1 | /*
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2 | =============================================================================
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3 | writern.c -- write a random sector onto a file
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4 | Version 6 -- 1987-12-15 -- D.N. Lynx Crowe
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5 |
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6 | int
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7 | WriteRN(fcp, buf)
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8 | struct fcb *fcp;
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9 | char *buf;
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10 |
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11 | Writes a sector onto file 'fcp' from 'buf'. Seeks as needed.
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12 | Returns SUCCESS (0) if OK, FAILURE (-1) for errors.
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13 | =============================================================================
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14 | */
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15 |
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16 | #define DEBUGIT 0
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17 |
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18 | #include "stddefs.h"
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19 | #include "biosdefs.h"
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20 | #include "errno.h"
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21 | #include "errdefs.h"
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22 | #include "fspars.h"
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23 |
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24 | extern int32_t _berrno;
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25 | extern int16_t _seek(struct fcb *fcp);
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26 |
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27 | #if DEBUGIT
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28 | extern short fsdebug;
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29 | #endif
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30 |
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31 | #if TBUFFER
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32 | extern int32_t _secwr(int8_t *buf, int16_t rec);
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33 | #endif
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34 |
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35 | /* |
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36 |
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37 | */
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38 |
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39 | /*
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40 | =============================================================================
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41 | WriteRN(fcp, buf) -- Writes a sector onto file 'fcp' from 'buf'.
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42 | Seeks as needed. Returns SUCCESS (0) if OK, FAILURE (-1) for errors.
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43 | =============================================================================
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44 | */
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45 |
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46 | int16_t WriteRN(struct fcb *fcp, int8_t *buf)
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47 | {
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48 | int16_t sv; /* seek return code */
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49 | int32_t brc; /* bios return code */
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50 |
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51 | if (sv = _seek(fcp)) { /* try to find the sector we want */
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52 |
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53 | if (sv < 0) { /* seek error ? */
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54 |
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55 | #if DEBUGIT
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56 | if (fsdebug)
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57 | printf("WriteRN(): _seek FAILED (%d) - curlsn=%ld, curdsn=%ld\n",
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58 | sv, fcp->curlsn, fcp->curdsn);
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59 | #endif
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60 |
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61 | errno = EIO; /* I/O error or seek past EOF */
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62 | return(FAILURE);
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63 |
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64 | } else if (sv EQ 2) { /* at hard EOF ? */
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65 |
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66 | if (_alcnew(fcp)) { /* allocate a new cluster */
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67 |
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68 | errno = EIO;
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69 | return(FAILURE);
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70 | }
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71 | #if DEBUGIT
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72 | if (fsdebug)
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73 | printf("WriteRN(): cluster allocated - curcls=%d, clsec=%d\n",
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74 | fcp->curcls, fcp->clsec);
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75 | #endif
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76 |
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77 | }
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78 | }
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79 |
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80 | #if DEBUGIT
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81 | if (fsdebug)
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82 | printf("WriteRN(): curlsn=%ld, curdsn=%ld\n",
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83 | fcp->curlsn, fcp->curdsn);
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84 | #endif
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85 |
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86 | /* write the sector */
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87 |
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88 | if (brc = BIOS(B_RDWR, 1, buf, 1, (int16_t)fcp->curdsn, 0)) {
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89 |
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90 | #if DEBUGIT
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91 | if (fsdebug)
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92 | printf("WriteRN(): B_RDWR FAILED - brc=%ld\n", brc);
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93 | #endif
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94 |
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95 | _berrno = brc; /* log the error */
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96 | errno = EIO; /* ... as an I/O error */
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97 | return(FAILURE); /* return: ERROR */
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98 | }
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99 |
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100 | #if TBUFFER
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101 | _secwr(buf, (int16_t)fcp->curdsn);
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102 | #endif
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103 |
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104 | return(SUCCESS); /* return: SUCCESS */
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105 | }
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