#include <u.h>#include <libc.h>#include <authsrv.h> static long finddosfile(int, char*); static intcheck(void *x, int len, uchar sum, char *msg){ if(nvcsum(x, len) == sum) return 0; memset(x, 0, len); fprint(2, "%s\n", msg); return 1;} /* * get key info out of nvram. since there isn't room in the PC's nvram use * a disk partition there. */static struct { char *cputype; char *file; int off; int len;} nvtab[] = { "sparc", "#r/nvram", 1024+850, sizeof(Nvrsafe), "pc", "#S/%s%x/9fat", -1, 512, "pc", "#S/%s%x/nvram", 0, 512, "pc", "#f/fd0disk", -1, 512, /* 512: #f requires whole sector reads */ "pc", "#f/fd1disk", -1, 512, "amd64", "#S/%s%x/9fat", -1, 512, "amd64", "#S/%s%x/nvram", 0, 512, "mips", "#r/nvram", 1024+900, sizeof(Nvrsafe), "power", "#F/flash/flash0", 0x440000, sizeof(Nvrsafe), "power", "#F/flash/flash", 0x440000, sizeof(Nvrsafe), "power", "#r/nvram", 4352, sizeof(Nvrsafe), /* OK for MTX-604e */ "power", "/nvram", 0, sizeof(Nvrsafe), /* OK for Ucu */ "arm", "#F/flash/flash0", 0x100000, sizeof(Nvrsafe), "arm", "#F/flash/flash", 0x100000, sizeof(Nvrsafe), "debug", "/tmp/nvram", 0, sizeof(Nvrsafe),}; static char*readcons(char *prompt, char *def, int raw, char *buf, int nbuf, int nilok){ int fdin, fdout, ctl, n, m; char line[10]; fdin = open("/dev/cons", OREAD); if(fdin < 0) fdin = 0; fdout = open("/dev/cons", OWRITE); if(fdout < 0) fdout = 1;redux: if(def != nil) fprint(fdout, "%s[%s]: ", prompt, def); else fprint(fdout, "%s: ", prompt); if(raw){ ctl = open("/dev/consctl", OWRITE); if(ctl >= 0) write(ctl, "rawon", 5); } else ctl = -1; m = 0; for(;;){ n = read(fdin, line, 1); if(n == 0){ close(ctl); werrstr("readcons: EOF"); return nil; } if(n < 0){ close(ctl); werrstr("can't read cons"); return nil; } if(line[0] == 0x7f) exits(0); if(n == 0 || line[0] == '\n' || line[0] == '\r'){ if(raw){ write(ctl, "rawoff", 6); write(fdout, "\n", 1); close(ctl); } buf[m] = '\0'; if(buf[0]=='\0' && def) strcpy(buf, def); if(buf[0]=='\0' && !nilok) goto redux; return buf; } if(line[0] == '\b'){ if(m > 0) m--; }else if(line[0] == 0x15){ /* ^U: line kill */ m = 0; if(def != nil) fprint(fdout, "%s[%s]: ", prompt, def); else fprint(fdout, "%s: ", prompt); }else{ if(m >= nbuf-1){ fprint(fdout, "line too long\n"); m = 0; if(def != nil) fprint(fdout, "%s[%s]: ", prompt, def); else fprint(fdout, "%s: ", prompt); }else buf[m++] = line[0]; } }} static intsdnvram0(char *s, int l, int tabi){ char *p, *f[3], buf[16]; int fd, i; s[l] = 0; for(; p = strchr(s, '\n'); s = p + 1){ *p = 0; if(tokenize(s, f, nelem(f)) < 1) continue; for(i = 0; i < 0x10; i++){ snprint(buf, sizeof buf, nvtab[tabi].file, f[0], i); if((fd = open(buf, ORDWR)) >= 0) return fd; } } return -1;} static intsdnvram(int tabi){ char *s; int fd, l, r; fd = open("#S/sdctl", OREAD); if(fd == -1) return -1; r = -1; l = 1024; /* #S/sdctl has 0 size; guess */ if(s = malloc(l + 1)) if((l = read(fd, s, l)) > 0) r = sdnvram0(s, l, tabi); free(s); close(fd); return r;} typedef struct { int fd; int safeoff; int safelen;} Nvrwhere; /* returns with *locp filled in and locp->fd open, if possible */static voidfindnvram(Nvrwhere *locp){ char *cputype, *nvrfile, *nvrlen, *nvroff, *v[2]; int fd, i, safeoff, safelen; nvrfile = getenv("nvram"); cputype = getenv("cputype"); if(cputype == nil) cputype = strdup("mips"); if(strcmp(cputype, "386")==0 || strcmp(cputype, "alpha")==0) { free(cputype); cputype = strdup("pc"); } fd = -1; safeoff = -1; safelen = -1; if(nvrfile != nil && *nvrfile != '\0'){ /* accept device and device!file */ i = gettokens(nvrfile, v, nelem(v), "!"); if (i < 1) { i = 1; v[0] = ""; v[1] = nil; } fd = open(v[0], ORDWR); if (fd < 0) fd = open(v[0], OREAD); safelen = sizeof(Nvrsafe); if(strstr(v[0], "/9fat") == nil) safeoff = 0; nvrlen = getenv("nvrlen"); if(nvrlen != nil) safelen = atoi(nvrlen); nvroff = getenv("nvroff"); if(nvroff != nil) if(strcmp(nvroff, "dos") == 0) safeoff = -1; else safeoff = atoi(nvroff); if(safeoff < 0 && fd >= 0){ safelen = 512; safeoff = finddosfile(fd, i == 2? v[1]: "plan9.nvr"); if(safeoff < 0){ /* didn't find plan9.nvr? */ close(fd); fd = -1; } } free(nvroff); free(nvrlen); }else for(i=0; i<nelem(nvtab); i++){ if(strcmp(cputype, nvtab[i].cputype) != 0) continue; if(nvtab[i].file[0] == '#' && nvtab[i].file[1] == 'S') fd = sdnvram(i); else fd = open(nvtab[i].file, ORDWR); if(fd < 0) continue; safeoff = nvtab[i].off; safelen = nvtab[i].len; if(safeoff == -1){ safeoff = finddosfile(fd, "plan9.nvr"); if(safeoff < 0){ /* didn't find plan9.nvr? */ close(fd); fd = -1; continue; } } break; } free(nvrfile); free(cputype); locp->fd = fd; locp->safelen = safelen; locp->safeoff = safeoff;} /* * get key info out of nvram. since there isn't room in the PC's nvram use * a disk partition there. */intreadnvram(Nvrsafe *safep, int flag){ int err; char buf[512], in[128]; /* 512 for floppy i/o */ Nvrsafe *safe; Nvrwhere loc; err = 0; safe = (Nvrsafe*)buf; memset(&loc, 0, sizeof loc); findnvram(&loc); if (loc.safelen < 0) loc.safelen = sizeof *safe; else if (loc.safelen > sizeof buf) loc.safelen = sizeof buf; if (loc.safeoff < 0) { fprint(2, "readnvram: couldn't find nvram\n"); if(!(flag&NVwritemem)) memset(safep, 0, sizeof(*safep)); safe = safep; /* * allow user to type the data for authentication, * even if there's no nvram to store it in. */ } if(flag&NVwritemem) safe = safep; else { memset(safep, 0, sizeof(*safep)); if(loc.fd < 0 || seek(loc.fd, loc.safeoff, 0) < 0 || read(loc.fd, buf, loc.safelen) != loc.safelen){ err = 1; if(flag&(NVwrite|NVwriteonerr)) fprint(2, "can't read nvram: %r\n"); /* start from scratch */ memset(safep, 0, sizeof(*safep)); safe = safep; }else{ *safep = *safe; /* overwrite arg with data read */ safe = safep; /* verify data read */ err |= check(safe->machkey, DESKEYLEN, safe->machsum, "bad nvram key");// err |= check(safe->config, CONFIGLEN, safe->configsum,// "bad secstore key"); err |= check(safe->authid, ANAMELEN, safe->authidsum, "bad authentication id"); err |= check(safe->authdom, DOMLEN, safe->authdomsum, "bad authentication domain"); if(err == 0) if(safe->authid[0]==0 || safe->authdom[0]==0){ fprint(2, "empty nvram authid or authdom\n"); err = 1; } } } if((flag&(NVwrite|NVwritemem)) || (err && (flag&NVwriteonerr))){ if (!(flag&NVwritemem)) { readcons("authid", nil, 0, safe->authid, sizeof safe->authid, 0); readcons("authdom", nil, 0, safe->authdom, sizeof safe->authdom, 0); readcons("secstore key", nil, 1, safe->config, sizeof safe->config, 1); for(;;){ if(readcons("password", nil, 1, in, sizeof in, 0) == nil) goto Out; if(passtokey(safe->machkey, in)) break; } } // safe->authsum = nvcsum(safe->authkey, DESKEYLEN); safe->machsum = nvcsum(safe->machkey, DESKEYLEN); safe->configsum = nvcsum(safe->config, CONFIGLEN); safe->authidsum = nvcsum(safe->authid, sizeof safe->authid); safe->authdomsum = nvcsum(safe->authdom, sizeof safe->authdom); *(Nvrsafe*)buf = *safe; if(loc.fd < 0 || seek(loc.fd, loc.safeoff, 0) < 0 || write(loc.fd, buf, loc.safelen) != loc.safelen){ fprint(2, "can't write key to nvram: %r\n"); err = 1; }else err = 0; }Out: if (loc.fd >= 0) close(loc.fd); return err? -1: 0;} typedef struct Dosboot Dosboot;struct Dosboot{ uchar magic[3]; /* really an xx86 JMP instruction */ uchar version[8]; uchar sectsize[2]; uchar clustsize; uchar nresrv[2]; uchar nfats; uchar rootsize[2]; uchar volsize[2]; uchar mediadesc; uchar fatsize[2]; uchar trksize[2]; uchar nheads[2]; uchar nhidden[4]; uchar bigvolsize[4]; uchar driveno; uchar reserved0; uchar bootsig; uchar volid[4]; uchar label[11]; uchar type[8];};#define GETSHORT(p) (((p)[1]<<8) | (p)[0])#define GETLONG(p) ((GETSHORT((p)+2) << 16) | GETSHORT((p))) typedef struct Dosdir Dosdir;struct Dosdir{ char name[8]; char ext[3]; uchar attr; uchar reserved[10]; uchar time[2]; uchar date[2]; uchar start[2]; uchar length[4];}; static char*dosparse(char *from, char *to, int len){ char c; memset(to, ' ', len); if(from == 0) return 0; while(len-- > 0){ c = *from++; if(c == '.') return from; if(c == 0) break; if(c >= 'a' && c <= 'z') *to++ = c + 'A' - 'a'; else *to++ = c; } return 0;} /* * return offset of first file block * * This is a very simplistic dos file system. It only * works on floppies, only looks in the root, and only * returns a pointer to the first block of a file. * * This exists for cpu servers that have no hard disk * or nvram to store the key on. * * Please don't make this any smarter: it stays resident * and I'd prefer not to waste the space on something that * runs only at boottime -- presotto. */static longfinddosfile(int fd, char *file){ uchar secbuf[512]; char name[8]; char ext[3]; Dosboot *b; Dosdir *root, *dp; int nroot, sectsize, rootoff, rootsects, n; /* dos'ize file name */ file = dosparse(file, name, 8); dosparse(file, ext, 3); /* read boot block, check for sanity */ b = (Dosboot*)secbuf; if(read(fd, secbuf, sizeof(secbuf)) != sizeof(secbuf)) return -1; if(b->magic[0] != 0xEB || b->magic[1] != 0x3C || b->magic[2] != 0x90) return -1; sectsize = GETSHORT(b->sectsize); if(sectsize != 512) return -1; rootoff = (GETSHORT(b->nresrv) + b->nfats*GETSHORT(b->fatsize)) * sectsize; if(seek(fd, rootoff, 0) < 0) return -1; nroot = GETSHORT(b->rootsize); rootsects = (nroot*sizeof(Dosdir)+sectsize-1)/sectsize; if(rootsects <= 0 || rootsects > 64) return -1; /* * read root. it is contiguous to make stuff like * this easier */ root = malloc(rootsects*sectsize); if(read(fd, root, rootsects*sectsize) != rootsects*sectsize) return -1; n = -1; for(dp = root; dp < &root[nroot]; dp++) if(memcmp(name, dp->name, 8) == 0 && memcmp(ext, dp->ext, 3) == 0){ n = GETSHORT(dp->start); break; } free(root); if(n < 0) return -1; /* * dp->start is in cluster units, not sectors. The first * cluster is cluster 2 which starts immediately after the * root directory */ return rootoff + rootsects*sectsize + (n-2)*sectsize*b->clustsize;}
#include <u.h>
#include <libc.h>
#include <authsrv.h>
static long finddosfile(int, char*);
static int
check(void *x, int len, uchar sum, char *msg)
{
if(nvcsum(x, len) == sum)
return 0;
memset(x, 0, len);
fprint(2, "%s\n", msg);
return 1;
}
/*
* get key info out of nvram. since there isn't room in the PC's nvram use
* a disk partition there.
*/
static struct {
char *cputype;
char *file;
int off;
int len;
} nvtab[] = {
"sparc", "#r/nvram", 1024+850, sizeof(Nvrsafe),
"pc", "#S/%s%x/9fat", -1, 512,
"pc", "#S/%s%x/nvram", 0, 512,
"pc", "#f/fd0disk", -1, 512, /* 512: #f requires whole sector reads */
"pc", "#f/fd1disk", -1, 512,
"amd64", "#S/%s%x/9fat", -1, 512,
"amd64", "#S/%s%x/nvram", 0, 512,
"mips", "#r/nvram", 1024+900, sizeof(Nvrsafe),
"power", "#F/flash/flash0", 0x440000, sizeof(Nvrsafe),
"power", "#F/flash/flash", 0x440000, sizeof(Nvrsafe),
"power", "#r/nvram", 4352, sizeof(Nvrsafe), /* OK for MTX-604e */
"power", "/nvram", 0, sizeof(Nvrsafe), /* OK for Ucu */
"arm", "#F/flash/flash0", 0x100000, sizeof(Nvrsafe),
"arm", "#F/flash/flash", 0x100000, sizeof(Nvrsafe),
"debug", "/tmp/nvram", 0, sizeof(Nvrsafe),
};
static char*
readcons(char *prompt, char *def, int raw, char *buf, int nbuf, int nilok)
{
int fdin, fdout, ctl, n, m;
char line[10];
fdin = open("/dev/cons", OREAD);
if(fdin < 0)
fdin = 0;
fdout = open("/dev/cons", OWRITE);
if(fdout < 0)
fdout = 1;
redux:
if(def != nil)
fprint(fdout, "%s[%s]: ", prompt, def);
else
fprint(fdout, "%s: ", prompt);
if(raw){
ctl = open("/dev/consctl", OWRITE);
if(ctl >= 0)
write(ctl, "rawon", 5);
} else
ctl = -1;
m = 0;
for(;;){
n = read(fdin, line, 1);
if(n == 0){
close(ctl);
werrstr("readcons: EOF");
return nil;
}
if(n < 0){
close(ctl);
werrstr("can't read cons");
return nil;
}
if(line[0] == 0x7f)
exits(0);
if(n == 0 || line[0] == '\n' || line[0] == '\r'){
if(raw){
write(ctl, "rawoff", 6);
write(fdout, "\n", 1);
close(ctl);
}
buf[m] = '\0';
if(buf[0]=='\0' && def)
strcpy(buf, def);
if(buf[0]=='\0' && !nilok)
goto redux;
return buf;
}
if(line[0] == '\b'){
if(m > 0)
m--;
}else if(line[0] == 0x15){ /* ^U: line kill */
m = 0;
if(def != nil)
fprint(fdout, "%s[%s]: ", prompt, def);
else
fprint(fdout, "%s: ", prompt);
}else{
if(m >= nbuf-1){
fprint(fdout, "line too long\n");
m = 0;
if(def != nil)
fprint(fdout, "%s[%s]: ", prompt, def);
else
fprint(fdout, "%s: ", prompt);
}else
buf[m++] = line[0];
}
}
}
static int
sdnvram0(char *s, int l, int tabi)
{
char *p, *f[3], buf[16];
int fd, i;
s[l] = 0;
for(; p = strchr(s, '\n'); s = p + 1){
*p = 0;
if(tokenize(s, f, nelem(f)) < 1)
continue;
for(i = 0; i < 0x10; i++){
snprint(buf, sizeof buf, nvtab[tabi].file, f[0], i);
if((fd = open(buf, ORDWR)) >= 0)
return fd;
}
}
return -1;
}
static int
sdnvram(int tabi)
{
char *s;
int fd, l, r;
fd = open("#S/sdctl", OREAD);
if(fd == -1)
return -1;
r = -1;
l = 1024; /* #S/sdctl has 0 size; guess */
if(s = malloc(l + 1))
if((l = read(fd, s, l)) > 0)
r = sdnvram0(s, l, tabi);
free(s);
close(fd);
return r;
}
typedef struct {
int fd;
int safeoff;
int safelen;
} Nvrwhere;
/* returns with *locp filled in and locp->fd open, if possible */
static void
findnvram(Nvrwhere *locp)
{
char *cputype, *nvrfile, *nvrlen, *nvroff, *v[2];
int fd, i, safeoff, safelen;
nvrfile = getenv("nvram");
cputype = getenv("cputype");
if(cputype == nil)
cputype = strdup("mips");
if(strcmp(cputype, "386")==0 || strcmp(cputype, "alpha")==0) {
free(cputype);
cputype = strdup("pc");
}
fd = -1;
safeoff = -1;
safelen = -1;
if(nvrfile != nil && *nvrfile != '\0'){
/* accept device and device!file */
i = gettokens(nvrfile, v, nelem(v), "!");
if (i < 1) {
i = 1;
v[0] = "";
v[1] = nil;
}
fd = open(v[0], ORDWR);
if (fd < 0)
fd = open(v[0], OREAD);
safelen = sizeof(Nvrsafe);
if(strstr(v[0], "/9fat") == nil)
safeoff = 0;
nvrlen = getenv("nvrlen");
if(nvrlen != nil)
safelen = atoi(nvrlen);
nvroff = getenv("nvroff");
if(nvroff != nil)
if(strcmp(nvroff, "dos") == 0)
safeoff = -1;
else
safeoff = atoi(nvroff);
if(safeoff < 0 && fd >= 0){
safelen = 512;
safeoff = finddosfile(fd, i == 2? v[1]: "plan9.nvr");
if(safeoff < 0){ /* didn't find plan9.nvr? */
close(fd);
fd = -1;
}
}
free(nvroff);
free(nvrlen);
}else
for(i=0; i<nelem(nvtab); i++){
if(strcmp(cputype, nvtab[i].cputype) != 0)
continue;
if(nvtab[i].file[0] == '#' && nvtab[i].file[1] == 'S')
fd = sdnvram(i);
else
fd = open(nvtab[i].file, ORDWR);
if(fd < 0)
continue;
safeoff = nvtab[i].off;
safelen = nvtab[i].len;
if(safeoff == -1){
safeoff = finddosfile(fd, "plan9.nvr");
if(safeoff < 0){ /* didn't find plan9.nvr? */
close(fd);
fd = -1;
continue;
}
}
break;
}
free(nvrfile);
free(cputype);
locp->fd = fd;
locp->safelen = safelen;
locp->safeoff = safeoff;
}
/*
* get key info out of nvram. since there isn't room in the PC's nvram use
* a disk partition there.
*/
int
readnvram(Nvrsafe *safep, int flag)
{
int err;
char buf[512], in[128]; /* 512 for floppy i/o */
Nvrsafe *safe;
Nvrwhere loc;
err = 0;
safe = (Nvrsafe*)buf;
memset(&loc, 0, sizeof loc);
findnvram(&loc);
if (loc.safelen < 0)
loc.safelen = sizeof *safe;
else if (loc.safelen > sizeof buf)
loc.safelen = sizeof buf;
if (loc.safeoff < 0) {
fprint(2, "readnvram: couldn't find nvram\n");
if(!(flag&NVwritemem))
memset(safep, 0, sizeof(*safep));
safe = safep;
/*
* allow user to type the data for authentication,
* even if there's no nvram to store it in.
*/
}
if(flag&NVwritemem)
safe = safep;
else {
memset(safep, 0, sizeof(*safep));
if(loc.fd < 0
|| seek(loc.fd, loc.safeoff, 0) < 0
|| read(loc.fd, buf, loc.safelen) != loc.safelen){
err = 1;
if(flag&(NVwrite|NVwriteonerr))
fprint(2, "can't read nvram: %r\n");
/* start from scratch */
memset(safep, 0, sizeof(*safep));
safe = safep;
}else{
*safep = *safe; /* overwrite arg with data read */
safe = safep;
/* verify data read */
err |= check(safe->machkey, DESKEYLEN, safe->machsum,
"bad nvram key");
// err |= check(safe->config, CONFIGLEN, safe->configsum,
// "bad secstore key");
err |= check(safe->authid, ANAMELEN, safe->authidsum,
"bad authentication id");
err |= check(safe->authdom, DOMLEN, safe->authdomsum,
"bad authentication domain");
if(err == 0)
if(safe->authid[0]==0 || safe->authdom[0]==0){
fprint(2, "empty nvram authid or authdom\n");
err = 1;
}
}
}
if((flag&(NVwrite|NVwritemem)) || (err && (flag&NVwriteonerr))){
if (!(flag&NVwritemem)) {
readcons("authid", nil, 0, safe->authid,
sizeof safe->authid, 0);
readcons("authdom", nil, 0, safe->authdom,
sizeof safe->authdom, 0);
readcons("secstore key", nil, 1, safe->config,
sizeof safe->config, 1);
for(;;){
if(readcons("password", nil, 1, in, sizeof in, 0)
== nil)
goto Out;
if(passtokey(safe->machkey, in))
break;
}
}
// safe->authsum = nvcsum(safe->authkey, DESKEYLEN);
safe->machsum = nvcsum(safe->machkey, DESKEYLEN);
safe->configsum = nvcsum(safe->config, CONFIGLEN);
safe->authidsum = nvcsum(safe->authid, sizeof safe->authid);
safe->authdomsum = nvcsum(safe->authdom, sizeof safe->authdom);
*(Nvrsafe*)buf = *safe;
if(loc.fd < 0
|| seek(loc.fd, loc.safeoff, 0) < 0
|| write(loc.fd, buf, loc.safelen) != loc.safelen){
fprint(2, "can't write key to nvram: %r\n");
err = 1;
}else
err = 0;
}
Out:
if (loc.fd >= 0)
close(loc.fd);
return err? -1: 0;
}
typedef struct Dosboot Dosboot;
struct Dosboot{
uchar magic[3]; /* really an xx86 JMP instruction */
uchar version[8];
uchar sectsize[2];
uchar clustsize;
uchar nresrv[2];
uchar nfats;
uchar rootsize[2];
uchar volsize[2];
uchar mediadesc;
uchar fatsize[2];
uchar trksize[2];
uchar nheads[2];
uchar nhidden[4];
uchar bigvolsize[4];
uchar driveno;
uchar reserved0;
uchar bootsig;
uchar volid[4];
uchar label[11];
uchar type[8];
};
#define GETSHORT(p) (((p)[1]<<8) | (p)[0])
#define GETLONG(p) ((GETSHORT((p)+2) << 16) | GETSHORT((p)))
typedef struct Dosdir Dosdir;
struct Dosdir
{
char name[8];
char ext[3];
uchar attr;
uchar reserved[10];
uchar time[2];
uchar date[2];
uchar start[2];
uchar length[4];
};
static char*
dosparse(char *from, char *to, int len)
{
char c;
memset(to, ' ', len);
if(from == 0)
return 0;
while(len-- > 0){
c = *from++;
if(c == '.')
return from;
if(c == 0)
break;
if(c >= 'a' && c <= 'z')
*to++ = c + 'A' - 'a';
else
*to++ = c;
}
return 0;
}
/*
* return offset of first file block
*
* This is a very simplistic dos file system. It only
* works on floppies, only looks in the root, and only
* returns a pointer to the first block of a file.
*
* This exists for cpu servers that have no hard disk
* or nvram to store the key on.
*
* Please don't make this any smarter: it stays resident
* and I'd prefer not to waste the space on something that
* runs only at boottime -- presotto.
*/
static long
finddosfile(int fd, char *file)
{
uchar secbuf[512];
char name[8];
char ext[3];
Dosboot *b;
Dosdir *root, *dp;
int nroot, sectsize, rootoff, rootsects, n;
/* dos'ize file name */
file = dosparse(file, name, 8);
dosparse(file, ext, 3);
/* read boot block, check for sanity */
b = (Dosboot*)secbuf;
if(read(fd, secbuf, sizeof(secbuf)) != sizeof(secbuf))
return -1;
if(b->magic[0] != 0xEB || b->magic[1] != 0x3C || b->magic[2] != 0x90)
return -1;
sectsize = GETSHORT(b->sectsize);
if(sectsize != 512)
return -1;
rootoff = (GETSHORT(b->nresrv) + b->nfats*GETSHORT(b->fatsize)) * sectsize;
if(seek(fd, rootoff, 0) < 0)
return -1;
nroot = GETSHORT(b->rootsize);
rootsects = (nroot*sizeof(Dosdir)+sectsize-1)/sectsize;
if(rootsects <= 0 || rootsects > 64)
return -1;
/*
* read root. it is contiguous to make stuff like
* this easier
*/
root = malloc(rootsects*sectsize);
if(read(fd, root, rootsects*sectsize) != rootsects*sectsize)
return -1;
n = -1;
for(dp = root; dp < &root[nroot]; dp++)
if(memcmp(name, dp->name, 8) == 0 && memcmp(ext, dp->ext, 3) == 0){
n = GETSHORT(dp->start);
break;
}
free(root);
if(n < 0)
return -1;
/*
* dp->start is in cluster units, not sectors. The first
* cluster is cluster 2 which starts immediately after the
* root directory
*/
return rootoff + rootsects*sectsize + (n-2)*sectsize*b->clustsize;
}