ref: 614b18484cb754c4ba936d143016b558845073b1
dir: /sys/src/9/xen/dpart.c/
#include <u.h> #include <libc.h> #include <disk.h> typedef void Fs; #include "/sys/src/boot/pc/dosfs.h" enum { Npart = 32 }; #define GSHORT(p) (((p)[1]<<8)|(p)[0]) #define GLONG(p) ((GSHORT(p+2)<<16)|GSHORT(p)) int readdisk(Disk *d, void *buf, vlong off, int len) { if(seek(d->fd, off, 0) == -1 || read(d->fd, buf, len) != len) return -1; return 0; } void addpart(Disk *d, char *name, ulong s, ulong e) { print("%s: part %s %lud %lud\n", d->prefix, name, s, e); fprint(d->ctlfd, "part %s %lud %lud\n", name, s, e); } int isdos(int t) { return t==FAT12 || t==FAT16 || t==FATHUGE || t==FAT32 || t==FAT32X; } int isextend(int t) { return t==EXTEND || t==EXTHUGE || t==LEXTEND; } /* build a cdboot partition if there is an embedded boot floppy image */ int cdpart(Disk *d) { uchar buf[2048]; ulong a, n; uchar *p; if(readdisk(d, buf, 17*2048, 2048) == -1 || strcmp((char*)buf+1, "CD001\x01EL TORITO SPECIFICATION") != 0) return 0; p = buf + 0x47; a = p[0] | (p[1]<<8) | (p[2]<<16) | (p[3]<<24); if(readdisk(d, buf, a*2048, 2048) == -1 || memcmp((char*)buf, "\x01\x00\x00\x00", 4) != 0 || memcmp((char*)buf+30, "\x55\xAA", 2) != 0 || buf[0x20] != 0x88) return 0; p = buf+0x28; a = p[0]|(p[1]<<8)|(p[2]<<16)|(p[3]<<24); switch(buf[0x21]) { case 1: n = 1200*1024; break; case 2: n = 1440*1024; break; case 3: n = 2880*1024; break; default: return 0; } a = a * (uvlong)2048 / d->secsize; n /= d->secsize; addpart(d, "cdboot", a, a+n); return 1; } int p9part(Disk *d, char *name, ulong pstart) { char partbuf[512]; char *field[4], *line[Npart+1], *name2; ulong start, end; int i, n; name2 = smprint("%s%s", d->prefix, name); d = opendisk(name2, 1, 0); if(!d) { fprint(2, "%s: %r\n", name2); free(name2); return 0; } free(name2); if(readdisk(d, partbuf, 512, sizeof partbuf) == -1) return 0; partbuf[sizeof partbuf - 1] = '\0'; if(strncmp(partbuf, "part ", 5) != 0 || (n = getfields(partbuf, line, Npart+1, 0, "\n")) == 0) return 0; for(i = 0; i < n; i++) { if(strncmp(line[i], "part ", 5) != 0) break; if(getfields(line[i], field, 4, 0, " ") != 4) break; start = strtoul(field[2], 0, 0); end = strtoul(field[3], 0, 0); if(start >= end) break; addpart(d, field[1], pstart+start, pstart+end); } return 0; } int mbrpart(Disk *d) { uchar mbrbuf[512]; char name[10]; Dospart *dp; ulong taboffset, start, end; ulong firstxpart, nxtxpart; int i, nplan9, havedos; #define readmbr() \ if(readdisk(d, mbrbuf, (uvlong)taboffset*512, sizeof mbrbuf) == -1 \ || mbrbuf[0x1FE] != 0x55 || mbrbuf[0x1FF] != 0xAA) \ return 0 if(d->secsize > 512) return 0; dp = (Dospart*)&mbrbuf[0x1BE]; taboffset = 0; if(1) { /* get the MBR (allowing for DMDDO) */ readmbr(); for(i = 0; i < 4; i++) { if(dp[i].type == DMDDO) { taboffset = 63; readmbr(); i = -1; /* start over */ } } } /* * Read the partitions, first from the MBR and then * from successive extended partition tables. */ nplan9 = 0; havedos = 0; firstxpart = 0; for(;;) { readmbr(); nxtxpart = 0; for(i = 0; i < 4; i++) { /* partition offsets are relative to taboffset */ start = taboffset+GLONG(dp[i].start); end = start+GLONG(dp[i].len); if(dp[i].type == PLAN9) { if(nplan9 == 0) strcpy(name, "plan9"); else sprint(name, "plan9.%d", nplan9); addpart(d, name, start, end); p9part(d, name, start); nplan9++; } if(!havedos && isdos(dp[i].type)) { havedos = 1; addpart(d, "dos", start, end); } /* nxtxpart is relative to firstxpart (or 0), not taboffset */ if(isextend(dp[i].type)) nxtxpart = start-taboffset+firstxpart; } if(!nxtxpart) break; if(!firstxpart) firstxpart = nxtxpart; taboffset = nxtxpart; } return nplan9 + havedos; } void partall(void) { Disk *d; Dir *ent; char *name; int fd, i, n; fd = open("#S", OREAD); if(fd == -1) { fprint(2, "No disk\n"); return; } while((n = dirread(fd, &ent)) > 0) { for(i = 0; i < n; i++) { if(ent[i].mode & DMDIR) { name = smprint("#S/%s/data", ent[i].name); d = opendisk(name, 1, 0); if(!d) { fprint(2, "%s: %r\n", name); continue; } // XXX not safe yet: if(!mbrpart(d) && !cdpart(d) && !p9part(d, "data", 0)) if(!mbrpart(d) && !cdpart(d)) fprint(2, "%s: no partitions\n", name); close(d->fd); } } } close(fd); } void main(int argc, char **argv) { USED(argc, argv); fmtinstall('r', errfmt); bind("#c", "/dev", MBEFORE); open("/dev/cons", OREAD); open("/dev/cons", OWRITE); open("/dev/cons", OWRITE); partall(); close(0); close(1); close(2); exec("/boot/boot2", argv); exits(0); }