 113 break; 114 default: 115 bb_perror_msg("error %sing key '%s'", 116 option_mask32 & FLAG_WRITE ? 117 "sett" : "read", 118 outname); 119 break; 120 } 121 retval = EXIT_FAILURE; 122 goto end; 123 } 124 125 if (option_mask32 & FLAG_WRITE) { 126//TODO: procps 3.2.7 writes "value\n", note trailing "\n" 127 xwrite_str(fd, value); 128 close(fd); 129 if (option_mask32 & FLAG_SHOW_KEYS) 130 printf("%s = ", outname); 131 puts(value); 132 } else { 133 char c; 134 135 value = cptr = xmalloc_read(fd, NULL); 136 close(fd); 137 if (value == NULL) { 138 bb_perror_msg("error reading key '%s'", outname); 139 goto end; 140 } 141 142 /* dev.cdrom.info and sunrpc.transports, for example, 143 * are multi-line. Try "sysctl sunrpc.transports" 144 */ 145 while ((c = *cptr) != '\0') { 146 if (option_mask32 & FLAG_SHOW_KEYS) 147 printf("%s = ", outname); 148 while (1) { 149 fputc(c, stdout); 150 cptr++; 151 if (c == '\n') 152 break; 153 c = *cptr; 154 if (c == '\0') 155 break; 156 } 157 } 158 free(value); 159 } 160 end: 161 free(outname); 162 return retval; 163} 164 165static int sysctl_act_recursive(const char *path) 166{ 167 DIR *dirp; 168 struct stat buf; 169 struct dirent *entry; 170 char *next; 171 int retval = 0; 172 173 stat(path, &buf); 174 if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) { 175 dirp = opendir(path); 176 if (dirp == NULL) 177 return -1; 178 while ((entry = readdir(dirp)) != NULL) { 179 next = concat_subpath_file(path, entry->d_name); 180 if (next == NULL) 181 continue; /* d_name is "." or ".." */ 182 /* if path was ".", drop "./" prefix: */ 183 retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ? 184 next + 2 : next); 185 free(next); 186 } 187 closedir(dirp); 188 } else { 189 char *name = xstrdup(path); 190 retval |= sysctl_act_on_setting(name); 191 free(name); 192 } 193 194 return retval; 195} 196 197/* Set sysctl's from a conf file. Format example: 198 * # Controls IP packet forwarding 199 * net.ipv4.ip_forward = 0 200 */ 201static int sysctl_handle_preload_file(const char *filename) 202{ 203 char *token[2]; 204 parser_t *parser; 205 206 parser = config_open(filename); 207 /* Must do it _after_ config_open(): */ 208 xchdir("/proc/sys"); 209 /* xchroot(".") - if you are paranoid */ 210 211//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)) { 217 char *tp; 218 sysctl_dots_to_slashes(token[0]); 219 tp = xasprintf("%s=%s", token[0], token[1]); 220 sysctl_act_recursive(tp); 221 free(tp); 222 } 223 if (ENABLE_FEATURE_CLEAN_UP) 224 config_close(parser); 225 return 0; 226} 227 228int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE; 229int sysctl_main(int argc UNUSED_PARAM, char **argv) 230{ 231 int retval; 232 int opt; 233 234 opt = getopt32(argv, "+" OPTION_STR); /* '+' - stop on first non-option */ 235 argv += optind; 236 opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS); 237 option_mask32 = opt; 238 239 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"); 243 } 244 xchdir("/proc/sys"); 245 /* xchroot(".") - if you are paranoid */ 246 if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) { 247 return sysctl_act_recursive("."); 248 } 249 250 retval = 0; 251 while (*argv) { 252 sysctl_dots_to_slashes(*argv); 253 retval |= sysctl_act_recursive(*argv); 254 argv++; 255 } 256 257 return retval; 258} 259