diff options
Diffstat (limited to 'utils/libmach/access.c')
| -rw-r--r-- | utils/libmach/access.c | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/utils/libmach/access.c b/utils/libmach/access.c new file mode 100644 index 00000000..6a58cdea --- /dev/null +++ b/utils/libmach/access.c @@ -0,0 +1,215 @@ +/* + * functions to read and write an executable or file image + */ + +#include <lib9.h> +#include <bio.h> +#include "mach.h" + +static int mget(Map*, ulong, char*, int); +static int mput(Map*, ulong, char*, int); +struct segment* reloc(Map*, ulong, long*); + +/* + * routines to get/put various types + */ + +int +get8(Map *map, ulong addr, vlong *x) +{ + if (!map) { + werrstr("get8: invalid map"); + return -1; + } + + if (map->nsegs == 1 && map->seg[0].fd < 0) { + *x = (vlong)addr; + return 1; + } + if (mget(map, addr, (char *)x, 8) < 0) + return -1; + *x = machdata->swav(*x); + return (1); +} + +int +get4(Map *map, ulong addr, long *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, (char *)x, 4) < 0) + return -1; + *x = machdata->swal(*x); + return (1); +} + +int +get2(Map *map, ulong 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, (char *)x, 2) < 0) + return -1; + *x = machdata->swab(*x); + return (1); +} + +int +get1(Map *map, ulong 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, (char*)x, size); + return 1; +} + +int +put8(Map *map, ulong addr, vlong v) +{ + if (!map) { + werrstr("put8: invalid map"); + return -1; + } + v = machdata->swav(v); + return mput(map, addr, (char *)&v, 8); +} + +int +put4(Map *map, ulong addr, long v) +{ + if (!map) { + werrstr("put4: invalid map"); + return -1; + } + v = machdata->swal(v); + return mput(map, addr, (char *)&v, 4); +} + +int +put2(Map *map, ulong addr, ushort v) +{ + if (!map) { + werrstr("put2: invalid map"); + return -1; + } + v = machdata->swab(v); + return mput(map, addr, (char *)&v, 2); +} + +int +put1(Map *map, ulong addr, uchar *v, int size) +{ + if (!map) { + werrstr("put1: invalid map"); + return -1; + } + return mput(map, addr, (char *)v, size); +} + +static int +mget(Map *map, ulong addr, char *buf, int size) +{ + long off; + int i, j, k; + struct segment *s; + + s = reloc(map, addr, &off); + if (!s) + return -1; + if (s->fd < 0) { + werrstr("unreadable map"); + return -1; + } + if (s->mget) + return s->mget(s, addr, off, buf, size); + seek(s->fd, off, 0); + for (i = j = 0; i < 2; i++) { /* in case read crosses page */ + k = read(s->fd, buf, size-j); + if (k < 0) { + werrstr("can't read address %lux: %r", addr); + return -1; + } + j += k; + if (j == size) + return j; + } + werrstr("partial read at address %lux", addr); + return -1; +} + +static int +mput(Map *map, ulong addr, char *buf, int size) +{ + long 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; + } + if (s->mput) + return s->mput(s, addr, off, buf, size); + + 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 %lux: %r", addr); + return -1; + } + j += k; + if (j == size) + return j; + } + werrstr("partial write at address %lux", addr); + return -1; +} + +/* + * convert address to file offset; returns nonzero if ok + */ +struct segment* +reloc(Map *map, ulong addr, long *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 %lux", addr); + return 0; +} |