sendmail/libsm/stdio.c

/*
 * Copyright (c) 2000-2005 Proofpoint, 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_RCSID("@(#)$Id: stdio.c,v 1.72 2013-11-22 20:51:43 ca Exp $")
#include <unistd.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h> /* FreeBSD: FD_ZERO needs <string.h> */
#include <sys/stat.h>
#include <sm/time.h>
#include <sm/heap.h>
#include <sm/assert.h>
#include <sm/varargs.h>
#include <sm/io.h>
#include <sm/setjmp.h>
#include <sm/conf.h>
#include <sm/fdset.h>
#include "local.h"

static int  sm_stdsetmode __P((SM_FILE_T *, const int *));
static int  sm_stdgetmode __P((SM_FILE_T *, int *));

/*
**  Overall:
**  Small standard I/O/seek/close functions.
**  These maintain the `known seek offset' for seek optimization.
*/

/*
**  SM_STDOPEN -- open a file with stdio behavior
**
**  Not associated with the system's stdio in libc.
**
**  Parameters:
**      fp -- file pointer to be associated with the open
**      info -- pathname of the file to be opened
**      flags -- indicates type of access methods
**      rpool -- ignored
**
**  Returns:
**      Failure: -1 and set errno
**      Success: 0 or greater (fd of file from open(2)).
**
*/

/* ARGSUSED3 */
int
sm_stdopen(fp, info, flags, rpool)
    SM_FILE_T *fp;
    const void *info;
    int flags;
    const void *rpool;
{
    char *path = (char *) info;
    int oflags;

    switch (SM_IO_MODE(flags))
    {
      case SM_IO_RDWR:
        oflags = O_RDWR;
        break;
      case SM_IO_RDWRTR:
        oflags = O_RDWR | O_CREAT | O_TRUNC;
        break;
      case SM_IO_RDONLY:
        oflags = O_RDONLY;
        break;
      case SM_IO_WRONLY:
        oflags = O_WRONLY | O_CREAT | O_TRUNC;
        break;
      case SM_IO_APPEND:
        oflags = O_APPEND | O_WRONLY | O_CREAT;
        break;
      case SM_IO_APPENDRW:
        oflags = O_APPEND | O_RDWR | O_CREAT;
        break;
      default:
        errno = EINVAL;
        return -1;
    }
#ifdef O_BINARY
    if (SM_IS_BINARY(flags))
        oflags |= O_BINARY;
#endif /* O_BINARY */
    fp->f_file = open(path, oflags,
              S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
    if (fp->f_file < 0)
        return -1; /* errno set by open() */

    if (oflags & O_APPEND)
        (void) (*fp->f_seek)((void *)fp, (off_t)0, SEEK_END);

    return fp->f_file;
}

/*
**  SM_STDREAD -- read from the file
**
**  Parameters:
**      fp -- file pointer to read from
**      buf -- location to place read data
**      n -- number of bytes to read
**
**  Returns:
**      Failure: -1 and sets errno
**      Success: number of bytes read
**
**  Side Effects:
**      Updates internal offset into file.
*/

ssize_t
sm_stdread(fp, buf, n)
    SM_FILE_T *fp;
    char *buf;
    size_t n;
{
    register int ret;

    ret = read(fp->f_file, buf, n);

    /* if the read succeeded, update the current offset */
    if (ret > 0)
        fp->f_lseekoff += ret;
    return ret;
}

/*
**  SM_STDWRITE -- write to the file
**
**  Parameters:
**      fp -- file pointer ro write to
**      buf -- location of data to be written
**      n - number of bytes to write
**
**  Returns:
**      Failure: -1 and sets errno
**      Success: number of bytes written
*/

ssize_t
sm_stdwrite(fp, buf, n)
    SM_FILE_T *fp;
    char const *buf;
    size_t n;
{
    return write(fp->f_file, buf, n);
}

/*
**  SM_STDSEEK -- set the file offset position
**
**  Parmeters:
**      fp -- file pointer to position
**      offset -- how far to position from "base" (set by 'whence')
**      whence -- indicates where the "base" of the 'offset' to start
**
**  Results:
**      Failure: -1 and sets errno
**      Success: the current offset
**
**  Side Effects:
**      Updates the internal value of the offset.
*/

off_t
sm_stdseek(fp, offset, whence)
    SM_FILE_T *fp;
    off_t offset;
    int whence;
{
    register off_t ret;

    ret = lseek(fp->f_file, (off_t) offset, whence);
    if (ret != (off_t) -1)
        fp->f_lseekoff = ret;
    return ret;
}

/*
**  SM_STDCLOSE -- close the file
**
**  Parameters:
**      fp -- the file pointer to close
**
**  Returns:
**      Success: 0 (zero)
**      Failure: -1 and sets errno
*/

int
sm_stdclose(fp)
    SM_FILE_T *fp;
{
    return close(fp->f_file);
}

/*
**  SM_STDSETMODE -- set the access mode for the file
**
**  Called by sm_stdsetinfo().
**
**  Parameters:
**      fp -- file pointer
**      mode -- new mode to set the file access to
**
**  Results:
**      Success: 0 (zero);
**      Failure: -1 and sets errno
*/

static int
sm_stdsetmode(fp, mode)
    SM_FILE_T *fp;
    const int *mode;
{
    int flags = 0;

    switch (SM_IO_MODE(*mode))
    {
      case SM_IO_RDWR:
        flags |= SMRW;
        break;
      case SM_IO_RDONLY:
        flags |= SMRD;
        break;
      case SM_IO_WRONLY:
        flags |= SMWR;
        break;
      case SM_IO_APPEND:
      default:
        errno = EINVAL;
        return -1;
    }
    fp->f_flags = fp->f_flags & ~SMMODEMASK;
    fp->f_flags |= flags;
    return 0;
}

/*
**  SM_STDGETMODE -- for getinfo determine open mode
**
**  Called by sm_stdgetinfo().
**
**  Parameters:
**      fp -- the file mode being determined
**      mode -- internal mode to map to external value
**
**  Results:
**      Failure: -1 and sets errno
**      Success: external mode value
*/

static int
sm_stdgetmode(fp, mode)
    SM_FILE_T *fp;
    int *mode;
{
    switch (fp->f_flags & SMMODEMASK)
    {
      case SMRW:
        *mode = SM_IO_RDWR;
        break;
      case SMRD:
        *mode = SM_IO_RDONLY;
        break;
      case SMWR:
        *mode = SM_IO_WRONLY;
        break;
      default:
        errno = EINVAL;
        return -1;
    }
    return 0;
}

/*
**  SM_STDSETINFO -- set/modify information for a file
**
**  Parameters:
**      fp -- file to set info for
**      what -- type of info to set
**      valp -- location of data used for setting
**
**  Returns:
**      Failure: -1 and sets errno
**      Success: >=0
*/

int
sm_stdsetinfo(fp, what, valp)
    SM_FILE_T *fp;
    int what;
    void *valp;
{
    switch (what)
    {
      case SM_IO_WHAT_MODE:
        return sm_stdsetmode(fp, (const int *)valp);

      default:
        errno = EINVAL;
        return -1;
    }
}

/*
**  SM_GETINFO -- get information about the open file
**
**  Parameters:
**      fp -- file to get info for
**      what -- type of info to get
**      valp -- location to place found info
**
**  Returns:
**      Success: may or may not place info in 'valp' depending
**          on 'what' value, and returns values >=0. Return
**          value may be the obtained info
**      Failure: -1 and sets errno
*/

int
sm_stdgetinfo(fp, what, valp)
    SM_FILE_T *fp;
    int what;
    void *valp;
{
    switch (what)
    {
      case SM_IO_WHAT_MODE:
        return sm_stdgetmode(fp, (int *)valp);

      case SM_IO_WHAT_FD:
        return fp->f_file;

      case SM_IO_WHAT_SIZE:
      {
          struct stat st;

          if (fstat(fp->f_file, &st) == 0)
              return st.st_size;
          else
              return -1;
      }

      case SM_IO_IS_READABLE:
      {
          fd_set readfds;
          struct timeval timeout;

          if (SM_FD_SETSIZE > 0 && fp->f_file >= SM_FD_SETSIZE)
          {
              errno = EINVAL;
              return -1;
          }
          FD_ZERO(&readfds);
          SM_FD_SET(fp->f_file, &readfds);
          timeout.tv_sec = 0;
          timeout.tv_usec = 0;
          if (select(fp->f_file + 1, FDSET_CAST &readfds,
                 NULL, NULL, &timeout) > 0 &&
              SM_FD_ISSET(fp->f_file, &readfds))
              return 1;
          return 0;
      }

      default:
        errno = EINVAL;
        return -1;
    }
}

/*
**  SM_STDFDOPEN -- open file by primitive 'fd' rather than pathname
**
**  I/O function to handle fdopen() stdio equivalence. The rest of
**  the functions are the same as the sm_stdopen() above.
**
**  Parameters:
**      fp -- the file pointer to be associated with the open
**      name -- the primitive file descriptor for association
**      flags -- indicates type of access methods
**      rpool -- ignored
**
**  Results:
**      Success: primitive file descriptor value
**      Failure: -1 and sets errno
*/

/* ARGSUSED3 */
int
sm_stdfdopen(fp, info, flags, rpool)
    SM_FILE_T *fp;
    const void *info;
    int flags;
    const void *rpool;
{
    int oflags, tmp, fdflags, fd = *((int *) info);

    switch (SM_IO_MODE(flags))
    {
      case SM_IO_RDWR:
        oflags = O_RDWR | O_CREAT;
        break;
      case SM_IO_RDONLY:
        oflags = O_RDONLY;
        break;
      case SM_IO_WRONLY:
        oflags = O_WRONLY | O_CREAT | O_TRUNC;
        break;
      case SM_IO_APPEND:
        oflags = O_APPEND | O_WRONLY | O_CREAT;
        break;
      case SM_IO_APPENDRW:
        oflags = O_APPEND | O_RDWR | O_CREAT;
        break;
      default:
        errno = EINVAL;
        return -1;
    }
#ifdef O_BINARY
    if (SM_IS_BINARY(flags))
        oflags |= O_BINARY;
#endif /* O_BINARY */

    /* Make sure the mode the user wants is a subset of the actual mode. */
    if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
        return -1;
    tmp = fdflags & O_ACCMODE;
    if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE)))
    {
        errno = EINVAL;
        return -1;
    }
    fp->f_file = fd;
    if (oflags & O_APPEND)
        (void) (*fp->f_seek)(fp, (off_t)0, SEEK_END);
    return fp->f_file;
}

/*
**  SM_IO_FOPEN -- open a file
**
**  Same interface and semantics as the open() system call,
**  except that it returns SM_FILE_T* instead of a file descriptor.
**
**  Parameters:
**      pathname -- path of file to open
**      flags -- flags controlling the open
**      ...  -- option "mode" for opening the file
**
**  Returns:
**      Raises an exception on heap exhaustion.
**      Returns NULL and sets errno if open() fails.
**      Returns an SM_FILE_T pointer on success.
*/

SM_FILE_T *
#if SM_VA_STD
sm_io_fopen(char *pathname, int flags, ...)
#else /* SM_VA_STD */
sm_io_fopen(pathname, flags, va_alist)
    char *pathname;
    int flags;
    va_dcl
#endif /* SM_VA_STD */
{
    MODE_T mode;
    SM_FILE_T *fp;
    int ioflags;

    if (flags & O_CREAT)
    {
        SM_VA_LOCAL_DECL

        SM_VA_START(ap, flags);
        mode = (MODE_T) SM_VA_ARG(ap, int);
        SM_VA_END(ap);
    }
    else
        mode = 0;

    switch (flags & O_ACCMODE)
    {
      case O_RDONLY:
        ioflags = SMRD;
        break;
      case O_WRONLY:
        ioflags = SMWR;
        break;
      case O_RDWR:
        ioflags = SMRW;
        break;
      default:
        sm_abort("sm_io_fopen: bad flags 0%o", flags);
    }

    fp = sm_fp(SmFtStdio, ioflags, NULL);
    fp->f_file = open(pathname, flags, mode);
    if (fp->f_file == -1)
    {
        fp->f_flags = 0;
        fp->sm_magic = NULL;
        return NULL;
    }
    return fp;
}