fusl/src/ldso/dl_iterate_phdr.c

#include <elf.h>
#include <link.h>
#include "libc.h"

#define AUX_CNT 38

static int static_dl_iterate_phdr(int (*callback)(struct dl_phdr_info* info,
                                                  size_t size,
                                                  void* data),
                                  void* data) {
  unsigned char* p;
  ElfW(Phdr) * phdr, *tls_phdr = 0;
  size_t base = 0;
  size_t n;
  struct dl_phdr_info info;
  size_t i, aux[AUX_CNT];

  for (i = 0; libc.auxv[i]; i += 2)
    if (libc.auxv[i] < AUX_CNT)
      aux[libc.auxv[i]] = libc.auxv[i + 1];

  for (p = (void*)aux[AT_PHDR], n = aux[AT_PHNUM]; n; n--, p += aux[AT_PHENT]) {
    phdr = (void*)p;
    if (phdr->p_type == PT_PHDR)
      base = aux[AT_PHDR] - phdr->p_vaddr;
    if (phdr->p_type == PT_TLS)
      tls_phdr = phdr;
  }
  info.dlpi_addr = base;
  info.dlpi_name = "/proc/self/exe";
  info.dlpi_phdr = (void*)aux[AT_PHDR];
  info.dlpi_phnum = aux[AT_PHNUM];
  info.dlpi_adds = 0;
  info.dlpi_subs = 0;
  if (tls_phdr) {
    info.dlpi_tls_modid = 1;
    info.dlpi_tls_data = (void*)(base + tls_phdr->p_vaddr);
  } else {
    info.dlpi_tls_modid = 0;
    info.dlpi_tls_data = 0;
  }
  return (callback)(&info, sizeof(info), data);
}

weak_alias(static_dl_iterate_phdr, dl_iterate_phdr);