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/*
* functions to read and write an executable or file image
*/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <mach.h>
static int mget(Map*, uvlong, void*, int);
static int mput(Map*, uvlong, void*, int);
static struct segment* reloc(Map*, uvlong, vlong*);
/*
* routines to get/put various types
*/
int
geta(Map *map, uvlong addr, uvlong *x)
{
ulong l;
uvlong vl;
if (mach->szaddr == 8){
if (get8(map, addr, &vl) < 0)
return -1;
*x = vl;
return 1;
}
if (get4(map, addr, &l) < 0)
return -1;
*x = l;
return 1;
}
int
get8(Map *map, uvlong addr, uvlong *x)
{
if (!map) {
werrstr("get8: invalid map");
return -1;
}
if (map->nsegs == 1 && map->seg[0].fd < 0) {
*x = addr;
return 1;
}
if (mget(map, addr, x, 8) < 0)
return -1;
*x = machdata->swav(*x);
return 1;
}
int
get4(Map *map, uvlong addr, ulong *x)
{
if (!map) {
werrstr("get4: invalid map");
return -1;
}
if (map->nsegs == 1 && map->seg[0].fd < 0) {
*x = addr;
return 1;
}
if (mget(map, addr, x, 4) < 0)
return -1;
*x = machdata->swal(*x);
return 1;
}
int
get2(Map *map, uvlong addr, ushort *x)
{
if (!map) {
werrstr("get2: invalid map");
return -1;
}
if (map->nsegs == 1 && map->seg[0].fd < 0) {
*x = addr;
return 1;
}
if (mget(map, addr, x, 2) < 0)
return -1;
*x = machdata->swab(*x);
return 1;
}
int
get1(Map *map, uvlong addr, uchar *x, int size)
{
uchar *cp;
if (!map) {
werrstr("get1: invalid map");
return -1;
}
if (map->nsegs == 1 && map->seg[0].fd < 0) {
cp = (uchar*)&addr;
while (cp < (uchar*)(&addr+1) && size-- > 0)
*x++ = *cp++;
while (size-- > 0)
*x++ = 0;
} else
return mget(map, addr, x, size);
return 1;
}
int
puta(Map *map, uvlong addr, uvlong v)
{
if (mach->szaddr == 8)
return put8(map, addr, v);
return put4(map, addr, v);
}
int
put8(Map *map, uvlong addr, uvlong v)
{
if (!map) {
werrstr("put8: invalid map");
return -1;
}
v = machdata->swav(v);
return mput(map, addr, &v, 8);
}
int
put4(Map *map, uvlong addr, ulong v)
{
if (!map) {
werrstr("put4: invalid map");
return -1;
}
v = machdata->swal(v);
return mput(map, addr, &v, 4);
}
int
put2(Map *map, uvlong addr, ushort v)
{
if (!map) {
werrstr("put2: invalid map");
return -1;
}
v = machdata->swab(v);
return mput(map, addr, &v, 2);
}
int
put1(Map *map, uvlong addr, uchar *v, int size)
{
if (!map) {
werrstr("put1: invalid map");
return -1;
}
return mput(map, addr, v, size);
}
static int
spread(struct segment *s, void *buf, int n, uvlong off)
{
uvlong base;
static struct {
struct segment *s;
char a[8192];
uvlong off;
} cache;
if(s->cache){
base = off&~(sizeof cache.a-1);
if(cache.s != s || cache.off != base){
cache.off = ~0;
if(seek(s->fd, base, 0) >= 0
&& readn(s->fd, cache.a, sizeof cache.a) == sizeof cache.a){
cache.s = s;
cache.off = base;
}
}
if(cache.s == s && cache.off == base){
off &= sizeof cache.a-1;
if(off+n > sizeof cache.a)
n = sizeof cache.a - off;
memmove(buf, cache.a+off, n);
return n;
}
}
return pread(s->fd, buf, n, off);
}
static int
mget(Map *map, uvlong addr, void *buf, int size)
{
uvlong off;
int i, j, k;
struct segment *s;
s = reloc(map, addr, (vlong*)&off);
if (!s)
return -1;
if (s->fd < 0) {
werrstr("unreadable map");
return -1;
}
for (i = j = 0; i < 2; i++) { /* in case read crosses page */
k = spread(s, (void*)((uchar *)buf+j), size-j, off+j);
if (k < 0) {
werrstr("can't read address %llux: %r", addr);
return -1;
}
j += k;
if (j == size)
return j;
}
werrstr("partial read at address %llux (size %d j %d)", addr, size, j);
return -1;
}
static int
mput(Map *map, uvlong addr, void *buf, int size)
{
vlong off;
int i, j, k;
struct segment *s;
s = reloc(map, addr, &off);
if (!s)
return -1;
if (s->fd < 0) {
werrstr("unwritable map");
return -1;
}
seek(s->fd, off, 0);
for (i = j = 0; i < 2; i++) { /* in case read crosses page */
k = write(s->fd, buf, size-j);
if (k < 0) {
werrstr("can't write address %llux: %r", addr);
return -1;
}
j += k;
if (j == size)
return j;
}
werrstr("partial write at address %llux", addr);
return -1;
}
/*
* convert address to file offset; returns nonzero if ok
*/
static struct segment*
reloc(Map *map, uvlong addr, vlong *offp)
{
int i;
for (i = 0; i < map->nsegs; i++) {
if (map->seg[i].inuse)
if (map->seg[i].b <= addr && addr < map->seg[i].e) {
*offp = addr + map->seg[i].f - map->seg[i].b;
return &map->seg[i];
}
}
werrstr("can't translate address %llux", addr);
return 0;
}
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