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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * Copyright (C) 2021 Weidmüller Interface GmbH & Co. KG
- * Roland Gaudig <roland.gaudig@weidmueller.com>
- *
- * Copyright 1999 Dave Cinege
- * Portions copyright (C) 1990-1996 Free Software Foundation, Inc.
- *
- * Licensed under GPLv2 or later, see file LICENSE in this source tree.
- */
- /*
- * This file provides a shell printf like format string expansion as required
- * for the setexpr <name> fmt <format> <value> command.
- * This source file was mostly taken from the BusyBox project (www.busybox.net)
- * In contrast to the original sources the output is not written to stdout
- * anymore but into a char array, which can be used as input for the env_set()
- * function.
- */
- /* 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 */
- //config:config PRINTF
- //config: bool "printf (3.8 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"
- /* 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.
- */
- #include <common.h>
- #include <ctype.h>
- #include <errno.h>
- #include <stddef.h>
- #include <stdio.h>
- #include <stdlib.h>
- #define WANT_HEX_ESCAPES 0
- #define PRINT_CONVERSION_ERROR 1
- #define PRINT_TRUNCATED_ERROR 2
- #define PRINT_SIZE_ERROR 4
- struct print_inf {
- char *str;
- size_t size;
- size_t offset;
- unsigned int error;
- };
- typedef void (*converter)(const char *arg, void *result);
- /**
- * printf_str() - print formatted into char array with length checks
- *
- * This function povides a printf like function for printing into a char array
- * with checking the boundaries.
- * Unlike snprintf, all checks are performed inside this function and status
- * reports are stored inside the print_inf struct. That way, this function can
- * be used almost as drop-in replacement without needing much code changes.
- * Unlike snprintf errors are not reported by return value, but inside the
- * error member of struct print_inf. The output stored inside the struct
- * print_inf str member shall only be used when the error member is 0.
- *
- * @inf: Info structure for print operation
- * @char: format string with optional arguments
- */
- static void printf_str(struct print_inf *inf, char *format, ...)
- {
- va_list args;
- int i;
- if (!inf)
- return;
- /* Do not write anything if previous error is pending */
- if (inf->error)
- return;
- /* Check if end of receiving buffer is already reached */
- if (inf->offset >= inf->size) {
- inf->error |= PRINT_SIZE_ERROR;
- return;
- }
- size_t remaining = inf->size - inf->offset;
- va_start(args, format);
- i = vsnprintf(inf->str + inf->offset, remaining, format, args);
- va_end(args);
- if (i >= remaining)
- inf->error |= PRINT_TRUNCATED_ERROR;
- else if (i < 0)
- inf->error |= PRINT_CONVERSION_ERROR;
- else
- inf->offset += i;
- }
- /**
- * putchar_str() - Print single character into char array with length checks
- *
- * This function provices a putchar like function, which stores the output
- * into a char array with checking boundaries.
- *
- * @inf: Info structure for print operation
- * @char: Single character to be printed
- */
- static void putchar_str(struct print_inf *inf, char c)
- {
- printf_str(inf, "%c", c);
- }
- static char process_escape_sequence(const char **ptr)
- {
- const char *q;
- unsigned int num_digits;
- unsigned int n;
- unsigned int base;
- num_digits = 0;
- n = 0;
- base = 8;
- q = *ptr;
- if (WANT_HEX_ESCAPES && *q == 'x') {
- ++q;
- base = 16;
- ++num_digits;
- }
- /* bash requires leading 0 in octal escapes:
- * \02 works, \2 does not (prints \ and 2).
- * We treat \2 as a valid octal escape sequence.
- */
- do {
- unsigned int r;
- unsigned int d = (unsigned char)(*q) - '0';
- #if WANT_HEX_ESCAPES
- if (d >= 10) {
- d = (unsigned char)tolower(*q) - 'a';
- //d += 10;
- /* The above would map 'A'-'F' and 'a'-'f' to 10-15,
- * however, some chars like '@' would map to 9 < base.
- * Do not allow that, map invalid chars to N > base:
- */
- if ((int)d >= 0)
- d += 10;
- }
- #endif
- if (d >= base) {
- if (WANT_HEX_ESCAPES && base == 16) {
- --num_digits;
- if (num_digits == 0) {
- /* \x<bad_char>: return '\',
- * leave ptr pointing to x
- */
- return '\\';
- }
- }
- break;
- }
- r = n * base + d;
- if (r > 255)
- break;
- n = r;
- ++q;
- } while (++num_digits < 3);
- if (num_digits == 0) {
- /* Not octal or hex escape sequence.
- * Is it one-letter one?
- */
- /* bash builtin "echo -e '\ec'" interprets \e as ESC,
- * but coreutils "/bin/echo -e '\ec'" does not.
- * Manpages tend to support coreutils way.
- * Update: coreutils added support for \e on 28 Oct 2009.
- */
- static const char charmap[] = {
- 'a', 'b', 'e', 'f', 'n', 'r', 't', 'v', '\\', '\0',
- '\a', '\b', 27, '\f', '\n', '\r', '\t', '\v', '\\', '\\',
- };
- const char *p = charmap;
- do {
- if (*p == *q) {
- q++;
- break;
- }
- } while (*++p != '\0');
- /* p points to found escape char or NUL,
- * advance it and find what it translates to.
- * Note that \NUL and unrecognized sequence \z return '\'
- * and leave ptr pointing to NUL or z.
- */
- n = p[sizeof(charmap) / 2];
- }
- *ptr = q;
- return (char)n;
- }
- static char *skip_whitespace(const char *s)
- {
- /* In POSIX/C locale (the only locale we care about: do we REALLY want
- * to allow Unicode whitespace in, say, .conf files? nuts!)
- * isspace is only these chars: "\t\n\v\f\r" and space.
- * "\t\n\v\f\r" happen to have ASCII codes 9,10,11,12,13.
- * Use that.
- */
- while (*s == ' ' || (unsigned char)(*s - 9) <= (13 - 9))
- s++;
- return (char *)s;
- }
- /* Like strcpy but can copy overlapping strings. */
- static void overlapping_strcpy(char *dst, const char *src)
- {
- /* Cheap optimization for dst == src case -
- * better to have it here than in many callers.
- */
- if (dst != src) {
- while ((*dst = *src) != '\0') {
- dst++;
- src++;
- }
- }
- }
- static int multiconvert(const char *arg, void *result, converter convert)
- {
- if (*arg == '"' || *arg == '\'')
- sprintf((char *)arg + strlen(arg), "%u", (unsigned char)arg[1]);
- //errno = 0;
- convert(arg, result);
- /* Unlike their Posix counterparts, simple_strtoll and
- * simple_strtoull do not set errno
- *
- * if (errno) {
- * printf("error invalid number '%s'", arg);
- * return 1;
- * }
- */
- return 0;
- }
- static void conv_strtoull(const char *arg, void *result)
- {
- /* both coreutils 6.10 and bash 3.2:
- * $ printf '%x\n' -2
- * fffffffffffffffe
- * Mimic that:
- */
- if (arg[0] == '-') {
- *(unsigned long long *)result = simple_strtoll(arg, NULL, 16);
- return;
- }
- /* Allow leading '+' - simple_strtoull() by itself does not allow it,
- * and probably shouldn't (other callers might require purely numeric
- * inputs to be allowed.
- */
- if (arg[0] == '+')
- arg++;
- *(unsigned long long *)result = simple_strtoull(arg, NULL, 16);
- }
- static void conv_strtoll(const char *arg, void *result)
- {
- if (arg[0] == '+')
- arg++;
- *(long long *)result = simple_strtoll(arg, NULL, 16);
- }
- /* 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;
- }
- /* Handles %b; return 1 if output is to be short-circuited by \c */
- static int print_esc_string(struct print_inf *inf, 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 = process_escape_sequence(&z);
- str = z;
- }
- }
- putchar_str(inf, c);
- }
- return 0;
- }
- static void print_direc(struct print_inf *inf, char *format, unsigned int fmt_length,
- int field_width, int precision,
- const char *argument)
- {
- long long llv;
- 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;
- /* multiconvert sets errno = 0, but %s needs it cleared */
- errno = 0;
- switch (format[fmt_length - 1]) {
- case 'c':
- printf_str(inf, format, *argument);
- break;
- case 'd':
- case 'i':
- llv = my_xstrtoll(skip_whitespace(argument));
- print_long:
- if (!have_width) {
- if (!have_prec)
- printf_str(inf, format, llv);
- else
- printf_str(inf, format, precision, llv);
- } else {
- if (!have_prec)
- printf_str(inf, format, field_width, llv);
- else
- printf_str(inf, format, field_width, precision, llv);
- }
- break;
- case 'o':
- case 'u':
- case 'x':
- case 'X':
- llv = my_xstrtoull(skip_whitespace(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_str(inf, format, argument,
- /*unused:*/ argument, argument);
- else
- printf_str(inf, format, precision,
- argument, /*unused:*/ argument);
- } else {
- if (!have_prec)
- printf_str(inf, format, field_width,
- argument, /*unused:*/ argument);
- else
- printf_str(inf, format, field_width,
- precision, argument);
- }
- break;
- }
- break;
- } /* switch */
- format[fmt_length] = saved;
- }
- /* Handle params for "%*.*f". Negative numbers are ok (compat). */
- static int get_width_prec(const char *str)
- {
- long v = simple_strtol(str, NULL, 10);
- /* Unlike its Posix counterpart, simple_strtol does not set errno
- *
- * if (errno) {
- * printf("error invalid number '%s'", str);
- * v = 0;
- * }
- */
- return (int)v;
- }
- /* Print the text in FORMAT, using ARGV for arguments to any '%' directives.
- * Return advanced ARGV.
- */
- static char **print_formatted(struct print_inf *inf, char *f, char **argv, int *conv_err)
- {
- char *direc_start; /* Start of % directive. */
- unsigned int 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 = 0;
- precision = 0;
- if (*f == '%') {
- putchar_str(inf, '%');
- break;
- }
- if (*f == 'b') {
- if (*argv) {
- if (print_esc_string(inf, *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[] = "diouxXcs";
- char *p = strchr(format_chars, *f);
- /* needed - try "printf %" without it */
- if (!p || *f == '\0') {
- printf("`%s': invalid format\n", 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 = malloc(direc_length + 3);
- if (!p) {
- /* exit with error */
- return saved_argv - 1;
- }
- 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(inf, direc_start, direc_length,
- field_width, precision, *argv++);
- } else {
- print_direc(inf, direc_start, direc_length,
- field_width, precision, "");
- }
- *conv_err |= errno;
- free(p);
- }
- break;
- case '\\':
- if (*++f == 'c')
- return saved_argv; /* causes main() to exit */
- putchar_str(inf, process_escape_sequence((const char **)&f));
- f--;
- break;
- default:
- putchar_str(inf, *f);
- }
- }
- return argv;
- }
- /**
- * printf_setexpr() - Implements the setexpr <name> fmt <format> command
- *
- * This function implements the format string evaluation for the
- * setexpr <name> fmt <format> <value> command.
- *
- * @str: Output string of the evaluated expression
- * @size: Length of @str buffer
- * @argc: Number of arguments
- * @argv: Argument list
- * @return: 0 if OK, 1 on error
- */
- int printf_setexpr(char *str, size_t size, int argc, char *const *argv)
- {
- int conv_err;
- char *format;
- char **argv2;
- struct print_inf inf = {
- .str = str,
- .size = size,
- .offset = 0,
- .error = 0,
- };
- if (!str || !size)
- return 1;
- inf.str[0] = '\0';
- format = argv[0];
- argv2 = (char **)argv + 1;
- conv_err = 0;
- argv = argv2;
- /* In case any print_str call raises an error inf.error will be
- * set after print_formatted returns.
- */
- argv2 = print_formatted(&inf, format, (char **)argv, &conv_err);
- /* coreutils compat (bash doesn't do this):
- *if (*argv)
- * fprintf(stderr, "excess args ignored");
- */
- return (argv2 < argv) || /* if true, print_formatted errored out */
- conv_err || /* print_formatted saw invalid number */
- inf.error; /* print_str reported error */
- }
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