sendmail/libsm/vasprintf.c

/*
 * Copyright (c) 2000-2001 Sendmail, 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.
 */

/*
 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sm/gen.h>
SM_RCSID("@(#)$Id: vasprintf.c,v 1.26.2.1 2003/06/03 02:14:09 ca Exp $")
#include <stdlib.h>
#include <errno.h>
#include <sm/io.h>
#include <sm/heap.h>
#include "local.h"

/*
**  SM_VASPRINTF -- printf to a dynamically allocated string
**
**  Write 'printf' output to a dynamically allocated string
**  buffer which is returned to the caller.
**
**  Parameters:
**      str -- *str receives a pointer to the allocated string
**      fmt -- format directives for printing
**      ap -- variable argument list
**
**  Results:
**      On failure, set *str to NULL, set errno, and return -1.
**
**      On success, set *str to a pointer to a nul-terminated
**      string buffer containing printf output, and return the
**      length of the string (not counting the nul).
*/

#define SM_VA_BUFSIZE   128

int
sm_vasprintf(str, fmt, ap)
    char **str;
    const char *fmt;
    SM_VA_LOCAL_DECL
{
    int ret;
    SM_FILE_T fake;
    unsigned char *base;

    fake.sm_magic = SmFileMagic;
    fake.f_timeout = SM_TIME_FOREVER;
    fake.f_timeoutstate = SM_TIME_BLOCK;
    fake.f_file = -1;
    fake.f_flags = SMWR | SMSTR | SMALC;
    fake.f_bf.smb_base = fake.f_p = (unsigned char *)sm_malloc(SM_VA_BUFSIZE);
    if (fake.f_bf.smb_base == NULL)
        goto err2;
    fake.f_close = NULL;
    fake.f_open = NULL;
    fake.f_read = NULL;
    fake.f_write = NULL;
    fake.f_seek = NULL;
    fake.f_setinfo = fake.f_getinfo = NULL;
    fake.f_type = "sm_vasprintf:fake";
    fake.f_bf.smb_size = fake.f_w = SM_VA_BUFSIZE - 1;
    fake.f_timeout = SM_TIME_FOREVER;
    ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
    if (ret == -1)
        goto err;
    *fake.f_p = '\0';

    /* use no more space than necessary */
    base = (unsigned char *) sm_realloc(fake.f_bf.smb_base, ret + 1);
    if (base == NULL)
        goto err;
    *str = (char *)base;
    return ret;

err:
    if (fake.f_bf.smb_base != NULL)
    {
        sm_free(fake.f_bf.smb_base);
        fake.f_bf.smb_base = NULL;
    }
err2:
    *str = NULL;
    errno = ENOMEM;
    return -1;
}