/* TODO merge/factor in debugfs.c here */ #include <ctype.h>#include <errno.h>#include <stdbool.h>#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/vfs.h>#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h> #include "debugfs.h"#include "fs.h" static const char * const sysfs__fs_known_mountpoints[] = {	"/sys",	0,}; static const char * const procfs__known_mountpoints[] = {	"/proc",	0,}; struct fs {	const char		*name;	const char * const	*mounts;	char			 path[PATH_MAX + 1];	bool			 found;	long			 magic;}; enum {	FS__SYSFS  = 0,	FS__PROCFS = 1,}; static struct fs fs__entries[] = {	[FS__SYSFS] = {		.name	= "sysfs",		.mounts	= sysfs__fs_known_mountpoints,		.magic	= SYSFS_MAGIC,	},	[FS__PROCFS] = {		.name	= "proc",		.mounts	= procfs__known_mountpoints,		.magic	= PROC_SUPER_MAGIC,	},}; static bool fs__read_mounts(struct fs *fs){	bool found = false;	char type[100];	FILE *fp; 	fp = fopen("/proc/mounts", "r");	if (fp == NULL)		return NULL; 	while (!found &&	       fscanf(fp, "%*s %" STR(PATH_MAX) "s %99s %*s %*d %*d\n",		      fs->path, type) == 2) { 		if (strcmp(type, fs->name) == 0)			found = true;	} 	fclose(fp);	return fs->found = found;} static int fs__valid_mount(const char *fs, long magic){	struct statfs st_fs; 	if (statfs(fs, &st_fs) < 0)		return -ENOENT;	else if ((long)st_fs.f_type != magic)		return -ENOENT; 	return 0;} static bool fs__check_mounts(struct fs *fs){	const char * const *ptr; 	ptr = fs->mounts;	while (*ptr) {		if (fs__valid_mount(*ptr, fs->magic) == 0) {			fs->found = true;			strcpy(fs->path, *ptr);			return true;		}		ptr++;	} 	return false;} static void mem_toupper(char *f, size_t len){	while (len) {		*f = toupper(*f);		f++;		len--;	}} /* * Check for "NAME_PATH" environment variable to override fs location (for * testing). This matches the recommendation in Documentation/sysfs-rules.txt * for SYSFS_PATH. */static bool fs__env_override(struct fs *fs){	char *override_path;	size_t name_len = strlen(fs->name);	/* name + "_PATH" + '\0' */	char upper_name[name_len + 5 + 1];	memcpy(upper_name, fs->name, name_len);	mem_toupper(upper_name, name_len);	strcpy(&upper_name[name_len], "_PATH"); 	override_path = getenv(upper_name);	if (!override_path)		return false; 	fs->found = true;	strncpy(fs->path, override_path, sizeof(fs->path));	return true;} static const char *fs__get_mountpoint(struct fs *fs){	if (fs__env_override(fs))		return fs->path; 	if (fs__check_mounts(fs))		return fs->path; 	if (fs__read_mounts(fs))		return fs->path; 	return NULL;} static const char *fs__mountpoint(int idx){	struct fs *fs = &fs__entries[idx]; 	if (fs->found)		return (const char *)fs->path; 	return fs__get_mountpoint(fs);} #define FS__MOUNTPOINT(name, idx)	\const char *name##__mountpoint(void)	\{					\	return fs__mountpoint(idx);	\} FS__MOUNTPOINT(sysfs,  FS__SYSFS);FS__MOUNTPOINT(procfs, FS__PROCFS); int filename__read_int(const char *filename, int *value){	char line[64];	int fd = open(filename, O_RDONLY), err = -1; 	if (fd < 0)		return -1; 	if (read(fd, line, sizeof(line)) > 0) {		*value = atoi(line);		err = 0;	} 	close(fd);	return err;} int sysctl__read_int(const char *sysctl, int *value){	char path[PATH_MAX];	const char *procfs = procfs__mountpoint(); 	if (!procfs)		return -1; 	snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl); 	return filename__read_int(path, value);}