[f40a309] | 1 | /*
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| 2 | ============================================================================
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| 3 | write.c -- write() and friends
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| 4 | Version 17 -- 1987-10-27 -- D.N. Lynx Crowe
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| 5 | ============================================================================
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| 6 | */
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| 7 |
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| 8 | #define DEBUGIT 0
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| 9 |
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| 10 | #include "biosdefs.h"
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| 11 | #include "io.h"
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| 12 | #include "errno.h"
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| 13 | #include "stddefs.h"
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| 14 |
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| 15 | int _filewr();
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| 16 |
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| 17 | extern int _badfd(), _conwr(), blkwr();
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| 18 | extern int ReadRN(), WriteRN();
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| 19 | extern int _newcls(), micons(), _ptcl12();
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| 20 |
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| 21 | extern long miconl();
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| 22 |
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| 23 | extern char *memset();
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| 24 |
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| 25 | extern short _fatmod;
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| 26 |
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| 27 | extern unsigned _thefat[];
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| 28 |
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| 29 | extern struct bpb *_thebpb;
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| 30 |
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| 31 | #if DEBUGIT
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| 32 | extern short fsdebug;
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| 33 | #endif
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| 34 |
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| 35 | static int (*wr_tab[])() = { /* write routine dispatch table */
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| 36 |
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| 37 | _badfd, /* 0 - invalid entry */
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| 38 | _filewr, /* 1 - disk file */
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| 39 | _conwr /* 2 - console device */
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| 40 | };
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| 41 |
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| 42 | /* |
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| 43 |
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| 44 | */
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| 45 |
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| 46 | /*
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| 47 | ============================================================================
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| 48 | _putsec(fp, buf, len) -- write 'len' bytes from 'buf' on file 'fp'
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| 49 | ============================================================================
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| 50 | */
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| 51 |
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| 52 | int
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| 53 | _putsec(fp, buf, len)
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| 54 | register struct fcb *fp;
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| 55 | char *buf;
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| 56 | unsigned len;
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| 57 | {
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| 58 | #if DEBUGIT
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| 59 | if (fsdebug)
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| 60 | printf("_putsec($%08lX, $%08lx, %d): initial curlsn=%ld\n",
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| 61 | fp, buf, len, fp->curlsn);
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| 62 | #endif
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| 63 |
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| 64 | if ((errno = ReadRN(fp, Wrkbuf)) EQ 1) { /* try to read sector */
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| 65 |
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| 66 | #if DEBUGIT
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| 67 | if (fsdebug)
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| 68 | printf("_putsec(): ReadRN saw EOF at curlsn=%ld, asects=%ld\n",
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| 69 | fp->curlsn, fp->asects);
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| 70 | #endif
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| 71 |
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| 72 | errno = 0; /* we're at EOF */
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| 73 | memset(Wrkbuf, 0x1A, BPSEC); /* pad end of sector */
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| 74 |
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| 75 | } else if (errno)
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| 76 | return(FAILURE);
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| 77 |
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| 78 | memcpy(Wrkbuf + fp->offset, buf, len); /* move in the new data */
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| 79 |
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| 80 | if ((errno = WriteRN(fp, Wrkbuf)) NE 0) { /* write the sector */
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| 81 |
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| 82 | #if DEBUGIT
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| 83 | if (fsdebug)
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| 84 | printf("_putsec(): WriteRN() FAILED (%d) - curlsn=%ld\n",
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| 85 | errno, fp->curlsn);
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| 86 | #endif
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| 87 |
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| 88 | return(FAILURE);
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| 89 | }
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| 90 |
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| 91 | if ((fp->offset = (fp->offset + len) & (BPSEC - 1)) EQ 0) {
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| 92 |
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| 93 | ++fp->curlsn; /* update file position */
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| 94 |
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| 95 | if (_seek(fp) < 0) {
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| 96 |
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| 97 | #if DEBUGIT
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| 98 | if (fsdebug)
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| 99 | printf("_putsec(): _seek() failed - curlsn=%ld, asects=%ld\n",
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| 100 | fp->curlsn, fp->asects);
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| 101 | #endif
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| 102 |
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| 103 | return(FAILURE);
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| 104 | }
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| 105 | }
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| 106 |
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| 107 | #if DEBUGIT
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| 108 | if (fsdebug)
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| 109 | printf("_putsec(): final curlsn=%ld, offset=%d, len=%d\n",
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| 110 | fp->curlsn, fp->offset, len);
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| 111 | #endif
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| 112 |
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| 113 | return(SUCCESS);
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| 114 | }
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| 115 |
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| 116 | /* |
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| 117 |
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| 118 | */
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| 119 |
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| 120 | /*
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| 121 | ============================================================================
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| 122 | _filewr(fp, buffer, len) -- write 'len' bytes on file 'fp'
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| 123 | from 'buffer'.
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| 124 | ============================================================================
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| 125 | */
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| 126 |
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| 127 | int
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| 128 | _filewr(fp, buffer, len)
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| 129 | register struct fcb *fp;
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| 130 | register char *buffer;
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| 131 | register unsigned len;
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| 132 | {
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| 133 | register unsigned j, k, l;
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| 134 | int clustr;
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| 135 | register long curpos;
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| 136 |
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| 137 | curpos = fp->offset + (fp->curlsn << FILESHFT); /* get position */
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| 138 |
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| 139 | if (fp->de.bclust EQ 0) { /* see if we need to allocate */
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| 140 |
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| 141 | #if DEBUGIT
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| 142 | if (fsdebug)
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| 143 | if (curpos)
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| 144 | printf("_filewr(): ERROR - bclust EQ 0 and curpos (%ld) NE 0\n",
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| 145 | curpos);
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| 146 | #endif
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| 147 |
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| 148 | if (0 EQ (clustr = _newcls())) { /* allocate a cluster */
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| 149 |
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| 150 | errno = EIO;
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| 151 | return(len);
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| 152 | }
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| 153 |
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| 154 | fp->de.bclust = micons(clustr); /* update FCB */
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| 155 | _ptcl12(_thefat, clustr, 0x0FF8); /* update FAT */
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| 156 | _fatmod = TRUE;
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| 157 | fp->curdsn = _cl2lsn(_thebpb, clustr); /* set curdsn */
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| 158 | fp->curcls = clustr;
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| 159 | fp->clsec = 0;
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| 160 | fp->asects = _thebpb->clsiz;
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| 161 | #if DEBUGIT
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| 162 | if (fsdebug) {
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| 163 |
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| 164 | printf("_filewr(): allocated initial cluster=%d, asects=%ld\n",
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| 165 | clustr, fp->asects);
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| 166 | SnapFCB(fp);
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| 167 | }
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| 168 | #endif
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| 169 | }
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| 170 |
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| 171 | l = 0; /* zero the length-written counter */
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| 172 |
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| 173 | #if DEBUGIT
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| 174 | if (fsdebug)
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| 175 | printf("_filewr(): init pos=%ld, len=%u, curcls=%u, offset=%u\n",
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| 176 | curpos, len, fp->curcls, fp->offset);
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| 177 | #endif
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| 178 |
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| 179 | if (fp->offset) { /* see if we have a partial sector to fill */
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| 180 |
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| 181 | if ((l = (BPSEC - fp->offset)) > len)
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| 182 | l = len;
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| 183 |
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| 184 | if (_putsec(fp, buffer, l)) /* fill up the sector */
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| 185 | return(-1);
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| 186 | }
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| 187 |
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| 188 | if (k = (len - l) / BPSEC) { /* write out any full sectors */
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| 189 |
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| 190 | if ((j = blkwr(fp, buffer + l, k)) NE 0) {
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| 191 |
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| 192 | l += (k - j) * BPSEC; /* update amount written */
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| 193 |
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| 194 | if ((curpos + l) > fp->curlen) /* udpate file length */
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| 195 | fp->de.flen = miconl(fp->curlen = curpos + l);
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| 196 |
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| 197 | #if DEBUGIT
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| 198 | if (fsdebug)
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| 199 | printf("_filewr(): ERROR - curlen=%ld, curlsn=%ld, curdsn=%ld\n",
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| 200 | fp->curlen, fp->curlsn, fp->curdsn);
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| 201 | #endif
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| 202 |
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| 203 | return(l);
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| 204 | }
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| 205 |
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| 206 | l += k * BPSEC; /* update amount written */
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| 207 | }
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| 208 | /* |
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| 209 |
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| 210 | */
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| 211 | if (l < len) { /* write out partial sector at end */
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| 212 |
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| 213 | if (_putsec(fp, buffer + l, len - l)) {
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| 214 |
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| 215 | if ((curpos + l) > fp->curlen) /* update file length */
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| 216 | fp->de.flen = miconl(fp->curlen = curpos + l);
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| 217 |
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| 218 | #if DEBUGIT
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| 219 | if (fsdebug)
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| 220 | printf("_filewr(): ERROR - curlen=%ld, curlsn=%ld, curdsn=%ld\n",
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| 221 | fp->curlen, fp->curlsn, fp->curdsn);
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| 222 | #endif
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| 223 |
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| 224 | return(l);
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| 225 | }
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| 226 | }
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| 227 |
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| 228 | if ((curpos + len) > fp->curlen) /* update file length */
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| 229 | fp->de.flen = miconl(fp->curlen = curpos + len);
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| 230 |
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| 231 | #if DEBUGIT
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| 232 | if (fsdebug)
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| 233 | printf("_filewr(): final curlen=%ld, flen=$%08lX, curlsn=%ld, curdsn=%ld\n",
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| 234 | fp->curlen, fp->de.flen, fp->curlsn, fp->curdsn);
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| 235 | #endif
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| 236 |
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| 237 | return(len);
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| 238 | }
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| 239 |
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| 240 | /* |
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| 241 |
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| 242 | */
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| 243 |
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| 244 | /*
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| 245 | ============================================================================
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| 246 | write(fd, buff, len) -- write 'len' bytes from 'buff' on file 'fd'
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| 247 | ============================================================================
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| 248 | */
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| 249 |
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| 250 | int
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| 251 | write(fd, buff, len)
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| 252 | int fd;
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| 253 | char *buff;
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| 254 | unsigned len;
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| 255 | {
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| 256 | register struct channel *chp;
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| 257 |
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| 258 | if ((fd < 0) OR (fd > MAXCHAN)) {
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| 259 |
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| 260 | errno = EBADF;
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| 261 | return(-1);
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| 262 | }
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| 263 |
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| 264 | chp = &chantab[fd];
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| 265 |
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| 266 | return((*wr_tab[chp->c_write])(chp->c_arg, buff, len));
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| 267 | }
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