lib/other/fdopen.c

   1 /*
   2  * fdopen - convert a (UNIX) file descriptor into a FILE pointer
   3  */
   4 /* $Header$ */
   5
   6 #include        <stdlib.h>
   7 #include        "../stdio/loc_incl.h"
   8 #include        <stdio.h>
   9 #include        <sys/stat.h>
  10
  11 FILE *
  12 fdopen(fd, mode)
  13 int fd;
  14 _CONST char *mode;
  15 {
  16         register int i;
  17         struct stat st;
  18         FILE *stream;
  19         int flags = 0;
  20
  21         if (fd < 0) return (FILE *)NULL;
  22         for (i = 0; __iotab[i] != 0 ; i++)
  23                 if (i >= FOPEN_MAX-1)
  24                         return (FILE *)NULL;
  25
  26         switch(*mode++) {
  27         case 'r':
  28                 flags |= _IOREAD | _IOREADING;
  29                 break;
  30         case 'a':
  31                 flags |= _IOAPPEND;
  32         case 'w':
  33                 flags |= _IOWRITE | _IOWRITING;
  34                 break;
  35         default:
  36                 return (FILE *)NULL;
  37         }
  38         while(*mode) {
  39                 switch(*mode++) {
  40                 case 'b':
  41                         continue;
  42                 case '+':
  43                         flags |= _IOREAD | _IOWRITE;
  44                         continue;
  45                 /* The sequence may be followed by aditional characters */
  46                 default:
  47                         break;
  48                 }
  49                 break;
  50         }
  51
  52         if ( fstat( fd, &st ) < 0 ) {
  53                 return (FILE *)NULL;
  54         }
  55
  56         if ( st.st_mode & S_IFIFO ) {
  57                 flags |= _IOFIFO;
  58         }
  59
  60         if ((stream = (FILE *) malloc(sizeof(FILE))) == NULL) {
  61                 return (FILE *)NULL;
  62         }
  63
  64         if ((flags & _IOREAD) && (flags & _IOWRITE))
  65                 flags &= ~(_IOREADING | _IOWRITING);
  66
  67         stream->_count = 0;
  68         stream->_fd = fd;
  69         stream->_flags = flags;
  70         stream->_buf = NULL;
  71         __iotab[i] = stream;
  72         return stream;
  73 }