[linux.git] / lib / seq_buf.c

// SPDX-License-Identifier: GPL-2.0
/*
 * seq_buf.c
 *
 * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <[email protected]>
 *
 * The seq_buf is a handy tool that allows you to pass a descriptor around
 * to a buffer that other functions can write to. It is similar to the
 * seq_file functionality but has some differences.
 *
 * To use it, the seq_buf must be initialized with seq_buf_init().
 * This will set up the counters within the descriptor. You can call
 * seq_buf_init() more than once to reset the seq_buf to start
 * from scratch.
 */

#include <linux/bug.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/hex.h>
#include <linux/minmax.h>
#include <linux/printk.h>
#include <linux/seq_buf.h>
#include <linux/seq_file.h>
#include <linux/sprintf.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/uaccess.h>

/**
 * seq_buf_can_fit - can the new data fit in the current buffer?
 * @s: the seq_buf descriptor
 * @len: The length to see if it can fit in the current buffer
 *
 * Returns: true if there's enough unused space in the seq_buf buffer
 * to fit the amount of new data according to @len.
 */
static bool seq_buf_can_fit(struct seq_buf *s, size_t len)
{
	return s->len + len <= s->size;
}

/**
 * seq_buf_print_seq - move the contents of seq_buf into a seq_file
 * @m: the seq_file descriptor that is the destination
 * @s: the seq_buf descriptor that is the source.
 *
 * Returns: zero on success, non-zero otherwise.
 */
int seq_buf_print_seq(struct seq_file *m, struct seq_buf *s)
{
	unsigned int len = seq_buf_used(s);

	return seq_write(m, s->buffer, len);
}

/**
 * seq_buf_vprintf - sequence printing of information.
 * @s: seq_buf descriptor
 * @fmt: printf format string
 * @args: va_list of arguments from a printf() type function
 *
 * Writes a vnprintf() format into the sequence buffer.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_vprintf(struct seq_buf *s, const char *fmt, va_list args)
{
	int len;

	WARN_ON(s->size == 0);

	if (s->len < s->size) {
		len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
		if (s->len + len < s->size) {
			s->len += len;
			return 0;
		}
	}
	seq_buf_set_overflow(s);
	return -1;
}

/**
 * seq_buf_printf - sequence printing of information
 * @s: seq_buf descriptor
 * @fmt: printf format string
 *
 * Writes a printf() format into the sequence buffer.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_printf(struct seq_buf *s, const char *fmt, ...)
{
	va_list ap;
	int ret;

	va_start(ap, fmt);
	ret = seq_buf_vprintf(s, fmt, ap);
	va_end(ap);

	return ret;
}
EXPORT_SYMBOL_GPL(seq_buf_printf);

/**
 * seq_buf_do_printk - printk() seq_buf line by line
 * @s: seq_buf descriptor
 * @lvl: printk level
 *
 * printk()-s a multi-line sequential buffer line by line. The function
 * makes sure that the buffer in @s is NUL-terminated and safe to read
 * as a string.
 */
void seq_buf_do_printk(struct seq_buf *s, const char *lvl)
{
	const char *start, *lf;

	if (s->size == 0 || s->len == 0)
		return;

	start = seq_buf_str(s);
	while ((lf = strchr(start, '\n'))) {
		int len = lf - start + 1;

		printk("%s%.*s", lvl, len, start);
		start = ++lf;
	}

	/* No trailing LF */
	if (start < s->buffer + s->len)
		printk("%s%s\n", lvl, start);
}
EXPORT_SYMBOL_GPL(seq_buf_do_printk);

#ifdef CONFIG_BINARY_PRINTF
/**
 * seq_buf_bprintf - Write the printf string from binary arguments
 * @s: seq_buf descriptor
 * @fmt: The format string for the @binary arguments
 * @binary: The binary arguments for @fmt.
 *
 * When recording in a fast path, a printf may be recorded with just
 * saving the format and the arguments as they were passed to the
 * function, instead of wasting cycles converting the arguments into
 * ASCII characters. Instead, the arguments are saved in a 32 bit
 * word array that is defined by the format string constraints.
 *
 * This function will take the format and the binary array and finish
 * the conversion into the ASCII string within the buffer.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_bprintf(struct seq_buf *s, const char *fmt, const u32 *binary)
{
	unsigned int len = seq_buf_buffer_left(s);
	int ret;

	WARN_ON(s->size == 0);

	if (s->len < s->size) {
		ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
		if (s->len + ret < s->size) {
			s->len += ret;
			return 0;
		}
	}
	seq_buf_set_overflow(s);
	return -1;
}
#endif /* CONFIG_BINARY_PRINTF */

/**
 * seq_buf_puts - sequence printing of simple string
 * @s: seq_buf descriptor
 * @str: simple string to record
 *
 * Copy a simple string into the sequence buffer.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_puts(struct seq_buf *s, const char *str)
{
	size_t len = strlen(str);

	WARN_ON(s->size == 0);

	/* Add 1 to len for the trailing null byte which must be there */
	len += 1;

	if (seq_buf_can_fit(s, len)) {
		memcpy(s->buffer + s->len, str, len);
		/* Don't count the trailing null byte against the capacity */
		s->len += len - 1;
		return 0;
	}
	seq_buf_set_overflow(s);
	return -1;
}
EXPORT_SYMBOL_GPL(seq_buf_puts);

/**
 * seq_buf_putc - sequence printing of simple character
 * @s: seq_buf descriptor
 * @c: simple character to record
 *
 * Copy a single character into the sequence buffer.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_putc(struct seq_buf *s, unsigned char c)
{
	WARN_ON(s->size == 0);

	if (seq_buf_can_fit(s, 1)) {
		s->buffer[s->len++] = c;
		return 0;
	}
	seq_buf_set_overflow(s);
	return -1;
}
EXPORT_SYMBOL_GPL(seq_buf_putc);

/**
 * seq_buf_putmem - write raw data into the sequence buffer
 * @s: seq_buf descriptor
 * @mem: The raw memory to copy into the buffer
 * @len: The length of the raw memory to copy (in bytes)
 *
 * There may be cases where raw memory needs to be written into the
 * buffer and a strcpy() would not work. Using this function allows
 * for such cases.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_putmem(struct seq_buf *s, const void *mem, unsigned int len)
{
	WARN_ON(s->size == 0);

	if (seq_buf_can_fit(s, len)) {
		memcpy(s->buffer + s->len, mem, len);
		s->len += len;
		return 0;
	}
	seq_buf_set_overflow(s);
	return -1;
}

#define MAX_MEMHEX_BYTES	8U
#define HEX_CHARS		(MAX_MEMHEX_BYTES*2 + 1)

/**
 * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
 * @s: seq_buf descriptor
 * @mem: The raw memory to write its hex ASCII representation of
 * @len: The length of the raw memory to copy (in bytes)
 *
 * This is similar to seq_buf_putmem() except instead of just copying the
 * raw memory into the buffer it writes its ASCII representation of it
 * in hex characters.
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_putmem_hex(struct seq_buf *s, const void *mem,
		       unsigned int len)
{
	unsigned char hex[HEX_CHARS];
	const unsigned char *data = mem;
	unsigned int start_len;
	int i, j;

	WARN_ON(s->size == 0);

	BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS);

	while (len) {
		start_len = min(len, MAX_MEMHEX_BYTES);
#ifdef __BIG_ENDIAN
		for (i = 0, j = 0; i < start_len; i++) {
#else
		for (i = start_len-1, j = 0; i >= 0; i--) {
#endif
			hex[j++] = hex_asc_hi(data[i]);
			hex[j++] = hex_asc_lo(data[i]);
		}
		if (WARN_ON_ONCE(j == 0 || j/2 > len))
			break;

		/* j increments twice per loop */
		hex[j++] = ' ';

		seq_buf_putmem(s, hex, j);
		if (seq_buf_has_overflowed(s))
			return -1;

		len -= start_len;
		data += start_len;
	}
	return 0;
}

/**
 * seq_buf_path - copy a path into the sequence buffer
 * @s: seq_buf descriptor
 * @path: path to write into the sequence buffer.
 * @esc: set of characters to escape in the output
 *
 * Write a path name into the sequence buffer.
 *
 * Returns: the number of written bytes on success, -1 on overflow.
 */
int seq_buf_path(struct seq_buf *s, const struct path *path, const char *esc)
{
	char *buf;
	size_t size = seq_buf_get_buf(s, &buf);
	int res = -1;

	WARN_ON(s->size == 0);

	if (size) {
		char *p = d_path(path, buf, size);
		if (!IS_ERR(p)) {
			char *end = mangle_path(buf, p, esc);
			if (end)
				res = end - buf;
		}
	}
	seq_buf_commit(s, res);

	return res;
}

/**
 * seq_buf_to_user - copy the sequence buffer to user space
 * @s: seq_buf descriptor
 * @ubuf: The userspace memory location to copy to
 * @start: The first byte in the buffer to copy
 * @cnt: The amount to copy
 *
 * Copies the sequence buffer into the userspace memory pointed to
 * by @ubuf. It starts from @start and writes up to @cnt characters
 * or until it reaches the end of the content in the buffer (@s->len),
 * whichever comes first.
 *
 * Returns:
 * On success, it returns a positive number of the number of bytes
 * it copied.
 *
 * On failure it returns -EBUSY if all of the content in the
 * sequence has been already read, which includes nothing in the
 * sequence (@s->len == @start).
 *
 * Returns -EFAULT if the copy to userspace fails.
 */
int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, size_t start, int cnt)
{
	int len;
	int ret;

	if (!cnt)
		return 0;

	len = seq_buf_used(s);

	if (len <= start)
		return -EBUSY;

	len -= start;
	if (cnt > len)
		cnt = len;
	ret = copy_to_user(ubuf, s->buffer + start, cnt);
	if (ret == cnt)
		return -EFAULT;

	return cnt - ret;
}

/**
 * seq_buf_hex_dump - print formatted hex dump into the sequence buffer
 * @s: seq_buf descriptor
 * @prefix_str: string to prefix each line with;
 *  caller supplies trailing spaces for alignment if desired
 * @prefix_type: controls whether prefix of an offset, address, or none
 *  is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
 * @rowsize: number of bytes to print per line; must be 16 or 32
 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
 * @buf: data blob to dump
 * @len: number of bytes in the @buf
 * @ascii: include ASCII after the hex output
 *
 * Function is an analogue of print_hex_dump() and thus has similar interface.
 *
 * linebuf size is maximal length for one line.
 * 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for
 *	separating space
 * 2 - spaces separating hex dump and ASCII representation
 * 32 - ASCII representation
 * 1 - terminating '\0'
 *
 * Returns: zero on success, -1 on overflow.
 */
int seq_buf_hex_dump(struct seq_buf *s, const char *prefix_str, int prefix_type,
		     int rowsize, int groupsize,
		     const void *buf, size_t len, bool ascii)
{
	const u8 *ptr = buf;
	int i, linelen, remaining = len;
	unsigned char linebuf[32 * 3 + 2 + 32 + 1];
	int ret;

	if (rowsize != 16 && rowsize != 32)
		rowsize = 16;

	for (i = 0; i < len; i += rowsize) {
		linelen = min(remaining, rowsize);
		remaining -= rowsize;

		hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
				   linebuf, sizeof(linebuf), ascii);

		switch (prefix_type) {
		case DUMP_PREFIX_ADDRESS:
			ret = seq_buf_printf(s, "%s%p: %s\n",
			       prefix_str, ptr + i, linebuf);
			break;
		case DUMP_PREFIX_OFFSET:
			ret = seq_buf_printf(s, "%s%.8x: %s\n",
					     prefix_str, i, linebuf);
			break;
		default:
			ret = seq_buf_printf(s, "%s%s\n", prefix_str, linebuf);
			break;
		}
		if (ret)
			return ret;
	}
	return 0;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
3a161d99 SRRH	2	/*
	3	* seq_buf.c
	4	*
	5	* Copyright (C) 2014 Red Hat Inc, Steven Rostedt <[email protected]>
	6	*
	7	* The seq_buf is a handy tool that allows you to pass a descriptor around
	8	* to a buffer that other functions can write to. It is similar to the
	9	* seq_file functionality but has some differences.
	10	*
	11	* To use it, the seq_buf must be initialized with seq_buf_init().
	12	* This will set up the counters within the descriptor. You can call
	13	* seq_buf_init() more than once to reset the seq_buf to start
	14	* from scratch.
	15	*/
8a566f94 AS	16
	17	#include <linux/bug.h>
	18	#include <linux/err.h>
	19	#include <linux/export.h>
	20	#include <linux/hex.h>
	21	#include <linux/minmax.h>
	22	#include <linux/printk.h>
3a161d99	23	#include <linux/seq_buf.h>
8a566f94 AS	24	#include <linux/seq_file.h>
	25	#include <linux/sprintf.h>
	26	#include <linux/string.h>
	27	#include <linux/types.h>
	28	#include <linux/uaccess.h>
3a161d99	29
9b772153 SRRH	30	/**
	31	* seq_buf_can_fit - can the new data fit in the current buffer?
	32	* @s: the seq_buf descriptor
	33	* @len: The length to see if it can fit in the current buffer
	34	*
6efe4d18	35	* Returns: true if there's enough unused space in the seq_buf buffer
9b772153 SRRH	36	* to fit the amount of new data according to @len.
	37	*/
	38	static bool seq_buf_can_fit(struct seq_buf *s, size_t len)
	39	{
8cd709ae	40	return s->len + len <= s->size;
9b772153 SRRH	41	}
9b772153 SRRH	42
3a161d99 SRRH	43	/**
	44	* seq_buf_print_seq - move the contents of seq_buf into a seq_file
	45	* @m: the seq_file descriptor that is the destination
	46	* @s: the seq_buf descriptor that is the source.
	47	*
6efe4d18	48	* Returns: zero on success, non-zero otherwise.
3a161d99 SRRH	49	*/
	50	int seq_buf_print_seq(struct seq_file m, struct seq_buf s)
	51	{
eeab9815	52	unsigned int len = seq_buf_used(s);
3a161d99 SRRH	53
	54	return seq_write(m, s->buffer, len);
	55	}
	56
	57	/**
	58	* seq_buf_vprintf - sequence printing of information.
	59	* @s: seq_buf descriptor
	60	* @fmt: printf format string
	61	* @args: va_list of arguments from a printf() type function
	62	*
6efe4d18	63	* Writes a vnprintf() format into the sequence buffer.
3a161d99	64	*
6efe4d18	65	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	66	*/
	67	int seq_buf_vprintf(struct seq_buf s, const char fmt, va_list args)
	68	{
	69	int len;
	70
	71	WARN_ON(s->size == 0);
	72
	73	if (s->len < s->size) {
	74	len = vsnprintf(s->buffer + s->len, s->size - s->len, fmt, args);
4a8fe4e1	75	if (s->len + len < s->size) {
3a161d99 SRRH	76	s->len += len;
	77	return 0;
	78	}
	79	}
	80	seq_buf_set_overflow(s);
	81	return -1;
	82	}
	83
	84	/**
	85	* seq_buf_printf - sequence printing of information
	86	* @s: seq_buf descriptor
	87	* @fmt: printf format string
	88	*
	89	* Writes a printf() format into the sequence buffer.
	90	*
6efe4d18	91	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	92	*/
	93	int seq_buf_printf(struct seq_buf s, const char fmt, ...)
	94	{
	95	va_list ap;
	96	int ret;
	97
	98	va_start(ap, fmt);
	99	ret = seq_buf_vprintf(s, fmt, ap);
	100	va_end(ap);
	101
	102	return ret;
	103	}
97c02c72	104	EXPORT_SYMBOL_GPL(seq_buf_printf);
3a161d99	105
96928d90	106	/**
6efe4d18	107	* seq_buf_do_printk - printk() seq_buf line by line
96928d90 SS	108	* @s: seq_buf descriptor
	109	* @lvl: printk level
	110	*
	111	* printk()-s a multi-line sequential buffer line by line. The function
6efe4d18	112	* makes sure that the buffer in @s is NUL-terminated and safe to read
96928d90 SS	113	* as a string.
	114	*/
	115	void seq_buf_do_printk(struct seq_buf s, const char lvl)
	116	{
	117	const char start, lf;
	118
	119	if (s->size == 0 \|\| s->len == 0)
	120	return;
	121
dcc4e572	122	start = seq_buf_str(s);
96928d90 SS	123	while ((lf = strchr(start, '\n'))) {
	124	int len = lf - start + 1;
	125
	126	printk("%s%.*s", lvl, len, start);
	127	start = ++lf;
	128	}
	129
	130	/* No trailing LF */
	131	if (start < s->buffer + s->len)
	132	printk("%s%s\n", lvl, start);
	133	}
	134	EXPORT_SYMBOL_GPL(seq_buf_do_printk);
	135
2448913e	136	#ifdef CONFIG_BINARY_PRINTF
3a161d99 SRRH	137	/**
	138	* seq_buf_bprintf - Write the printf string from binary arguments
	139	* @s: seq_buf descriptor
	140	* @fmt: The format string for the @binary arguments
	141	* @binary: The binary arguments for @fmt.
	142	*
	143	* When recording in a fast path, a printf may be recorded with just
	144	* saving the format and the arguments as they were passed to the
	145	* function, instead of wasting cycles converting the arguments into
	146	* ASCII characters. Instead, the arguments are saved in a 32 bit
	147	* word array that is defined by the format string constraints.
	148	*
	149	* This function will take the format and the binary array and finish
	150	* the conversion into the ASCII string within the buffer.
	151	*
6efe4d18	152	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	153	*/
	154	int seq_buf_bprintf(struct seq_buf s, const char fmt, const u32 *binary)
	155	{
	156	unsigned int len = seq_buf_buffer_left(s);
	157	int ret;
	158
	159	WARN_ON(s->size == 0);
	160
	161	if (s->len < s->size) {
	162	ret = bstr_printf(s->buffer + s->len, len, fmt, binary);
4d4eb4d4	163	if (s->len + ret < s->size) {
3a161d99 SRRH	164	s->len += ret;
	165	return 0;
	166	}
	167	}
	168	seq_buf_set_overflow(s);
	169	return -1;
	170	}
2448913e	171	#endif /* CONFIG_BINARY_PRINTF */
3a161d99 SRRH	172
	173	/**
	174	* seq_buf_puts - sequence printing of simple string
	175	* @s: seq_buf descriptor
	176	* @str: simple string to record
	177	*
	178	* Copy a simple string into the sequence buffer.
	179	*
6efe4d18	180	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	181	*/
	182	int seq_buf_puts(struct seq_buf s, const char str)
	183	{
29924e50	184	size_t len = strlen(str);
3a161d99 SRRH	185
	186	WARN_ON(s->size == 0);
	187
0464ed24 ME	188	/* Add 1 to len for the trailing null byte which must be there */
	189	len += 1;
	190
9b772153	191	if (seq_buf_can_fit(s, len)) {
3a161d99	192	memcpy(s->buffer + s->len, str, len);
0464ed24 ME	193	/* Don't count the trailing null byte against the capacity */
0464ed24 ME	194	s->len += len - 1;
3a161d99 SRRH	195	return 0;
	196	}
	197	seq_buf_set_overflow(s);
	198	return -1;
	199	}
70a9affa	200	EXPORT_SYMBOL_GPL(seq_buf_puts);
3a161d99 SRRH	201
	202	/**
	203	* seq_buf_putc - sequence printing of simple character
	204	* @s: seq_buf descriptor
	205	* @c: simple character to record
	206	*
	207	* Copy a single character into the sequence buffer.
	208	*
6efe4d18	209	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	210	*/
	211	int seq_buf_putc(struct seq_buf *s, unsigned char c)
	212	{
	213	WARN_ON(s->size == 0);
	214
9b772153	215	if (seq_buf_can_fit(s, 1)) {
3a161d99 SRRH	216	s->buffer[s->len++] = c;
	217	return 0;
	218	}
	219	seq_buf_set_overflow(s);
	220	return -1;
	221	}
685b38c7	222	EXPORT_SYMBOL_GPL(seq_buf_putc);
3a161d99 SRRH	223
3a161d99 SRRH	224	/**
6efe4d18	225	* seq_buf_putmem - write raw data into the sequence buffer
3a161d99 SRRH	226	* @s: seq_buf descriptor
	227	* @mem: The raw memory to copy into the buffer
	228	* @len: The length of the raw memory to copy (in bytes)
	229	*
	230	* There may be cases where raw memory needs to be written into the
	231	* buffer and a strcpy() would not work. Using this function allows
	232	* for such cases.
	233	*
6efe4d18	234	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	235	*/
	236	int seq_buf_putmem(struct seq_buf s, const void mem, unsigned int len)
	237	{
	238	WARN_ON(s->size == 0);
	239
9b772153	240	if (seq_buf_can_fit(s, len)) {
3a161d99 SRRH	241	memcpy(s->buffer + s->len, mem, len);
	242	s->len += len;
	243	return 0;
	244	}
	245	seq_buf_set_overflow(s);
	246	return -1;
	247	}
	248
	249	#define MAX_MEMHEX_BYTES 8U
	250	#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
	251
	252	/**
	253	* seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
	254	* @s: seq_buf descriptor
	255	* @mem: The raw memory to write its hex ASCII representation of
	256	* @len: The length of the raw memory to copy (in bytes)
	257	*
	258	* This is similar to seq_buf_putmem() except instead of just copying the
	259	* raw memory into the buffer it writes its ASCII representation of it
	260	* in hex characters.
	261	*
6efe4d18	262	* Returns: zero on success, -1 on overflow.
3a161d99 SRRH	263	*/
	264	int seq_buf_putmem_hex(struct seq_buf s, const void mem,
	265	unsigned int len)
	266	{
	267	unsigned char hex[HEX_CHARS];
	268	const unsigned char *data = mem;
	269	unsigned int start_len;
	270	int i, j;
	271
	272	WARN_ON(s->size == 0);
	273
d3b16034 YZ	274	BUILD_BUG_ON(MAX_MEMHEX_BYTES * 2 >= HEX_CHARS);
d3b16034 YZ	275
3a161d99	276	while (len) {
d3b16034	277	start_len = min(len, MAX_MEMHEX_BYTES);
3a161d99 SRRH	278	#ifdef __BIG_ENDIAN
	279	for (i = 0, j = 0; i < start_len; i++) {
	280	#else
	281	for (i = start_len-1, j = 0; i >= 0; i--) {
	282	#endif
	283	hex[j++] = hex_asc_hi(data[i]);
	284	hex[j++] = hex_asc_lo(data[i]);
	285	}
	286	if (WARN_ON_ONCE(j == 0 \|\| j/2 > len))
	287	break;
	288
	289	/* j increments twice per loop */
3a161d99 SRRH	290	hex[j++] = ' ';
	291
	292	seq_buf_putmem(s, hex, j);
	293	if (seq_buf_has_overflowed(s))
	294	return -1;
6a2cbc58 YZ	295
	296	len -= start_len;
	297	data += start_len;
3a161d99 SRRH	298	}
	299	return 0;
	300	}
	301
	302	/**
	303	* seq_buf_path - copy a path into the sequence buffer
	304	* @s: seq_buf descriptor
	305	* @path: path to write into the sequence buffer.
dd23180a	306	* @esc: set of characters to escape in the output
3a161d99 SRRH	307	*
	308	* Write a path name into the sequence buffer.
	309	*
6efe4d18	310	* Returns: the number of written bytes on success, -1 on overflow.
3a161d99	311	*/
dd23180a	312	int seq_buf_path(struct seq_buf s, const struct path path, const char *esc)
3a161d99	313	{
01cb06a4 SRRH	314	char *buf;
01cb06a4 SRRH	315	size_t size = seq_buf_get_buf(s, &buf);
dd23180a	316	int res = -1;
3a161d99 SRRH	317
	318	WARN_ON(s->size == 0);
	319
dd23180a SRRH	320	if (size) {
	321	char *p = d_path(path, buf, size);
	322	if (!IS_ERR(p)) {
	323	char *end = mangle_path(buf, p, esc);
	324	if (end)
	325	res = end - buf;
3a161d99 SRRH	326	}
3a161d99 SRRH	327	}
01cb06a4	328	seq_buf_commit(s, res);
dd23180a SRRH	329
dd23180a SRRH	330	return res;
3a161d99 SRRH	331	}
	332
	333	/**
9dbbc3b9	334	* seq_buf_to_user - copy the sequence buffer to user space
3a161d99 SRRH	335	* @s: seq_buf descriptor
3a161d99 SRRH	336	* @ubuf: The userspace memory location to copy to
d0ed46b6	337	* @start: The first byte in the buffer to copy
3a161d99 SRRH	338	* @cnt: The amount to copy
	339	*
	340	* Copies the sequence buffer into the userspace memory pointed to
d0ed46b6 MWO	341	* by @ubuf. It starts from @start and writes up to @cnt characters
	342	* or until it reaches the end of the content in the buffer (@s->len),
	343	* whichever comes first.
3a161d99	344	*
6efe4d18	345	* Returns:
3a161d99 SRRH	346	* On success, it returns a positive number of the number of bytes
	347	* it copied.
	348	*
	349	* On failure it returns -EBUSY if all of the content in the
	350	* sequence has been already read, which includes nothing in the
d0ed46b6	351	* sequence (@s->len == @start).
3a161d99 SRRH	352	*
	353	* Returns -EFAULT if the copy to userspace fails.
	354	*/
d0ed46b6	355	int seq_buf_to_user(struct seq_buf s, char __user ubuf, size_t start, int cnt)
3a161d99 SRRH	356	{
	357	int len;
	358	int ret;
	359
	360	if (!cnt)
	361	return 0;
	362
ff078d8f JS	363	len = seq_buf_used(s);
ff078d8f JS	364
d0ed46b6	365	if (len <= start)
3a161d99 SRRH	366	return -EBUSY;
3a161d99 SRRH	367
d0ed46b6	368	len -= start;
3a161d99 SRRH	369	if (cnt > len)
3a161d99 SRRH	370	cnt = len;
d0ed46b6	371	ret = copy_to_user(ubuf, s->buffer + start, cnt);
3a161d99 SRRH	372	if (ret == cnt)
	373	return -EFAULT;
	374
d0ed46b6	375	return cnt - ret;
3a161d99	376	}
353cade3 PM	377
	378	/**
	379	* seq_buf_hex_dump - print formatted hex dump into the sequence buffer
	380	* @s: seq_buf descriptor
	381	* @prefix_str: string to prefix each line with;
	382	* caller supplies trailing spaces for alignment if desired
	383	* @prefix_type: controls whether prefix of an offset, address, or none
	384	* is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
	385	* @rowsize: number of bytes to print per line; must be 16 or 32
	386	* @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
	387	* @buf: data blob to dump
	388	* @len: number of bytes in the @buf
	389	* @ascii: include ASCII after the hex output
	390	*
	391	* Function is an analogue of print_hex_dump() and thus has similar interface.
	392	*
	393	* linebuf size is maximal length for one line.
	394	* 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for
	395	* separating space
6efe4d18 AS	396	* 2 - spaces separating hex dump and ASCII representation
6efe4d18 AS	397	* 32 - ASCII representation
353cade3 PM	398	* 1 - terminating '\0'
353cade3 PM	399	*
6efe4d18	400	* Returns: zero on success, -1 on overflow.
353cade3 PM	401	*/
	402	int seq_buf_hex_dump(struct seq_buf s, const char prefix_str, int prefix_type,
	403	int rowsize, int groupsize,
	404	const void *buf, size_t len, bool ascii)
	405	{
	406	const u8 *ptr = buf;
	407	int i, linelen, remaining = len;
	408	unsigned char linebuf[32 * 3 + 2 + 32 + 1];
	409	int ret;
	410
	411	if (rowsize != 16 && rowsize != 32)
	412	rowsize = 16;
	413
	414	for (i = 0; i < len; i += rowsize) {
	415	linelen = min(remaining, rowsize);
	416	remaining -= rowsize;
	417
	418	hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
	419	linebuf, sizeof(linebuf), ascii);
	420
	421	switch (prefix_type) {
	422	case DUMP_PREFIX_ADDRESS:
	423	ret = seq_buf_printf(s, "%s%p: %s\n",
	424	prefix_str, ptr + i, linebuf);
	425	break;
	426	case DUMP_PREFIX_OFFSET:
	427	ret = seq_buf_printf(s, "%s%.8x: %s\n",
	428	prefix_str, i, linebuf);
	429	break;
	430	default:
	431	ret = seq_buf_printf(s, "%s%s\n", prefix_str, linebuf);
	432	break;
	433	}
	434	if (ret)
	435	return ret;
	436	}
	437	return 0;
	438	}