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