source: MondoRescue/branches/3.3/mindi-busybox/coreutils/printf.c@ 3655

/* 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 GPLv2 or later, see file LICENSE in this source tree.
*/

/* 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 */

//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"

/* 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;
}

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)
{
    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;

    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 */

    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("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)
{
    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 (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) {
                    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);
        }
    }

    return argv;
}

int printf_main(int argc UNUSED_PARAM, char **argv)
{
    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_BUILTIN_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");
    */

    return (argv2 < argv) /* if true, print_formatted errored out */
        || conv_err; /* print_formatted saw invalid number */
}