sys/src/libbio/binit.c

   1 #include        <u.h>
   2 #include        <libc.h>
   3 #include        <bio.h>
   4
   5 static  Biobufhdr*      wbufs[20];
   6 static  int             atexitflag;
   7
   8 static
   9 void
  10 batexit(void)
  11 {
  12         Biobufhdr *bp;
  13         int i;
  14
  15         for(i=0; i<nelem(wbufs); i++) {
  16                 bp = wbufs[i];
  17                 if(bp != 0) {
  18                         wbufs[i] = 0;
  19                         Bflush(bp);
  20                 }
  21         }
  22 }
  23
  24 static
  25 void
  26 deinstall(Biobufhdr *bp)
  27 {
  28         int i;
  29
  30         for(i=0; i<nelem(wbufs); i++)
  31                 if(wbufs[i] == bp)
  32                         wbufs[i] = 0;
  33 }
  34
  35 static
  36 void
  37 install(Biobufhdr *bp)
  38 {
  39         int i;
  40
  41         deinstall(bp);
  42         for(i=0; i<nelem(wbufs); i++)
  43                 if(wbufs[i] == 0) {
  44                         wbufs[i] = bp;
  45                         break;
  46                 }
  47         if(atexitflag == 0) {
  48                 atexitflag = 1;
  49                 atexit(batexit);
  50         }
  51 }
  52
  53 int
  54 Binits(Biobufhdr *bp, int f, int mode, uchar *p, int size)
  55 {
  56
  57         p += Bungetsize;        /* make room for Bungets */
  58         size -= Bungetsize;
  59
  60         switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
  61         default:
  62                 fprint(2, "Binits: unknown mode %d\n", mode);
  63                 return Beof;
  64
  65         case OREAD:
  66                 bp->state = Bractive;
  67                 bp->ocount = 0;
  68                 break;
  69
  70         case OWRITE:
  71                 install(bp);
  72                 bp->state = Bwactive;
  73                 bp->ocount = -size;
  74                 break;
  75         }
  76         bp->bbuf = p;
  77         bp->ebuf = p+size;
  78         bp->bsize = size;
  79         bp->icount = 0;
  80         bp->gbuf = bp->ebuf;
  81         bp->fid = f;
  82         bp->flag = 0;
  83         bp->rdline = 0;
  84         bp->offset = 0;
  85         bp->runesize = 0;
  86         return 0;
  87 }
  88
  89
  90 int
  91 Binit(Biobuf *bp, int f, int mode)
  92 {
  93         return Binits(bp, f, mode, bp->b, sizeof(bp->b));
  94 }
  95
  96 Biobuf*
  97 Bopen(char *name, int mode)
  98 {
  99         Biobuf *bp;
 100         int f;
 101
 102         switch(mode&~(OCEXEC|ORCLOSE|OTRUNC)) {
 103         default:
 104                 fprint(2, "Bopen: unknown mode %#x\n", mode);
 105                 return 0;
 106         case OREAD:
 107                 f = open(name, mode);
 108                 break;
 109         case OWRITE:
 110                 f = create(name, mode, 0666);
 111                 break;
 112         }
 113         if(f < 0)
 114                 return 0;
 115         bp = malloc(sizeof(Biobuf));
 116         Binits(bp, f, mode, bp->b, sizeof(bp->b));
 117         bp->flag = Bmagic;                      /* mark bp open & malloced */
 118         return bp;
 119 }
 120
 121 int
 122 Bterm(Biobufhdr *bp)
 123 {
 124         int r;
 125
 126         deinstall(bp);
 127         r = Bflush(bp);
 128         if(bp->flag == Bmagic) {
 129                 bp->flag = 0;
 130                 close(bp->fid);
 131                 bp->fid = -1;                   /* prevent accidents */
 132                 free(bp);
 133         }
 134         /* otherwise opened with Binit(s) */
 135         return r;
 136 }