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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, buf, 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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