#include "util.h"#include "debugfs.h"#include "cache.h" static int debugfs_premounted;static char debugfs_mountpoint[MAX_PATH+1]; static const char *debugfs_known_mountpoints[] = {	"/sys/kernel/debug/",	"/debug/",	0,}; /* use this to force a umount */void debugfs_force_cleanup(void){	debugfs_find_mountpoint();	debugfs_premounted = 0;	debugfs_umount();} /* construct a full path to a debugfs element */int debugfs_make_path(const char *element, char *buffer, int size){	int len; 	if (strlen(debugfs_mountpoint) == 0) {		buffer[0] = '\0';		return -1;	} 	len = strlen(debugfs_mountpoint) + strlen(element) + 1;	if (len >= size)		return len+1; 	snprintf(buffer, size-1, "%s/%s", debugfs_mountpoint, element);	return 0;} static int debugfs_found; /* find the path to the mounted debugfs */const char *debugfs_find_mountpoint(void){	const char **ptr;	char type[100];	FILE *fp; 	if (debugfs_found)		return (const char *) debugfs_mountpoint; 	ptr = debugfs_known_mountpoints;	while (*ptr) {		if (debugfs_valid_mountpoint(*ptr) == 0) {			debugfs_found = 1;			strcpy(debugfs_mountpoint, *ptr);			return debugfs_mountpoint;		}		ptr++;	} 	/* give up and parse /proc/mounts */	fp = fopen("/proc/mounts", "r");	if (fp == NULL)		die("Can't open /proc/mounts for read"); 	while (fscanf(fp, "%*s %"		      STR(MAX_PATH)		      "s %99s %*s %*d %*d\n",		      debugfs_mountpoint, type) == 2) {		if (strcmp(type, "debugfs") == 0)			break;	}	fclose(fp); 	if (strcmp(type, "debugfs") != 0)		return NULL; 	debugfs_found = 1; 	return debugfs_mountpoint;} /* verify that a mountpoint is actually a debugfs instance */ int debugfs_valid_mountpoint(const char *debugfs){	struct statfs st_fs; 	if (statfs(debugfs, &st_fs) < 0)		return -ENOENT;	else if (st_fs.f_type != (long) DEBUGFS_MAGIC)		return -ENOENT; 	return 0;}  int debugfs_valid_entry(const char *path){	struct stat st; 	if (stat(path, &st))		return -errno; 	return 0;} /* mount the debugfs somewhere if it's not mounted */ char *debugfs_mount(const char *mountpoint){	/* see if it's already mounted */	if (debugfs_find_mountpoint()) {		debugfs_premounted = 1;		return debugfs_mountpoint;	} 	/* if not mounted and no argument */	if (mountpoint == NULL) {		/* see if environment variable set */		mountpoint = getenv(PERF_DEBUGFS_ENVIRONMENT);		/* if no environment variable, use default */		if (mountpoint == NULL)			mountpoint = "/sys/kernel/debug";	} 	if (mount(NULL, mountpoint, "debugfs", 0, NULL) < 0)		return NULL; 	/* save the mountpoint */	strncpy(debugfs_mountpoint, mountpoint, sizeof(debugfs_mountpoint));	debugfs_found = 1; 	return debugfs_mountpoint;} /* umount the debugfs */ int debugfs_umount(void){	char umountcmd[128];	int ret; 	/* if it was already mounted, leave it */	if (debugfs_premounted)		return 0; 	/* make sure it's a valid mount point */	ret = debugfs_valid_mountpoint(debugfs_mountpoint);	if (ret)		return ret; 	snprintf(umountcmd, sizeof(umountcmd),		 "/bin/umount %s", debugfs_mountpoint);	return system(umountcmd);} int debugfs_write(const char *entry, const char *value){	char path[MAX_PATH+1];	int ret, count;	int fd; 	/* construct the path */	snprintf(path, sizeof(path), "%s/%s", debugfs_mountpoint, entry); 	/* verify that it exists */	ret = debugfs_valid_entry(path);	if (ret)		return ret; 	/* get how many chars we're going to write */	count = strlen(value); 	/* open the debugfs entry */	fd = open(path, O_RDWR);	if (fd < 0)		return -errno; 	while (count > 0) {		/* write it */		ret = write(fd, value, count);		if (ret <= 0) {			if (ret == EAGAIN)				continue;			close(fd);			return -errno;		}		count -= ret;	} 	/* close it */	close(fd); 	/* return success */	return 0;} /* * read a debugfs entry * returns the number of chars read or a negative errno */int debugfs_read(const char *entry, char *buffer, size_t size){	char path[MAX_PATH+1];	int ret;	int fd; 	/* construct the path */	snprintf(path, sizeof(path), "%s/%s", debugfs_mountpoint, entry); 	/* verify that it exists */	ret = debugfs_valid_entry(path);	if (ret)		return ret; 	/* open the debugfs entry */	fd = open(path, O_RDONLY);	if (fd < 0)		return -errno; 	do {		/* read it */		ret = read(fd, buffer, size);		if (ret == 0) {			close(fd);			return EOF;		}	} while (ret < 0 && errno == EAGAIN); 	/* close it */	close(fd); 	/* make *sure* there's a null character at the end */	buffer[ret] = '\0'; 	/* return the number of chars read */	return ret;}