1 // SPDX-License-Identifier: GPL-2.0 2 #include <stdio.h> 3 #include <errno.h> 4 #include <string.h> 5 6 #include "sysctl_helpers.h" 7 #include "test_progs.h" 8 9 int sysctl_set(const char *sysctl_path, char *old_val, const char *new_val) 10 { 11 int ret = 0; 12 FILE *fp; 13 14 fp = fopen(sysctl_path, "r+"); 15 if (!fp) 16 return -errno; 17 if (old_val && fscanf(fp, "%s", old_val) <= 0) { 18 ret = -ENOENT; 19 } else if (!old_val || strcmp(old_val, new_val) != 0) { 20 fseek(fp, 0, SEEK_SET); 21 if (fprintf(fp, "%s", new_val) < 0) 22 ret = -errno; 23 } 24 fclose(fp); 25 26 return ret; 27 } 28 29 int sysctl_set_or_fail(const char *sysctl_path, char *old_val, const char *new_val) 30 { 31 int err; 32 33 err = sysctl_set(sysctl_path, old_val, new_val); 34 if (err) 35 PRINT_FAIL("failed to set %s to %s: %s\n", sysctl_path, new_val, strerror(-err)); 36 return err; 37 } 38