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