find_exidx.c raw

   1  #define _GNU_SOURCE
   2  #include <link.h>
   3  #include <stdint.h>
   4  
   5  struct find_exidx_data {
   6  	uintptr_t pc, exidx_start;
   7  	int exidx_len;
   8  };
   9  
  10  static int find_exidx(struct dl_phdr_info *info, size_t size, void *ptr)
  11  {
  12  	struct find_exidx_data *data = ptr;
  13  	const ElfW(Phdr) *phdr = info->dlpi_phdr;
  14  	uintptr_t addr, exidx_start = 0;
  15  	int i, match = 0, exidx_len = 0;
  16  
  17  	for (i = info->dlpi_phnum; i > 0; i--, phdr++) {
  18  		addr = info->dlpi_addr + phdr->p_vaddr;
  19  		switch (phdr->p_type) {
  20  		case PT_LOAD:
  21  			match |= data->pc >= addr && data->pc < addr + phdr->p_memsz;
  22  			break;
  23  		case PT_ARM_EXIDX:
  24  			exidx_start = addr;
  25  			exidx_len = phdr->p_memsz;
  26  			break;
  27  		}
  28  	}
  29  	data->exidx_start = exidx_start;
  30  	data->exidx_len = exidx_len;
  31  	return match;
  32  }
  33  
  34  uintptr_t __gnu_Unwind_Find_exidx(uintptr_t pc, int *pcount)
  35  {
  36  	struct find_exidx_data data;
  37  	data.pc = pc;
  38  	if (dl_iterate_phdr(find_exidx, &data) <= 0)
  39  		return 0;
  40  	*pcount = data.exidx_len / 8;
  41  	return data.exidx_start;
  42  }
  43