cmd/printf/printf.c

/*
 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
 * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
 * Copyright (c) 1989, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/types.h>

#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <alloca.h>
#include <ctype.h>
#include <locale.h>
#include <note.h>

#define warnx1(a, b, c)     warnx(a)
#define warnx2(a, b, c)     warnx(a, b)
#define warnx3(a, b, c)     warnx(a, b, c)

#define PTRDIFF(x, y)   ((uintptr_t)(x) - (uintptr_t)(y))

#define _(x)    gettext(x)

#define PF(f, func) do {                        \
    char *b = NULL;                         \
    if (havewidth)                          \
        if (haveprec)                       \
            (void) asprintf(&b, f, fieldwidth, precision, func); \
        else                            \
            (void) asprintf(&b, f, fieldwidth, func);   \
    else if (haveprec)                      \
        (void) asprintf(&b, f, precision, func);        \
    else                                \
        (void) asprintf(&b, f, func);               \
    if (b) {                            \
        (void) fputs(b, stdout);                \
        free(b);                        \
    }                               \
_NOTE(CONSTCOND) } while (0)

static int   asciicode(void);
static char *doformat(char *, int *);
static int   escape(char *, int, size_t *);
static int   getchr(void);
static int   getfloating(long double *, int);
static int   getint(int *);
static int   getnum(intmax_t *, uintmax_t *, int);
static const char
        *getstr(void);
static char *mknum(char *, char);
static void  usage(void);

static const char digits[] = "0123456789";

static int  myargc;
static char **myargv;
static char **gargv;
static char **maxargv;

int
main(int argc, char *argv[])
{
    size_t len;
    int end, rval;
    char *format, *fmt, *start;

    (void) setlocale(LC_ALL, "");

    argv++;
    argc--;

    /*
     * POSIX says: Standard utilities that do not accept options,
     * but that do accept operands, shall recognize "--" as a
     * first argument to be discarded.
     */
    if (argc && strcmp(argv[0], "--") == 0) {
        argc--;
        argv++;
    }

    if (argc < 1) {
        usage();
        return (1);
    }

    /*
     * Basic algorithm is to scan the format string for conversion
     * specifications -- once one is found, find out if the field
     * width or precision is a '*'; if it is, gather up value.  Note,
     * format strings are reused as necessary to use up the provided
     * arguments, arguments of zero/null string are provided to use
     * up the format string.
     */
    fmt = format = *argv;
    (void) escape(fmt, 1, &len);    /* backslash interpretation */
    rval = end = 0;
    gargv = ++argv;

    for (;;) {
        maxargv = gargv;

        myargv = gargv;
        for (myargc = 0; gargv[myargc]; myargc++)
            /* nop */;
        start = fmt;
        while (fmt < format + len) {
            if (fmt[0] == '%') {
                (void) fwrite(start, 1, PTRDIFF(fmt, start),
                    stdout);
                if (fmt[1] == '%') {
                    /* %% prints a % */
                    (void) putchar('%');
                    fmt += 2;
                } else {
                    fmt = doformat(fmt, &rval);
                    if (fmt == NULL)
                        return (1);
                    end = 0;
                }
                start = fmt;
            } else
                fmt++;
            if (gargv > maxargv)
                maxargv = gargv;
        }
        gargv = maxargv;

        if (end == 1) {
            warnx1(_("missing format character"), NULL, NULL);
            return (1);
        }
        (void) fwrite(start, 1, PTRDIFF(fmt, start), stdout);
        if (!*gargv)
            return (rval);
        /* Restart at the beginning of the format string. */
        fmt = format;
        end = 1;
    }
    /* NOTREACHED */
}


static char *
doformat(char *fmt, int *rval)
{
    static const char skip1[] = "#'-+ 0";
    int fieldwidth, haveprec, havewidth, mod_ldbl, precision;
    char convch, nextch;
    char *start;
    char **fargv;
    char *dptr;
    int l;

    start = alloca(strlen(fmt) + 1);

    dptr = start;
    *dptr++ = '%';
    *dptr = 0;

    fmt++;

    /* look for "n$" field index specifier */
    l = strspn(fmt, digits);
    if ((l > 0) && (fmt[l] == '$')) {
        int idx = atoi(fmt);
        if (idx <= myargc) {
            gargv = &myargv[idx - 1];
        } else {
            gargv = &myargv[myargc];
        }
        if (gargv > maxargv) {
            maxargv = gargv;
        }
        fmt += l + 1;

        /* save format argument */
        fargv = gargv;
    } else {
        fargv = NULL;
    }

    /* skip to field width */
    while (*fmt && strchr(skip1, *fmt) != NULL) {
        *dptr++ = *fmt++;
        *dptr = 0;
    }


    if (*fmt == '*') {

        fmt++;
        l = strspn(fmt, digits);
        if ((l > 0) && (fmt[l] == '$')) {
            int idx = atoi(fmt);
            if (fargv == NULL) {
                warnx1(_("incomplete use of n$"), NULL, NULL);
                return (NULL);
            }
            if (idx <= myargc) {
                gargv = &myargv[idx - 1];
            } else {
                gargv = &myargv[myargc];
            }
            fmt += l + 1;
        } else if (fargv != NULL) {
            warnx1(_("incomplete use of n$"), NULL, NULL);
            return (NULL);
        }

        if (getint(&fieldwidth))
            return (NULL);
        if (gargv > maxargv) {
            maxargv = gargv;
        }
        havewidth = 1;

        *dptr++ = '*';
        *dptr = 0;
    } else {
        havewidth = 0;

        /* skip to possible '.', get following precision */
        while (isdigit(*fmt)) {
            *dptr++ = *fmt++;
            *dptr = 0;
        }
    }

    if (*fmt == '.') {
        /* precision present? */
        fmt++;
        *dptr++ = '.';

        if (*fmt == '*') {

            fmt++;
            l = strspn(fmt, digits);
            if ((l > 0) && (fmt[l] == '$')) {
                int idx = atoi(fmt);
                if (fargv == NULL) {
                    warnx1(_("incomplete use of n$"),
                        NULL, NULL);
                    return (NULL);
                }
                if (idx <= myargc) {
                    gargv = &myargv[idx - 1];
                } else {
                    gargv = &myargv[myargc];
                }
                fmt += l + 1;
            } else if (fargv != NULL) {
                warnx1(_("incomplete use of n$"), NULL, NULL);
                return (NULL);
            }

            if (getint(&precision))
                return (NULL);
            if (gargv > maxargv) {
                maxargv = gargv;
            }
            haveprec = 1;
            *dptr++ = '*';
            *dptr = 0;
        } else {
            haveprec = 0;

            /* skip to conversion char */
            while (isdigit(*fmt)) {
                *dptr++ = *fmt++;
                *dptr = 0;
            }
        }
    } else
        haveprec = 0;
    if (!*fmt) {
        warnx1(_("missing format character"), NULL, NULL);
        return (NULL);
    }
    *dptr++ = *fmt;
    *dptr = 0;

    /*
     * Look for a length modifier.  POSIX doesn't have these, so
     * we only support them for floating-point conversions, which
     * are extensions.  This is useful because the L modifier can
     * be used to gain extra range and precision, while omitting
     * it is more likely to produce consistent results on different
     * architectures.  This is not so important for integers
     * because overflow is the only bad thing that can happen to
     * them, but consider the command  printf %a 1.1
     */
    if (*fmt == 'L') {
        mod_ldbl = 1;
        fmt++;
        if (!strchr("aAeEfFgG", *fmt)) {
            warnx2(_("bad modifier L for %%%c"), *fmt, NULL);
            return (NULL);
        }
    } else {
        mod_ldbl = 0;
    }

    /* save the current arg offset, and set to the format arg */
    if (fargv != NULL) {
        gargv = fargv;
    }

    convch = *fmt;
    nextch = *++fmt;

    *fmt = '\0';
    switch (convch) {
    case 'b': {
        size_t len;
        char *p;
        int getout;

        p = strdup(getstr());
        if (p == NULL) {
            warnx2("%s", strerror(ENOMEM), NULL);
            return (NULL);
        }
        getout = escape(p, 0, &len);
        (void) fputs(p, stdout);
        free(p);

        if (getout)
            exit(*rval);
        break;
    }
    case 'c': {
        char p;

        p = getchr();
        PF(start, p);
        break;
    }
    case 's': {
        const char *p;

        p = getstr();
        PF(start, p);
        break;
    }
    case 'd': case 'i': case 'o': case 'u': case 'x': case 'X': {
        char *f;
        intmax_t val;
        uintmax_t uval;
        int signedconv;

        signedconv = (convch == 'd' || convch == 'i');
        if ((f = mknum(start, convch)) == NULL)
            return (NULL);
        if (getnum(&val, &uval, signedconv))
            *rval = 1;
        if (signedconv)
            PF(f, val);
        else
            PF(f, uval);
        break;
    }
    case 'e': case 'E':
    case 'f': case 'F':
    case 'g': case 'G':
    case 'a': case 'A': {
        long double p;

        if (getfloating(&p, mod_ldbl))
            *rval = 1;
        if (mod_ldbl)
            PF(start, p);
        else
            PF(start, (double)p);
        break;
    }
    default:
        warnx2(_("illegal format character %c"), convch, NULL);
        return (NULL);
    }
    *fmt = nextch;

    /* return the gargv to the next element */
    return (fmt);
}

static char *
mknum(char *str, char ch)
{
    static char *copy;
    static size_t copy_size;
    char *newcopy;
    size_t len, newlen;

    len = strlen(str) + 2;
    if (len > copy_size) {
        newlen = ((len + 1023) >> 10) << 10;
        if ((newcopy = realloc(copy, newlen)) == NULL) {
            warnx2("%s", strerror(ENOMEM), NULL);
            return (NULL);
        }
        copy = newcopy;
        copy_size = newlen;
    }

    (void) memmove(copy, str, len - 3);
    copy[len - 3] = 'j';
    copy[len - 2] = ch;
    copy[len - 1] = '\0';
    return (copy);
}

static int
escape(char *fmt, int percent, size_t *len)
{
    char *save, *store, c;
    int value;

    for (save = store = fmt; ((c = *fmt) != 0); ++fmt, ++store) {
        if (c != '\\') {
            *store = c;
            continue;
        }
        switch (*++fmt) {
        case '\0':      /* EOS, user error */
            *store = '\\';
            *++store = '\0';
            *len = PTRDIFF(store, save);
            return (0);
        case '\\':      /* backslash */
        case '\'':      /* single quote */
            *store = *fmt;
            break;
        case 'a':       /* bell/alert */
            *store = '\a';
            break;
        case 'b':       /* backspace */
            *store = '\b';
            break;
        case 'c':
            if (!percent) {
                *store = '\0';
                *len = PTRDIFF(store, save);
                return (1);
            }
            *store = 'c';
            break;
        case 'f':       /* form-feed */
            *store = '\f';
            break;
        case 'n':       /* newline */
            *store = '\n';
            break;
        case 'r':       /* carriage-return */
            *store = '\r';
            break;
        case 't':       /* horizontal tab */
            *store = '\t';
            break;
        case 'v':       /* vertical tab */
            *store = '\v';
            break;
                    /* octal constant */
        case '0': case '1': case '2': case '3':
        case '4': case '5': case '6': case '7':
            c = (!percent && *fmt == '0') ? 4 : 3;
            for (value = 0;
                c-- && *fmt >= '0' && *fmt <= '7'; ++fmt) {
                value <<= 3;
                value += *fmt - '0';
            }
            --fmt;
            if (percent && value == '%') {
                *store++ = '%';
                *store = '%';
            } else
                *store = (char)value;
            break;
        default:
            *store = *fmt;
            break;
        }
    }
    *store = '\0';
    *len = PTRDIFF(store, save);
    return (0);
}

static int
getchr(void)
{
    if (!*gargv)
        return ('\0');
    return ((int)**gargv++);
}

static const char *
getstr(void)
{
    if (!*gargv)
        return ("");
    return (*gargv++);
}

static int
getint(int *ip)
{
    intmax_t val;
    uintmax_t uval;
    int rval;

    if (getnum(&val, &uval, 1))
        return (1);
    rval = 0;
    if (val < INT_MIN || val > INT_MAX) {
        warnx3("%s: %s", *gargv, strerror(ERANGE));
        rval = 1;
    }
    *ip = (int)val;
    return (rval);
}

static int
getnum(intmax_t *ip, uintmax_t *uip, int signedconv)
{
    char *ep;
    int rval;

    if (!*gargv) {
        *ip = *uip = 0;
        return (0);
    }
    if (**gargv == '"' || **gargv == '\'') {
        if (signedconv)
            *ip = asciicode();
        else
            *uip = asciicode();
        return (0);
    }
    rval = 0;
    errno = 0;
    if (signedconv)
        *ip = strtoimax(*gargv, &ep, 0);
    else
        *uip = strtoumax(*gargv, &ep, 0);
    if (ep == *gargv) {
        warnx2(_("%s: expected numeric value"), *gargv, NULL);
        rval = 1;
    } else if (*ep != '\0') {
        warnx2(_("%s: not completely converted"), *gargv, NULL);
        rval = 1;
    }
    if (errno == ERANGE) {
        warnx3("%s: %s", *gargv, strerror(ERANGE));
        rval = 1;
    }
    ++gargv;
    return (rval);
}

static int
getfloating(long double *dp, int mod_ldbl)
{
    char *ep;
    int rval;

    if (!*gargv) {
        *dp = 0.0;
        return (0);
    }
    if (**gargv == '"' || **gargv == '\'') {
        *dp = asciicode();
        return (0);
    }
    rval = 0;
    errno = 0;
    if (mod_ldbl)
        *dp = strtold(*gargv, &ep);
    else
        *dp = strtod(*gargv, &ep);
    if (ep == *gargv) {
        warnx2(_("%s: expected numeric value"), *gargv, NULL);
        rval = 1;
    } else if (*ep != '\0') {
        warnx2(_("%s: not completely converted"), *gargv, NULL);
        rval = 1;
    }
    if (errno == ERANGE) {
        warnx3("%s: %s", *gargv, strerror(ERANGE));
        rval = 1;
    }
    ++gargv;
    return (rval);
}

static int
asciicode(void)
{
    int ch;

    ch = **gargv;
    if (ch == '\'' || ch == '"')
        ch = (*gargv)[1];
    ++gargv;
    return (ch);
}

static void
usage(void)
{
    (void) fprintf(stderr, _("usage: printf format [arguments ...]\n"));
}