projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| c6bee192 BJ |
1 | /* Copyright (c) 1979 Regents of the University of California */ |
| 2 | #include <nstdio.h> | |
| 3 | ||
| 4 | struct _iobuf *fopen(file, mode) | |
| 5 | register char *mode; | |
| 6 | { | |
| 7 | register f; | |
| 8 | register struct _iobuf *iop; | |
| 9 | int unixmode, a_flag, noclob; | |
| 10 | ||
| 11 | for (iop = _iob; iop->_flag&(_IOREAD|_IOWRT); iop++) | |
| 12 | if (iop >= _iob + _NFILE) | |
| 13 | return(NULL); | |
| 14 | iop->_flag = 0; | |
| 15 | iop->_delta = 0; | |
| 16 | a_flag = 0; | |
| 17 | noclob = 0; | |
| 18 | for(;*mode;mode++) { | |
| 19 | switch(*mode) { | |
| 20 | ||
| 21 | case 'w': | |
| 22 | iop->_flag |= _IOWRT; | |
| 23 | break; | |
| 24 | ||
| 25 | case 'r': | |
| 26 | iop->_flag |= _IOREAD; | |
| 27 | break; | |
| 28 | ||
| 29 | case 'a': | |
| 30 | a_flag = 1; | |
| 31 | noclob = 1; | |
| 32 | iop->_flag |= _IOWRT ; | |
| 33 | break; | |
| 34 | ||
| 35 | case '+': | |
| 36 | if (iop->_flag & _IOREAD) | |
| 37 | noclob = 1; | |
| 38 | iop->_flag |= (_IOREAD | _IOWRT); | |
| 39 | break; | |
| 40 | } | |
| 41 | } | |
| 42 | if((unixmode = (iop->_flag & 3) - 1) < 0) { | |
| 43 | unixmode = 0; | |
| 44 | iop->_flag = 1; | |
| 45 | } | |
| 46 | if ((iop->_flag & _IOWRT) && noclob==0 ) { | |
| 47 | f = creat(file, 0644); | |
| 48 | if((iop->_flag & _IOREAD) && (f>0)) { | |
| 49 | close(f); | |
| 50 | f = open(file,2); | |
| 51 | } | |
| 52 | } | |
| 53 | else | |
| 54 | if ((0 >(f = open(file, unixmode))) && (noclob || !(iop->_flag&_IOREAD))) { | |
| 55 | f = creat(file, 0644); | |
| 56 | close(f); | |
| 57 | f = open(file,unixmode); | |
| 58 | } | |
| 59 | ||
| 60 | if (f < 0) | |
| 61 | return(NULL); | |
| 62 | if (a_flag) | |
| 63 | lseek(f, (long) 0, 2); | |
| 64 | iop->_file = f; | |
| 65 | return(iop); | |
| 66 | } |