mirror of
https://github.com/sheumann/hush.git
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259 lines
6.1 KiB
C
259 lines
6.1 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Sysctl 1.01 - A utility to read and manipulate the sysctl parameters
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*
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* Copyright 1999 George Staikos
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*
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* Changelog:
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* v1.01 - added -p <preload> to preload values from a file
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* v1.01.1 - busybox applet aware by <solar@gentoo.org>
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*/
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#include "libbb.h"
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enum {
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FLAG_SHOW_KEYS = 1 << 0,
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FLAG_SHOW_KEY_ERRORS = 1 << 1,
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FLAG_TABLE_FORMAT = 1 << 2, /* not implemented */
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FLAG_SHOW_ALL = 1 << 3,
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FLAG_PRELOAD_FILE = 1 << 4,
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FLAG_WRITE = 1 << 5,
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};
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#define OPTION_STR "neAapw"
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static void sysctl_dots_to_slashes(char *name)
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{
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char *cptr, *last_good, *end;
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/* Convert minimum number of '.' to '/' so that
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* we end up with existing file's name.
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*
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* Example from bug 3894:
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* net.ipv4.conf.eth0.100.mc_forwarding ->
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* net/ipv4/conf/eth0.100/mc_forwarding
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* NB: net/ipv4/conf/eth0/mc_forwarding *also exists*,
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* therefore we must start from the end, and if
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* we replaced even one . -> /, start over again,
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* but never replace dots before the position
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* where last replacement occurred.
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*
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* Another bug we later had is that
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* net.ipv4.conf.eth0.100
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* (without .mc_forwarding) was mishandled.
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*
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* To set up testing: modprobe 8021q; vconfig add eth0 100
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*/
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end = name + strlen(name);
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last_good = name - 1;
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*end = '.'; /* trick the loop into trying full name too */
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again:
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cptr = end;
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while (cptr > last_good) {
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if (*cptr == '.') {
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*cptr = '\0';
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//bb_error_msg("trying:'%s'", name);
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if (access(name, F_OK) == 0) {
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*cptr = '/';
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//bb_error_msg("replaced:'%s'", name);
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last_good = cptr;
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goto again;
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}
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*cptr = '.';
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}
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cptr--;
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}
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*end = '\0';
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}
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static int sysctl_act_on_setting(char *setting)
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{
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int fd, retval = EXIT_SUCCESS;
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char *cptr, *outname;
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char *value = value; /* for compiler */
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outname = xstrdup(setting);
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cptr = outname;
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while (*cptr) {
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if (*cptr == '/')
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*cptr = '.';
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cptr++;
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}
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if (option_mask32 & FLAG_WRITE) {
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cptr = strchr(setting, '=');
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if (cptr == NULL) {
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bb_error_msg("error: '%s' must be of the form name=value",
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outname);
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retval = EXIT_FAILURE;
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goto end;
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}
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value = cptr + 1; /* point to the value in name=value */
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if (setting == cptr || !*value) {
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bb_error_msg("error: malformed setting '%s'", outname);
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retval = EXIT_FAILURE;
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goto end;
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}
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*cptr = '\0';
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outname[cptr - setting] = '\0';
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/* procps 3.2.7 actually uses these flags */
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fd = open(setting, O_WRONLY|O_CREAT|O_TRUNC, 0666);
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} else {
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fd = open(setting, O_RDONLY);
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}
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if (fd < 0) {
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switch (errno) {
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case ENOENT:
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if (option_mask32 & FLAG_SHOW_KEY_ERRORS)
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bb_error_msg("error: '%s' is an unknown key", outname);
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break;
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default:
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bb_perror_msg("error %sing key '%s'",
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option_mask32 & FLAG_WRITE ?
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"sett" : "read",
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outname);
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break;
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}
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retval = EXIT_FAILURE;
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goto end;
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}
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if (option_mask32 & FLAG_WRITE) {
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//TODO: procps 3.2.7 writes "value\n", note trailing "\n"
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xwrite_str(fd, value);
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close(fd);
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if (option_mask32 & FLAG_SHOW_KEYS)
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printf("%s = ", outname);
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puts(value);
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} else {
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char c;
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value = cptr = xmalloc_read(fd, NULL);
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close(fd);
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if (value == NULL) {
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bb_perror_msg("error reading key '%s'", outname);
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goto end;
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}
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/* dev.cdrom.info and sunrpc.transports, for example,
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* are multi-line. Try "sysctl sunrpc.transports"
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*/
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while ((c = *cptr) != '\0') {
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if (option_mask32 & FLAG_SHOW_KEYS)
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printf("%s = ", outname);
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while (1) {
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fputc(c, stdout);
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cptr++;
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if (c == '\n')
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break;
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c = *cptr;
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if (c == '\0')
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break;
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}
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}
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free(value);
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}
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end:
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free(outname);
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return retval;
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}
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static int sysctl_act_recursive(const char *path)
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{
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DIR *dirp;
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struct stat buf;
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struct dirent *entry;
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char *next;
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int retval = 0;
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stat(path, &buf);
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if (S_ISDIR(buf.st_mode) && !(option_mask32 & FLAG_WRITE)) {
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dirp = opendir(path);
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if (dirp == NULL)
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return -1;
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while ((entry = readdir(dirp)) != NULL) {
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next = concat_subpath_file(path, entry->d_name);
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if (next == NULL)
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continue; /* d_name is "." or ".." */
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/* if path was ".", drop "./" prefix: */
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retval |= sysctl_act_recursive((next[0] == '.' && next[1] == '/') ?
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next + 2 : next);
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free(next);
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}
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closedir(dirp);
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} else {
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char *name = xstrdup(path);
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retval |= sysctl_act_on_setting(name);
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free(name);
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}
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return retval;
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}
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/* Set sysctl's from a conf file. Format example:
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* # Controls IP packet forwarding
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* net.ipv4.ip_forward = 0
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*/
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static int sysctl_handle_preload_file(const char *filename)
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{
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char *token[2];
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parser_t *parser;
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parser = config_open(filename);
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/* Must do it _after_ config_open(): */
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xchdir("/proc/sys");
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/* xchroot(".") - if you are paranoid */
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//TODO: ';' is comment char too
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//TODO: comment may be only at line start. "var=1 #abc" - "1 #abc" is the value
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// (but _whitespace_ from ends should be trimmed first (and we do it right))
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//TODO: "var==1" is mishandled (must use "=1" as a value, but uses "1")
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// can it be fixed by removing PARSE_COLLAPSE bit?
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while (config_read(parser, token, 2, 2, "# \t=", PARSE_NORMAL)) {
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char *tp;
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sysctl_dots_to_slashes(token[0]);
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tp = xasprintf("%s=%s", token[0], token[1]);
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sysctl_act_recursive(tp);
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free(tp);
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}
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if (ENABLE_FEATURE_CLEAN_UP)
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config_close(parser);
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return 0;
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}
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int sysctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int sysctl_main(int argc UNUSED_PARAM, char **argv)
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{
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int retval;
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int opt;
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opt = getopt32(argv, "+" OPTION_STR); /* '+' - stop on first non-option */
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argv += optind;
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opt ^= (FLAG_SHOW_KEYS | FLAG_SHOW_KEY_ERRORS);
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option_mask32 = opt;
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if (opt & FLAG_PRELOAD_FILE) {
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option_mask32 |= FLAG_WRITE;
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/* xchdir("/proc/sys") is inside */
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return sysctl_handle_preload_file(*argv ? *argv : "/etc/sysctl.conf");
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}
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xchdir("/proc/sys");
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/* xchroot(".") - if you are paranoid */
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if (opt & (FLAG_TABLE_FORMAT | FLAG_SHOW_ALL)) {
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return sysctl_act_recursive(".");
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}
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retval = 0;
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while (*argv) {
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sysctl_dots_to_slashes(*argv);
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retval |= sysctl_act_recursive(*argv);
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argv++;
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}
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return retval;
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}
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