ref: a38e34bead8788b81def8ebe03683c2ce2edb576
dir: /sys/src/cmd/vac/pack.c/
#include "stdinc.h"
#include "vac.h"
#include "dat.h"
#include "fns.h"
#include "error.h"
typedef struct MetaChunk MetaChunk;
struct MetaChunk {
ushort offset;
ushort size;
ushort index;
};
static int stringunpack(char **s, uchar **p, int *n);
/*
* integer conversion routines
*/
#define U8GET(p) ((p)[0])
#define U16GET(p) (((p)[0]<<8)|(p)[1])
#define U32GET(p) (((p)[0]<<24)|((p)[1]<<16)|((p)[2]<<8)|(p)[3])
#define U48GET(p) (((uvlong)U16GET(p)<<32)|(uvlong)U32GET((p)+2))
#define U64GET(p) (((uvlong)U32GET(p)<<32)|(uvlong)U32GET((p)+4))
#define U8PUT(p,v) (p)[0]=(v)&0xFF
#define U16PUT(p,v) (p)[0]=((v)>>8)&0xFF;(p)[1]=(v)&0xFF
#define U32PUT(p,v) (p)[0]=((v)>>24)&0xFF;(p)[1]=((v)>>16)&0xFF;(p)[2]=((v)>>8)&0xFF;(p)[3]=(v)&0xFF
#define U48PUT(p,v,t32) t32=(v)>>32;U16PUT(p,t32);t32=(v);U32PUT((p)+2,t32)
#define U64PUT(p,v,t32) t32=(v)>>32;U32PUT(p,t32);t32=(v);U32PUT((p)+4,t32)
static int
stringunpack(char **s, uchar **p, int *n)
{
int nn;
if(*n < 2)
return -1;
nn = U16GET(*p);
*p += 2;
*n -= 2;
if(nn > *n)
return -1;
*s = vtmalloc(nn+1);
memmove(*s, *p, nn);
(*s)[nn] = 0;
*p += nn;
*n -= nn;
return 0;
}
static int
stringpack(char *s, uchar *p)
{
int n;
n = strlen(s);
U16PUT(p, n);
memmove(p+2, s, n);
return n+2;
}
int
mbunpack(MetaBlock *mb, uchar *p, int n)
{
u32int magic;
mb->maxsize = n;
mb->buf = p;
if(n == 0) {
memset(mb, 0, sizeof(MetaBlock));
return 0;
}
magic = U32GET(p);
if(magic != MetaMagic && magic != MetaMagic+1) {
werrstr("bad meta block magic");
return -1;
}
mb->size = U16GET(p+4);
mb->free = U16GET(p+6);
mb->maxindex = U16GET(p+8);
mb->nindex = U16GET(p+10);
mb->unbotch = (magic == MetaMagic+1);
if(mb->size > n) {
werrstr("bad meta block size");
return -1;
}
p += MetaHeaderSize;
n -= MetaHeaderSize;
USED(p);
if(n < mb->maxindex*MetaIndexSize) {
werrstr("truncated meta block 2");
return -1;
}
return 0;
}
void
mbpack(MetaBlock *mb)
{
uchar *p;
p = mb->buf;
U32PUT(p, MetaMagic);
U16PUT(p+4, mb->size);
U16PUT(p+6, mb->free);
U16PUT(p+8, mb->maxindex);
U16PUT(p+10, mb->nindex);
}
void
mbdelete(MetaBlock *mb, int i, MetaEntry *me)
{
uchar *p;
int n;
assert(i < mb->nindex);
if(me->p - mb->buf + me->size == mb->size)
mb->size -= me->size;
else
mb->free += me->size;
p = mb->buf + MetaHeaderSize + i*MetaIndexSize;
n = (mb->nindex-i-1)*MetaIndexSize;
memmove(p, p+MetaIndexSize, n);
memset(p+n, 0, MetaIndexSize);
mb->nindex--;
}
void
mbinsert(MetaBlock *mb, int i, MetaEntry *me)
{
uchar *p;
int o, n;
assert(mb->nindex < mb->maxindex);
o = me->p - mb->buf;
n = me->size;
if(o+n > mb->size) {
mb->free -= mb->size - o;
mb->size = o + n;
} else
mb->free -= n;
p = mb->buf + MetaHeaderSize + i*MetaIndexSize;
n = (mb->nindex-i)*MetaIndexSize;
memmove(p+MetaIndexSize, p, n);
U16PUT(p, me->p - mb->buf);
U16PUT(p+2, me->size);
mb->nindex++;
}
int
meunpack(MetaEntry *me, MetaBlock *mb, int i)
{
uchar *p;
int eo, en;
if(i < 0 || i >= mb->nindex) {
werrstr("bad meta entry index");
return -1;
}
p = mb->buf + MetaHeaderSize + i*MetaIndexSize;
eo = U16GET(p);
en = U16GET(p+2);
if(0)print("eo = %d en = %d\n", eo, en);
if(eo < MetaHeaderSize + mb->maxindex*MetaIndexSize) {
werrstr("corrupted entry in meta block");
return -1;
}
if(eo+en > mb->size) {
werrstr("truncated meta block");
return -1;
}
p = mb->buf + eo;
/* make sure entry looks ok and includes an elem name */
if(en < 8 || U32GET(p) != DirMagic || en < 8 + U16GET(p+6)) {
werrstr("corrupted meta block entry");
return -1;
}
me->p = p;
me->size = en;
return 0;
}
/* assumes a small amount of checking has been done in mbentry */
int
mecmp(MetaEntry *me, char *s)
{
int n;
uchar *p;
p = me->p;
p += 6;
n = U16GET(p);
p += 2;
assert(n + 8 < me->size);
while(n > 0) {
if(*s == 0)
return -1;
if(*p < (uchar)*s)
return -1;
if(*p > (uchar)*s)
return 1;
p++;
s++;
n--;
}
return *s != 0;
}
int
mecmpnew(MetaEntry *me, char *s)
{
int n;
uchar *p;
p = me->p;
p += 6;
n = U16GET(p);
p += 2;
assert(n + 8 < me->size);
while(n > 0) {
if(*s == 0)
return 1;
if(*p < (uchar)*s)
return -1;
if(*p > (uchar)*s)
return 1;
p++;
s++;
n--;
}
return -(*s != 0);
}
static int
offsetcmp(const void *s0, const void *s1)
{
const MetaChunk *mc0, *mc1;
mc0 = s0;
mc1 = s1;
if(mc0->offset < mc1->offset)
return -1;
if(mc0->offset > mc1->offset)
return 1;
return 0;
}
static MetaChunk *
metachunks(MetaBlock *mb)
{
MetaChunk *mc;
int oo, o, n, i;
uchar *p;
mc = vtmalloc(mb->nindex*sizeof(MetaChunk));
p = mb->buf + MetaHeaderSize;
for(i = 0; i<mb->nindex; i++) {
mc[i].offset = U16GET(p);
mc[i].size = U16GET(p+2);
mc[i].index = i;
p += MetaIndexSize;
}
qsort(mc, mb->nindex, sizeof(MetaChunk), offsetcmp);
/* check block looks ok */
oo = MetaHeaderSize + mb->maxindex*MetaIndexSize;
o = oo;
n = 0;
for(i=0; i<mb->nindex; i++) {
o = mc[i].offset;
n = mc[i].size;
if(o < oo)
goto Err;
oo += n;
}
if(o+n <= mb->size)
goto Err;
if(mb->size - oo != mb->free)
goto Err;
return mc;
Err:
vtfree(mc);
return nil;
}
static void
mbcompact(MetaBlock *mb, MetaChunk *mc)
{
int oo, o, n, i;
oo = MetaHeaderSize + mb->maxindex*MetaIndexSize;
for(i=0; i<mb->nindex; i++) {
o = mc[i].offset;
n = mc[i].size;
if(o != oo) {
memmove(mb->buf + oo, mb->buf + o, n);
U16PUT(mb->buf + MetaHeaderSize + mc[i].index*MetaIndexSize, oo);
}
oo += n;
}
mb->size = oo;
mb->free = 0;
}
uchar *
mballoc(MetaBlock *mb, int n)
{
int i, o;
MetaChunk *mc;
/* off the end */
if(mb->maxsize - mb->size >= n)
return mb->buf + mb->size;
/* check if possible */
if(mb->maxsize - mb->size + mb->free < n)
return nil;
mc = metachunks(mb);
/* look for hole */
o = MetaHeaderSize + mb->maxindex*MetaIndexSize;
for(i=0; i<mb->nindex; i++) {
if(mc[i].offset - o >= n) {
vtfree(mc);
return mb->buf + o;
}
o = mc[i].offset + mc[i].size;
}
if(mb->maxsize - o >= n) {
vtfree(mc);
return mb->buf + o;
}
/* compact and return off the end */
mbcompact(mb, mc);
vtfree(mc);
assert(mb->maxsize - mb->size >= n);
return mb->buf + mb->size;
}
int
vdsize(VacDir *dir, int version)
{
int n;
if(version < 8 || version > 9)
sysfatal("bad version %d in vdpack", version);
/* constant part */
n = 4 + /* magic */
2 + /* version */
4 + /* entry */
8 + /* qid */
4 + /* mtime */
4 + /* mcount */
4 + /* ctime */
4 + /* atime */
4 + /* mode */
0;
if(version == 9){
n += 4 + /* gen */
4 + /* mentry */
4 + /* mgen */
0;
}
/* strings */
n += 2 + strlen(dir->elem);
n += 2 + strlen(dir->uid);
n += 2 + strlen(dir->gid);
n += 2 + strlen(dir->mid);
/* optional sections */
if(version < 9 && dir->plan9) {
n += 3 + /* option header */
8 + /* path */
4; /* version */
}
if(dir->qidspace) {
n += 3 + /* option header */
8 + /* qid offset */
8; /* qid max */
}
if(version < 9 && dir->gen) {
n += 3 + /* option header */
4; /* gen */
}
return n;
}
void
vdpack(VacDir *dir, MetaEntry *me, int version)
{
uchar *p;
ulong t32;
if(version < 8 || version > 9)
sysfatal("bad version %d in vdpack", version);
p = me->p;
U32PUT(p, DirMagic);
U16PUT(p+4, version); /* version */
p += 6;
p += stringpack(dir->elem, p);
U32PUT(p, dir->entry);
p += 4;
if(version == 9){
U32PUT(p, dir->gen);
U32PUT(p+4, dir->mentry);
U32PUT(p+8, dir->mgen);
p += 12;
}
U64PUT(p, dir->qid, t32);
p += 8;
p += stringpack(dir->uid, p);
p += stringpack(dir->gid, p);
p += stringpack(dir->mid, p);
U32PUT(p, dir->mtime);
U32PUT(p+4, dir->mcount);
U32PUT(p+8, dir->ctime);
U32PUT(p+12, dir->atime);
U32PUT(p+16, dir->mode);
p += 5*4;
if(dir->plan9 && version < 9) {
U8PUT(p, DirPlan9Entry);
U16PUT(p+1, 8+4);
p += 3;
U64PUT(p, dir->p9path, t32);
U32PUT(p+8, dir->p9version);
p += 12;
}
if(dir->qidspace) {
U8PUT(p, DirQidSpaceEntry);
U16PUT(p+1, 2*8);
p += 3;
U64PUT(p, dir->qidoffset, t32);
U64PUT(p+8, dir->qidmax, t32);
p += 16;
}
if(dir->gen && version < 9) {
U8PUT(p, DirGenEntry);
U16PUT(p+1, 4);
p += 3;
U32PUT(p, dir->gen);
p += 4;
}
assert(p == me->p + me->size);
}
int
vdunpack(VacDir *dir, MetaEntry *me)
{
int t, nn, n, version;
uchar *p;
p = me->p;
n = me->size;
memset(dir, 0, sizeof(VacDir));
/* magic */
if(n < 4 || U32GET(p) != DirMagic)
goto Err;
p += 4;
n -= 4;
/* version */
if(n < 2)
goto Err;
version = U16GET(p);
if(version < 7 || version > 9)
goto Err;
p += 2;
n -= 2;
/* elem */
if(stringunpack(&dir->elem, &p, &n) < 0)
goto Err;
/* entry */
if(n < 4)
goto Err;
dir->entry = U32GET(p);
p += 4;
n -= 4;
if(version < 9) {
dir->gen = 0;
dir->mentry = dir->entry+1;
dir->mgen = 0;
} else {
if(n < 3*4)
goto Err;
dir->gen = U32GET(p);
dir->mentry = U32GET(p+4);
dir->mgen = U32GET(p+8);
p += 3*4;
n -= 3*4;
}
/* size is gotten from DirEntry */
/* qid */
if(n < 8)
goto Err;
dir->qid = U64GET(p);
p += 8;
n -= 8;
/* skip replacement */
if(version == 7) {
if(n < VtScoreSize)
goto Err;
p += VtScoreSize;
n -= VtScoreSize;
}
/* uid */
if(stringunpack(&dir->uid, &p, &n) < 0)
goto Err;
/* gid */
if(stringunpack(&dir->gid, &p, &n) < 0)
goto Err;
/* mid */
if(stringunpack(&dir->mid, &p, &n) < 0)
goto Err;
if(n < 5*4)
goto Err;
dir->mtime = U32GET(p);
dir->mcount = U32GET(p+4);
dir->ctime = U32GET(p+8);
dir->atime = U32GET(p+12);
dir->mode = U32GET(p+16);
p += 5*4;
n -= 5*4;
/* optional meta data */
while(n > 0) {
if(n < 3)
goto Err;
t = p[0];
nn = U16GET(p+1);
p += 3;
n -= 3;
if(n < nn)
goto Err;
switch(t) {
case DirPlan9Entry:
/* not valid in version >= 9 */
if(version >= 9)
break;
if(dir->plan9 || nn != 12)
goto Err;
dir->plan9 = 1;
dir->p9path = U64GET(p);
dir->p9version = U32GET(p+8);
if(dir->mcount == 0)
dir->mcount = dir->p9version;
break;
case DirGenEntry:
/* not valid in version >= 9 */
if(version >= 9)
break;
break;
case DirQidSpaceEntry:
if(dir->qidspace || nn != 16)
goto Err;
dir->qidspace = 1;
dir->qidoffset = U64GET(p);
dir->qidmax = U64GET(p+8);
break;
}
p += nn;
n -= nn;
}
if(p != me->p + me->size)
goto Err;
return 0;
Err:
werrstr(EBadMeta);
vdcleanup(dir);
return -1;
}
void
vdcleanup(VacDir *dir)
{
vtfree(dir->elem);
dir->elem = nil;
vtfree(dir->uid);
dir->uid = nil;
vtfree(dir->gid);
dir->gid = nil;
vtfree(dir->mid);
dir->mid = nil;
}
void
vdcopy(VacDir *dst, VacDir *src)
{
*dst = *src;
dst->elem = vtstrdup(dst->elem);
dst->uid = vtstrdup(dst->uid);
dst->gid = vtstrdup(dst->gid);
dst->mid = vtstrdup(dst->mid);
}
int
mbsearch(MetaBlock *mb, char *elem, int *ri, MetaEntry *me)
{
int i;
int b, t, x;
/* binary search within block */
b = 0;
t = mb->nindex;
while(b < t) {
i = (b+t)>>1;
if(meunpack(me, mb, i) < 0)
return 0;
if(mb->unbotch)
x = mecmpnew(me, elem);
else
x = mecmp(me, elem);
if(x == 0) {
*ri = i;
return 1;
}
if(x < 0)
b = i+1;
else /* x > 0 */
t = i;
}
assert(b == t);
*ri = b; /* b is the index to insert this entry */
memset(me, 0, sizeof(*me));
return -1;
}
void
mbinit(MetaBlock *mb, uchar *p, int n, int entries)
{
memset(mb, 0, sizeof(MetaBlock));
mb->maxsize = n;
mb->buf = p;
mb->maxindex = entries;
mb->size = MetaHeaderSize + mb->maxindex*MetaIndexSize;
}
int
mbresize(MetaBlock *mb, MetaEntry *me, int n)
{
uchar *p, *ep;
/* easy case */
if(n <= me->size){
me->size = n;
return 0;
}
/* try and expand entry */
p = me->p + me->size;
ep = mb->buf + mb->maxsize;
while(p < ep && *p == 0)
p++;
if(n <= p - me->p){
me->size = n;
return 0;
}
p = mballoc(mb, n);
if(p != nil){
me->p = p;
me->size = n;
return 0;
}
return -1;
}