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/* sysctl.c - A utility to read and manipulate the sysctl parameters.
*
* Copyright 2014 Bilal Qureshi <bilal.jmi@gmail.com>
* Copyright 2014 Kyungwan Han <asura321@gmail.com>
*
* No Standard
USE_SYSCTL(NEWTOY(sysctl, "^neNqwpaA[!ap][!aq][!aw][+aA]", TOYFLAG_USR|TOYFLAG_BIN))
config SYSCTL
bool "sysctl"
default n
help
usage: sysctl [OPTIONS] [KEY[=VALUE]]...
Configure kernel parameters at runtime.
-a, A Show all values
-e Don't warn about unknown keys
-N Show only key names
-n Show only key values
-p FILE Set values from FILE (default /etc/sysctl.conf)
-q Set values silently
-w Set values
*/
#define FOR_sysctl
#include "toys.h"
#define PROC_SYS_DIR "/proc/sys"
#define MAX_BYTES_LINE 1024
static void parse_key_name_value(char *param, char **key_name, char **key_value)
{
char *name, *value;
if (!(name = strchr(param, '='))) goto show_error_msg;
value = name;
value++;
if (!(*value)) goto show_error_msg;
*name = '\0';
*key_name = param;
*key_value = value;
return;
show_error_msg:
error_msg("error: '%s' must be of the form name=value", param);
}
static void replace_char(char *str, char old, char new)
{
for (; *str; str++) if (*str == old) *str = new;
}
static void handle_file_error(char *key_name)
{
replace_char(key_name, '/', '.');
if (errno == ENOENT) {
if (!(toys.optflags & FLAG_e))
error_msg("error: '%s' is an unknown key", key_name);
else toys.exitval = 1;
} else perror_msg("error: %s key '%s'", (toys.optflags & FLAG_w) ?
"setting" : "reading", key_name);
}
static void write_to_file(char *fpath, char *key_name, char *key_value)
{
int fd;
replace_char(key_name, '.', '/');
sprintf(toybuf, "%s/%s", fpath, key_name);
if ((fd = open(toybuf, O_WRONLY)) < 0) {
handle_file_error(key_name);
return;
}
xwrite(fd, key_value, strlen(key_value));
xclose(fd);
if (!(toys.optflags & FLAG_q)) {
replace_char(key_name, '/', '.');
if (toys.optflags & FLAG_N) xprintf("%s\n", key_name);
else if (toys.optflags & FLAG_n) xprintf("%s\n", key_value);
else xprintf("%s = %s\n", key_name, key_value);
}
}
static char *get_key_value(char *buff, int *offset)
{
char *line, *tmp = buff + *offset;
int index = 0, multiplier = 1;
if (!*tmp) return 0;
line = xmalloc(MAX_BYTES_LINE);
for (; *tmp != '\n'; tmp++) {
line[index++] = *tmp;
if (MAX_BYTES_LINE == index) { // buffer overflow
multiplier++;
line = (char *) xrealloc(line, multiplier * MAX_BYTES_LINE);
}
}
line[index++] = '\0';
*offset += index;
return line;
}
static void trim_spaces(char **param)
{
int len = 0;
char *str = *param, *p_start = str, *p_end;
if (p_start) { // start pointer to string
p_end = str + strlen(str) - 1; // end pointer to string
while (*p_start == ' ') p_start++;
str = p_start;
while (*p_end == ' ') p_end--;
p_end++;
*p_end = '\0';
len = (int) (p_end - str) + 1;
memmove(*param, str, len);
}
}
// Read config file and write values to corresponding key name files
static void read_config_file(char *fname)
{
char *line, *name = NULL, *value = NULL;
int fd = xopen(fname, O_RDONLY);
for (; (line = get_line(fd)); free(line), name = NULL, value = NULL) {
char *ptr = line;
while (*ptr == ' ' || *ptr == '\t') ptr++;
if (*ptr != '#' && *ptr != ';' && *ptr !='\n' && *ptr) {
parse_key_name_value(ptr, &name, &value);
trim_spaces(&name);
trim_spaces(&value);
if (name && value) write_to_file(PROC_SYS_DIR, name, value);
}
}
xclose(fd);
}
// Open file for each and every key name and read file contents
void read_key_values(char *fpath)
{
char *key_value, *fdata, *key_name, *tmp = xstrdup(fpath);
int offset = 0;
key_name = (tmp + strlen(PROC_SYS_DIR) + 1);
replace_char(key_name, '/', '.');
if (!(fdata = readfile(fpath, NULL, 0))) {
handle_file_error(key_name);
free(tmp);
return;
}
if (toys.optflags & FLAG_N) {
xprintf("%s\n", key_name);
free(tmp);
free(fdata);
return;
}
for (; (key_value = get_key_value(fdata, &offset)); free(key_value)) {
if (!(toys.optflags & FLAG_q)) {
if (!(toys.optflags & FLAG_n)) xprintf("%s = ", key_name);
xprintf("%s\n", key_value);
}
}
free(tmp);
free(fdata);
}
static int do_flag_a(struct dirtree *dt)
{
char *fpath;
if (!dirtree_notdotdot(dt)) return 0; // Skip . and ..
if (S_ISDIR(dt->st.st_mode)) return DIRTREE_RECURSE;
if ((fpath = dirtree_path(dt, 0))) {
read_key_values(fpath);
free(fpath);
}
return 0;
}
void sysctl_main()
{
char *name = 0, *value = 0, **args = 0;
if (toys.optflags & FLAG_a) {
dirtree_read(PROC_SYS_DIR, do_flag_a);
return;
}
if (toys.optflags & FLAG_p) {
if (*toys.optargs) read_config_file(*toys.optargs);
else read_config_file("/etc/sysctl.conf");
return;
}
if (toys.optflags & FLAG_w) {
for (args = toys.optargs; *args; args++, name = NULL, value = NULL) {
parse_key_name_value(*args, &name, &value);
if (name && value) write_to_file(PROC_SYS_DIR, name, value);
}
return;
}
for (args = toys.optargs; *args; args++) {
replace_char(*args, '.', '/');
sprintf(toybuf, "%s/%s", PROC_SYS_DIR, *args);
read_key_values(toybuf);
}
}
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