ref: 7a503757b1251c2746df7bdcd891814c1518cc28
dir: /sys/src/cmd/aux/flashfs/devfs.c/
#include <u.h> #include <libc.h> #include <auth.h> #include <fcall.h> #include <thread.h> #include <9p.h> #include "flashfs.h" static char* file; static int fd; static uchar *ones; static int isdev; struct { int dfd; /* data */ int cfd; /* control */ } flash; void initdata(char *f, int) { char err[ERRMAX]; char buf[1024], *fld[8]; int n; Dir *d; isdev = 1; flash.dfd = open(f, ORDWR); if(flash.dfd < 0){ errstr(err, sizeof err); if((flash.dfd = create(f, ORDWR, 0666)) >= 0){ fprint(2, "warning: created plain file %s\n", buf); goto Plain; } errstr(err, sizeof err); /* restore open error */ sysfatal("opening %s: %r", f); } if(snprint(buf, sizeof buf, "%sctl", f) != strlen(f)+3) sysfatal("path too long: %s", f); flash.cfd = open(buf, ORDWR); if(flash.cfd < 0){ fprint(2, "warning: cannot open %s (%r); assuming plain file\n", buf); Plain: isdev = 0; if(sectsize == 0) sectsize = 512; if(nsects == 0){ if((d = dirstat(f)) == nil) sysfatal("stat %s: %r", f); nsects = d->length / sectsize; free(d); } ones = emalloc9p(sectsize); memset(ones, ~0, sectsize); }else{ n = read(flash.cfd, buf, sizeof(buf)-1); if(n <= 0) sysfatal("reading %sctl: %r", f); buf[n] = 0; n = tokenize(buf, fld, nelem(fld)); if(n < 7) sysfatal("bad flash geometry"); nsects = atoi(fld[5]); sectsize = atoi(fld[6]); if(nsects < 8) sysfatal("unreasonable value for nsects: %lud", nsects); if(sectsize < 512) sysfatal("unreasonable value for sectsize: %lud", sectsize); } } void clearsect(int sect) { if(isdev==0){ if(pwrite(flash.dfd, ones, sectsize, sect*sectsize) != sectsize) sysfatal("couldn't erase sector %d: %r", sect); }else{ if(fprint(flash.cfd, "erase %lud", sect * sectsize) < 0) sysfatal("couldn't erase sector %d: %r", sect); } } void readdata(int sect, void *buff, ulong count, ulong off) { long n; ulong m; m = sect * sectsize + off; n = pread(flash.dfd, buff, count, m); if(n < 0) sysfatal("error reading at %lux: %r", m); if(n != count) sysfatal("short read at %lux, %ld instead of %lud", m, n, count); } int writedata(int err, int sect, void *buff, ulong count, ulong off) { long n; ulong m; m = sect*sectsize + off; n = pwrite(flash.dfd, buff, count, m); if(n < 0){ if(err) return 0; sysfatal("error writing at %lux: %r", m); } if(n != count){ if(err) return 0; sysfatal("short write at %lud, %ld instead of %lud", m, n, count); } return 1; }