Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) #include <linux/stringify.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3) #include <sys/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4) #include <sys/stat.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) #include <fcntl.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) #include <stdio.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7) #include <stdlib.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) #include <string.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) #include "fs.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) int cgroupfs_find_mountpoint(char *buf, size_t maxlen, const char *subsys)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) 	FILE *fp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) 	char mountpoint[PATH_MAX + 1], tokens[PATH_MAX + 1], type[PATH_MAX + 1];
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 	char path_v1[PATH_MAX + 1], path_v2[PATH_MAX + 2], *path;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) 	char *token, *saved_ptr = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) 	fp = fopen("/proc/mounts", "r");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) 	if (!fp)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) 		return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) 	 * in order to handle split hierarchy, we need to scan /proc/mounts
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	 * and inspect every cgroupfs mount point to find one that has
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 	 * perf_event subsystem
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 	path_v1[0] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 	path_v2[0] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 	while (fscanf(fp, "%*s %"__stringify(PATH_MAX)"s %"__stringify(PATH_MAX)"s %"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 				__stringify(PATH_MAX)"s %*d %*d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 				mountpoint, type, tokens) == 3) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 		if (!path_v1[0] && !strcmp(type, "cgroup")) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 			token = strtok_r(tokens, ",", &saved_ptr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 			while (token != NULL) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 				if (subsys && !strcmp(token, subsys)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 					strcpy(path_v1, mountpoint);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 					break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 				}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 				token = strtok_r(NULL, ",", &saved_ptr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 			}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) 		if (!path_v2[0] && !strcmp(type, "cgroup2"))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) 			strcpy(path_v2, mountpoint);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) 		if (path_v1[0] && path_v2[0])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) 			break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) 	fclose(fp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) 	if (path_v1[0])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) 		path = path_v1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) 	else if (path_v2[0])
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) 		path = path_v2;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) 		return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) 	if (strlen(path) < maxlen) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) 		strcpy(buf, path);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) 	return -1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) }