1// SPDX-License-Identifier: LGPL-2.1+
2/* Copyright (C) 2022 Kent Overstreet */
3
4#include <linux/bitmap.h>
5#include <linux/err.h>
6#include <linux/export.h>
7#include <linux/kernel.h>
8#include <linux/slab.h>
9#include <linux/string_helpers.h>
10
11#include "printbuf.h"
12
13static inline unsigned printbuf_linelen(struct printbuf *buf)
14{
15 return buf->pos - buf->last_newline;
16}
17
18int bch2_printbuf_make_room(struct printbuf *out, unsigned extra)
19{
20 unsigned new_size;
21 char *buf;
22
23 if (!out->heap_allocated)
24 return 0;
25
26 /* Reserved space for terminating nul: */
27 extra += 1;
28
29 if (out->pos + extra < out->size)
30 return 0;
31
32 new_size = roundup_pow_of_two(out->size + extra);
33
34 /*
35 * Note: output buffer must be freeable with kfree(), it's not required
36 * that the user use printbuf_exit().
37 */
38 buf = krealloc(objp: out->buf, new_size, flags: !out->atomic ? GFP_KERNEL : GFP_NOWAIT);
39
40 if (!buf) {
41 out->allocation_failure = true;
42 return -ENOMEM;
43 }
44
45 out->buf = buf;
46 out->size = new_size;
47 return 0;
48}
49
50void bch2_prt_vprintf(struct printbuf *out, const char *fmt, va_list args)
51{
52 int len;
53
54 do {
55 va_list args2;
56
57 va_copy(args2, args);
58 len = vsnprintf(buf: out->buf + out->pos, size: printbuf_remaining(out), fmt, args: args2);
59 va_end(args2);
60 } while (len + 1 >= printbuf_remaining(out) &&
61 !bch2_printbuf_make_room(out, extra: len + 1));
62
63 len = min_t(size_t, len,
64 printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0);
65 out->pos += len;
66}
67
68void bch2_prt_printf(struct printbuf *out, const char *fmt, ...)
69{
70 va_list args;
71 int len;
72
73 do {
74 va_start(args, fmt);
75 len = vsnprintf(buf: out->buf + out->pos, size: printbuf_remaining(out), fmt, args);
76 va_end(args);
77 } while (len + 1 >= printbuf_remaining(out) &&
78 !bch2_printbuf_make_room(out, extra: len + 1));
79
80 len = min_t(size_t, len,
81 printbuf_remaining(out) ? printbuf_remaining(out) - 1 : 0);
82 out->pos += len;
83}
84
85/**
86 * bch2_printbuf_str() - returns printbuf's buf as a C string, guaranteed to be
87 * null terminated
88 * @buf: printbuf to terminate
89 * Returns: Printbuf contents, as a nul terminated C string
90 */
91const char *bch2_printbuf_str(const struct printbuf *buf)
92{
93 /*
94 * If we've written to a printbuf then it's guaranteed to be a null
95 * terminated string - but if we haven't, then we might not have
96 * allocated a buffer at all:
97 */
98 return buf->pos
99 ? buf->buf
100 : "";
101}
102
103/**
104 * bch2_printbuf_exit() - exit a printbuf, freeing memory it owns and poisoning it
105 * against accidental use.
106 * @buf: printbuf to exit
107 */
108void bch2_printbuf_exit(struct printbuf *buf)
109{
110 if (buf->heap_allocated) {
111 kfree(objp: buf->buf);
112 buf->buf = ERR_PTR(error: -EINTR); /* poison value */
113 }
114}
115
116void bch2_printbuf_tabstops_reset(struct printbuf *buf)
117{
118 buf->nr_tabstops = 0;
119}
120
121void bch2_printbuf_tabstop_pop(struct printbuf *buf)
122{
123 if (buf->nr_tabstops)
124 --buf->nr_tabstops;
125}
126
127/*
128 * bch2_printbuf_tabstop_set() - add a tabstop, n spaces from the previous tabstop
129 *
130 * @buf: printbuf to control
131 * @spaces: number of spaces from previous tabpstop
132 *
133 * In the future this function may allocate memory if setting more than
134 * PRINTBUF_INLINE_TABSTOPS or setting tabstops more than 255 spaces from start
135 * of line.
136 */
137int bch2_printbuf_tabstop_push(struct printbuf *buf, unsigned spaces)
138{
139 unsigned prev_tabstop = buf->nr_tabstops
140 ? buf->_tabstops[buf->nr_tabstops - 1]
141 : 0;
142
143 if (WARN_ON(buf->nr_tabstops >= ARRAY_SIZE(buf->_tabstops)))
144 return -EINVAL;
145
146 buf->_tabstops[buf->nr_tabstops++] = prev_tabstop + spaces;
147 buf->has_indent_or_tabstops = true;
148 return 0;
149}
150
151/**
152 * bch2_printbuf_indent_add() - add to the current indent level
153 *
154 * @buf: printbuf to control
155 * @spaces: number of spaces to add to the current indent level
156 *
157 * Subsequent lines, and the current line if the output position is at the start
158 * of the current line, will be indented by @spaces more spaces.
159 */
160void bch2_printbuf_indent_add(struct printbuf *buf, unsigned spaces)
161{
162 if (WARN_ON_ONCE(buf->indent + spaces < buf->indent))
163 spaces = 0;
164
165 buf->indent += spaces;
166 prt_chars(out: buf, c: ' ', n: spaces);
167
168 buf->has_indent_or_tabstops = true;
169}
170
171/**
172 * bch2_printbuf_indent_sub() - subtract from the current indent level
173 *
174 * @buf: printbuf to control
175 * @spaces: number of spaces to subtract from the current indent level
176 *
177 * Subsequent lines, and the current line if the output position is at the start
178 * of the current line, will be indented by @spaces less spaces.
179 */
180void bch2_printbuf_indent_sub(struct printbuf *buf, unsigned spaces)
181{
182 if (WARN_ON_ONCE(spaces > buf->indent))
183 spaces = buf->indent;
184
185 if (buf->last_newline + buf->indent == buf->pos) {
186 buf->pos -= spaces;
187 printbuf_nul_terminate(out: buf);
188 }
189 buf->indent -= spaces;
190
191 if (!buf->indent && !buf->nr_tabstops)
192 buf->has_indent_or_tabstops = false;
193}
194
195void bch2_prt_newline(struct printbuf *buf)
196{
197 unsigned i;
198
199 bch2_printbuf_make_room(out: buf, extra: 1 + buf->indent);
200
201 __prt_char(out: buf, c: '\n');
202
203 buf->last_newline = buf->pos;
204
205 for (i = 0; i < buf->indent; i++)
206 __prt_char(out: buf, c: ' ');
207
208 printbuf_nul_terminate(out: buf);
209
210 buf->last_field = buf->pos;
211 buf->cur_tabstop = 0;
212}
213
214/*
215 * Returns spaces from start of line, if set, or 0 if unset:
216 */
217static inline unsigned cur_tabstop(struct printbuf *buf)
218{
219 return buf->cur_tabstop < buf->nr_tabstops
220 ? buf->_tabstops[buf->cur_tabstop]
221 : 0;
222}
223
224static void __prt_tab(struct printbuf *out)
225{
226 int spaces = max_t(int, 0, cur_tabstop(out) - printbuf_linelen(out));
227
228 prt_chars(out, c: ' ', n: spaces);
229
230 out->last_field = out->pos;
231 out->cur_tabstop++;
232}
233
234/**
235 * bch2_prt_tab() - Advance printbuf to the next tabstop
236 * @out: printbuf to control
237 *
238 * Advance output to the next tabstop by printing spaces.
239 */
240void bch2_prt_tab(struct printbuf *out)
241{
242 if (WARN_ON(!cur_tabstop(out)))
243 return;
244
245 __prt_tab(out);
246}
247
248static void __prt_tab_rjust(struct printbuf *buf)
249{
250 unsigned move = buf->pos - buf->last_field;
251 int pad = (int) cur_tabstop(buf) - (int) printbuf_linelen(buf);
252
253 if (pad > 0) {
254 bch2_printbuf_make_room(out: buf, extra: pad);
255
256 if (buf->last_field + pad < buf->size)
257 memmove(buf->buf + buf->last_field + pad,
258 buf->buf + buf->last_field,
259 min(move, buf->size - 1 - buf->last_field - pad));
260
261 if (buf->last_field < buf->size)
262 memset(buf->buf + buf->last_field, ' ',
263 min((unsigned) pad, buf->size - buf->last_field));
264
265 buf->pos += pad;
266 printbuf_nul_terminate(out: buf);
267 }
268
269 buf->last_field = buf->pos;
270 buf->cur_tabstop++;
271}
272
273/**
274 * bch2_prt_tab_rjust - Advance printbuf to the next tabstop, right justifying
275 * previous output
276 *
277 * @buf: printbuf to control
278 *
279 * Advance output to the next tabstop by inserting spaces immediately after the
280 * previous tabstop, right justifying previously outputted text.
281 */
282void bch2_prt_tab_rjust(struct printbuf *buf)
283{
284 if (WARN_ON(!cur_tabstop(buf)))
285 return;
286
287 __prt_tab_rjust(buf);
288}
289
290/**
291 * bch2_prt_bytes_indented() - Print an array of chars, handling embedded control characters
292 *
293 * @out: output printbuf
294 * @str: string to print
295 * @count: number of bytes to print
296 *
297 * The following contol characters are handled as so:
298 * \n: prt_newline newline that obeys current indent level
299 * \t: prt_tab advance to next tabstop
300 * \r: prt_tab_rjust advance to next tabstop, with right justification
301 */
302void bch2_prt_bytes_indented(struct printbuf *out, const char *str, unsigned count)
303{
304 const char *unprinted_start = str;
305 const char *end = str + count;
306
307 if (!out->has_indent_or_tabstops || out->suppress_indent_tabstop_handling) {
308 prt_bytes(out, b: str, n: count);
309 return;
310 }
311
312 while (str != end) {
313 switch (*str) {
314 case '\n':
315 prt_bytes(out, b: unprinted_start, n: str - unprinted_start);
316 unprinted_start = str + 1;
317 bch2_prt_newline(buf: out);
318 break;
319 case '\t':
320 if (likely(cur_tabstop(out))) {
321 prt_bytes(out, b: unprinted_start, n: str - unprinted_start);
322 unprinted_start = str + 1;
323 __prt_tab(out);
324 }
325 break;
326 case '\r':
327 if (likely(cur_tabstop(out))) {
328 prt_bytes(out, b: unprinted_start, n: str - unprinted_start);
329 unprinted_start = str + 1;
330 __prt_tab_rjust(buf: out);
331 }
332 break;
333 }
334
335 str++;
336 }
337
338 prt_bytes(out, b: unprinted_start, n: str - unprinted_start);
339}
340
341/**
342 * bch2_prt_human_readable_u64() - Print out a u64 in human readable units
343 * @out: output printbuf
344 * @v: integer to print
345 *
346 * Units of 2^10 (default) or 10^3 are controlled via @out->si_units
347 */
348void bch2_prt_human_readable_u64(struct printbuf *out, u64 v)
349{
350 bch2_printbuf_make_room(out, extra: 10);
351 out->pos += string_get_size(size: v, blk_size: 1, units: !out->si_units,
352 buf: out->buf + out->pos,
353 len: printbuf_remaining_size(out));
354}
355
356/**
357 * bch2_prt_human_readable_s64() - Print out a s64 in human readable units
358 * @out: output printbuf
359 * @v: integer to print
360 *
361 * Units of 2^10 (default) or 10^3 are controlled via @out->si_units
362 */
363void bch2_prt_human_readable_s64(struct printbuf *out, s64 v)
364{
365 if (v < 0)
366 prt_char(out, c: '-');
367 bch2_prt_human_readable_u64(out, abs(v));
368}
369
370/**
371 * bch2_prt_units_u64() - Print out a u64 according to printbuf unit options
372 * @out: output printbuf
373 * @v: integer to print
374 *
375 * Units are either raw (default), or human reabable units (controlled via
376 * @buf->human_readable_units)
377 */
378void bch2_prt_units_u64(struct printbuf *out, u64 v)
379{
380 if (out->human_readable_units)
381 bch2_prt_human_readable_u64(out, v);
382 else
383 bch2_prt_printf(out, fmt: "%llu", v);
384}
385
386/**
387 * bch2_prt_units_s64() - Print out a s64 according to printbuf unit options
388 * @out: output printbuf
389 * @v: integer to print
390 *
391 * Units are either raw (default), or human reabable units (controlled via
392 * @buf->human_readable_units)
393 */
394void bch2_prt_units_s64(struct printbuf *out, s64 v)
395{
396 if (v < 0)
397 prt_char(out, c: '-');
398 bch2_prt_units_u64(out, abs(v));
399}
400
401void bch2_prt_string_option(struct printbuf *out,
402 const char * const list[],
403 size_t selected)
404{
405 size_t i;
406
407 for (i = 0; list[i]; i++)
408 bch2_prt_printf(out, fmt: i == selected ? "[%s] " : "%s ", list[i]);
409}
410
411void bch2_prt_bitflags(struct printbuf *out,
412 const char * const list[], u64 flags)
413{
414 unsigned bit, nr = 0;
415 bool first = true;
416
417 while (list[nr])
418 nr++;
419
420 while (flags && (bit = __ffs64(word: flags)) < nr) {
421 if (!first)
422 bch2_prt_printf(out, fmt: ",");
423 first = false;
424 bch2_prt_printf(out, fmt: "%s", list[bit]);
425 flags ^= BIT_ULL(bit);
426 }
427}
428
429void bch2_prt_bitflags_vector(struct printbuf *out,
430 const char * const list[],
431 unsigned long *v, unsigned nr)
432{
433 bool first = true;
434 unsigned i;
435
436 for (i = 0; i < nr; i++)
437 if (!list[i]) {
438 nr = i - 1;
439 break;
440 }
441
442 for_each_set_bit(i, v, nr) {
443 if (!first)
444 bch2_prt_printf(out, fmt: ",");
445 first = false;
446 bch2_prt_printf(out, fmt: "%s", list[i]);
447 }
448}
449

source code of linux/fs/bcachefs/printbuf.c