fdpic_crt.h raw

   1  #include <stdint.h>
   2  #include <features.h>
   3  
   4  hidden 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