ref: 57f8b3d1acf273a88568c49d0b83b6863485b9e0
dir: /sys/src/cmd/cwfs/fworm.c/
#include "all.h" #define FDEV(d) ((d)->fw.fw) Devsize fwormsize(Device *d) { Devsize l; l = devsize(FDEV(d)); l -= l/(BUFSIZE*8) + 1; return l; } void fwormream(Device *d) { Iobuf *p; Device *fdev; Off a, b; if(chatty) print("fworm ream\n"); devinit(d); fdev = FDEV(d); a = fwormsize(d); b = devsize(fdev); if(chatty){ print("\tfwsize = %lld\n", (Wideoff)a); print("\tbwsize = %lld\n", (Wideoff)b-a); } for(; a < b; a++) { p = getbuf(fdev, a, Bmod|Bres); if(!p) panic("fworm: init"); memset(p->iobuf, 0, RBUFSIZE); settag(p, Tvirgo, a); putbuf(p); } } void fworminit(Device *d) { print("fworm init\n"); devinit(FDEV(d)); } int fwormread(Device *d, Off b, void *c) { Iobuf *p; Device *fdev; Devsize l; if(chatty > 1) fprint(2, "fworm read %lld\n", (Wideoff)b); fdev = FDEV(d); l = devsize(fdev); l -= l/(BUFSIZE*8) + 1; if(b >= l) panic("fworm: rbounds %lld", (Wideoff)b); l += b/(BUFSIZE*8); p = getbuf(fdev, l, Brd|Bres); if(!p || checktag(p, Tvirgo, l)) panic("fworm: checktag %lld", (Wideoff)l); l = b % (BUFSIZE*8); if(!(p->iobuf[l/8] & (1<<(l%8)))) { putbuf(p); fprint(2, "fworm: read %lld\n", (Wideoff)b); return 1; } putbuf(p); return devread(fdev, b, c); } int fwormwrite(Device *d, Off b, void *c) { Iobuf *p; Device *fdev; Devsize l; if(chatty > 1) fprint(2, "fworm write %lld\n", (Wideoff)b); fdev = FDEV(d); l = devsize(fdev); l -= l/(BUFSIZE*8) + 1; if(b >= l) panic("fworm: wbounds %lld", (Wideoff)b); l += b/(BUFSIZE*8); p = getbuf(fdev, l, Brd|Bmod|Bres); if(!p || checktag(p, Tvirgo, l)) panic("fworm: checktag %lld", (Wideoff)l); l = b % (BUFSIZE*8); if((p->iobuf[l/8] & (1<<(l%8)))) { putbuf(p); fprint(2, "fworm: write %lld\n", (Wideoff)b); return 1; } p->iobuf[l/8] |= 1<<(l%8); putbuf(p); return devwrite(fdev, b, c); }