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- #include <elf.h>
- //#include <stdio.h>
- #include <string.h>
- #include "sys/auxv.h"
- //#include <linux/time.h>
- //#include <time.h>
- #include "ldso.h"
- #include "generated/autoconf.h"
- #ifndef ELF_BITS
- # if ULONG_MAX > 0xffffffffUL
- # define ELF_BITS 64
- # else
- # define ELF_BITS 32
- # endif
- #endif
- #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x
- #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x)
- #define ELF(x) ELF_BITS_XFORM(ELF_BITS, x)
- #ifndef __VDSO_SUPPORT__
- void load_vdso( uint32_t sys_info_ehdr, char **envp ){
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2,"_dl_vdso support not enabled\n" );
- }
- #endif
- }
- #else
-
- //typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
- void* _dl__vdso_gettimeofday = 0;
- //typedef long (*clock_gettime_t)(int clk_id, struct timespec *tp);
- void* _dl__vdso_clock_gettime = 0;
- typedef struct{
- void* base_addr;
- ELF(Ehdr) *hdr;
- char* section_header_strtab;
- ELF(Sym) *dynsym_table;
- uint32_t dynsym_table_num;
- char* dynstr_table;
- uint16_t *versym_table;
- ELF(Verdef) *verdef_table;
- uint32_t verdef_num;
- ELF(Dyn) *dynamic_section;
- uint32_t dynamic_section_num;
- char* text_section;
- char* vers_strings[10];
- }elf_infos;
- /*
- * the raise() dummy function is needed because of divisons in this code
- * but keep it hidden in this object
- *
- * fixes link error with gcc 12 for arm
- */
- #pragma GCC visibility push(hidden)
- int raise(int sig){
- sig = sig;
- return 0;
- }
- #pragma GCC visibility pop
- static int vdso_check_elf_header( elf_infos* elf ){
-
- if ( 0 != _dl_memcmp( ELFMAG, elf->base_addr, 4 ) ){
- return 1;
- }
-
- if (elf->hdr->e_ident[EI_CLASS] != (ELF_BITS == 32 ? ELFCLASS32 : ELFCLASS64)) {
- _dl_dprintf(2,"vdso ELF Bits check error\n");
- return 1; /* Wrong ELF class -- check ELF_BITS */
- }
-
- return 0;
- }
- static ELF(Shdr) *vdso_get_sec_header( elf_infos* elf, int index ){
-
- return (ELF(Shdr) *) ( elf->base_addr + elf->hdr->e_shoff + ( index * sizeof( ELF(Shdr) )) );
-
- }
- void load_vdso( uint32_t sys_info_ehdr, char **envp ){
- elf_infos vdso_infos;
-
-
-
- if ( sys_info_ehdr == 0 ){
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2,"_dl_vdso no vdso provied by kernel\n" );
- }
- #endif
- return;
-
- }
-
- char* _dl_vdso_disable = _dl_getenv("VDSO_DISABLE", envp);
- if ( _dl_vdso_disable != 0 ){
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2,"_dl_vdso vdso support disabled\n" );
- }
- #endif
- return;
- }
-
-
- _dl_memset( &vdso_infos, 0 , sizeof( elf_infos ) );
-
-
- vdso_infos.base_addr = (void*)sys_info_ehdr;
- vdso_infos.hdr = (ELF(Ehdr)*)vdso_infos.base_addr;
-
- //printf("base : %p\n",vdso_infos.base_addr);
-
- if ( 0 != vdso_check_elf_header( &vdso_infos ) ){
- return;
- }
-
-
-
- ELF(Shdr) *sec_header = vdso_get_sec_header( &vdso_infos, vdso_infos.hdr->e_shstrndx);
- vdso_infos.section_header_strtab = ( vdso_infos.base_addr + sec_header->sh_offset );
-
- /*
- *
- * load ELF section headers
- *
- */
-
- for ( int i = 0 ; i < vdso_infos.hdr->e_shnum; i++ ){
-
- sec_header = vdso_get_sec_header( &vdso_infos, i );
-
- char* name = vdso_infos.section_header_strtab + sec_header->sh_name;
-
- if( ( SHT_DYNSYM == sec_header->sh_type ) && ( 0 == _dl_strcmp( ".dynsym",name ) ) ){
- vdso_infos.dynsym_table = ( vdso_infos.base_addr + sec_header->sh_offset );
- vdso_infos.dynsym_table_num = sec_header->sh_size / sec_header->sh_entsize ;
- continue;
- }
-
- if( ( SHT_STRTAB == sec_header->sh_type ) && ( 0 == _dl_strcmp( ".dynstr",name ) ) ){
- vdso_infos.dynstr_table = ( vdso_infos.base_addr + sec_header->sh_offset );
- continue;
- }
-
- if( ( SHT_GNU_versym == sec_header->sh_type ) && ( 0 == _dl_strcmp( ".gnu.version",name ) ) ){
- vdso_infos.versym_table = ( vdso_infos.base_addr + sec_header->sh_offset );
- continue;
- }
-
- if( ( SHT_GNU_verdef == sec_header->sh_type ) && ( 0 == _dl_strcmp( ".gnu.version_d",name ) ) ){
- vdso_infos.verdef_table = ( vdso_infos.base_addr + sec_header->sh_offset );
- continue;
- }
-
- if( ( SHT_DYNAMIC == sec_header->sh_type ) && ( 0 == _dl_strcmp( ".dynamic",name ) ) ){
- vdso_infos.dynamic_section = ( vdso_infos.base_addr + sec_header->sh_offset );
- vdso_infos.dynamic_section_num = sec_header->sh_size / sec_header->sh_entsize ;
- continue;
- }
-
- if( ( SHT_PROGBITS == sec_header->sh_type ) && ( 0 == _dl_strcmp( ".text",name ) ) ){
- vdso_infos.text_section = ( vdso_infos.base_addr + sec_header->sh_offset );
- continue;
- }
-
- }
- /*
- *
- * check section header -> dynamic table consistence
- *
- */
-
-
- for( int i = 0 ; i < vdso_infos.dynamic_section_num ; i++ ){
- ELF(Dyn) *dyn_sec = &vdso_infos.dynamic_section[i];
- if ( dyn_sec->d_tag == 0 ) continue;
-
-
- if ( dyn_sec->d_tag == DT_STRTAB ){
- char* strtab = ( vdso_infos.base_addr + dyn_sec->d_un.d_ptr );
- if ( strtab != (char*) vdso_infos.dynstr_table ){
- _dl_dprintf(2,"vdso elf DT_STRTAB check error\n");
- return;
- }
- continue;
- }
-
- if ( dyn_sec->d_tag == DT_SYMTAB ){
- char* symtab = ( vdso_infos.base_addr + dyn_sec->d_un.d_ptr );
- if ( symtab != (char*) vdso_infos.dynsym_table ){
- _dl_dprintf(2,"vdso elf DT_SYMTAB check error\n");
- return;
- }
- continue;
- }
-
- if ( dyn_sec->d_tag == DT_VERDEF ){
- Elf32_Verdef* verdef = ( vdso_infos.base_addr + dyn_sec->d_un.d_ptr );
- if ( verdef != (Elf32_Verdef*) vdso_infos.verdef_table ){
- _dl_dprintf(2,"vdso elf DT_VERDEF check error\n");
- return;
- }
- continue;
- }
-
- if ( dyn_sec->d_tag == DT_VERDEFNUM ){
- vdso_infos.verdef_num = dyn_sec->d_un.d_val;
- continue;
- }
-
- if ( dyn_sec->d_tag == DT_VERSYM ){
- uint16_t* versym = ( vdso_infos.base_addr + dyn_sec->d_un.d_ptr );
- if ( versym != vdso_infos.versym_table ){
- _dl_dprintf(2,"vdso elf DT_VERSYM check error\n");
- return;
- }
- continue;
- }
-
- }
-
- /*
- *
- * load vdso version definition strings
- *
- */
-
- ELF(Verdef) *vd = vdso_infos.verdef_table;
- for( int i = 0 ; i < vdso_infos.verdef_num ; i++ ){
-
- ELF(Verdaux) *vd_aux = (ELF(Verdaux) *)(( ( char*)vd ) + vd->vd_aux);
-
- vdso_infos.vers_strings[ vd->vd_ndx ] = vdso_infos.dynstr_table + vd_aux->vda_name;
-
- vd = ( ELF(Verdef) *)(( ( char*)vd ) + vd->vd_next);
-
- }
-
- /*
- *
- * load function from the vdso
- *
- */
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- int vdso_functions = 0;
- for( int i = 0 ; i < vdso_infos.dynsym_table_num ; i++ ){
- ELF(Sym)* sym = &vdso_infos.dynsym_table[i];
-
- if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC)
- continue;
-
- char* name = vdso_infos.dynstr_table + sym->st_name;
- if ( name[0] == 0 ){
- continue;
- }
- vdso_functions++;
- }
- _dl_dprintf(2,"_dl_vdso_load functions found : %d\n", vdso_functions );
- }
- #endif
-
- for( int i = 0 ; i < vdso_infos.dynsym_table_num ; i++ ){
- ELF(Sym)* sym = &vdso_infos.dynsym_table[i];
-
- if (ELF64_ST_TYPE(sym->st_info) != STT_FUNC)
- continue;
- char* name = vdso_infos.dynstr_table + sym->st_name;
- char* vers = vdso_infos.vers_strings[ vdso_infos.versym_table[i] ];
- void* func_addr = (void*)( vdso_infos.base_addr + sym->st_value );
-
- // the function name is patched to zero if the kernel has no timer which is
- // usable for the function
- if ( name[0] == 0 ){
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2," function at address %p disabled by the kernel\n", sym->st_value );
- }
- #endif
- continue;
- }
- //printf(" %s@@%s\n", name , vers );
-
- //print_sym( sym );
- if ( 0 == _dl_strcmp( name, "__vdso_gettimeofday" ) ){
- _dl__vdso_gettimeofday = func_addr;
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2," %s at address %p\n", name, func_addr );
- }
- #endif
- continue;
- }
-
- if ( 0 == _dl_strcmp( name, "__vdso_clock_gettime" ) ){
- _dl__vdso_clock_gettime = func_addr;
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2," %s at address %p\n", name, func_addr );
- }
- #endif
- continue;
- }
-
- #ifdef __SUPPORT_LD_DEBUG__
- if ( _dl_debug_vdso != 0 ){
- _dl_dprintf(2," <%s> not handled\n", name );
- }
- #endif
-
-
- }
-
-
- }
- #endif // __VDSO_SUPPORT__
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