177 lines
2.7 KiB
C
177 lines
2.7 KiB
C
/* See LICENSE file for copyright and license details. */
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#include <fcntl.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "util.h"
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static void
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replacestr(char *s, int a, int b)
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{
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for (; *s; s++)
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if (*s == a)
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*s = b;
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}
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static int
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getsysctl(char *variable, char **value)
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{
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char path[PATH_MAX];
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char *p;
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char *buf, *tmp, c;
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int fd;
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ssize_t n;
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size_t sz, i;
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replacestr(variable, '.', '/');
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strlcpy(path, "/proc/sys/", sizeof(path));
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if (strlcat(path, variable, sizeof(path)) >= sizeof(path)) {
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replacestr(variable, '/', '.');
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return -1;
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}
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replacestr(variable, '/', '.');
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fd = open(path, O_RDONLY);
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if (fd < 0)
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return -1;
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i = 0;
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sz = 1;
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buf = NULL;
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while (1) {
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n = read(fd, &c, 1);
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if (n < 0) {
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close(fd);
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free(buf);
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return -1;
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}
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if (n == 0)
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break;
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if (i == sz - 1) {
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sz *= 2;
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tmp = realloc(buf, sz);
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if (!tmp) {
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close(fd);
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free(buf);
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return -1;
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}
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buf = tmp;
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}
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buf[i++] = c;
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}
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buf[i] = '\0';
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p = strrchr(buf, '\n');
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if (p)
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*p = '\0';
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*value = buf;
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close(fd);
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return 0;
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}
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static int
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setsysctl(char *variable, char *value)
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{
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char path[PATH_MAX];
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int fd;
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ssize_t n;
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replacestr(variable, '.', '/');
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strlcpy(path, "/proc/sys/", sizeof(path));
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if (strlcat(path, variable, sizeof(path)) >= sizeof(path)) {
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replacestr(variable, '/', '.');
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return -1;
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}
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replacestr(variable, '/', '.');
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fd = open(path, O_WRONLY);
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if (fd < 0)
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return -1;
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n = write(fd, value, strlen(value));
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if ((size_t)n != strlen(value)) {
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close(fd);
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return -1;
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}
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close(fd);
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return 0;
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}
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static void
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usage(void)
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{
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eprintf("usage: %s variable[=value]...\n", argv0);
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}
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int
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main(int argc, char *argv[])
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{
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char *variable;
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char *value;
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char *p;
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int i;
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int r = EXIT_SUCCESS;
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argv0 = argv[0];
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argv++;
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argc--;
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if (argc < 1)
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usage();
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for (i = 0; i < argc; i++) {
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for (p = argv[i]; *p; p++) {
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if (p[0] == '.' && p[1] == '.') {
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r = EXIT_FAILURE;
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weprintf("malformed input: %s\n", argv[i]);
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break;
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}
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}
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if (*p != '\0')
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continue;
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p = strchr(argv[i], '=');
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if (p) {
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if (p[1] == '\0') {
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r = EXIT_FAILURE;
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weprintf("malformed input: %s\n", argv[i]);
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continue;
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}
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*p = '\0';
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value = &p[1];
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} else {
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value = NULL;
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}
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variable = argv[i];
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if (value) {
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if (setsysctl(variable, value) < 0) {
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r = EXIT_FAILURE;
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weprintf("failed to set sysctl for %s\n", variable);
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continue;
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}
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}
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else {
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if (getsysctl(variable, &value) < 0) {
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r = EXIT_FAILURE;
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weprintf("failed to get sysctl for %s\n", variable);
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continue;
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}
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printf("%s = %s\n", variable, value);
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free(value);
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}
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}
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return r;
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}
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