1 #include <stdint.h>
2
3 __attribute__((__visibility__("hidden")))
__fdpic_fixup(void * map,uintptr_t * a,uintptr_t * z)4 void *__fdpic_fixup(void *map, uintptr_t *a, uintptr_t *z)
5 {
6 /* If map is a null pointer, the program was loaded by a
7 * non-FDPIC-aware ELF loader, and fixups are not needed,
8 * but the value for the GOT pointer is. */
9 if (!map) return (void *)z[-1];
10
11 struct {
12 unsigned short version, nsegs;
13 struct fdpic_loadseg {
14 uintptr_t addr, p_vaddr, p_memsz;
15 } segs[];
16 } *lm = map;
17 int nsegs = lm->nsegs, rseg = 0, vseg = 0;
18 for (;;) {
19 while (*a-lm->segs[rseg].p_vaddr >= lm->segs[rseg].p_memsz)
20 if (++rseg == nsegs) rseg = 0;
21 uintptr_t *r = (uintptr_t *)
22 (*a + lm->segs[rseg].addr - lm->segs[rseg].p_vaddr);
23 if (++a == z) return r;
24 while (*r-lm->segs[vseg].p_vaddr >= lm->segs[vseg].p_memsz)
25 if (++vseg == nsegs) vseg = 0;
26 *r += lm->segs[vseg].addr - lm->segs[vseg].p_vaddr;
27 }
28 }
29