busybox/coreutils/printf.c

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/* vi: set sw=4 ts=4: */
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/* printf - format and print data
Copyright 1999 Dave Cinege
Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
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Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
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/* 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
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The 'format' argument is re-used as many times as necessary
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to convert all of the given arguments.
David MacKenzie <djm@gnu.ai.mit.edu>
*/
/* 19990508 Busy Boxed! Dave Cinege */
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//config:config PRINTF
//config: bool "printf (3.3 kb)"
//config: default y
//config: help
//config: printf is used to format and print specified strings.
//config: It's similar to 'echo' except it has more options.
//applet:IF_PRINTF(APPLET_NOFORK(printf, printf, BB_DIR_USR_BIN, BB_SUID_DROP, printf))
//kbuild:lib-$(CONFIG_PRINTF) += printf.o
//kbuild:lib-$(CONFIG_ASH_PRINTF) += printf.o
//kbuild:lib-$(CONFIG_HUSH_PRINTF) += printf.o
//usage:#define printf_trivial_usage
//usage: "FORMAT [ARG]..."
//usage:#define printf_full_usage "\n\n"
//usage: "Format and print ARG(s) according to FORMAT (a-la C printf)"
//usage:
//usage:#define printf_example_usage
//usage: "$ printf \"Val=%d\\n\" 5\n"
//usage: "Val=5\n"
#include "libbb.h"
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/* 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.
*/
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("invalid number '%s'", arg);
return 1;
}
return 0;
}
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static void FAST_FUNC conv_strtoull(const char *arg, void *result)
{
*(unsigned long long*)result = bb_strtoull(arg, NULL, 0);
/* both coreutils 6.10 and bash 3.2:
* $ printf '%x\n' -2
* fffffffffffffffe
* Mimic that:
*/
if (errno) {
*(unsigned long long*)result = bb_strtoll(arg, NULL, 0);
}
}
static void FAST_FUNC conv_strtoll(const char *arg, void *result)
{
*(long long*)result = bb_strtoll(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 long my_xstrtoull(const char *arg)
{
unsigned long long result;
if (multiconvert(arg, &result, conv_strtoull))
result = 0;
return result;
}
static long long my_xstrtoll(const char *arg)
{
long long result;
if (multiconvert(arg, &result, conv_strtoll))
result = 0;
return result;
}
static double my_xstrtod(const char *arg)
{
double result;
multiconvert(arg, &result, conv_strtod);
return result;
}
/* Handles %b; return 1 if output is to be short-circuited by \c */
static int print_esc_string(const char *str)
{
char c;
while ((c = *str) != '\0') {
str++;
if (c == '\\') {
/* %b also accepts 4-digit octals of the form \0### */
if (*str == '0') {
if ((unsigned char)(str[1] - '0') < 8) {
/* 2nd char is 0..7: skip leading '0' */
str++;
}
}
else if (*str == 'c') {
return 1;
}
{
/* optimization: don't force arg to be on-stack,
* use another variable for that. */
const char *z = str;
c = bb_process_escape_sequence(&z);
str = z;
}
}
putchar(c);
}
return 0;
}
static void print_direc(char *format, unsigned fmt_length,
int field_width, int precision,
const char *argument)
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{
long long llv;
double dv;
char saved;
char *have_prec, *have_width;
saved = format[fmt_length];
format[fmt_length] = '\0';
have_prec = strstr(format, ".*");
have_width = strchr(format, '*');
if (have_width - 1 == have_prec)
have_width = NULL;
errno = 0;
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switch (format[fmt_length - 1]) {
case 'c':
printf(format, *argument);
break;
case 'd':
case 'i':
llv = my_xstrtoll(argument);
print_long:
if (!have_width) {
if (!have_prec)
printf(format, llv);
else
printf(format, precision, llv);
} else {
if (!have_prec)
printf(format, field_width, llv);
else
printf(format, field_width, precision, llv);
}
break;
case 'o':
case 'u':
case 'x':
case 'X':
llv = my_xstrtoull(argument);
/* cheat: unsigned long and long have same width, so... */
goto print_long;
case 's':
/* Are char* and long long the same? */
if (sizeof(argument) == sizeof(llv)) {
llv = (long long)(ptrdiff_t)argument;
goto print_long;
} else {
/* Hope compiler will optimize it out by moving call
* instruction after the ifs... */
if (!have_width) {
if (!have_prec)
printf(format, argument, /*unused:*/ argument, argument);
else
printf(format, precision, argument, /*unused:*/ argument);
} else {
if (!have_prec)
printf(format, field_width, argument, /*unused:*/ argument);
else
printf(format, field_width, precision, argument);
}
break;
}
case 'f':
case 'e':
case 'E':
case 'g':
case 'G':
dv = my_xstrtod(argument);
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 */
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format[fmt_length] = saved;
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}
/* 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("invalid number '%s'", 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, int *conv_err)
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{
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) {
if (print_esc_string(*argv))
return saved_argv; /* causes main() to exit */
++argv;
}
break;
}
if (*f && 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 "lLhz" size modifiers, repeatedly.
* bash does not like "%lld", but coreutils
* happily takes even "%Llllhhzhhzd"!
* We are permissive like coreutils */
while ((*f | 0x20) == 'l' || *f == 'h' || *f == 'z') {
overlapping_strcpy(f, f + 1);
}
/* Add "ll" if integer modifier, then print */
{
static const char format_chars[] ALIGN1 = "diouxXfeEgGcs";
char *p = strchr(format_chars, *f);
/* needed - try "printf %" without it */
if (p == NULL || *f == '\0') {
bb_error_msg("%s: invalid format", direc_start);
/* causes main() to exit with error */
return saved_argv - 1;
}
++direc_length;
if (p - format_chars <= 5) {
/* it is one of "diouxX" */
p = xmalloc(direc_length + 3);
memcpy(p, direc_start, direc_length);
p[direc_length + 1] = p[direc_length - 1];
p[direc_length - 1] = 'l';
p[direc_length] = 'l';
//bb_error_msg("<%s>", p);
direc_length += 2;
direc_start = p;
} else {
p = NULL;
}
if (*argv) {
print_direc(direc_start, direc_length, field_width,
precision, *argv++);
} else {
print_direc(direc_start, direc_length, field_width,
precision, "");
}
*conv_err |= errno;
free(p);
}
break;
case '\\':
if (*++f == 'c') {
return saved_argv; /* causes main() to exit */
}
bb_putchar(bb_process_escape_sequence((const char **)&f));
f--;
break;
default:
putchar(*f);
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}
}
return argv;
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}
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int printf_main(int argc UNUSED_PARAM, char **argv)
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{
int conv_err;
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. */
// TODO: check fcntl() & O_ACCMODE == O_WRONLY or O_RDWR?
if (fcntl(1, F_GETFL) == -1)
return 1; /* match coreutils 6.10 (sans error msg to stderr) */
//if (dup2(1, 1) != 1) - old way
// 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]) {
if (ENABLE_ASH_PRINTF
&& applet_name[0] != 'p'
) {
bb_error_msg("usage: printf FORMAT [ARGUMENT...]");
return 2; /* bash compat */
}
bb_show_usage();
}
format = argv[1];
argv2 = argv + 2;
conv_err = 0;
do {
argv = argv2;
argv2 = print_formatted(format, argv, &conv_err);
} while (argv2 > argv && *argv2);
/* coreutils compat (bash doesn't do this):
if (*argv)
fprintf(stderr, "excess args ignored");
*/
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return (argv2 < argv) /* if true, print_formatted errored out */
|| conv_err; /* print_formatted saw invalid number */
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}