| 1 | /* @(#)findfp.c 1.2 (Berkeley) %G% */ |
| 2 | #include <stdio.h> |
| 3 | |
| 4 | #define NSTATIC 10 /* stdin, stdout, stderr, plus slack */ |
| 5 | |
| 6 | extern char *calloc(); |
| 7 | |
| 8 | static FILE *dummy[NSTATIC]; |
| 9 | static FILE **iov = NULL; |
| 10 | static FILE **iovend; |
| 11 | |
| 12 | FILE _iob[NSTATIC] = { |
| 13 | { 0, NULL, NULL, NULL, _IOREAD, 0 }, /* stdin */ |
| 14 | { 0, NULL, NULL, NULL, _IOWRT, 1 }, /* stdout */ |
| 15 | { 0, NULL, NULL, NULL, _IOWRT|_IONBF, 2 }, /* stderr */ |
| 16 | }; |
| 17 | |
| 18 | static char smallbuf[NSTATIC]; |
| 19 | static char *unbufp = NULL; |
| 20 | |
| 21 | FILE * |
| 22 | _findiop() |
| 23 | { |
| 24 | register FILE **iovp; |
| 25 | register FILE *fp; |
| 26 | register int nfiles; |
| 27 | |
| 28 | if (iov == NULL) { |
| 29 | unbufp = NULL; |
| 30 | iov = NULL; |
| 31 | fp = NULL; |
| 32 | |
| 33 | nfiles = getdtablesize(); |
| 34 | if (nfiles > NSTATIC) { |
| 35 | fp = (FILE *)calloc(nfiles - NSTATIC, sizeof *fp); |
| 36 | if (fp != NULL) { |
| 37 | iov = (FILE **)calloc(nfiles, sizeof *iov); |
| 38 | if (iov != NULL) |
| 39 | unbufp = calloc(nfiles, sizeof *unbufp); |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | if (unbufp != NULL) { |
| 44 | iovend = iov + nfiles; |
| 45 | for (iovp = iov + NSTATIC; iovp < iovend; /* void */) |
| 46 | *iovp++ = fp++; |
| 47 | } else { |
| 48 | if (fp != NULL) { |
| 49 | free((char *)fp); |
| 50 | if (iov != NULL) |
| 51 | free((char *)iov); |
| 52 | } |
| 53 | |
| 54 | iovend = dummy + NSTATIC; |
| 55 | iov = dummy; |
| 56 | } |
| 57 | |
| 58 | iovp = iov; |
| 59 | for (fp = _iob; fp < _iob + NSTATIC; /* void */) |
| 60 | *iovp++ = fp++; |
| 61 | } |
| 62 | |
| 63 | for (iovp = iov; (*iovp)->_flag & (_IOREAD|_IOWRT|_IORW); /* void */) |
| 64 | if (++iovp >= iovend) |
| 65 | return (NULL); |
| 66 | |
| 67 | return (*iovp); |
| 68 | } |
| 69 | |
| 70 | _cleanup() |
| 71 | { |
| 72 | register FILE *_lastbuf = _iob + NSTATIC; |
| 73 | register FILE **iovp; |
| 74 | register FILE *iop; |
| 75 | |
| 76 | if (iov == NULL) |
| 77 | for (iop = _iob; iop < _lastbuf; iop++) |
| 78 | fclose(iop); |
| 79 | else |
| 80 | for (iovp = iov; iovp < iovend; iovp++) |
| 81 | fclose(*iovp); |
| 82 | } |
| 83 | |
| 84 | char * |
| 85 | _smallbuf(iop) |
| 86 | register FILE *iop; |
| 87 | { |
| 88 | if (unbufp == NULL) |
| 89 | return (&smallbuf[iop - _iob]); |
| 90 | else |
| 91 | return (&unbufp[fileno(iop)]); |
| 92 | } |