[fusl] Update fusl

fusl/src/ldso/dlstart.c

-#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