busybox/coreutils/printf.c
2008-07-22 20:16:55 +00:00

377 lines
9.1 KiB
C

/* vi: set sw=4 ts=4: */
/* printf - format and print data
Copyright 1999 Dave Cinege
Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
Licensed under GPL v2 or later, see file LICENSE in this tarball for details.
*/
/* Usage: printf format [argument...]
A front end to the printf function that lets it be used from the shell.
Backslash escapes:
\" = double quote
\\ = backslash
\a = alert (bell)
\b = backspace
\c = produce no further output
\f = form feed
\n = new line
\r = carriage return
\t = horizontal tab
\v = vertical tab
\0ooo = octal number (ooo is 0 to 3 digits)
\xhhh = hexadecimal number (hhh is 1 to 3 digits)
Additional directive:
%b = print an argument string, interpreting backslash escapes
The 'format' argument is re-used as many times as necessary
to convert all of the given arguments.
David MacKenzie <djm@gnu.ai.mit.edu>
*/
// 19990508 Busy Boxed! Dave Cinege
#include "libbb.h"
/* A note on bad input: neither bash 3.2 nor coreutils 6.10 stop on it.
* They report it:
* bash: printf: XXX: invalid number
* printf: XXX: expected a numeric value
* bash: printf: 123XXX: invalid number
* printf: 123XXX: value not completely converted
* but then they use 0 (or partially converted numeric prefix) as a value
* and continue. They exit with 1 in this case.
* Both accept insane field width/precision (e.g. %9999999999.9999999999d).
* Both print error message and assume 0 if %*.*f width/precision is "bad"
* (but negative numbers are not "bad").
* Both accept negative numbers for %u specifier.
*
* We try to be compatible. We are not compatible here:
* - we do not accept -NUM for %u
* - exit code is 0 even if "invalid number" was seen (FIXME)
* See "if (errno)" checks in the code below.
*/
typedef void FAST_FUNC (*converter)(const char *arg, void *result);
static int multiconvert(const char *arg, void *result, converter convert)
{
if (*arg == '"' || *arg == '\'') {
arg = utoa((unsigned char)arg[1]);
}
errno = 0;
convert(arg, result);
if (errno) {
bb_error_msg("%s: invalid number", arg);
return 1;
}
return 0;
}
static void FAST_FUNC conv_strtoul(const char *arg, void *result)
{
*(unsigned long*)result = bb_strtoul(arg, NULL, 0);
}
static void FAST_FUNC conv_strtol(const char *arg, void *result)
{
*(long*)result = bb_strtol(arg, NULL, 0);
}
static void FAST_FUNC conv_strtod(const char *arg, void *result)
{
char *end;
/* Well, this one allows leading whitespace... so what? */
/* What I like much less is that "-" accepted too! :( */
*(double*)result = strtod(arg, &end);
if (end[0]) {
errno = ERANGE;
*(double*)result = 0;
}
}
/* Callers should check errno to detect errors */
static unsigned long my_xstrtoul(const char *arg)
{
unsigned long result;
if (multiconvert(arg, &result, conv_strtoul))
result = 0;
return result;
}
static long my_xstrtol(const char *arg)
{
long result;
if (multiconvert(arg, &result, conv_strtol))
result = 0;
return result;
}
static double my_xstrtod(const char *arg)
{
double result;
multiconvert(arg, &result, conv_strtod);
return result;
}
static void print_esc_string(char *str)
{
while (*str) {
if (*str == '\\') {
str++;
bb_putchar(bb_process_escape_sequence((const char **)&str));
} else {
bb_putchar(*str);
str++;
}
}
}
static void print_direc(char *format, unsigned fmt_length,
int field_width, int precision,
const char *argument)
{
long lv;
double dv;
char saved;
char *have_prec, *have_width;
have_prec = strstr(format, ".*");
have_width = strchr(format, '*');
if (have_width - 1 == have_prec)
have_width = NULL;
saved = format[fmt_length];
format[fmt_length] = '\0';
switch (format[fmt_length - 1]) {
case 'c':
printf(format, *argument);
break;
case 'd':
case 'i':
lv = my_xstrtol(argument);
print_long:
/* if (errno) return; - see comment at the top */
if (!have_width) {
if (!have_prec)
printf(format, lv);
else
printf(format, precision, lv);
} else {
if (!have_prec)
printf(format, field_width, lv);
else
printf(format, field_width, precision, lv);
}
break;
case 'o':
case 'u':
case 'x':
case 'X':
lv = my_xstrtoul(argument);
/* cheat: unsigned long and long have same width, so... */
goto print_long;
case 's':
/* Are char* and long the same? (true for most arches) */
if (sizeof(argument) == sizeof(lv)) {
lv = (long)(ptrdiff_t)argument;
goto print_long;
} else { /* Hope compiler will optimize it out */
if (!have_width) {
if (!have_prec)
printf(format, argument);
else
printf(format, precision, argument);
} else {
if (!have_prec)
printf(format, field_width, argument);
else
printf(format, field_width, precision, argument);
}
break;
}
case 'f':
case 'e':
case 'E':
case 'g':
case 'G':
dv = my_xstrtod(argument);
/* if (errno) return; */
if (!have_width) {
if (!have_prec)
printf(format, dv);
else
printf(format, precision, dv);
} else {
if (!have_prec)
printf(format, field_width, dv);
else
printf(format, field_width, precision, dv);
}
break;
} /* switch */
format[fmt_length] = saved;
}
/* Handle params for "%*.*f". Negative numbers are ok (compat). */
static int get_width_prec(const char *str)
{
int v = bb_strtoi(str, NULL, 10);
if (errno) {
bb_error_msg("%s: invalid number", str);
v = 0;
}
return v;
}
/* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
Return advanced ARGV. */
static char **print_formatted(char *f, char **argv)
{
char *direc_start; /* Start of % directive. */
unsigned direc_length; /* Length of % directive. */
int field_width; /* Arg to first '*' */
int precision; /* Arg to second '*' */
char **saved_argv = argv;
for (; *f; ++f) {
switch (*f) {
case '%':
direc_start = f++;
direc_length = 1;
field_width = precision = 0;
if (*f == '%') {
bb_putchar('%');
break;
}
if (*f == 'b') {
if (*argv) {
print_esc_string(*argv);
++argv;
}
break;
}
if (strchr("-+ #", *f)) {
++f;
++direc_length;
}
if (*f == '*') {
++f;
++direc_length;
if (*argv)
field_width = get_width_prec(*argv++);
} else {
while (isdigit(*f)) {
++f;
++direc_length;
}
}
if (*f == '.') {
++f;
++direc_length;
if (*f == '*') {
++f;
++direc_length;
if (*argv)
precision = get_width_prec(*argv++);
} else {
while (isdigit(*f)) {
++f;
++direc_length;
}
}
}
/* Remove size modifiers - "%Ld" would try to printf
* long long, we pass long, and it spews garbage */
if ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z') {
overlapping_strcpy(f, f + 1);
}
//FIXME: actually, the same happens with bare "%d":
//it printfs an int, but we pass long!
//What saves us is that on most arches stack slot
//is pointer-sized -> long-sized -> ints are promoted to longs
// for variadic functions -> printf("%d", int_v) is in reality
// indistinqushable from printf("%d", long_v) ->
// since printf("%d", int_v) works, printf("%d", long_v) has to work.
//But "clean" solution would be to add "l" to d,i,o,x,X.
//Probably makes sense to go all the way to "ll" then.
//Coreutils support long long-sized arguments.
/* needed - try "printf %" without it */
if (!strchr("diouxXfeEgGcs", *f)) {
bb_error_msg("%s: invalid format", direc_start);
/* causes main() to exit with error */
return saved_argv - 1;
}
++direc_length;
if (*argv) {
print_direc(direc_start, direc_length, field_width,
precision, *argv);
++argv;
} else {
print_direc(direc_start, direc_length, field_width,
precision, "");
}
/* if (errno) return saved_argv - 1; */
break;
case '\\':
if (*++f == 'c') {
return saved_argv; /* causes main() to exit */
}
bb_putchar(bb_process_escape_sequence((const char **)&f));
f--;
break;
default:
bb_putchar(*f);
}
}
return argv;
}
int printf_main(int argc UNUSED_PARAM, char **argv)
{
char *format;
char **argv2;
/* We must check that stdout is not closed.
* The reason for this is highly non-obvious.
* printf_main is used from shell.
* Shell must correctly handle 'printf "%s" foo'
* if stdout is closed. With stdio, output gets shoveled into
* stdout buffer, and even fflush cannot clear it out. It seems that
* even if libc receives EBADF on write attempts, it feels determined
* to output data no matter what. So it will try later,
* and possibly will clobber future output. Not good. */
if (dup2(1, 1) != 1)
return -1;
/* bash builtin errors out on "printf '-%s-\n' foo",
* coreutils-6.9 works. Both work with "printf -- '-%s-\n' foo".
* We will mimic coreutils. */
if (argv[1] && argv[1][0] == '-' && argv[1][1] == '-' && !argv[1][2])
argv++;
if (!argv[1])
bb_show_usage();
format = argv[1];
argv2 = argv + 2;
do {
argv = argv2;
argv2 = print_formatted(format, argv);
} while (argv2 > argv && *argv2);
/* coreutils compat (bash doesn't do this):
if (*argv)
fprintf(stderr, "excess args ignored");
*/
return (argv2 < argv); /* if true, print_formatted errored out */
}