[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
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| 4 | *
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| 5 | * Copyright 1999 George Staikos
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| 6 | *
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| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | *
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| 9 | * Changelog:
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| 10 | * v1.01 - added -p <preload> to preload values from a file
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| 11 | * v1.01.1 - busybox applet aware by <solar@gentoo.org>
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| 12 | */
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| 13 |
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| 14 | #include "libbb.h"
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| 15 |
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| 16 | enum {
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| 17 | FLAG_SHOW_KEYS = 1 << 0,
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| 18 | FLAG_SHOW_KEY_ERRORS = 1 << 1,
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| 19 | FLAG_TABLE_FORMAT = 1 << 2, /* not implemented */
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| 20 | FLAG_SHOW_ALL = 1 << 3,
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| 21 | FLAG_PRELOAD_FILE = 1 << 4,
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| 22 | FLAG_WRITE = 1 << 5,
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| 23 | };
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| 24 | #define OPTION_STR "neAapw"
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| 25 |
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| 26 | static void sysctl_dots_to_slashes(char *name)
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| 27 | {
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| 28 | char *cptr, *last_good, *end;
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| 29 |
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| 30 | /* Convert minimum number of '.' to '/' so that
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| 31 | * we end up with existing file's name.
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| 32 | *
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| 33 | * Example from bug 3894:
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| 34 | * net.ipv4.conf.eth0.100.mc_forwarding ->
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| 35 | * net/ipv4/conf/eth0.100/mc_forwarding
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| 36 | * NB: net/ipv4/conf/eth0/mc_forwarding *also exists*,
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| 37 | * therefore we must start from the end, and if
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| 38 | * we replaced even one . -> /, start over again,
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| 39 | * but never replace dots before the position
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| 40 | * where last replacement occurred.
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| 41 | *
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| 42 | * Another bug we later had is that
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| 43 | * net.ipv4.conf.eth0.100
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| 44 | * (without .mc_forwarding) was mishandled.
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| 45 | *
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| 46 | * To set up testing: modprobe 8021q; vconfig add eth0 100
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| 47 | */
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| 48 | end = name + strlen(name);
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| 49 | last_good = name - 1;
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| 50 | *end = '.'; /* trick the loop into trying full name too */
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| 51 |
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| 52 | again:
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| 53 | cptr = end;
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| 54 | while (cptr > last_good) {
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| 55 | if (*cptr == '.') {
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| 56 | *cptr = '\0';
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| 57 | //bb_error_msg("trying:'%s'", name);
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| 58 | if (access(name, F_OK) == 0) {
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| 59 | *cptr = '/';
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| 60 | //bb_error_msg("replaced:'%s'", name);
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| 61 | last_good = cptr;
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| 62 | goto again;
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| 63 | }
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| 64 | *cptr = '.';
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| 65 | }
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| 66 | cptr--;
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| 67 | }
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| 68 | *end = '\0';
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| 69 | }
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| 70 |
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| 71 | static int sysctl_act_on_setting(char *setting)
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| 72 | {
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| 73 | int fd, retval = EXIT_SUCCESS;
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| 74 | char *cptr, *outname;
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| 75 | char *value = value; /* for compiler */
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| 76 |
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| 77 | outname = xstrdup(setting);
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| 78 |
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| 79 | cptr = outname;
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| 80 | while (*cptr) {
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| 81 | if (*cptr == '/')
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| 82 | *cptr = '.';
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| 83 | cptr++;
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| 84 | }
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| 85 |
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| 86 | if (option_mask32 & FLAG_WRITE) {
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| 87 | cptr = strchr(setting, '=');
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| 88 | if (cptr == NULL) {
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| 89 | bb_error_msg("error: '%s' must be of the form name=value",
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| 90 | outname);
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| 91 | retval = EXIT_FAILURE;
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| 92 | goto end;
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| 93 | }
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| 94 | value = cptr + 1; /* point to the value in name=value */
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| 95 | if (setting == cptr || !*value) {
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| 96 | bb_error_msg("error: malformed setting '%s'", outname);
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| 97 | retval = EXIT_FAILURE;
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| 98 | goto end;
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| 99 | }
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| 100 | *cptr = '\0';
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| 101 | outname[cptr - setting] = '\0';
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| 102 | /* procps 3.2.7 actually uses these flags */
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| 103 | fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666);
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| 104 | } else {
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| 105 | fd = open(setting, O_RDONLY);
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| 106 | }
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| 107 |
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| 108 | if (fd < 0) {
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| 109 | switch (errno) {
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| 110 | case ENOENT:
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| 111 | if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
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| 112 | bb_error_msg("error: '%s' is an unknown key", outname);
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| 113 | break;
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| 114 | default:
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| 115 | bb_perror_msg("error %sing key '%s'",
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| 116 | option_mask32 & FLAG_WRITE ?
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| 117 | "sett" : "read",
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| 118 | outname);
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| 119 | break;
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| 120 | }
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| 121 | retval = EXIT_FAILURE;
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| 122 | goto end;
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| 123 | }
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| 124 |
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| 125 | if (option_mask32 & FLAG_WRITE) {
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| 126 | //TODO: procps 3.2.7 writes "value\n", note trailing "\n"
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| 127 | xwrite_str(fd, value);
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| 128 | close(fd);
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| 129 | if (option_mask32 & FLAG_SHOW_KEYS)
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| 130 | printf("%s = ", outname);
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| 131 | puts(value);
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| 132 | } else {
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| 133 | char c;
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| 134 |
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| 135 | value = cptr = xmalloc_read(fd, NULL);
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| 136 | close(fd);
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| 137 | if (value == NULL) {
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| 138 | bb_perror_msg("error reading key '%s'", outname);
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| 139 | goto end;
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| 140 | }
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| 141 |
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| 142 | /* dev.cdrom.info and sunrpc.transports, for example,
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| 143 | * are multi-line. Try "sysctl sunrpc.transports"
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| 144 | */
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| 145 | while ((c = *cptr) != '\0') {
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| 146 | if (option_mask32 & FLAG_SHOW_KEYS)
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| 147 | printf("%s = ", outname);
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| 148 | while (1) {
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| 149 | fputc(c, stdout);
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| 150 | cptr++;
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| 151 | if (c == '\n')
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| 152 | break;
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| 153 | c = *cptr;
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| 154 | if (c == '\0')
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| 155 | break;
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| 156 | }
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| 157 | }
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| 158 | free(value);
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| 159 | }
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| 160 | end:
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| 161 | free(outname);
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| 162 | return retval;
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| 163 | }
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| 164 |
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| 165 | static int sysctl_act_recursive(const char *path)
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| 166 | {
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| 167 | DIR *dirp;
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| 168 | struct stat buf;
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| 169 | struct dirent *entry;
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| 170 | char *next;
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| 171 | int retval = 0;
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| 172 |
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| 173 | stat(path, &buf);
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| 174 | if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) {
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| 175 | dirp = opendir(path);
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| 176 | if (dirp == NULL)
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| 177 | return -1;
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| 178 | while ((entry = readdir(dirp)) != NULL) {
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| 179 | next = concat_subpath_file(path, entry->d_name);
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| 180 | if (next == NULL)
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| 181 | continue; /* d_name is "." or ".." */
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| 182 | /* if path was ".", drop "./" prefix: */
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| 183 | retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ?
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| 184 | next + 2 : next);
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| 185 | free(next);
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| 186 | }
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| 187 | closedir(dirp);
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| 188 | } else {
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| 189 | char *name = xstrdup(path);
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| 190 | retval |= sysctl_act_on_setting(name);
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| 191 | free(name);
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| 192 | }
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| 193 |
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| 194 | return retval;
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| 195 | }
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| 196 |
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| 197 | /* Set sysctl's from a conf file. Format example:
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| 198 | * # Controls IP packet forwarding
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| 199 | * net.ipv4.ip_forward = 0
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| 200 | */
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| 201 | static int sysctl_handle_preload_file(const char *filename)
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| 202 | {
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| 203 | char *token[2];
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| 204 | parser_t *parser;
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| 205 |
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| 206 | parser = config_open(filename);
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| 207 | /* Must do it _after_ config_open(): */
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| 208 | xchdir("/proc/sys");
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| 209 | /* xchroot(".") - if you are paranoid */
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| 210 |
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| 211 | //TODO: ';' is comment char too
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| 212 | //TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
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| 213 | // (but _whitespace_ from ends should be trimmed first (and we do it right))
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| 214 | //TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
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| 215 | // can it be fixed by removing PARSE_COLLAPSE bit?
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| 216 | while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) {
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| 217 | char *tp;
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| 218 | sysctl_dots_to_slashes(token[0]);
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| 219 | tp = xasprintf("%s=%s", token[0], token[1]);
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| 220 | sysctl_act_recursive(tp);
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| 221 | free(tp);
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| 222 | }
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| 223 | if (ENABLE_FEATURE_CLEAN_UP)
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| 224 | config_close(parser);
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| 225 | return 0;
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| 226 | }
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| 227 |
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| 228 | int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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| 229 | int sysctl_main(int argc UNUSED_PARAM, char **argv)
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| 230 | {
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| 231 | int retval;
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| 232 | int opt;
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| 233 |
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| 234 | opt = getopt32(argv, "+" OPTION_STR); /* '+' - stop on first non-option */
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| 235 | argv += optind;
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| 236 | opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
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| 237 | option_mask32 = opt;
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| 238 |
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| 239 | if (opt & FLAG_PRELOAD_FILE) {
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| 240 | option_mask32 |= FLAG_WRITE;
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| 241 | /* xchdir("/proc/sys") is inside */
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| 242 | return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf");
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| 243 | }
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| 244 | xchdir("/proc/sys");
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| 245 | /* xchroot(".") - if you are paranoid */
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| 246 | if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) {
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| 247 | return sysctl_act_recursive(".");
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| 248 | }
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| 249 |
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| 250 | retval = 0;
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| 251 | while (*argv) {
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| 252 | sysctl_dots_to_slashes(*argv);
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| 253 | retval |= sysctl_act_recursive(*argv);
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| 254 | argv++;
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| 255 | }
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| 256 |
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| 257 | return retval;
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| 258 | }
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