sendmail/libsm/util.c

/*
 * Copyright (c) 2006 Proofpoint, Inc. and its suppliers.
 *  All rights reserved.
 *
 * 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_RCSID("@(#)$Id: util.c,v 1.10 2013-11-22 20:51:44 ca Exp $")
#include <sm/setjmp.h>
#include <sm/conf.h>
#include <sm/assert.h>
#include <sm/heap.h>
#include <sm/string.h>
#include <sm/sendmail.h>
#include <ctype.h>

/*
**  STR2PRT -- convert "unprintable" characters in a string to \oct
**
**  Parameters:
**      s -- string to convert
**
**  Returns:
**      converted string.
**      This is a static local buffer, string must be copied
**      before this function is called again!
*/

char *
str2prt(s)
    char *s;
{
    int l;
    char c, *h;
    bool ok;
    static int len = 0;
    static char *buf = NULL;

    if (s == NULL)
        return NULL;
    ok = true;
    for (h = s, l = 1; *h != '\0'; h++, l++)
    {
        if (*h == '\\')
        {
            ++l;
            ok = false;
        }
        else if (!(isascii(*h) && isprint(*h)))
        {
            l += 3;
            ok = false;
        }
    }
    if (ok)
        return s;
    if (l > len)
    {
        char *nbuf = sm_pmalloc_x(l);

        if (buf != NULL)
            sm_free(buf);
        len = l;
        buf = nbuf;
    }
    for (h = buf; *s != '\0' && l > 0; s++, l--)
    {
        c = *s;
        if (isascii(c) && isprint(c) && c != '\\')
        {
            *h++ = c;
        }
        else
        {
            *h++ = '\\';
            --l;
            switch (c)
            {
              case '\\':
                *h++ = '\\';
                break;
              case '\t':
                *h++ = 't';
                break;
              case '\n':
                *h++ = 'n';
                break;
              case '\r':
                *h++ = 'r';
                break;
              default:
                SM_ASSERT(l >= 2);
                (void) sm_snprintf(h, l, "%03o",
                    (unsigned int)((unsigned char) c));

                /*
                **  XXX since l is unsigned this may
                **  wrap around if the calculation is screwed
                **  up...
                */

                l -= 2;
                h += 3;
                break;
            }
        }
    }
    *h = '\0';
    buf[len - 1] = '\0';
    return buf;
}

/*
**  QUOTE_INTERNAL_CHARS -- do quoting of internal characters
**
**  Necessary to make sure that we don't have metacharacters such
**  as the internal versions of "$*" or "$&" in a string.
**  The input and output pointers can be the same.
**
**  Parameters:
**      ibp -- a pointer to the string to translate
**      obp -- a pointer to an output buffer
**      bsp -- pointer to the length of the output buffer
**
**  Returns:
**      A possibly new bp (if the buffer needed to grow); if
**      it is different, *bsp will updated to the size of
**      the new buffer and the caller is responsible for
**      freeing the memory.
*/

#define SM_MM_QUOTE(ch) (((ch) & 0377) == METAQUOTE || (((ch) & 0340) == 0200))

char *
quote_internal_chars(ibp, obp, bsp)
    char *ibp;
    char *obp;
    int *bsp;
{
    char *ip, *op;
    int bufused, olen;
    bool buffer_same, needs_quoting;

    buffer_same = ibp == obp;
    needs_quoting = false;

    /* determine length of output string (starts at 1 for trailing '\0') */
    for (ip = ibp, olen = 1; *ip != '\0'; ip++, olen++)
    {
        if (SM_MM_QUOTE(*ip))
        {
            olen++;
            needs_quoting = true;
        }
    }

    /* is the output buffer big enough? */
    if (olen > *bsp)
    {
        obp = sm_malloc_x(olen);
        buffer_same = false;
        *bsp = olen;
    }

    /*
    **  shortcut: no change needed?
    **  Note: we don't check this first as some bozo may use the same
    **  buffers but restrict the size of the output buffer to less
    **  than the length of the input buffer in which case we need to
    **  allocate a new buffer.
    */

    if (!needs_quoting)
    {
        if (!buffer_same)
        {
            bufused = sm_strlcpy(obp, ibp, *bsp);
            SM_ASSERT(bufused <= olen);
        }
        return obp;
    }

    if (buffer_same)
    {
        obp = sm_malloc_x(olen);
        buffer_same = false;
        *bsp = olen;
    }

    for (ip = ibp, op = obp, bufused = 0; *ip != '\0'; ip++)
    {
        if (SM_MM_QUOTE(*ip))
        {
            SM_ASSERT(bufused < olen);
            op[bufused++] = METAQUOTE;
        }
        SM_ASSERT(bufused < olen);
        op[bufused++] = *ip;
    }
    op[bufused] = '\0';
    return obp;
}

/*
**  DEQUOTE_INTERNAL_CHARS -- undo the effect of quote_internal_chars
**
**  Parameters:
**      ibp -- a pointer to the string to be translated.
**      obp -- a pointer to the output buffer.  Can be the
**          same as ibp.
**      obs -- the size of the output buffer.
**
**  Returns:
**      number of character added to obp
*/

int
dequote_internal_chars(ibp, obp, obs)
    char *ibp;
    char *obp;
    int obs;
{
    char *ip, *op;
    int len;
    bool quoted;

    quoted = false;
    len = 0;
    for (ip = ibp, op = obp; *ip != '\0'; ip++)
    {
        if ((*ip & 0377) == METAQUOTE && !quoted)
        {
            quoted = true;
            continue;
        }
        if (op < &obp[obs - 1])
        {
            *op++ = *ip;
            ++len;
        }
        quoted = false;
    }
    *op = '\0';
    return len;
}