nsz Git - musl/blob - src/ldso/dl_iterate_phdr.c

   1 #include <elf.h>
   2 #include <link.h>
   3 #include "libc.h"
   4
   5 #define AUX_CNT 38
   6
   7 extern weak hidden const size_t _DYNAMIC[];
   8
   9 static int static_dl_iterate_phdr(int(*callback)(struct dl_phdr_info *info, size_t size, void *data), void *data)
  10 {
  11         unsigned char *p;
  12         ElfW(Phdr) *phdr, *tls_phdr=0;
  13         size_t base = 0;
  14         size_t n;
  15         struct dl_phdr_info info;
  16         size_t i, aux[AUX_CNT] = {0};
  17
  18         for (i=0; libc.auxv[i]; i+=2)
  19                 if (libc.auxv[i]<AUX_CNT) aux[libc.auxv[i]] = libc.auxv[i+1];
  20
  21         for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
  22                 phdr = (void *)p;
  23                 if (phdr->p_type == PT_PHDR)
  24                         base = aux[AT_PHDR] - phdr->p_vaddr;
  25                 if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
  26                         base = (size_t)_DYNAMIC - phdr->p_vaddr;
  27                 if (phdr->p_type == PT_TLS)
  28                         tls_phdr = phdr;
  29         }
  30         info.dlpi_addr  = base;
  31         info.dlpi_name  = "/proc/self/exe";
  32         info.dlpi_phdr  = (void *)aux[AT_PHDR];
  33         info.dlpi_phnum = aux[AT_PHNUM];
  34         info.dlpi_adds  = 0;
  35         info.dlpi_subs  = 0;
  36         if (tls_phdr) {
  37                 info.dlpi_tls_modid = 1;
  38                 info.dlpi_tls_data = (void *)(base + tls_phdr->p_vaddr);
  39         } else {
  40                 info.dlpi_tls_modid = 0;
  41                 info.dlpi_tls_data = 0;
  42         }
  43         return (callback)(&info, sizeof (info), data);
  44 }
  45
  46 weak_alias(static_dl_iterate_phdr, dl_iterate_phdr);