[mirror_ubuntu-bionic-kernel.git] / tools / lib / api / fs / fs.c

// SPDX-License-Identifier: GPL-2.0
#include <ctype.h>
#include <errno.h>
#include <limits.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 <sys/mount.h>

#include "fs.h"
#include "debug-internal.h"

#define _STR(x) #x
#define STR(x) _STR(x)

#ifndef SYSFS_MAGIC
#define SYSFS_MAGIC            0x62656572
#endif

#ifndef PROC_SUPER_MAGIC
#define PROC_SUPER_MAGIC       0x9fa0
#endif

#ifndef DEBUGFS_MAGIC
#define DEBUGFS_MAGIC          0x64626720
#endif

#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC          0x74726163
#endif

#ifndef HUGETLBFS_MAGIC
#define HUGETLBFS_MAGIC        0x958458f6
#endif

#ifndef BPF_FS_MAGIC
#define BPF_FS_MAGIC           0xcafe4a11
#endif

static const char * const sysfs__fs_known_mountpoints[] = {
	"/sys",
	0,
};

static const char * const procfs__known_mountpoints[] = {
	"/proc",
	0,
};

#ifndef DEBUGFS_DEFAULT_PATH
#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
#endif

static const char * const debugfs__known_mountpoints[] = {
	DEBUGFS_DEFAULT_PATH,
	"/debug",
	0,
};


#ifndef TRACEFS_DEFAULT_PATH
#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
#endif

static const char * const tracefs__known_mountpoints[] = {
	TRACEFS_DEFAULT_PATH,
	"/sys/kernel/debug/tracing",
	"/tracing",
	"/trace",
	0,
};

static const char * const hugetlbfs__known_mountpoints[] = {
	0,
};

static const char * const bpf_fs__known_mountpoints[] = {
	"/sys/fs/bpf",
	0,
};

struct fs {
	const char		*name;
	const char * const	*mounts;
	char			 path[PATH_MAX];
	bool			 found;
	long			 magic;
};

enum {
	FS__SYSFS   = 0,
	FS__PROCFS  = 1,
	FS__DEBUGFS = 2,
	FS__TRACEFS = 3,
	FS__HUGETLBFS = 4,
	FS__BPF_FS = 5,
};

#ifndef TRACEFS_MAGIC
#define TRACEFS_MAGIC 0x74726163
#endif

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,
	},
	[FS__DEBUGFS] = {
		.name	= "debugfs",
		.mounts	= debugfs__known_mountpoints,
		.magic	= DEBUGFS_MAGIC,
	},
	[FS__TRACEFS] = {
		.name	= "tracefs",
		.mounts	= tracefs__known_mountpoints,
		.magic	= TRACEFS_MAGIC,
	},
	[FS__HUGETLBFS] = {
		.name	= "hugetlbfs",
		.mounts = hugetlbfs__known_mountpoints,
		.magic	= HUGETLBFS_MAGIC,
	},
	[FS__BPF_FS] = {
		.name	= "bpf",
		.mounts = bpf_fs__known_mountpoints,
		.magic	= BPF_FS_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);
}

static const char *mount_overload(struct fs *fs)
{
	size_t name_len = strlen(fs->name);
	/* "PERF_" + name + "_ENVIRONMENT" + '\0' */
	char upper_name[5 + name_len + 12 + 1];

	snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
	mem_toupper(upper_name, name_len);

	return getenv(upper_name) ?: *fs->mounts;
}

static const char *fs__mount(int idx)
{
	struct fs *fs = &fs__entries[idx];
	const char *mountpoint;

	if (fs__mountpoint(idx))
		return (const char *)fs->path;

	mountpoint = mount_overload(fs);

	if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
		return NULL;

	return fs__check_mounts(fs) ? fs->path : NULL;
}

#define FS(name, idx)				\
const char *name##__mountpoint(void)		\
{						\
	return fs__mountpoint(idx);		\
}						\
						\
const char *name##__mount(void)			\
{						\
	return fs__mount(idx);			\
}						\
						\
bool name##__configured(void)			\
{						\
	return name##__mountpoint() != NULL;	\
}

FS(sysfs,   FS__SYSFS);
FS(procfs,  FS__PROCFS);
FS(debugfs, FS__DEBUGFS);
FS(tracefs, FS__TRACEFS);
FS(hugetlbfs, FS__HUGETLBFS);
FS(bpf_fs, FS__BPF_FS);

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;
}

/*
 * Parses @value out of @filename with strtoull.
 * By using 0 for base, the strtoull detects the
 * base automatically (see man strtoull).
 */
int filename__read_ull(const char *filename, unsigned long long *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 = strtoull(line, NULL, 0);
		if (*value != ULLONG_MAX)
			err = 0;
	}

	close(fd);
	return err;
}

#define STRERR_BUFSIZE  128     /* For the buffer size of strerror_r */

int filename__read_str(const char *filename, char **buf, size_t *sizep)
{
	size_t size = 0, alloc_size = 0;
	void *bf = NULL, *nbf;
	int fd, n, err = 0;
	char sbuf[STRERR_BUFSIZE];

	fd = open(filename, O_RDONLY);
	if (fd < 0)
		return -errno;

	do {
		if (size == alloc_size) {
			alloc_size += BUFSIZ;
			nbf = realloc(bf, alloc_size);
			if (!nbf) {
				err = -ENOMEM;
				break;
			}

			bf = nbf;
		}

		n = read(fd, bf + size, alloc_size - size);
		if (n < 0) {
			if (size) {
				pr_warning("read failed %d: %s\n", errno,
					 strerror_r(errno, sbuf, sizeof(sbuf)));
				err = 0;
			} else
				err = -errno;

			break;
		}

		size += n;
	} while (n > 0);

	if (!err) {
		*sizep = size;
		*buf   = bf;
	} else
		free(bf);

	close(fd);
	return err;
}

int filename__write_int(const char *filename, int value)
{
	int fd = open(filename, O_WRONLY), err = -1;
	char buf[64];

	if (fd < 0)
		return err;

	sprintf(buf, "%d", value);
	if (write(fd, buf, sizeof(buf)) == sizeof(buf))
		err = 0;

	close(fd);
	return err;
}

int procfs__read_str(const char *entry, char **buf, size_t *sizep)
{
	char path[PATH_MAX];
	const char *procfs = procfs__mountpoint();

	if (!procfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", procfs, entry);

	return filename__read_str(path, buf, sizep);
}

int sysfs__read_ull(const char *entry, unsigned long long *value)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);

	return filename__read_ull(path, value);
}

int sysfs__read_int(const char *entry, int *value)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);

	return filename__read_int(path, value);
}

int sysfs__read_str(const char *entry, char **buf, size_t *sizep)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);

	return filename__read_str(path, buf, sizep);
}

int sysfs__read_bool(const char *entry, bool *value)
{
	char *buf;
	size_t size;
	int ret;

	ret = sysfs__read_str(entry, &buf, &size);
	if (ret < 0)
		return ret;

	switch (buf[0]) {
	case '1':
	case 'y':
	case 'Y':
		*value = true;
		break;
	case '0':
	case 'n':
	case 'N':
		*value = false;
		break;
	default:
		ret = -1;
	}

	free(buf);

	return ret;
}
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);
}

int sysfs__write_int(const char *entry, int value)
{
	char path[PATH_MAX];
	const char *sysfs = sysfs__mountpoint();

	if (!sysfs)
		return -1;

	if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX)
		return -1;

	return filename__write_int(path, value);
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
f2d9627b	2	#include <ctype.h>
cd0cfad7	3	#include <errno.h>
2d729f6a	4	#include <limits.h>
cd0cfad7 BP	5	#include <stdbool.h>
cd0cfad7 BP	6	#include <stdio.h>
f2d9627b	7	#include <stdlib.h>
cd0cfad7 BP	8	#include <string.h>
cd0cfad7 BP	9	#include <sys/vfs.h>
3a351127 ACM	10	#include <sys/types.h>
	11	#include <sys/stat.h>
	12	#include <fcntl.h>
	13	#include <unistd.h>
73ca85ad	14	#include <sys/mount.h>
4299a549	15
cd0cfad7	16	#include "fs.h"
607bfbd7	17	#include "debug-internal.h"
4299a549	18
b86b0d35 JO	19	#define _STR(x) #x
	20	#define STR(x) _STR(x)
	21
41e3a1fe JO	22	#ifndef SYSFS_MAGIC
	23	#define SYSFS_MAGIC 0x62656572
	24	#endif
	25
	26	#ifndef PROC_SUPER_MAGIC
	27	#define PROC_SUPER_MAGIC 0x9fa0
	28	#endif
	29
8ccfabdb JO	30	#ifndef DEBUGFS_MAGIC
	31	#define DEBUGFS_MAGIC 0x64626720
	32	#endif
	33
c495afb4 JO	34	#ifndef TRACEFS_MAGIC
	35	#define TRACEFS_MAGIC 0x74726163
	36	#endif
	37
5e7be3e1 WN	38	#ifndef HUGETLBFS_MAGIC
	39	#define HUGETLBFS_MAGIC 0x958458f6
	40	#endif
	41
71dc4c30 JS	42	#ifndef BPF_FS_MAGIC
	43	#define BPF_FS_MAGIC 0xcafe4a11
	44	#endif
	45
4299a549 JO	46	static const char * const sysfs__fs_known_mountpoints[] = {
	47	"/sys",
	48	0,
	49	};
	50
a9862418 JO	51	static const char * const procfs__known_mountpoints[] = {
	52	"/proc",
	53	0,
	54	};
	55
8ccfabdb JO	56	#ifndef DEBUGFS_DEFAULT_PATH
	57	#define DEBUGFS_DEFAULT_PATH "/sys/kernel/debug"
	58	#endif
	59
	60	static const char * const debugfs__known_mountpoints[] = {
	61	DEBUGFS_DEFAULT_PATH,
	62	"/debug",
	63	0,
	64	};
	65
c495afb4 JO	66
	67	#ifndef TRACEFS_DEFAULT_PATH
	68	#define TRACEFS_DEFAULT_PATH "/sys/kernel/tracing"
	69	#endif
	70
	71	static const char * const tracefs__known_mountpoints[] = {
	72	TRACEFS_DEFAULT_PATH,
	73	"/sys/kernel/debug/tracing",
	74	"/tracing",
	75	"/trace",
	76	0,
	77	};
	78
5e7be3e1 WN	79	static const char * const hugetlbfs__known_mountpoints[] = {
	80	0,
	81	};
	82
71dc4c30 JS	83	static const char * const bpf_fs__known_mountpoints[] = {
	84	"/sys/fs/bpf",
	85	0,
	86	};
	87
4299a549 JO	88	struct fs {
	89	const char *name;
	90	const char * const *mounts;
ccb5597f	91	char path[PATH_MAX];
4299a549 JO	92	bool found;
	93	long magic;
	94	};
	95
	96	enum {
8ccfabdb JO	97	FS__SYSFS = 0,
	98	FS__PROCFS = 1,
	99	FS__DEBUGFS = 2,
c495afb4	100	FS__TRACEFS = 3,
5e7be3e1	101	FS__HUGETLBFS = 4,
71dc4c30	102	FS__BPF_FS = 5,
4299a549 JO	103	};
4299a549 JO	104
c495afb4 JO	105	#ifndef TRACEFS_MAGIC
	106	#define TRACEFS_MAGIC 0x74726163
	107	#endif
	108
4299a549 JO	109	static struct fs fs__entries[] = {
	110	[FS__SYSFS] = {
	111	.name = "sysfs",
	112	.mounts = sysfs__fs_known_mountpoints,
	113	.magic = SYSFS_MAGIC,
	114	},
a9862418 JO	115	[FS__PROCFS] = {
	116	.name = "proc",
	117	.mounts = procfs__known_mountpoints,
	118	.magic = PROC_SUPER_MAGIC,
	119	},
8ccfabdb JO	120	[FS__DEBUGFS] = {
	121	.name = "debugfs",
	122	.mounts = debugfs__known_mountpoints,
	123	.magic = DEBUGFS_MAGIC,
	124	},
c495afb4 JO	125	[FS__TRACEFS] = {
	126	.name = "tracefs",
	127	.mounts = tracefs__known_mountpoints,
	128	.magic = TRACEFS_MAGIC,
	129	},
5e7be3e1 WN	130	[FS__HUGETLBFS] = {
	131	.name = "hugetlbfs",
	132	.mounts = hugetlbfs__known_mountpoints,
	133	.magic = HUGETLBFS_MAGIC,
	134	},
71dc4c30 JS	135	[FS__BPF_FS] = {
	136	.name = "bpf",
	137	.mounts = bpf_fs__known_mountpoints,
	138	.magic = BPF_FS_MAGIC,
	139	},
4299a549 JO	140	};
	141
	142	static bool fs__read_mounts(struct fs *fs)
	143	{
	144	bool found = false;
	145	char type[100];
	146	FILE *fp;
	147
	148	fp = fopen("/proc/mounts", "r");
	149	if (fp == NULL)
	150	return NULL;
	151
	152	while (!found &&
	153	fscanf(fp, "%s %" STR(PATH_MAX) "s %99s %s %d %d\n",
	154	fs->path, type) == 2) {
	155
	156	if (strcmp(type, fs->name) == 0)
	157	found = true;
	158	}
	159
	160	fclose(fp);
	161	return fs->found = found;
	162	}
	163
	164	static int fs__valid_mount(const char *fs, long magic)
	165	{
	166	struct statfs st_fs;
	167
	168	if (statfs(fs, &st_fs) < 0)
	169	return -ENOENT;
db1806ed	170	else if ((long)st_fs.f_type != magic)
4299a549 JO	171	return -ENOENT;
	172
	173	return 0;
	174	}
	175
	176	static bool fs__check_mounts(struct fs *fs)
	177	{
	178	const char * const *ptr;
	179
	180	ptr = fs->mounts;
	181	while (*ptr) {
	182	if (fs__valid_mount(*ptr, fs->magic) == 0) {
	183	fs->found = true;
	184	strcpy(fs->path, *ptr);
	185	return true;
	186	}
	187	ptr++;
	188	}
	189
	190	return false;
	191	}
	192
f2d9627b CS	193	static void mem_toupper(char *f, size_t len)
	194	{
	195	while (len) {
	196	f = toupper(f);
	197	f++;
	198	len--;
	199	}
	200	}
	201
	202	/*
	203	* Check for "NAME_PATH" environment variable to override fs location (for
	204	* testing). This matches the recommendation in Documentation/sysfs-rules.txt
	205	* for SYSFS_PATH.
	206	*/
	207	static bool fs__env_override(struct fs *fs)
	208	{
	209	char *override_path;
	210	size_t name_len = strlen(fs->name);
	211	/* name + "_PATH" + '\0' */
	212	char upper_name[name_len + 5 + 1];
	213	memcpy(upper_name, fs->name, name_len);
	214	mem_toupper(upper_name, name_len);
	215	strcpy(&upper_name[name_len], "_PATH");
	216
	217	override_path = getenv(upper_name);
	218	if (!override_path)
	219	return false;
	220
	221	fs->found = true;
	222	strncpy(fs->path, override_path, sizeof(fs->path));
	223	return true;
	224	}
	225
4299a549 JO	226	static const char fs__get_mountpoint(struct fs fs)
4299a549 JO	227	{
f2d9627b CS	228	if (fs__env_override(fs))
	229	return fs->path;
	230
4299a549 JO	231	if (fs__check_mounts(fs))
	232	return fs->path;
	233
f2d9627b CS	234	if (fs__read_mounts(fs))
	235	return fs->path;
	236
	237	return NULL;
4299a549 JO	238	}
4299a549 JO	239
cf38fada	240	static const char *fs__mountpoint(int idx)
4299a549 JO	241	{
	242	struct fs *fs = &fs__entries[idx];
	243
	244	if (fs->found)
	245	return (const char *)fs->path;
	246
	247	return fs__get_mountpoint(fs);
	248	}
	249
73ca85ad JO	250	static const char mount_overload(struct fs fs)
	251	{
	252	size_t name_len = strlen(fs->name);
	253	/* "PERF_" + name + "_ENVIRONMENT" + '\0' */
	254	char upper_name[5 + name_len + 12 + 1];
	255
	256	snprintf(upper_name, name_len, "PERF_%s_ENVIRONMENT", fs->name);
	257	mem_toupper(upper_name, name_len);
	258
	259	return getenv(upper_name) ?: *fs->mounts;
	260	}
	261
	262	static const char *fs__mount(int idx)
	263	{
	264	struct fs *fs = &fs__entries[idx];
	265	const char *mountpoint;
	266
	267	if (fs__mountpoint(idx))
	268	return (const char *)fs->path;
	269
	270	mountpoint = mount_overload(fs);
	271
	272	if (mount(NULL, mountpoint, fs->name, 0, NULL) < 0)
	273	return NULL;
	274
	275	return fs__check_mounts(fs) ? fs->path : NULL;
	276	}
	277
709adcb3 JO	278	#define FS(name, idx) \
	279	const char *name##__mountpoint(void) \
	280	{ \
	281	return fs__mountpoint(idx); \
	282	} \
	283	\
	284	const char *name##__mount(void) \
	285	{ \
	286	return fs__mount(idx); \
	287	} \
	288	\
	289	bool name##__configured(void) \
	290	{ \
	291	return name##__mountpoint() != NULL; \
4299a549 JO	292	}
4299a549 JO	293
73ca85ad JO	294	FS(sysfs, FS__SYSFS);
	295	FS(procfs, FS__PROCFS);
	296	FS(debugfs, FS__DEBUGFS);
	297	FS(tracefs, FS__TRACEFS);
5e7be3e1	298	FS(hugetlbfs, FS__HUGETLBFS);
71dc4c30	299	FS(bpf_fs, FS__BPF_FS);
3a351127 ACM	300
	301	int filename__read_int(const char filename, int value)
	302	{
	303	char line[64];
	304	int fd = open(filename, O_RDONLY), err = -1;
	305
	306	if (fd < 0)
	307	return -1;
	308
	309	if (read(fd, line, sizeof(line)) > 0) {
	310	*value = atoi(line);
	311	err = 0;
	312	}
	313
	314	close(fd);
	315	return err;
	316	}
42e3c4a1	317
db49120a JO	318	/*
	319	* Parses @value out of @filename with strtoull.
	320	* By using 0 for base, the strtoull detects the
	321	* base automatically (see man strtoull).
	322	*/
2d729f6a ACM	323	int filename__read_ull(const char filename, unsigned long long value)
	324	{
	325	char line[64];
	326	int fd = open(filename, O_RDONLY), err = -1;
	327
	328	if (fd < 0)
	329	return -1;
	330
	331	if (read(fd, line, sizeof(line)) > 0) {
db49120a	332	*value = strtoull(line, NULL, 0);
2d729f6a ACM	333	if (*value != ULLONG_MAX)
	334	err = 0;
	335	}
	336
	337	close(fd);
	338	return err;
	339	}
	340
607bfbd7 JO	341	#define STRERR_BUFSIZE 128 /* For the buffer size of strerror_r */
	342
	343	int filename__read_str(const char filename, char buf, size_t sizep)
	344	{
	345	size_t size = 0, alloc_size = 0;
	346	void bf = NULL, nbf;
	347	int fd, n, err = 0;
	348	char sbuf[STRERR_BUFSIZE];
	349
	350	fd = open(filename, O_RDONLY);
	351	if (fd < 0)
	352	return -errno;
	353
	354	do {
	355	if (size == alloc_size) {
	356	alloc_size += BUFSIZ;
	357	nbf = realloc(bf, alloc_size);
	358	if (!nbf) {
	359	err = -ENOMEM;
	360	break;
	361	}
	362
	363	bf = nbf;
	364	}
	365
	366	n = read(fd, bf + size, alloc_size - size);
	367	if (n < 0) {
	368	if (size) {
	369	pr_warning("read failed %d: %s\n", errno,
	370	strerror_r(errno, sbuf, sizeof(sbuf)));
	371	err = 0;
	372	} else
	373	err = -errno;
	374
	375	break;
	376	}
	377
	378	size += n;
	379	} while (n > 0);
	380
	381	if (!err) {
	382	*sizep = size;
	383	*buf = bf;
	384	} else
	385	free(bf);
	386
	387	close(fd);
	388	return err;
	389	}
4bd112df	390
3b00ea93 KL	391	int filename__write_int(const char *filename, int value)
	392	{
	393	int fd = open(filename, O_WRONLY), err = -1;
	394	char buf[64];
	395
	396	if (fd < 0)
	397	return err;
	398
	399	sprintf(buf, "%d", value);
	400	if (write(fd, buf, sizeof(buf)) == sizeof(buf))
	401	err = 0;
	402
	403	close(fd);
	404	return err;
	405	}
	406
4bd112df ACM	407	int procfs__read_str(const char entry, char buf, size_t sizep)
	408	{
	409	char path[PATH_MAX];
	410	const char *procfs = procfs__mountpoint();
	411
	412	if (!procfs)
	413	return -1;
	414
	415	snprintf(path, sizeof(path), "%s/%s", procfs, entry);
	416
	417	return filename__read_str(path, buf, sizep);
	418	}
607bfbd7	419
2d729f6a ACM	420	int sysfs__read_ull(const char entry, unsigned long long value)
	421	{
	422	char path[PATH_MAX];
	423	const char *sysfs = sysfs__mountpoint();
	424
	425	if (!sysfs)
	426	return -1;
	427
	428	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
	429
	430	return filename__read_ull(path, value);
	431	}
	432
	433	int sysfs__read_int(const char entry, int value)
	434	{
	435	char path[PATH_MAX];
	436	const char *sysfs = sysfs__mountpoint();
	437
	438	if (!sysfs)
	439	return -1;
	440
	441	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
	442
	443	return filename__read_int(path, value);
	444	}
	445
51c0396c JO	446	int sysfs__read_str(const char entry, char buf, size_t sizep)
	447	{
	448	char path[PATH_MAX];
	449	const char *sysfs = sysfs__mountpoint();
	450
	451	if (!sysfs)
	452	return -1;
	453
	454	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
	455
	456	return filename__read_str(path, buf, sizep);
	457	}
	458
b9835a90 AS	459	int sysfs__read_bool(const char entry, bool value)
	460	{
	461	char *buf;
	462	size_t size;
	463	int ret;
	464
	465	ret = sysfs__read_str(entry, &buf, &size);
	466	if (ret < 0)
	467	return ret;
	468
	469	switch (buf[0]) {
	470	case '1':
	471	case 'y':
	472	case 'Y':
	473	*value = true;
	474	break;
	475	case '0':
	476	case 'n':
	477	case 'N':
	478	*value = false;
	479	break;
	480	default:
	481	ret = -1;
	482	}
	483
	484	free(buf);
	485
	486	return ret;
	487	}
42e3c4a1 ACM	488	int sysctl__read_int(const char sysctl, int value)
	489	{
	490	char path[PATH_MAX];
	491	const char *procfs = procfs__mountpoint();
	492
	493	if (!procfs)
	494	return -1;
	495
	496	snprintf(path, sizeof(path), "%s/sys/%s", procfs, sysctl);
	497
	498	return filename__read_int(path, value);
	499	}
3b00ea93 KL	500
	501	int sysfs__write_int(const char *entry, int value)
	502	{
	503	char path[PATH_MAX];
	504	const char *sysfs = sysfs__mountpoint();
	505
	506	if (!sysfs)
	507	return -1;
	508
	509	if (snprintf(path, sizeof(path), "%s/%s", sysfs, entry) >= PATH_MAX)
	510	return -1;
	511
	512	return filename__write_int(path, value);
	513	}