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git.proxmox.com Git - mirror_ubuntu-kernels.git/blob - lib/seq_buf.c
1 // SPDX-License-Identifier: GPL-2.0
5 * Copyright (C) 2014 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
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.
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
16 #include <linux/uaccess.h>
17 #include <linux/seq_file.h>
18 #include <linux/seq_buf.h>
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
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.
28 static bool seq_buf_can_fit(struct seq_buf
*s
, size_t len
)
30 return s
->len
+ len
<= s
->size
;
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.
38 * Returns zero on success, non zero otherwise
40 int seq_buf_print_seq(struct seq_file
*m
, struct seq_buf
*s
)
42 unsigned int len
= seq_buf_used(s
);
44 return seq_write(m
, s
->buffer
, len
);
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
53 * Writes a vnprintf() format into the sequencce buffer.
55 * Returns zero on success, -1 on overflow.
57 int seq_buf_vprintf(struct seq_buf
*s
, const char *fmt
, va_list args
)
61 WARN_ON(s
->size
== 0);
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
) {
70 seq_buf_set_overflow(s
);
75 * seq_buf_printf - sequence printing of information
76 * @s: seq_buf descriptor
77 * @fmt: printf format string
79 * Writes a printf() format into the sequence buffer.
81 * Returns zero on success, -1 on overflow.
83 int seq_buf_printf(struct seq_buf
*s
, const char *fmt
, ...)
89 ret
= seq_buf_vprintf(s
, fmt
, ap
);
94 EXPORT_SYMBOL_GPL(seq_buf_printf
);
97 * seq_buf_do_printk - printk seq_buf line by line
98 * @s: seq_buf descriptor
101 * printk()-s a multi-line sequential buffer line by line. The function
102 * makes sure that the buffer in @s is nul terminated and safe to read
105 void seq_buf_do_printk(struct seq_buf
*s
, const char *lvl
)
107 const char *start
, *lf
;
109 if (s
->size
== 0 || s
->len
== 0)
112 seq_buf_terminate(s
);
115 while ((lf
= strchr(start
, '\n'))) {
116 int len
= lf
- start
+ 1;
118 printk("%s%.*s", lvl
, len
, start
);
123 if (start
< s
->buffer
+ s
->len
)
124 printk("%s%s\n", lvl
, start
);
126 EXPORT_SYMBOL_GPL(seq_buf_do_printk
);
128 #ifdef CONFIG_BINARY_PRINTF
130 * seq_buf_bprintf - Write the printf string from binary arguments
131 * @s: seq_buf descriptor
132 * @fmt: The format string for the @binary arguments
133 * @binary: The binary arguments for @fmt.
135 * When recording in a fast path, a printf may be recorded with just
136 * saving the format and the arguments as they were passed to the
137 * function, instead of wasting cycles converting the arguments into
138 * ASCII characters. Instead, the arguments are saved in a 32 bit
139 * word array that is defined by the format string constraints.
141 * This function will take the format and the binary array and finish
142 * the conversion into the ASCII string within the buffer.
144 * Returns zero on success, -1 on overflow.
146 int seq_buf_bprintf(struct seq_buf
*s
, const char *fmt
, const u32
*binary
)
148 unsigned int len
= seq_buf_buffer_left(s
);
151 WARN_ON(s
->size
== 0);
153 if (s
->len
< s
->size
) {
154 ret
= bstr_printf(s
->buffer
+ s
->len
, len
, fmt
, binary
);
155 if (s
->len
+ ret
< s
->size
) {
160 seq_buf_set_overflow(s
);
163 #endif /* CONFIG_BINARY_PRINTF */
166 * seq_buf_puts - sequence printing of simple string
167 * @s: seq_buf descriptor
168 * @str: simple string to record
170 * Copy a simple string into the sequence buffer.
172 * Returns zero on success, -1 on overflow
174 int seq_buf_puts(struct seq_buf
*s
, const char *str
)
176 size_t len
= strlen(str
);
178 WARN_ON(s
->size
== 0);
180 /* Add 1 to len for the trailing null byte which must be there */
183 if (seq_buf_can_fit(s
, len
)) {
184 memcpy(s
->buffer
+ s
->len
, str
, len
);
185 /* Don't count the trailing null byte against the capacity */
189 seq_buf_set_overflow(s
);
194 * seq_buf_putc - sequence printing of simple character
195 * @s: seq_buf descriptor
196 * @c: simple character to record
198 * Copy a single character into the sequence buffer.
200 * Returns zero on success, -1 on overflow
202 int seq_buf_putc(struct seq_buf
*s
, unsigned char c
)
204 WARN_ON(s
->size
== 0);
206 if (seq_buf_can_fit(s
, 1)) {
207 s
->buffer
[s
->len
++] = c
;
210 seq_buf_set_overflow(s
);
215 * seq_buf_putmem - write raw data into the sequenc buffer
216 * @s: seq_buf descriptor
217 * @mem: The raw memory to copy into the buffer
218 * @len: The length of the raw memory to copy (in bytes)
220 * There may be cases where raw memory needs to be written into the
221 * buffer and a strcpy() would not work. Using this function allows
224 * Returns zero on success, -1 on overflow
226 int seq_buf_putmem(struct seq_buf
*s
, const void *mem
, unsigned int len
)
228 WARN_ON(s
->size
== 0);
230 if (seq_buf_can_fit(s
, len
)) {
231 memcpy(s
->buffer
+ s
->len
, mem
, len
);
235 seq_buf_set_overflow(s
);
239 #define MAX_MEMHEX_BYTES 8U
240 #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1)
243 * seq_buf_putmem_hex - write raw memory into the buffer in ASCII hex
244 * @s: seq_buf descriptor
245 * @mem: The raw memory to write its hex ASCII representation of
246 * @len: The length of the raw memory to copy (in bytes)
248 * This is similar to seq_buf_putmem() except instead of just copying the
249 * raw memory into the buffer it writes its ASCII representation of it
252 * Returns zero on success, -1 on overflow
254 int seq_buf_putmem_hex(struct seq_buf
*s
, const void *mem
,
257 unsigned char hex
[HEX_CHARS
];
258 const unsigned char *data
= mem
;
259 unsigned int start_len
;
262 WARN_ON(s
->size
== 0);
264 BUILD_BUG_ON(MAX_MEMHEX_BYTES
* 2 >= HEX_CHARS
);
267 start_len
= min(len
, MAX_MEMHEX_BYTES
);
269 for (i
= 0, j
= 0; i
< start_len
; i
++) {
271 for (i
= start_len
-1, j
= 0; i
>= 0; i
--) {
273 hex
[j
++] = hex_asc_hi(data
[i
]);
274 hex
[j
++] = hex_asc_lo(data
[i
]);
276 if (WARN_ON_ONCE(j
== 0 || j
/2 > len
))
279 /* j increments twice per loop */
282 seq_buf_putmem(s
, hex
, j
);
283 if (seq_buf_has_overflowed(s
))
293 * seq_buf_path - copy a path into the sequence buffer
294 * @s: seq_buf descriptor
295 * @path: path to write into the sequence buffer.
296 * @esc: set of characters to escape in the output
298 * Write a path name into the sequence buffer.
300 * Returns the number of written bytes on success, -1 on overflow
302 int seq_buf_path(struct seq_buf
*s
, const struct path
*path
, const char *esc
)
305 size_t size
= seq_buf_get_buf(s
, &buf
);
308 WARN_ON(s
->size
== 0);
311 char *p
= d_path(path
, buf
, size
);
313 char *end
= mangle_path(buf
, p
, esc
);
318 seq_buf_commit(s
, res
);
324 * seq_buf_to_user - copy the sequence buffer to user space
325 * @s: seq_buf descriptor
326 * @ubuf: The userspace memory location to copy to
327 * @cnt: The amount to copy
329 * Copies the sequence buffer into the userspace memory pointed to
330 * by @ubuf. It starts from the last read position (@s->readpos)
331 * and writes up to @cnt characters or till it reaches the end of
332 * the content in the buffer (@s->len), which ever comes first.
334 * On success, it returns a positive number of the number of bytes
337 * On failure it returns -EBUSY if all of the content in the
338 * sequence has been already read, which includes nothing in the
339 * sequence (@s->len == @s->readpos).
341 * Returns -EFAULT if the copy to userspace fails.
343 int seq_buf_to_user(struct seq_buf
*s
, char __user
*ubuf
, int cnt
)
351 len
= seq_buf_used(s
);
353 if (len
<= s
->readpos
)
359 ret
= copy_to_user(ubuf
, s
->buffer
+ s
->readpos
, cnt
);
370 * seq_buf_hex_dump - print formatted hex dump into the sequence buffer
371 * @s: seq_buf descriptor
372 * @prefix_str: string to prefix each line with;
373 * caller supplies trailing spaces for alignment if desired
374 * @prefix_type: controls whether prefix of an offset, address, or none
375 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
376 * @rowsize: number of bytes to print per line; must be 16 or 32
377 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
378 * @buf: data blob to dump
379 * @len: number of bytes in the @buf
380 * @ascii: include ASCII after the hex output
382 * Function is an analogue of print_hex_dump() and thus has similar interface.
384 * linebuf size is maximal length for one line.
385 * 32 * 3 - maximum bytes per line, each printed into 2 chars + 1 for
387 * 2 - spaces separating hex dump and ascii representation
388 * 32 - ascii representation
389 * 1 - terminating '\0'
391 * Returns zero on success, -1 on overflow
393 int seq_buf_hex_dump(struct seq_buf
*s
, const char *prefix_str
, int prefix_type
,
394 int rowsize
, int groupsize
,
395 const void *buf
, size_t len
, bool ascii
)
398 int i
, linelen
, remaining
= len
;
399 unsigned char linebuf
[32 * 3 + 2 + 32 + 1];
402 if (rowsize
!= 16 && rowsize
!= 32)
405 for (i
= 0; i
< len
; i
+= rowsize
) {
406 linelen
= min(remaining
, rowsize
);
407 remaining
-= rowsize
;
409 hex_dump_to_buffer(ptr
+ i
, linelen
, rowsize
, groupsize
,
410 linebuf
, sizeof(linebuf
), ascii
);
412 switch (prefix_type
) {
413 case DUMP_PREFIX_ADDRESS
:
414 ret
= seq_buf_printf(s
, "%s%p: %s\n",
415 prefix_str
, ptr
+ i
, linebuf
);
417 case DUMP_PREFIX_OFFSET
:
418 ret
= seq_buf_printf(s
, "%s%.8x: %s\n",
419 prefix_str
, i
, linebuf
);
422 ret
= seq_buf_printf(s
, "%s%s\n", prefix_str
, linebuf
);