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    Contents of /trunk/mkinitrd-magellan/busybox/procps/sysctl.c

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    Revision 984 - (show annotations) (download)
    Sun May 30 11:32:42 2010 UTC (13 years, 11 months ago) by niro
    File MIME type: text/plain
    File size: 6206 byte(s) 
    -updated to busybox-1.16.1 and enabled blkid/uuid support in default config
    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
    16 enum {
    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
    26 static 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 if (cptr != end) /* prevent trailing '/' */
    60 *cptr = '/';
    61 //bb_error_msg("replaced:'%s'", name);
    62 last_good = cptr;
    63 goto again;
    64 }
    65 *cptr = '.';
    66 }
    67 cptr--;
    68 }
    69 *end = '\0';
    70 }
    71
    72 static int sysctl_act_on_setting(char *setting)
    73 {
    74 int fd, retval = EXIT_SUCCESS;
    75 char *cptr, *outname;
    76 char *value = value; /* for compiler */
    77
    78 outname = xstrdup(setting);
    79
    80 cptr = outname;
    81 while (*cptr) {
    82 if (*cptr == '/')
    83 *cptr = '.';
    84 cptr++;
    85 }
    86
    87 if (option_mask32 & FLAG_WRITE) {
    88 cptr = strchr(setting, '=');
    89 if (cptr == NULL) {
    90 bb_error_msg("error: '%s' must be of the form name=value",
    91 outname);
    92 retval = EXIT_FAILURE;
    93 goto end;
    94 }
    95 value = cptr + 1; /* point to the value in name=value */
    96 if (setting == cptr || !*value) {
    97 bb_error_msg("error: malformed setting '%s'", outname);
    98 retval = EXIT_FAILURE;
    99 goto end;
    100 }
    101 *cptr = '\0';
    102 outname[cptr - setting] = '\0';
    103 /* procps 3.2.7 actually uses these flags */
    104 fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666);
    105 } else {
    106 fd = open(setting, O_RDONLY);
    107 }
    108
    109 if (fd < 0) {
    110 switch (errno) {
    111 case ENOENT:
    112 if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
    113 bb_error_msg("error: '%s' is an unknown key", outname);
    114 break;
    115 default:
    116 bb_perror_msg("error %sing key '%s'",
    117 option_mask32 & FLAG_WRITE ?
    118 "sett" : "read",
    119 outname);
    120 break;
    121 }
    122 retval = EXIT_FAILURE;
    123 goto end;
    124 }
    125
    126 if (option_mask32 & FLAG_WRITE) {
    127 //TODO: procps 3.2.7 writes "value\n", note trailing "\n"
    128 xwrite_str(fd, value);
    129 close(fd);
    130 if (option_mask32 & FLAG_SHOW_KEYS)
    131 printf("%s = ", outname);
    132 puts(value);
    133 } else {
    134 char c;
    135
    136 value = cptr = xmalloc_read(fd, NULL);
    137 close(fd);
    138 if (value == NULL) {
    139 bb_perror_msg("error reading key '%s'", outname);
    140 goto end;
    141 }
    142
    143 /* dev.cdrom.info and sunrpc.transports, for example,
    144 * are multi-line. Try "sysctl sunrpc.transports"
    145 */
    146 while ((c = *cptr) != '\0') {
    147 if (option_mask32 & FLAG_SHOW_KEYS)
    148 printf("%s = ", outname);
    149 while (1) {
    150 fputc(c, stdout);
    151 cptr++;
    152 if (c == '\n')
    153 break;
    154 c = *cptr;
    155 if (c == '\0')
    156 break;
    157 }
    158 }
    159 free(value);
    160 }
    161 end:
    162 free(outname);
    163 return retval;
    164 }
    165
    166 static int sysctl_act_recursive(const char *path)
    167 {
    168 DIR *dirp;
    169 struct stat buf;
    170 struct dirent *entry;
    171 char *next;
    172 int retval = 0;
    173
    174 stat(path, &buf);
    175 if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) {
    176 dirp = opendir(path);
    177 if (dirp == NULL)
    178 return -1;
    179 while ((entry = readdir(dirp)) != NULL) {
    180 next = concat_subpath_file(path, entry->d_name);
    181 if (next == NULL)
    182 continue; /* d_name is "." or ".." */
    183 /* if path was ".", drop "./" prefix: */
    184 retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ?
    185 next + 2 : next);
    186 free(next);
    187 }
    188 closedir(dirp);
    189 } else {
    190 char *name = xstrdup(path);
    191 retval |= sysctl_act_on_setting(name);
    192 free(name);
    193 }
    194
    195 return retval;
    196 }
    197
    198 /* Set sysctl's from a conf file. Format example:
    199 * # Controls IP packet forwarding
    200 * net.ipv4.ip_forward = 0
    201 */
    202 static int sysctl_handle_preload_file(const char *filename)
    203 {
    204 char *token[2];
    205 parser_t *parser;
    206
    207 parser = config_open(filename);
    208 /* Must do it _after_ config_open(): */
    209 xchdir("/proc/sys");
    210 /* xchroot(".") - if you are paranoid */
    211
    212 //TODO: ';' is comment char too
    213 //TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
    214 // (but _whitespace_ from ends should be trimmed first (and we do it right))
    215 //TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
    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
    228 int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
    229 int 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 }