Index: fusl/src/ldso/dlstart.c |
diff --git a/fusl/src/ldso/dlstart.c b/fusl/src/ldso/dlstart.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..46f50114c0c434329ec0d0c37fdce28fc766ae66 |
--- /dev/null |
+++ b/fusl/src/ldso/dlstart.c |
@@ -0,0 +1,150 @@ |
+#include <stddef.h> |
+#include "dynlink.h" |
+ |
+#ifdef SHARED |
+ |
+#ifndef START |
+#define START "_dlstart" |
+#endif |
+ |
+#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=argc+1; argv[i]; i++); |
+ size_t *auxv = (void *)(argv+i+1); |
+ |
+ for (i=0; i<AUX_CNT; i++) aux[i] = 0; |
+ 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. */ |
+ 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 = (size_t)dynv - ph->p_vaddr; |
+ break; |
+ } |
+ } |
+ } |
+ |
+ /* MIPS uses an ugly packed form for GOT relocations. Since we |
+ * can't make function calls yet and the code is tiny anyway, |
+ * it's simply inlined here. */ |
+ if (NEED_MIPS_GOT_RELOCS) { |
+ size_t local_cnt = 0; |
+ 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] += base; |
+ } |
+ |
+ 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], 0)) continue; |
+ size_t *rel_addr = (void *)(base + rel[0]); |
+ *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], 0)) continue; |
+ size_t *rel_addr = (void *)(base + rel[0]); |
+ *rel_addr = base + rel[2]; |
+ } |
+#endif |
+ |
+ stage2_func dls2; |
+ GETFUNCSYM(&dls2, __dls2, base+dyn[DT_PLTGOT]); |
+ dls2((void *)base, sp); |
+} |
+ |
+#endif |