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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