#include "crt_arch.h"
+#ifndef GETFUNCSYM
+#define GETFUNCSYM(fp, sym, got) do { \
+ __attribute__((__visibility__("hidden"))) void sym(); \
+ static void (*static_func_ptr)() = sym; \
+ __asm__ __volatile__ ( "" : "+m"(static_func_ptr) : : "memory"); \
+ *(fp) = static_func_ptr; } while(0)
+#endif
+
__attribute__((__visibility__("hidden")))
void _dlstart_c(size_t *sp, size_t *dynv)
{
size_t i, aux[AUX_CNT], dyn[DYN_CNT];
+ size_t *rel, rel_size, base;
int argc = *sp;
char **argv = (void *)(sp+1);
for (i=0; auxv[i]; i+=2) if (auxv[i]<AUX_CNT)
aux[auxv[i]] = auxv[i+1];
+#if DL_FDPIC
+ struct fdpic_loadseg *segs, fakeseg;
+ size_t j;
+ if (dynv) {
+ /* crt_arch.h entry point asm is responsible for reserving
+ * space and moving the extra fdpic arguments to the stack
+ * vector where they are easily accessible from C. */
+ segs = ((struct fdpic_loadmap *)(sp[-1] ? sp[-1] : sp[-2]))->segs;
+ } else {
+ /* If dynv is null, the entry point was started from loader
+ * that is not fdpic-aware. We can assume normal fixed-
+ * displacement ELF loading was performed, but when ldso was
+ * run as a command, finding the Ehdr is a heursitic: we
+ * have to assume Phdrs start in the first 4k of the file. */
+ base = aux[AT_BASE];
+ if (!base) base = aux[AT_PHDR] & -4096;
+ segs = &fakeseg;
+ segs[0].addr = base;
+ segs[0].p_vaddr = 0;
+ segs[0].p_memsz = -1;
+ Ehdr *eh = (void *)base;
+ Phdr *ph = (void *)(base + eh->e_phoff);
+ size_t phnum = eh->e_phnum;
+ size_t phent = eh->e_phentsize;
+ while (phnum-- && ph->p_type != PT_DYNAMIC)
+ ph = (void *)((size_t)ph + phent);
+ dynv = (void *)(base + ph->p_vaddr);
+ }
+#endif
+
for (i=0; i<DYN_CNT; i++) dyn[i] = 0;
for (i=0; dynv[i]; i+=2) if (dynv[i]<DYN_CNT)
dyn[dynv[i]] = dynv[i+1];
+#if DL_FDPIC
+ for (i=0; i<DYN_CNT; i++) {
+ if (i==DT_RELASZ || i==DT_RELSZ) continue;
+ if (!dyn[i]) continue;
+ for (j=0; dyn[i]-segs[j].p_vaddr >= segs[j].p_memsz; j++);
+ dyn[i] += segs[j].addr - segs[j].p_vaddr;
+ }
+ base = 0;
+
+ const Sym *syms = (void *)dyn[DT_SYMTAB];
+
+ rel = (void *)dyn[DT_RELA];
+ rel_size = dyn[DT_RELASZ];
+ for (; rel_size; rel+=3, rel_size-=3*sizeof(size_t)) {
+ if (!IS_RELATIVE(rel[1], syms)) continue;
+ for (j=0; rel[0]-segs[j].p_vaddr >= segs[j].p_memsz; j++);
+ size_t *rel_addr = (void *)
+ (rel[0] + segs[j].addr - segs[j].p_vaddr);
+ if (R_TYPE(rel[1]) == REL_FUNCDESC_VAL) {
+ *rel_addr += segs[rel_addr[1]].addr
+ - segs[rel_addr[1]].p_vaddr
+ + syms[R_SYM(rel[1])].st_value;
+ rel_addr[1] = dyn[DT_PLTGOT];
+ } else {
+ size_t val = syms[R_SYM(rel[1])].st_value;
+ for (j=0; val-segs[j].p_vaddr >= segs[j].p_memsz; j++);
+ *rel_addr = rel[2] + segs[j].addr - segs[j].p_vaddr + val;
+ }
+ }
+#else
/* If the dynamic linker is invoked as a command, its load
* address is not available in the aux vector. Instead, compute
* the load address as the difference between &_DYNAMIC and the
* virtual address in the PT_DYNAMIC program header. */
- unsigned char *base = (void *)aux[AT_BASE];
+ base = aux[AT_BASE];
if (!base) {
size_t phnum = aux[AT_PHNUM];
size_t phentsize = aux[AT_PHENT];
Phdr *ph = (void *)aux[AT_PHDR];
for (i=phnum; i--; ph = (void *)((char *)ph + phentsize)) {
if (ph->p_type == PT_DYNAMIC) {
- base = (void *)((size_t)dynv - ph->p_vaddr);
+ base = (size_t)dynv - ph->p_vaddr;
break;
}
}
size_t *got = (void *)(base + dyn[DT_PLTGOT]);
for (i=0; dynv[i]; i+=2) if (dynv[i]==DT_MIPS_LOCAL_GOTNO)
local_cnt = dynv[i+1];
- for (i=0; i<local_cnt; i++) got[i] += (size_t)base;
+ for (i=0; i<local_cnt; i++) got[i] += base;
}
- size_t *rel, rel_size;
-
rel = (void *)(base+dyn[DT_REL]);
rel_size = dyn[DT_RELSZ];
for (; rel_size; rel+=2, rel_size-=2*sizeof(size_t)) {
- if (!IS_RELATIVE(rel[1])) continue;
+ if (!IS_RELATIVE(rel[1], 0)) continue;
size_t *rel_addr = (void *)(base + rel[0]);
- *rel_addr += (size_t)base;
+ *rel_addr += base;
}
rel = (void *)(base+dyn[DT_RELA]);
rel_size = dyn[DT_RELASZ];
for (; rel_size; rel+=3, rel_size-=3*sizeof(size_t)) {
- if (!IS_RELATIVE(rel[1])) continue;
+ if (!IS_RELATIVE(rel[1], 0)) continue;
size_t *rel_addr = (void *)(base + rel[0]);
- *rel_addr = (size_t)base + rel[2];
+ *rel_addr = base + rel[2];
}
+#endif
- const char *strings = (void *)(base + dyn[DT_STRTAB]);
- const Sym *syms = (void *)(base + dyn[DT_SYMTAB]);
-
- /* Call dynamic linker stage-2, __dls2 */
- for (i=0; ;i++) {
- const char *s = strings + syms[i].st_name;
- if (s[0]=='_' && s[1]=='_' && s[2]=='d'
- && s[3]=='l' && s[4]=='s' && s[5]=='2' && !s[6])
- break;
- }
- ((stage2_func)(base + syms[i].st_value))(base, sp);
+ stage2_func dls2;
+ GETFUNCSYM(&dls2, __dls2, base+dyn[DT_PLTGOT]);
+ dls2((void *)base, sp);
}
#endif
projects / musl / blobdiff