1 /* vi: set sw=4 ts=4: */
2 /*
3 * printf - format and print data
4 *
5 * Copyright 1999 Dave Cinege
6 * Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
7 *
8 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
9 */
10 /* Usage: printf format [argument...]
11 *
12 * A front end to the printf function that lets it be used from the shell.
13 *
14 * Backslash escapes:
15 *
16 * \" = double quote
17 * \\ = backslash
18 * \a = alert (bell)
19 * \b = backspace
20 * \c = produce no further output
21 * \f = form feed
22 * \n = new line
23 * \r = carriage return
24 * \t = horizontal tab
25 * \v = vertical tab
26 * \0ooo = octal number (ooo is 0 to 3 digits)
27 * \xhhh = hexadecimal number (hhh is 1 to 3 digits)
28 *
29 * Additional directive:
30 *
31 * %b = print an argument string, interpreting backslash escapes
32 *
33 * The 'format' argument is re-used as many times as necessary
34 * to convert all of the given arguments.
35 *
36 * David MacKenzie <djm@gnu.ai.mit.edu>
37 */
38 /* 19990508 Busy Boxed! Dave Cinege */
39
40 //config:config PRINTF
41 //config: bool "printf (3.8 kb)"
42 //config: default y
43 //config: help
44 //config: printf is used to format and print specified strings.
45 //config: It's similar to 'echo' except it has more options.
46
47 //applet:IF_PRINTF(APPLET_NOFORK(printf, printf, BB_DIR_USR_BIN, BB_SUID_DROP, printf))
48
49 //kbuild:lib-$(CONFIG_PRINTF) += printf.o
50 //kbuild:lib-$(CONFIG_ASH_PRINTF) += printf.o
51 //kbuild:lib-$(CONFIG_HUSH_PRINTF) += printf.o
52
53 //usage:#define printf_trivial_usage
54 //usage: "FORMAT [ARG]..."
55 //usage:#define printf_full_usage "\n\n"
56 //usage: "Format and print ARG(s) according to FORMAT (a-la C printf)"
57 //usage:
58 //usage:#define printf_example_usage
59 //usage: "$ printf \"Val=%d\\n\" 5\n"
60 //usage: "Val=5\n"
61
62 #include "libbb.h"
63
64 /* A note on bad input: neither bash 3.2 nor coreutils 6.10 stop on it.
65 * They report it:
66 * bash: printf: XXX: invalid number
67 * printf: XXX: expected a numeric value
68 * bash: printf: 123XXX: invalid number
69 * printf: 123XXX: value not completely converted
70 * but then they use 0 (or partially converted numeric prefix) as a value
71 * and continue. They exit with 1 in this case.
72 * Both accept insane field width/precision (e.g. %9999999999.9999999999d).
73 * Both print error message and assume 0 if %*.*f width/precision is "bad"
74 * (but negative numbers are not "bad").
75 * Both accept negative numbers for %u specifier.
76 *
77 * We try to be compatible.
78 */
79
80 typedef void FAST_FUNC (*converter)(const char *arg, void *result);
81
multiconvert(const char * arg,void * result,converter convert)82 static int multiconvert(const char *arg, void *result, converter convert)
83 {
84 if (*arg == '"' || *arg == '\'') {
85 arg = utoa((unsigned char)arg[1]);
86 }
87 errno = 0;
88 convert(arg, result);
89 if (errno) {
90 bb_error_msg("invalid number '%s'", arg);
91 return 1;
92 }
93 return 0;
94 }
95
conv_strtoull(const char * arg,void * result)96 static void FAST_FUNC conv_strtoull(const char *arg, void *result)
97 {
98 /* Allow leading '+' - bb_strtoull() by itself does not allow it,
99 * and probably shouldn't (other callers might require purely numeric
100 * inputs to be allowed.
101 */
102 if (arg[0] == '+')
103 arg++;
104 *(unsigned long long*)result = bb_strtoull(arg, NULL, 0);
105 /* both coreutils 6.10 and bash 3.2:
106 * $ printf '%x\n' -2
107 * fffffffffffffffe
108 * Mimic that:
109 */
110 if (errno) {
111 *(unsigned long long*)result = bb_strtoll(arg, NULL, 0);
112 }
113 }
conv_strtoll(const char * arg,void * result)114 static void FAST_FUNC conv_strtoll(const char *arg, void *result)
115 {
116 if (arg[0] == '+')
117 arg++;
118 *(long long*)result = bb_strtoll(arg, NULL, 0);
119 }
conv_strtod(const char * arg,void * result)120 static void FAST_FUNC conv_strtod(const char *arg, void *result)
121 {
122 char *end;
123 /* Well, this one allows leading whitespace... so what? */
124 /* What I like much less is that "-" accepted too! :( */
125 //TODO: needs setlocale(LC_NUMERIC, "C")?
126 *(double*)result = strtod(arg, &end);
127 if (end[0]) {
128 errno = ERANGE;
129 *(double*)result = 0;
130 }
131 }
132
133 /* Callers should check errno to detect errors */
my_xstrtoull(const char * arg)134 static unsigned long long my_xstrtoull(const char *arg)
135 {
136 unsigned long long result;
137 if (multiconvert(arg, &result, conv_strtoull))
138 result = 0;
139 return result;
140 }
my_xstrtoll(const char * arg)141 static long long my_xstrtoll(const char *arg)
142 {
143 long long result;
144 if (multiconvert(arg, &result, conv_strtoll))
145 result = 0;
146 return result;
147 }
my_xstrtod(const char * arg)148 static double my_xstrtod(const char *arg)
149 {
150 double result;
151 multiconvert(arg, &result, conv_strtod);
152 return result;
153 }
154
155 /* Handles %b; return 1 if output is to be short-circuited by \c */
print_esc_string(const char * str)156 static int print_esc_string(const char *str)
157 {
158 char c;
159 while ((c = *str) != '\0') {
160 str++;
161 if (c == '\\') {
162 /* %b also accepts 4-digit octals of the form \0### */
163 if (*str == '0') {
164 if ((unsigned char)(str[1] - '0') < 8) {
165 /* 2nd char is 0..7: skip leading '0' */
166 str++;
167 }
168 }
169 else if (*str == 'c') {
170 return 1;
171 }
172 {
173 /* optimization: don't force arg to be on-stack,
174 * use another variable for that. */
175 const char *z = str;
176 c = bb_process_escape_sequence(&z);
177 str = z;
178 }
179 }
180 putchar(c);
181 }
182
183 return 0;
184 }
185
print_direc(char * format,unsigned fmt_length,int field_width,int precision,const char * argument)186 static void print_direc(char *format, unsigned fmt_length,
187 int field_width, int precision,
188 const char *argument)
189 {
190 long long llv;
191 double dv;
192 char saved;
193 char *have_prec, *have_width;
194
195 saved = format[fmt_length];
196 format[fmt_length] = '\0';
197
198 have_prec = strstr(format, ".*");
199 have_width = strchr(format, '*');
200 if (have_width - 1 == have_prec)
201 have_width = NULL;
202
203 /* multiconvert sets errno = 0, but %s needs it cleared */
204 errno = 0;
205
206 switch (format[fmt_length - 1]) {
207 case 'c':
208 printf(format, *argument);
209 break;
210 case 'd':
211 case 'i':
212 llv = my_xstrtoll(skip_whitespace(argument));
213 print_long:
214 if (!have_width) {
215 if (!have_prec)
216 printf(format, llv);
217 else
218 printf(format, precision, llv);
219 } else {
220 if (!have_prec)
221 printf(format, field_width, llv);
222 else
223 printf(format, field_width, precision, llv);
224 }
225 break;
226 case 'o':
227 case 'u':
228 case 'x':
229 case 'X':
230 llv = my_xstrtoull(skip_whitespace(argument));
231 /* cheat: unsigned long and long have same width, so... */
232 goto print_long;
233 case 's':
234 /* Are char* and long long the same? */
235 if (sizeof(argument) == sizeof(llv)) {
236 llv = (long long)(ptrdiff_t)argument;
237 goto print_long;
238 } else {
239 /* Hope compiler will optimize it out by moving call
240 * instruction after the ifs... */
241 if (!have_width) {
242 if (!have_prec)
243 printf(format, argument, /*unused:*/ argument, argument);
244 else
245 printf(format, precision, argument, /*unused:*/ argument);
246 } else {
247 if (!have_prec)
248 printf(format, field_width, argument, /*unused:*/ argument);
249 else
250 printf(format, field_width, precision, argument);
251 }
252 break;
253 }
254 case 'f':
255 case 'e':
256 case 'E':
257 case 'g':
258 case 'G':
259 dv = my_xstrtod(argument);
260 if (!have_width) {
261 if (!have_prec)
262 printf(format, dv);
263 else
264 printf(format, precision, dv);
265 } else {
266 if (!have_prec)
267 printf(format, field_width, dv);
268 else
269 printf(format, field_width, precision, dv);
270 }
271 break;
272 } /* switch */
273
274 format[fmt_length] = saved;
275 }
276
277 /* Handle params for "%*.*f". Negative numbers are ok (compat). */
get_width_prec(const char * str)278 static int get_width_prec(const char *str)
279 {
280 int v = bb_strtoi(str, NULL, 10);
281 if (errno) {
282 bb_error_msg("invalid number '%s'", str);
283 v = 0;
284 }
285 return v;
286 }
287
288 /* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
289 Return advanced ARGV. */
print_formatted(char * f,char ** argv,int * conv_err)290 static char **print_formatted(char *f, char **argv, int *conv_err)
291 {
292 char *direc_start; /* Start of % directive. */
293 unsigned direc_length; /* Length of % directive. */
294 int field_width; /* Arg to first '*' */
295 int precision; /* Arg to second '*' */
296 char **saved_argv = argv;
297
298 for (; *f; ++f) {
299 switch (*f) {
300 case '%':
301 direc_start = f++;
302 direc_length = 1;
303 field_width = precision = 0;
304 if (*f == '%') {
305 bb_putchar('%');
306 break;
307 }
308 if (*f == 'b') {
309 if (*argv) {
310 if (print_esc_string(*argv))
311 return saved_argv; /* causes main() to exit */
312 ++argv;
313 }
314 break;
315 }
316 while (*f && strchr("-+ #0", *f)) {
317 ++f;
318 ++direc_length;
319 }
320 if (*f == '*') {
321 ++f;
322 ++direc_length;
323 if (*argv)
324 field_width = get_width_prec(*argv++);
325 } else {
326 while (isdigit(*f)) {
327 ++f;
328 ++direc_length;
329 }
330 }
331 if (*f == '.') {
332 ++f;
333 ++direc_length;
334 if (*f == '*') {
335 ++f;
336 ++direc_length;
337 if (*argv)
338 precision = get_width_prec(*argv++);
339 } else {
340 while (isdigit(*f)) {
341 ++f;
342 ++direc_length;
343 }
344 }
345 }
346
347 /* Remove "lLhz" size modifiers, repeatedly.
348 * bash does not like "%lld", but coreutils
349 * happily takes even "%Llllhhzhhzd"!
350 * We are permissive like coreutils */
351 while ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z') {
352 overlapping_strcpy(f, f + 1);
353 }
354 /* Add "ll" if integer modifier, then print */
355 {
356 static const char format_chars[] ALIGN1 = "diouxXfeEgGcs";
357 char *p = strchr(format_chars, *f);
358 /* needed - try "printf %" without it */
359 if (p == NULL || *f == '\0') {
360 bb_error_msg("%s: invalid format", direc_start);
361 /* causes main() to exit with error */
362 return saved_argv - 1;
363 }
364 ++direc_length;
365 if (p - format_chars <= 5) {
366 /* it is one of "diouxX" */
367 p = xmalloc(direc_length + 3);
368 memcpy(p, direc_start, direc_length);
369 p[direc_length + 1] = p[direc_length - 1];
370 p[direc_length - 1] = 'l';
371 p[direc_length] = 'l';
372 //bb_error_msg("<%s>", p);
373 direc_length += 2;
374 direc_start = p;
375 } else {
376 p = NULL;
377 }
378 if (*argv) {
379 print_direc(direc_start, direc_length, field_width,
380 precision, *argv++);
381 } else {
382 print_direc(direc_start, direc_length, field_width,
383 precision, "");
384 }
385 *conv_err |= errno;
386 free(p);
387 }
388 break;
389 case '\\':
390 if (*++f == 'c') {
391 return saved_argv; /* causes main() to exit */
392 }
393 bb_putchar(bb_process_escape_sequence((const char **)&f));
394 f--;
395 break;
396 default:
397 putchar(*f);
398 }
399 }
400
401 return argv;
402 }
403
printf_main(int argc UNUSED_PARAM,char ** argv)404 int printf_main(int argc UNUSED_PARAM, char **argv)
405 {
406 int conv_err;
407 char *format;
408 char **argv2;
409
410 /* We must check that stdout is not closed.
411 * The reason for this is highly non-obvious.
412 * printf_main is used from shell.
413 * Shell must correctly handle 'printf "%s" foo'
414 * if stdout is closed. With stdio, output gets shoveled into
415 * stdout buffer, and even fflush cannot clear it out. It seems that
416 * even if libc receives EBADF on write attempts, it feels determined
417 * to output data no matter what. So it will try later,
418 * and possibly will clobber future output. Not good. */
419 // TODO: check fcntl() & O_ACCMODE == O_WRONLY or O_RDWR?
420 if (fcntl(1, F_GETFL) == -1)
421 return 1; /* match coreutils 6.10 (sans error msg to stderr) */
422 //if (dup2(1, 1) != 1) - old way
423 // return 1;
424
425 /* bash builtin errors out on "printf '-%s-\n' foo",
426 * coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
427 * We will mimic coreutils. */
428 if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && !argv[1][2])
429 argv++;
430 if (!argv[1]) {
431 if (ENABLE_ASH_PRINTF
432 && applet_name[0] != 'p'
433 ) {
434 bb_simple_error_msg("usage: printf FORMAT [ARGUMENT...]");
435 return 2; /* bash compat */
436 }
437 bb_show_usage();
438 }
439
440 format = argv[1];
441 argv2 = argv + 2;
442
443 conv_err = 0;
444 do {
445 argv = argv2;
446 argv2 = print_formatted(format, argv, &conv_err);
447 } while (argv2 > argv && *argv2);
448
449 /* coreutils compat (bash doesn't do this):
450 if (*argv)
451 fprintf(stderr, "excess args ignored");
452 */
453
454 return (argv2 < argv) /* if true, print_formatted errored out */
455 || conv_err; /* print_formatted saw invalid number */
456 }
457