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vfscanf.c

/*
 * Copyright (c) 2000-2001, 2004 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 * Copyright (c) 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

#include <sm/gen.h>
SM_IDSTR(id, "@(#)$Id: vfscanf.c,v 1.54 2006/10/12 22:03:52 ca Exp $")

#include <ctype.h>
#include <stdlib.h>
#include <errno.h>
#include <setjmp.h>
#include <sm/time.h>
#include <sm/varargs.h>
#include <sm/config.h>
#include <sm/io.h>
#include <sm/signal.h>
#include <sm/clock.h>
#include <sm/string.h>
#include "local.h"

#define BUF       513   /* Maximum length of numeric string. */

/* Flags used during conversion. */
#define LONG            0x01  /* l: long or double */
#define SHORT           0x04  /* h: short */
#define QUAD            0x08  /* q: quad (same as ll) */
#define SUPPRESS  0x10  /* suppress assignment */
#define POINTER         0x20  /* weird %p pointer (`fake hex') */
#define NOSKIP          0x40  /* do not skip blanks */

/*
**  The following are used in numeric conversions only:
**  SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
**  SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
*/

#define SIGNOK          0x080 /* +/- is (still) legal */
#define NDIGITS         0x100 /* no digits detected */

#define DPTOK           0x200 /* (float) decimal point is still legal */
#define EXPOK           0x400 /* (float) exponent (e+3, etc) still legal */

#define PFXOK           0x200 /* 0x prefix is (still) legal */
#define NZDIGITS  0x400 /* no zero digits detected */

/* Conversion types. */
#define CT_CHAR         0     /* %c conversion */
#define CT_CCL          1     /* %[...] conversion */
#define CT_STRING 2     /* %s conversion */
#define CT_INT          3     /* integer, i.e., strtoll or strtoull */
#define CT_FLOAT  4     /* floating, i.e., strtod */

static void       scanalrm __P((int));
static unsigned char    *sm_sccl __P((char *, unsigned char *));
static jmp_buf          ScanTimeOut;

/*
**  SCANALRM -- handler when timeout activated for sm_io_vfscanf()
**
**  Returns flow of control to where setjmp(ScanTimeOut) was set.
**
**    Parameters:
**          sig -- unused
**
**    Returns:
**          does not return
**
**    Side Effects:
**          returns flow of control to setjmp(ScanTimeOut).
**
**    NOTE: THIS CAN BE CALLED FROM A SIGNAL HANDLER.  DO NOT ADD
**          ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
**          DOING.
*/

/* ARGSUSED0 */
static void
scanalrm(sig)
      int sig;
{
      longjmp(ScanTimeOut, 1);
}

/*
**  SM_VFSCANF -- convert input into data units
**
**    Parameters:
**          fp -- file pointer for input data
**          timeout -- time intvl allowed to complete (milliseconds)
**          fmt0 -- format for finding data units
**          ap -- vectors for memory location for storing data units
**
**    Results:
**          Success: number of data units assigned
**          Failure: SM_IO_EOF
*/

int
sm_vfscanf(fp, timeout, fmt0, ap)
      register SM_FILE_T *fp;
      int SM_NONVOLATILE timeout;
      char const *fmt0;
      va_list SM_NONVOLATILE ap;
{
      register unsigned char *SM_NONVOLATILE fmt = (unsigned char *) fmt0;
      register int c;         /* character from format, or conversion */
      register size_t width;  /* field width, or 0 */
      register char *p; /* points into all kinds of strings */
      register int n;         /* handy integer */
      register int flags;     /* flags as defined above */
      register char *p0;      /* saves original value of p when necessary */
      int nassigned;          /* number of fields assigned */
      int nread;        /* number of characters consumed from fp */
      int base;         /* base argument to strtoll/strtoull */

      /* conversion function (strtoll/strtoull) */
      ULONGLONG_T (*ccfn) __P((const char *, char **, int));
      char ccltab[256]; /* character class table for %[...] */
      char buf[BUF];          /* buffer for numeric conversions */
      SM_EVENT *evt = NULL;

      /* `basefix' is used to avoid `if' tests in the integer scanner */
      static short basefix[17] =
            { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };

      if (timeout == SM_TIME_DEFAULT)
            timeout = fp->f_timeout;
      if (timeout == SM_TIME_IMMEDIATE)
      {
            /*
            **  Filling the buffer will take time and we are wanted to
            **  return immediately. So...
            */

            errno = EAGAIN;
            return SM_IO_EOF;
      }

      if (timeout != SM_TIME_FOREVER)
      {
            if (setjmp(ScanTimeOut) != 0)
            {
                  errno = EAGAIN;
                  return SM_IO_EOF;
            }

            evt = sm_seteventm(timeout, scanalrm, 0);
      }

      nassigned = 0;
      nread = 0;
      base = 0;         /* XXX just to keep gcc happy */
      ccfn = NULL;            /* XXX just to keep gcc happy */
      for (;;)
      {
            c = *fmt++;
            if (c == 0)
            {
                  if (evt != NULL)
                        sm_clrevent(evt); /*  undo our timeout */
                  return nassigned;
            }
            if (isspace(c))
            {
                  while ((fp->f_r > 0 || sm_refill(fp, SM_TIME_FOREVER)
                                    == 0) &&
                      isspace(*fp->f_p))
                        nread++, fp->f_r--, fp->f_p++;
                  continue;
            }
            if (c != '%')
                  goto literal;
            width = 0;
            flags = 0;

            /*
            **  switch on the format.  continue if done;
            **  break once format type is derived.
            */

again:            c = *fmt++;
            switch (c)
            {
              case '%':
literal:
                  if (fp->f_r <= 0 && sm_refill(fp, SM_TIME_FOREVER))
                        goto input_failure;
                  if (*fp->f_p != c)
                        goto match_failure;
                  fp->f_r--, fp->f_p++;
                  nread++;
                  continue;

              case '*':
                  flags |= SUPPRESS;
                  goto again;
              case 'h':
                  flags |= SHORT;
                  goto again;
              case 'l':
                  if (*fmt == 'l')
                  {
                        fmt++;
                        flags |= QUAD;
                  }
                  else
                  {
                        flags |= LONG;
                  }
                  goto again;
              case 'q':
                  flags |= QUAD;
                  goto again;

              case '0': case '1': case '2': case '3': case '4':
              case '5': case '6': case '7': case '8': case '9':
                  width = width * 10 + c - '0';
                  goto again;

            /*
            **  Conversions.
            **  Those marked `compat' are for 4.[123]BSD compatibility.
            **
            **  (According to ANSI, E and X formats are supposed
            **  to the same as e and x.  Sorry about that.)
            */

              case 'D': /* compat */
                  flags |= LONG;
                  /* FALLTHROUGH */
              case 'd':
                  c = CT_INT;
                  ccfn = (ULONGLONG_T (*)())sm_strtoll;
                  base = 10;
                  break;

              case 'i':
                  c = CT_INT;
                  ccfn = (ULONGLONG_T (*)())sm_strtoll;
                  base = 0;
                  break;

              case 'O': /* compat */
                  flags |= LONG;
                  /* FALLTHROUGH */
              case 'o':
                  c = CT_INT;
                  ccfn = sm_strtoull;
                  base = 8;
                  break;

              case 'u':
                  c = CT_INT;
                  ccfn = sm_strtoull;
                  base = 10;
                  break;

              case 'X':
              case 'x':
                  flags |= PFXOK;   /* enable 0x prefixing */
                  c = CT_INT;
                  ccfn = sm_strtoull;
                  base = 16;
                  break;

              case 'E':
              case 'G':
              case 'e':
              case 'f':
              case 'g':
                  c = CT_FLOAT;
                  break;

              case 's':
                  c = CT_STRING;
                  break;

              case '[':
                  fmt = sm_sccl(ccltab, fmt);
                  flags |= NOSKIP;
                  c = CT_CCL;
                  break;

              case 'c':
                  flags |= NOSKIP;
                  c = CT_CHAR;
                  break;

              case 'p': /* pointer format is like hex */
                  flags |= POINTER | PFXOK;
                  c = CT_INT;
                  ccfn = sm_strtoull;
                  base = 16;
                  break;

              case 'n':
                  if (flags & SUPPRESS)   /* ??? */
                        continue;
                  if (flags & SHORT)
                        *SM_VA_ARG(ap, short *) = nread;
                  else if (flags & LONG)
                        *SM_VA_ARG(ap, long *) = nread;
                  else
                        *SM_VA_ARG(ap, int *) = nread;
                  continue;

            /* Disgusting backwards compatibility hacks.    XXX */
              case '\0':      /* compat */
                  if (evt != NULL)
                        sm_clrevent(evt); /*  undo our timeout */
                  return SM_IO_EOF;

              default:  /* compat */
                  if (isupper(c))
                        flags |= LONG;
                  c = CT_INT;
                  ccfn = (ULONGLONG_T (*)()) sm_strtoll;
                  base = 10;
                  break;
            }

            /* We have a conversion that requires input. */
            if (fp->f_r <= 0 && sm_refill(fp, SM_TIME_FOREVER))
                  goto input_failure;

            /*
            **  Consume leading white space, except for formats
            **  that suppress this.
            */

            if ((flags & NOSKIP) == 0)
            {
                  while (isspace(*fp->f_p))
                  {
                        nread++;
                        if (--fp->f_r > 0)
                              fp->f_p++;
                        else if (sm_refill(fp, SM_TIME_FOREVER))
                              goto input_failure;
                  }
                  /*
                  **  Note that there is at least one character in
                  **  the buffer, so conversions that do not set NOSKIP
                  **  can no longer result in an input failure.
                  */
            }

            /* Do the conversion. */
            switch (c)
            {
              case CT_CHAR:
                  /* scan arbitrary characters (sets NOSKIP) */
                  if (width == 0)
                        width = 1;
                  if (flags & SUPPRESS)
                  {
                        size_t sum = 0;
                        for (;;)
                        {
                              if ((size_t) (n = fp->f_r) < width)
                              {
                                    sum += n;
                                    width -= n;
                                    fp->f_p += n;
                                    if (sm_refill(fp,
                                                SM_TIME_FOREVER))
                                    {
                                          if (sum == 0)
                                                goto input_failure;
                                          break;
                                    }
                              }
                              else
                              {
                                    sum += width;
                                    fp->f_r -= width;
                                    fp->f_p += width;
                                    break;
                              }
                        }
                        nread += sum;
                  }
                  else
                  {
                        size_t r;

                        r = sm_io_read(fp, SM_TIME_FOREVER,
                                    (void *) SM_VA_ARG(ap, char *),
                                    width);
                        if (r == 0)
                              goto input_failure;
                        nread += r;
                        nassigned++;
                  }
                  break;

              case CT_CCL:
                  /* scan a (nonempty) character class (sets NOSKIP) */
                  if (width == 0)
                        width = (size_t)~0;     /* `infinity' */

                  /* take only those things in the class */
                  if (flags & SUPPRESS)
                  {
                        n = 0;
                        while (ccltab[*fp->f_p] != '\0')
                        {
                              n++, fp->f_r--, fp->f_p++;
                              if (--width == 0)
                                    break;
                              if (fp->f_r <= 0 &&
                                  sm_refill(fp, SM_TIME_FOREVER))
                              {
                                    if (n == 0) /* XXX how? */
                                          goto input_failure;
                                    break;
                              }
                        }
                        if (n == 0)
                              goto match_failure;
                  }
                  else
                  {
                        p0 = p = SM_VA_ARG(ap, char *);
                        while (ccltab[*fp->f_p] != '\0')
                        {
                              fp->f_r--;
                              *p++ = *fp->f_p++;
                              if (--width == 0)
                                    break;
                              if (fp->f_r <= 0 &&
                                  sm_refill(fp, SM_TIME_FOREVER))
                              {
                                    if (p == p0)
                                          goto input_failure;
                                    break;
                              }
                        }
                        n = p - p0;
                        if (n == 0)
                              goto match_failure;
                        *p = 0;
                        nassigned++;
                  }
                  nread += n;
                  break;

              case CT_STRING:
                  /* like CCL, but zero-length string OK, & no NOSKIP */
                  if (width == 0)
                        width = (size_t)~0;
                  if (flags & SUPPRESS)
                  {
                        n = 0;
                        while (!isspace(*fp->f_p))
                        {
                              n++, fp->f_r--, fp->f_p++;
                              if (--width == 0)
                                    break;
                              if (fp->f_r <= 0 &&
                                  sm_refill(fp, SM_TIME_FOREVER))
                                    break;
                        }
                        nread += n;
                  }
                  else
                  {
                        p0 = p = SM_VA_ARG(ap, char *);
                        while (!isspace(*fp->f_p))
                        {
                              fp->f_r--;
                              *p++ = *fp->f_p++;
                              if (--width == 0)
                                    break;
                              if (fp->f_r <= 0 &&
                                  sm_refill(fp, SM_TIME_FOREVER))
                                    break;
                        }
                        *p = 0;
                        nread += p - p0;
                        nassigned++;
                  }
                  continue;

              case CT_INT:
                  /* scan an integer as if by strtoll/strtoull */
#if SM_CONF_BROKEN_SIZE_T
                  if (width == 0 || width > sizeof(buf) - 1)
                        width = sizeof(buf) - 1;
#else /* SM_CONF_BROKEN_SIZE_T */
                  /* size_t is unsigned, hence this optimisation */
                  if (--width > sizeof(buf) - 2)
                        width = sizeof(buf) - 2;
                  width++;
#endif /* SM_CONF_BROKEN_SIZE_T */
                  flags |= SIGNOK | NDIGITS | NZDIGITS;
                  for (p = buf; width > 0; width--)
                  {
                        c = *fp->f_p;

                        /*
                        **  Switch on the character; `goto ok'
                        **  if we accept it as a part of number.
                        */

                        switch (c)
                        {

                        /*
                        **  The digit 0 is always legal, but is
                        **  special.  For %i conversions, if no
                        **  digits (zero or nonzero) have been
                        **  scanned (only signs), we will have
                        **  base==0.  In that case, we should set
                        **  it to 8 and enable 0x prefixing.
                        **  Also, if we have not scanned zero digits
                        **  before this, do not turn off prefixing
                        **  (someone else will turn it off if we
                        **  have scanned any nonzero digits).
                        */

                          case '0':
                              if (base == 0)
                              {
                                    base = 8;
                                    flags |= PFXOK;
                              }
                              if (flags & NZDIGITS)
                                  flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
                              else
                                  flags &= ~(SIGNOK|PFXOK|NDIGITS);
                              goto ok;

                        /* 1 through 7 always legal */
                          case '1': case '2': case '3':
                          case '4': case '5': case '6': case '7':
                              base = basefix[base];
                              flags &= ~(SIGNOK | PFXOK | NDIGITS);
                              goto ok;

                        /* digits 8 and 9 ok iff decimal or hex */
                          case '8': case '9':
                              base = basefix[base];
                              if (base <= 8)
                                    break;      /* not legal here */
                              flags &= ~(SIGNOK | PFXOK | NDIGITS);
                              goto ok;

                        /* letters ok iff hex */
                          case 'A': case 'B': case 'C':
                          case 'D': case 'E': case 'F':
                          case 'a': case 'b': case 'c':
                          case 'd': case 'e': case 'f':

                              /* no need to fix base here */
                              if (base <= 10)
                                    break;      /* not legal here */
                              flags &= ~(SIGNOK | PFXOK | NDIGITS);
                              goto ok;

                        /* sign ok only as first character */
                          case '+': case '-':
                              if (flags & SIGNOK)
                              {
                                    flags &= ~SIGNOK;
                                    goto ok;
                              }
                              break;

                        /* x ok iff flag still set & 2nd char */
                          case 'x': case 'X':
                              if (flags & PFXOK && p == buf + 1)
                              {
                                    base = 16;  /* if %i */
                                    flags &= ~PFXOK;
                                    goto ok;
                              }
                              break;
                        }

                        /*
                        **  If we got here, c is not a legal character
                        **  for a number.  Stop accumulating digits.
                        */

                        break;
            ok:
                        /* c is legal: store it and look at the next. */
                        *p++ = c;
                        if (--fp->f_r > 0)
                              fp->f_p++;
                        else if (sm_refill(fp, SM_TIME_FOREVER))
                              break;            /* SM_IO_EOF */
                  }

                  /*
                  **  If we had only a sign, it is no good; push
                  **  back the sign.  If the number ends in `x',
                  **  it was [sign] '0' 'x', so push back the x
                  **  and treat it as [sign] '0'.
                  */

                  if (flags & NDIGITS)
                  {
                        if (p > buf)
                              (void) sm_io_ungetc(fp, SM_TIME_DEFAULT,
                                              *(unsigned char *)--p);
                        goto match_failure;
                  }
                  c = ((unsigned char *)p)[-1];
                  if (c == 'x' || c == 'X')
                  {
                        --p;
                        (void) sm_io_ungetc(fp, SM_TIME_DEFAULT, c);
                  }
                  if ((flags & SUPPRESS) == 0)
                  {
                        ULONGLONG_T res;

                        *p = 0;
                        res = (*ccfn)(buf, (char **)NULL, base);
                        if (flags & POINTER)
                              *SM_VA_ARG(ap, void **) =
                                  (void *)(long) res;
                        else if (flags & QUAD)
                              *SM_VA_ARG(ap, LONGLONG_T *) = res;
                        else if (flags & LONG)
                              *SM_VA_ARG(ap, long *) = res;
                        else if (flags & SHORT)
                              *SM_VA_ARG(ap, short *) = res;
                        else
                              *SM_VA_ARG(ap, int *) = res;
                        nassigned++;
                  }
                  nread += p - buf;
                  break;

              case CT_FLOAT:
                  /* scan a floating point number as if by strtod */
                  if (width == 0 || width > sizeof(buf) - 1)
                        width = sizeof(buf) - 1;
                  flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
                  for (p = buf; width; width--)
                  {
                        c = *fp->f_p;

                        /*
                        **  This code mimicks the integer conversion
                        **  code, but is much simpler.
                        */

                        switch (c)
                        {

                          case '0': case '1': case '2': case '3':
                          case '4': case '5': case '6': case '7':
                          case '8': case '9':
                              flags &= ~(SIGNOK | NDIGITS);
                              goto fok;

                          case '+': case '-':
                              if (flags & SIGNOK)
                              {
                                    flags &= ~SIGNOK;
                                    goto fok;
                              }
                              break;
                          case '.':
                              if (flags & DPTOK)
                              {
                                    flags &= ~(SIGNOK | DPTOK);
                                    goto fok;
                              }
                              break;
                          case 'e': case 'E':

                              /* no exponent without some digits */
                              if ((flags&(NDIGITS|EXPOK)) == EXPOK)
                              {
                                    flags =
                                        (flags & ~(EXPOK|DPTOK)) |
                                        SIGNOK | NDIGITS;
                                    goto fok;
                              }
                              break;
                        }
                        break;
            fok:
                        *p++ = c;
                        if (--fp->f_r > 0)
                              fp->f_p++;
                        else if (sm_refill(fp, SM_TIME_FOREVER))
                              break;      /* SM_IO_EOF */
                  }

                  /*
                  **  If no digits, might be missing exponent digits
                  **  (just give back the exponent) or might be missing
                  **  regular digits, but had sign and/or decimal point.
                  */

                  if (flags & NDIGITS)
                  {
                        if (flags & EXPOK)
                        {
                              /* no digits at all */
                              while (p > buf)
                                    (void) sm_io_ungetc(fp,
                                               SM_TIME_DEFAULT,
                                               *(unsigned char *)--p);
                              goto match_failure;
                        }

                        /* just a bad exponent (e and maybe sign) */
                        c = *(unsigned char *) --p;
                        if (c != 'e' && c != 'E')
                        {
                              (void) sm_io_ungetc(fp, SM_TIME_DEFAULT,
                                              c); /* sign */
                              c = *(unsigned char *)--p;
                        }
                        (void) sm_io_ungetc(fp, SM_TIME_DEFAULT, c);
                  }
                  if ((flags & SUPPRESS) == 0)
                  {
                        double res;

                        *p = 0;
                        res = strtod(buf, (char **) NULL);
                        if (flags & LONG)
                              *SM_VA_ARG(ap, double *) = res;
                        else
                              *SM_VA_ARG(ap, float *) = res;
                        nassigned++;
                  }
                  nread += p - buf;
                  break;
            }
      }
input_failure:
      if (evt != NULL)
            sm_clrevent(evt); /*  undo our timeout */
      return nassigned ? nassigned : -1;
match_failure:
      if (evt != NULL)
            sm_clrevent(evt); /*  undo our timeout */
      return nassigned;
}

/*
**  SM_SCCL -- sequenced character comparison list
**
**  Fill in the given table from the scanset at the given format
**  (just after `[').  Return a pointer to the character past the
**  closing `]'.  The table has a 1 wherever characters should be
**  considered part of the scanset.
**
**    Parameters:
**          tab -- array flagging "active" char's to match (returned)
**          fmt -- character list (within "[]")
**
**    Results:
*/

static unsigned char *
sm_sccl(tab, fmt)
      register char *tab;
      register unsigned char *fmt;
{
      register int c, n, v;

      /* first `clear' the whole table */
      c = *fmt++;       /* first char hat => negated scanset */
      if (c == '^')
      {
            v = 1;            /* default => accept */
            c = *fmt++; /* get new first char */
      }
      else
            v = 0;            /* default => reject */

      /* should probably use memset here */
      for (n = 0; n < 256; n++)
            tab[n] = v;
      if (c == 0)
            return fmt - 1;   /* format ended before closing ] */

      /*
      **  Now set the entries corresponding to the actual scanset
      **  to the opposite of the above.
      **
      **  The first character may be ']' (or '-') without being special;
      **  the last character may be '-'.
      */

      v = 1 - v;
      for (;;)
      {
            tab[c] = v;       /* take character c */
doswitch:
            n = *fmt++;       /* and examine the next */
            switch (n)
            {

              case 0:               /* format ended too soon */
                  return fmt - 1;

              case '-':
                  /*
                  **  A scanset of the form
                  **    [01+-]
                  **  is defined as `the digit 0, the digit 1,
                  **  the character +, the character -', but
                  **  the effect of a scanset such as
                  **    [a-zA-Z0-9]
                  **  is implementation defined.  The V7 Unix
                  **  scanf treats `a-z' as `the letters a through
                  **  z', but treats `a-a' as `the letter a, the
                  **  character -, and the letter a'.
                  **
                  **  For compatibility, the `-' is not considerd
                  **  to define a range if the character following
                  **  it is either a close bracket (required by ANSI)
                  **  or is not numerically greater than the character
                  **  we just stored in the table (c).
                  */

                  n = *fmt;
                  if (n == ']' || n < c)
                  {
                        c = '-';
                        break;      /* resume the for(;;) */
                  }
                  fmt++;
                  do
                  {
                        /* fill in the range */
                        tab[++c] = v;
                  } while (c < n);
#if 1 /* XXX another disgusting compatibility hack */

                  /*
                  **  Alas, the V7 Unix scanf also treats formats
                  **  such as [a-c-e] as `the letters a through e'.
                  **  This too is permitted by the standard....
                  */

                  goto doswitch;
#else
                  c = *fmt++;
                  if (c == 0)
                        return fmt - 1;
                  if (c == ']')
                        return fmt;
                  break;
#endif

              case ']':       /* end of scanset */
                  return fmt;

              default:        /* just another character */
                  c = n;
                  break;
            }
      }
      /* NOTREACHED */
}

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