xref: /linux/tools/include/nolibc/stdio.h (revision 7fc2cd2e4b398c57c9cf961cfea05eadbf34c05c) 
1 /* SPDX-License-Identifier: LGPL-2.1 OR MIT */
2 /*
3  * minimal stdio function definitions for NOLIBC
4  * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
5  */
6 
7 /* make sure to include all global symbols */
8 #include "nolibc.h"
9 
10 #ifndef _NOLIBC_STDIO_H
11 #define _NOLIBC_STDIO_H
12 
13 #include "std.h"
14 #include "arch.h"
15 #include "errno.h"
16 #include "fcntl.h"
17 #include "types.h"
18 #include "sys.h"
19 #include "stdarg.h"
20 #include "stdlib.h"
21 #include "string.h"
22 #include "compiler.h"
23 
24 static const char *strerror(int errnum);
25 
26 #ifndef EOF
27 #define EOF (-1)
28 #endif
29 
30 /* Buffering mode used by setvbuf.  */
31 #define _IOFBF 0	/* Fully buffered. */
32 #define _IOLBF 1	/* Line buffered. */
33 #define _IONBF 2	/* No buffering. */
34 
35 /* just define FILE as a non-empty type. The value of the pointer gives
36  * the FD: FILE=~fd for fd>=0 or NULL for fd<0. This way positive FILE
37  * are immediately identified as abnormal entries (i.e. possible copies
38  * of valid pointers to something else).
39  */
40 typedef struct FILE {
41 	char dummy[1];
42 } FILE;
43 
44 static __attribute__((unused)) FILE* const stdin  = (FILE*)(intptr_t)~STDIN_FILENO;
45 static __attribute__((unused)) FILE* const stdout = (FILE*)(intptr_t)~STDOUT_FILENO;
46 static __attribute__((unused)) FILE* const stderr = (FILE*)(intptr_t)~STDERR_FILENO;
47 
48 /* provides a FILE* equivalent of fd. The mode is ignored. */
49 static __attribute__((unused))
50 FILE *fdopen(int fd, const char *mode __attribute__((unused)))
51 {
52 	if (fd < 0) {
53 		SET_ERRNO(EBADF);
54 		return NULL;
55 	}
56 	return (FILE*)(intptr_t)~fd;
57 }
58 
59 static __attribute__((unused))
60 FILE *fopen(const char *pathname, const char *mode)
61 {
62 	int flags, fd;
63 
64 	switch (*mode) {
65 	case 'r':
66 		flags = O_RDONLY;
67 		break;
68 	case 'w':
69 		flags = O_WRONLY | O_CREAT | O_TRUNC;
70 		break;
71 	case 'a':
72 		flags = O_WRONLY | O_CREAT | O_APPEND;
73 		break;
74 	default:
75 		SET_ERRNO(EINVAL); return NULL;
76 	}
77 
78 	if (mode[1] == '+')
79 		flags = (flags & ~(O_RDONLY | O_WRONLY)) | O_RDWR;
80 
81 	fd = open(pathname, flags, 0666);
82 	return fdopen(fd, mode);
83 }
84 
85 /* provides the fd of stream. */
86 static __attribute__((unused))
87 int fileno(FILE *stream)
88 {
89 	intptr_t i = (intptr_t)stream;
90 
91 	if (i >= 0) {
92 		SET_ERRNO(EBADF);
93 		return -1;
94 	}
95 	return ~i;
96 }
97 
98 /* flush a stream. */
99 static __attribute__((unused))
100 int fflush(FILE *stream)
101 {
102 	intptr_t i = (intptr_t)stream;
103 
104 	/* NULL is valid here. */
105 	if (i > 0) {
106 		SET_ERRNO(EBADF);
107 		return -1;
108 	}
109 
110 	/* Don't do anything, nolibc does not support buffering. */
111 	return 0;
112 }
113 
114 /* flush a stream. */
115 static __attribute__((unused))
116 int fclose(FILE *stream)
117 {
118 	intptr_t i = (intptr_t)stream;
119 
120 	if (i >= 0) {
121 		SET_ERRNO(EBADF);
122 		return -1;
123 	}
124 
125 	if (close(~i))
126 		return EOF;
127 
128 	return 0;
129 }
130 
131 /* getc(), fgetc(), getchar() */
132 
133 #define getc(stream) fgetc(stream)
134 
135 static __attribute__((unused))
136 int fgetc(FILE* stream)
137 {
138 	unsigned char ch;
139 
140 	if (read(fileno(stream), &ch, 1) <= 0)
141 		return EOF;
142 	return ch;
143 }
144 
145 static __attribute__((unused))
146 int getchar(void)
147 {
148 	return fgetc(stdin);
149 }
150 
151 
152 /* putc(), fputc(), putchar() */
153 
154 #define putc(c, stream) fputc(c, stream)
155 
156 static __attribute__((unused))
157 int fputc(int c, FILE* stream)
158 {
159 	unsigned char ch = c;
160 
161 	if (write(fileno(stream), &ch, 1) <= 0)
162 		return EOF;
163 	return ch;
164 }
165 
166 static __attribute__((unused))
167 int putchar(int c)
168 {
169 	return fputc(c, stdout);
170 }
171 
172 
173 /* fwrite(), puts(), fputs(). Note that puts() emits '\n' but not fputs(). */
174 
175 /* internal fwrite()-like function which only takes a size and returns 0 on
176  * success or EOF on error. It automatically retries on short writes.
177  */
178 static __attribute__((unused))
179 int _fwrite(const void *buf, size_t size, FILE *stream)
180 {
181 	ssize_t ret;
182 	int fd = fileno(stream);
183 
184 	while (size) {
185 		ret = write(fd, buf, size);
186 		if (ret <= 0)
187 			return EOF;
188 		size -= ret;
189 		buf += ret;
190 	}
191 	return 0;
192 }
193 
194 static __attribute__((unused))
195 size_t fwrite(const void *s, size_t size, size_t nmemb, FILE *stream)
196 {
197 	size_t written;
198 
199 	for (written = 0; written < nmemb; written++) {
200 		if (_fwrite(s, size, stream) != 0)
201 			break;
202 		s += size;
203 	}
204 	return written;
205 }
206 
207 static __attribute__((unused))
208 int fputs(const char *s, FILE *stream)
209 {
210 	return _fwrite(s, strlen(s), stream);
211 }
212 
213 static __attribute__((unused))
214 int puts(const char *s)
215 {
216 	if (fputs(s, stdout) == EOF)
217 		return EOF;
218 	return putchar('\n');
219 }
220 
221 
222 /* fgets() */
223 static __attribute__((unused))
224 char *fgets(char *s, int size, FILE *stream)
225 {
226 	int ofs;
227 	int c;
228 
229 	for (ofs = 0; ofs + 1 < size;) {
230 		c = fgetc(stream);
231 		if (c == EOF)
232 			break;
233 		s[ofs++] = c;
234 		if (c == '\n')
235 			break;
236 	}
237 	if (ofs < size)
238 		s[ofs] = 0;
239 	return ofs ? s : NULL;
240 }
241 
242 
243 /* minimal printf(). It supports the following formats:
244  *  - %[l*]{d,u,c,x,p}
245  *  - %s
246  *  - unknown modifiers are ignored.
247  */
248 typedef int (*__nolibc_printf_cb)(intptr_t state, const char *buf, size_t size);
249 
250 static __attribute__((unused, format(printf, 4, 0)))
251 int __nolibc_printf(__nolibc_printf_cb cb, intptr_t state, size_t n, const char *fmt, va_list args)
252 {
253 	char escape, lpref, c;
254 	unsigned long long v;
255 	unsigned int written, width;
256 	size_t len, ofs, w;
257 	char tmpbuf[21];
258 	const char *outstr;
259 
260 	written = ofs = escape = lpref = 0;
261 	while (1) {
262 		c = fmt[ofs++];
263 		width = 0;
264 
265 		if (escape) {
266 			/* we're in an escape sequence, ofs == 1 */
267 			escape = 0;
268 
269 			/* width */
270 			while (c >= '0' && c <= '9') {
271 				width *= 10;
272 				width += c - '0';
273 
274 				c = fmt[ofs++];
275 			}
276 
277 			if (c == 'c' || c == 'd' || c == 'u' || c == 'x' || c == 'p') {
278 				char *out = tmpbuf;
279 
280 				if (c == 'p')
281 					v = va_arg(args, unsigned long);
282 				else if (lpref) {
283 					if (lpref > 1)
284 						v = va_arg(args, unsigned long long);
285 					else
286 						v = va_arg(args, unsigned long);
287 				} else
288 					v = va_arg(args, unsigned int);
289 
290 				if (c == 'd') {
291 					/* sign-extend the value */
292 					if (lpref == 0)
293 						v = (long long)(int)v;
294 					else if (lpref == 1)
295 						v = (long long)(long)v;
296 				}
297 
298 				switch (c) {
299 				case 'c':
300 					out[0] = v;
301 					out[1] = 0;
302 					break;
303 				case 'd':
304 					i64toa_r(v, out);
305 					break;
306 				case 'u':
307 					u64toa_r(v, out);
308 					break;
309 				case 'p':
310 					*(out++) = '0';
311 					*(out++) = 'x';
312 					__nolibc_fallthrough;
313 				default: /* 'x' and 'p' above */
314 					u64toh_r(v, out);
315 					break;
316 				}
317 				outstr = tmpbuf;
318 			}
319 			else if (c == 's') {
320 				outstr = va_arg(args, char *);
321 				if (!outstr)
322 					outstr="(null)";
323 			}
324 			else if (c == 'm') {
325 #ifdef NOLIBC_IGNORE_ERRNO
326 				outstr = "unknown error";
327 #else
328 				outstr = strerror(errno);
329 #endif /* NOLIBC_IGNORE_ERRNO */
330 			}
331 			else if (c == '%') {
332 				/* queue it verbatim */
333 				continue;
334 			}
335 			else {
336 				/* modifiers or final 0 */
337 				if (c == 'l') {
338 					/* long format prefix, maintain the escape */
339 					lpref++;
340 				} else if (c == 'j') {
341 					lpref = 2;
342 				}
343 				escape = 1;
344 				goto do_escape;
345 			}
346 			len = strlen(outstr);
347 			goto flush_str;
348 		}
349 
350 		/* not an escape sequence */
351 		if (c == 0 || c == '%') {
352 			/* flush pending data on escape or end */
353 			escape = 1;
354 			lpref = 0;
355 			outstr = fmt;
356 			len = ofs - 1;
357 		flush_str:
358 			if (n) {
359 				w = len < n ? len : n;
360 				n -= w;
361 				while (width-- > w) {
362 					if (cb(state, " ", 1) != 0)
363 						return -1;
364 					written += 1;
365 				}
366 				if (cb(state, outstr, w) != 0)
367 					return -1;
368 			}
369 
370 			written += len;
371 		do_escape:
372 			if (c == 0)
373 				break;
374 			fmt += ofs;
375 			ofs = 0;
376 			continue;
377 		}
378 
379 		/* literal char, just queue it */
380 	}
381 	return written;
382 }
383 
384 static int __nolibc_fprintf_cb(intptr_t state, const char *buf, size_t size)
385 {
386 	return _fwrite(buf, size, (FILE *)state);
387 }
388 
389 static __attribute__((unused, format(printf, 2, 0)))
390 int vfprintf(FILE *stream, const char *fmt, va_list args)
391 {
392 	return __nolibc_printf(__nolibc_fprintf_cb, (intptr_t)stream, SIZE_MAX, fmt, args);
393 }
394 
395 static __attribute__((unused, format(printf, 1, 0)))
396 int vprintf(const char *fmt, va_list args)
397 {
398 	return vfprintf(stdout, fmt, args);
399 }
400 
401 static __attribute__((unused, format(printf, 2, 3)))
402 int fprintf(FILE *stream, const char *fmt, ...)
403 {
404 	va_list args;
405 	int ret;
406 
407 	va_start(args, fmt);
408 	ret = vfprintf(stream, fmt, args);
409 	va_end(args);
410 	return ret;
411 }
412 
413 static __attribute__((unused, format(printf, 1, 2)))
414 int printf(const char *fmt, ...)
415 {
416 	va_list args;
417 	int ret;
418 
419 	va_start(args, fmt);
420 	ret = vfprintf(stdout, fmt, args);
421 	va_end(args);
422 	return ret;
423 }
424 
425 static __attribute__((unused, format(printf, 2, 0)))
426 int vdprintf(int fd, const char *fmt, va_list args)
427 {
428 	FILE *stream;
429 
430 	stream = fdopen(fd, NULL);
431 	if (!stream)
432 		return -1;
433 	/* Technically 'stream' is leaked, but as it's only a wrapper around 'fd' that is fine */
434 	return vfprintf(stream, fmt, args);
435 }
436 
437 static __attribute__((unused, format(printf, 2, 3)))
438 int dprintf(int fd, const char *fmt, ...)
439 {
440 	va_list args;
441 	int ret;
442 
443 	va_start(args, fmt);
444 	ret = vdprintf(fd, fmt, args);
445 	va_end(args);
446 
447 	return ret;
448 }
449 
450 static int __nolibc_sprintf_cb(intptr_t _state, const char *buf, size_t size)
451 {
452 	char **state = (char **)_state;
453 
454 	memcpy(*state, buf, size);
455 	*state += size;
456 	return 0;
457 }
458 
459 static __attribute__((unused, format(printf, 3, 0)))
460 int vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
461 {
462 	char *state = buf;
463 	int ret;
464 
465 	ret = __nolibc_printf(__nolibc_sprintf_cb, (intptr_t)&state, size, fmt, args);
466 	if (ret < 0)
467 		return ret;
468 	buf[(size_t)ret < size ? (size_t)ret : size - 1] = '\0';
469 	return ret;
470 }
471 
472 static __attribute__((unused, format(printf, 3, 4)))
473 int snprintf(char *buf, size_t size, const char *fmt, ...)
474 {
475 	va_list args;
476 	int ret;
477 
478 	va_start(args, fmt);
479 	ret = vsnprintf(buf, size, fmt, args);
480 	va_end(args);
481 
482 	return ret;
483 }
484 
485 static __attribute__((unused, format(printf, 2, 0)))
486 int vsprintf(char *buf, const char *fmt, va_list args)
487 {
488 	return vsnprintf(buf, SIZE_MAX, fmt, args);
489 }
490 
491 static __attribute__((unused, format(printf, 2, 3)))
492 int sprintf(char *buf, const char *fmt, ...)
493 {
494 	va_list args;
495 	int ret;
496 
497 	va_start(args, fmt);
498 	ret = vsprintf(buf, fmt, args);
499 	va_end(args);
500 
501 	return ret;
502 }
503 
504 static __attribute__((unused))
505 int vsscanf(const char *str, const char *format, va_list args)
506 {
507 	uintmax_t uval;
508 	intmax_t ival;
509 	int base;
510 	char *endptr;
511 	int matches;
512 	int lpref;
513 
514 	matches = 0;
515 
516 	while (1) {
517 		if (*format == '%') {
518 			/* start of pattern */
519 			lpref = 0;
520 			format++;
521 
522 			if (*format == 'l') {
523 				/* same as in printf() */
524 				lpref = 1;
525 				format++;
526 				if (*format == 'l') {
527 					lpref = 2;
528 					format++;
529 				}
530 			}
531 
532 			if (*format == '%') {
533 				/* literal % */
534 				if ('%' != *str)
535 					goto done;
536 				str++;
537 				format++;
538 				continue;
539 			} else if (*format == 'd') {
540 				ival = strtoll(str, &endptr, 10);
541 				if (lpref == 0)
542 					*va_arg(args, int *) = ival;
543 				else if (lpref == 1)
544 					*va_arg(args, long *) = ival;
545 				else if (lpref == 2)
546 					*va_arg(args, long long *) = ival;
547 			} else if (*format == 'u' || *format == 'x' || *format == 'X') {
548 				base = *format == 'u' ? 10 : 16;
549 				uval = strtoull(str, &endptr, base);
550 				if (lpref == 0)
551 					*va_arg(args, unsigned int *) = uval;
552 				else if (lpref == 1)
553 					*va_arg(args, unsigned long *) = uval;
554 				else if (lpref == 2)
555 					*va_arg(args, unsigned long long *) = uval;
556 			} else if (*format == 'p') {
557 				*va_arg(args, void **) = (void *)strtoul(str, &endptr, 16);
558 			} else {
559 				SET_ERRNO(EILSEQ);
560 				goto done;
561 			}
562 
563 			format++;
564 			str = endptr;
565 			matches++;
566 
567 		} else if (*format == '\0') {
568 			goto done;
569 		} else if (isspace(*format)) {
570 			/* skip spaces in format and str */
571 			while (isspace(*format))
572 				format++;
573 			while (isspace(*str))
574 				str++;
575 		} else if (*format == *str) {
576 			/* literal match */
577 			format++;
578 			str++;
579 		} else {
580 			if (!matches)
581 				matches = EOF;
582 			goto done;
583 		}
584 	}
585 
586 done:
587 	return matches;
588 }
589 
590 static __attribute__((unused, format(scanf, 2, 3)))
591 int sscanf(const char *str, const char *format, ...)
592 {
593 	va_list args;
594 	int ret;
595 
596 	va_start(args, format);
597 	ret = vsscanf(str, format, args);
598 	va_end(args);
599 	return ret;
600 }
601 
602 static __attribute__((unused))
603 void perror(const char *msg)
604 {
605 #ifdef NOLIBC_IGNORE_ERRNO
606 	fprintf(stderr, "%s%sunknown error\n", (msg && *msg) ? msg : "", (msg && *msg) ? ": " : "");
607 #else
608 	fprintf(stderr, "%s%serrno=%d\n", (msg && *msg) ? msg : "", (msg && *msg) ? ": " : "", errno);
609 #endif
610 }
611 
612 static __attribute__((unused))
613 int setvbuf(FILE *stream __attribute__((unused)),
614 	    char *buf __attribute__((unused)),
615 	    int mode,
616 	    size_t size __attribute__((unused)))
617 {
618 	/*
619 	 * nolibc does not support buffering so this is a nop. Just check mode
620 	 * is valid as required by the spec.
621 	 */
622 	switch (mode) {
623 	case _IOFBF:
624 	case _IOLBF:
625 	case _IONBF:
626 		break;
627 	default:
628 		return EOF;
629 	}
630 
631 	return 0;
632 }
633 
634 static __attribute__((unused))
635 const char *strerror(int errno)
636 {
637 	static char buf[18] = "errno=";
638 
639 	i64toa_r(errno, &buf[6]);
640 
641 	return buf;
642 }
643 
644 #endif /* _NOLIBC_STDIO_H */
645