diff options
Diffstat (limited to 'src/pkg/runtime/vdso_linux_amd64.c')
| -rw-r--r-- | src/pkg/runtime/vdso_linux_amd64.c | 366 |
1 files changed, 0 insertions, 366 deletions
diff --git a/src/pkg/runtime/vdso_linux_amd64.c b/src/pkg/runtime/vdso_linux_amd64.c deleted file mode 100644 index 38e115243..000000000 --- a/src/pkg/runtime/vdso_linux_amd64.c +++ /dev/null @@ -1,366 +0,0 @@ -// Copyright 2012 The Go Authors. All rights reserved. -// Use of this source code is governed by a BSD-style -// license that can be found in the LICENSE file. - -#include "runtime.h" - -// Look up symbols in the Linux vDSO. - -// This code was originally based on the sample Linux vDSO parser at -// https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/vDSO/parse_vdso.c - -// This implements the ELF dynamic linking spec at -// http://sco.com/developers/gabi/latest/ch5.dynamic.html - -// The version section is documented at -// http://refspecs.linuxfoundation.org/LSB_3.2.0/LSB-Core-generic/LSB-Core-generic/symversion.html - -#define AT_RANDOM 25 -#define AT_SYSINFO_EHDR 33 -#define AT_NULL 0 /* End of vector */ -#define PT_LOAD 1 /* Loadable program segment */ -#define PT_DYNAMIC 2 /* Dynamic linking information */ -#define DT_NULL 0 /* Marks end of dynamic section */ -#define DT_HASH 4 /* Dynamic symbol hash table */ -#define DT_STRTAB 5 /* Address of string table */ -#define DT_SYMTAB 6 /* Address of symbol table */ -#define DT_VERSYM 0x6ffffff0 -#define DT_VERDEF 0x6ffffffc - -#define VER_FLG_BASE 0x1 /* Version definition of file itself */ -#define SHN_UNDEF 0 /* Undefined section */ -#define SHT_DYNSYM 11 /* Dynamic linker symbol table */ -#define STT_FUNC 2 /* Symbol is a code object */ -#define STB_GLOBAL 1 /* Global symbol */ -#define STB_WEAK 2 /* Weak symbol */ - -/* How to extract and insert information held in the st_info field. */ -#define ELF64_ST_BIND(val) (((byte) (val)) >> 4) -#define ELF64_ST_TYPE(val) ((val) & 0xf) - -#define EI_NIDENT (16) - -typedef uint16 Elf64_Half; -typedef uint32 Elf64_Word; -typedef int32 Elf64_Sword; -typedef uint64 Elf64_Xword; -typedef int64 Elf64_Sxword; -typedef uint64 Elf64_Addr; -typedef uint64 Elf64_Off; -typedef uint16 Elf64_Section; -typedef Elf64_Half Elf64_Versym; - - -typedef struct -{ - Elf64_Word st_name; - byte st_info; - byte st_other; - Elf64_Section st_shndx; - Elf64_Addr st_value; - Elf64_Xword st_size; -} Elf64_Sym; - -typedef struct -{ - Elf64_Half vd_version; /* Version revision */ - Elf64_Half vd_flags; /* Version information */ - Elf64_Half vd_ndx; /* Version Index */ - Elf64_Half vd_cnt; /* Number of associated aux entries */ - Elf64_Word vd_hash; /* Version name hash value */ - Elf64_Word vd_aux; /* Offset in bytes to verdaux array */ - Elf64_Word vd_next; /* Offset in bytes to next verdef entry */ -} Elf64_Verdef; - -typedef struct -{ - byte e_ident[EI_NIDENT]; /* Magic number and other info */ - Elf64_Half e_type; /* Object file type */ - Elf64_Half e_machine; /* Architecture */ - Elf64_Word e_version; /* Object file version */ - Elf64_Addr e_entry; /* Entry point virtual address */ - Elf64_Off e_phoff; /* Program header table file offset */ - Elf64_Off e_shoff; /* Section header table file offset */ - Elf64_Word e_flags; /* Processor-specific flags */ - Elf64_Half e_ehsize; /* ELF header size in bytes */ - Elf64_Half e_phentsize; /* Program header table entry size */ - Elf64_Half e_phnum; /* Program header table entry count */ - Elf64_Half e_shentsize; /* Section header table entry size */ - Elf64_Half e_shnum; /* Section header table entry count */ - Elf64_Half e_shstrndx; /* Section header string table index */ -} Elf64_Ehdr; - -typedef struct -{ - Elf64_Word p_type; /* Segment type */ - Elf64_Word p_flags; /* Segment flags */ - Elf64_Off p_offset; /* Segment file offset */ - Elf64_Addr p_vaddr; /* Segment virtual address */ - Elf64_Addr p_paddr; /* Segment physical address */ - Elf64_Xword p_filesz; /* Segment size in file */ - Elf64_Xword p_memsz; /* Segment size in memory */ - Elf64_Xword p_align; /* Segment alignment */ -} Elf64_Phdr; - -typedef struct -{ - Elf64_Word sh_name; /* Section name (string tbl index) */ - Elf64_Word sh_type; /* Section type */ - Elf64_Xword sh_flags; /* Section flags */ - Elf64_Addr sh_addr; /* Section virtual addr at execution */ - Elf64_Off sh_offset; /* Section file offset */ - Elf64_Xword sh_size; /* Section size in bytes */ - Elf64_Word sh_link; /* Link to another section */ - Elf64_Word sh_info; /* Additional section information */ - Elf64_Xword sh_addralign; /* Section alignment */ - Elf64_Xword sh_entsize; /* Entry size if section holds table */ -} Elf64_Shdr; - -typedef struct -{ - Elf64_Sxword d_tag; /* Dynamic entry type */ - union - { - Elf64_Xword d_val; /* Integer value */ - Elf64_Addr d_ptr; /* Address value */ - } d_un; -} Elf64_Dyn; - -typedef struct -{ - Elf64_Word vda_name; /* Version or dependency names */ - Elf64_Word vda_next; /* Offset in bytes to next verdaux entry */ -} Elf64_Verdaux; - -typedef struct -{ - uint64 a_type; /* Entry type */ - union - { - uint64 a_val; /* Integer value */ - } a_un; -} Elf64_auxv_t; - - -typedef struct { - byte* name; - int32 sym_hash; - void** var_ptr; -} symbol_key; - -typedef struct { - byte* version; - int32 ver_hash; -} version_key; - -struct vdso_info { - bool valid; - - /* Load information */ - uintptr load_addr; - uintptr load_offset; /* load_addr - recorded vaddr */ - - /* Symbol table */ - Elf64_Sym *symtab; - const byte *symstrings; - Elf64_Word *bucket, *chain; - Elf64_Word nbucket, nchain; - - /* Version table */ - Elf64_Versym *versym; - Elf64_Verdef *verdef; -}; - -static version_key linux26 = { (byte*)"LINUX_2.6", 0x3ae75f6 }; - -// initialize with vsyscall fallbacks -void* runtime·__vdso_time_sym = (void*)0xffffffffff600400ULL; -void* runtime·__vdso_gettimeofday_sym = (void*)0xffffffffff600000ULL; -void* runtime·__vdso_clock_gettime_sym = (void*)0; - -#define SYM_KEYS_COUNT 3 -static symbol_key sym_keys[] = { - { (byte*)"__vdso_time", 0xa33c485, &runtime·__vdso_time_sym }, - { (byte*)"__vdso_gettimeofday", 0x315ca59, &runtime·__vdso_gettimeofday_sym }, - { (byte*)"__vdso_clock_gettime", 0xd35ec75, &runtime·__vdso_clock_gettime_sym }, -}; - -static void -vdso_init_from_sysinfo_ehdr(struct vdso_info *vdso_info, Elf64_Ehdr* hdr) -{ - uint64 i; - bool found_vaddr = false; - Elf64_Phdr *pt; - Elf64_Dyn *dyn; - Elf64_Word *hash; - - vdso_info->valid = false; - vdso_info->load_addr = (uintptr) hdr; - - pt = (Elf64_Phdr*)(vdso_info->load_addr + hdr->e_phoff); - dyn = nil; - - // We need two things from the segment table: the load offset - // and the dynamic table. - for(i=0; i<hdr->e_phnum; i++) { - if(pt[i].p_type == PT_LOAD && found_vaddr == false) { - found_vaddr = true; - vdso_info->load_offset = (uintptr)hdr - + (uintptr)pt[i].p_offset - - (uintptr)pt[i].p_vaddr; - } else if(pt[i].p_type == PT_DYNAMIC) { - dyn = (Elf64_Dyn*)((uintptr)hdr + pt[i].p_offset); - } - } - - if(found_vaddr == false || dyn == nil) - return; // Failed - - // Fish out the useful bits of the dynamic table. - hash = nil; - vdso_info->symstrings = nil; - vdso_info->symtab = nil; - vdso_info->versym = nil; - vdso_info->verdef = nil; - for(i=0; dyn[i].d_tag!=DT_NULL; i++) { - switch(dyn[i].d_tag) { - case DT_STRTAB: - vdso_info->symstrings = (const byte *) - ((uintptr)dyn[i].d_un.d_ptr - + vdso_info->load_offset); - break; - case DT_SYMTAB: - vdso_info->symtab = (Elf64_Sym *) - ((uintptr)dyn[i].d_un.d_ptr - + vdso_info->load_offset); - break; - case DT_HASH: - hash = (Elf64_Word *) - ((uintptr)dyn[i].d_un.d_ptr - + vdso_info->load_offset); - break; - case DT_VERSYM: - vdso_info->versym = (Elf64_Versym *) - ((uintptr)dyn[i].d_un.d_ptr - + vdso_info->load_offset); - break; - case DT_VERDEF: - vdso_info->verdef = (Elf64_Verdef *) - ((uintptr)dyn[i].d_un.d_ptr - + vdso_info->load_offset); - break; - } - } - if(vdso_info->symstrings == nil || vdso_info->symtab == nil || hash == nil) - return; // Failed - - if(vdso_info->verdef == nil) - vdso_info->versym = 0; - - // Parse the hash table header. - vdso_info->nbucket = hash[0]; - vdso_info->nchain = hash[1]; - vdso_info->bucket = &hash[2]; - vdso_info->chain = &hash[vdso_info->nbucket + 2]; - - // That's all we need. - vdso_info->valid = true; -} - -static int32 -vdso_find_version(struct vdso_info *vdso_info, version_key* ver) -{ - if(vdso_info->valid == false) { - return 0; - } - Elf64_Verdef *def = vdso_info->verdef; - while(true) { - if((def->vd_flags & VER_FLG_BASE) == 0) { - Elf64_Verdaux *aux = (Elf64_Verdaux*)((byte *)def + def->vd_aux); - if(def->vd_hash == ver->ver_hash && - runtime·strcmp(ver->version, vdso_info->symstrings + aux->vda_name) == 0) { - return def->vd_ndx & 0x7fff; - } - } - - if(def->vd_next == 0) { - break; - } - def = (Elf64_Verdef *)((byte *)def + def->vd_next); - } - return -1; // can not match any version -} - -static void -vdso_parse_symbols(struct vdso_info *vdso_info, int32 version) -{ - int32 i; - Elf64_Word chain; - Elf64_Sym *sym; - - if(vdso_info->valid == false) - return; - - for(i=0; i<SYM_KEYS_COUNT; i++) { - for(chain = vdso_info->bucket[sym_keys[i].sym_hash % vdso_info->nbucket]; - chain != 0; chain = vdso_info->chain[chain]) { - - sym = &vdso_info->symtab[chain]; - if(ELF64_ST_TYPE(sym->st_info) != STT_FUNC) - continue; - if(ELF64_ST_BIND(sym->st_info) != STB_GLOBAL && - ELF64_ST_BIND(sym->st_info) != STB_WEAK) - continue; - if(sym->st_shndx == SHN_UNDEF) - continue; - if(runtime·strcmp(sym_keys[i].name, vdso_info->symstrings + sym->st_name) != 0) - continue; - - // Check symbol version. - if(vdso_info->versym != nil && version != 0 - && vdso_info->versym[chain] & 0x7fff != version) - continue; - - *sym_keys[i].var_ptr = (void *)(vdso_info->load_offset + sym->st_value); - break; - } - } -} - -static void -runtime·linux_setup_vdso(int32 argc, uint8** argv) -{ - struct vdso_info vdso_info; - - // skip argvc - byte **p = argv; - p = &p[argc+1]; - - // skip envp to get to ELF auxiliary vector. - for(; *p!=0; p++) {} - - // skip NULL separator - p++; - - // now, p points to auxv - Elf64_auxv_t *elf_auxv = (Elf64_auxv_t*) p; - - for(int32 i=0; elf_auxv[i].a_type!=AT_NULL; i++) { - if(elf_auxv[i].a_type == AT_SYSINFO_EHDR) { - if(elf_auxv[i].a_un.a_val == 0) { - // Something went wrong - continue; - } - vdso_init_from_sysinfo_ehdr(&vdso_info, (Elf64_Ehdr*)elf_auxv[i].a_un.a_val); - vdso_parse_symbols(&vdso_info, vdso_find_version(&vdso_info, &linux26)); - continue; - } - if(elf_auxv[i].a_type == AT_RANDOM) { - runtime·startup_random_data = (byte*)elf_auxv[i].a_un.a_val; - runtime·startup_random_data_len = 16; - continue; - } - } -} - -void (*runtime·sysargs)(int32, uint8**) = runtime·linux_setup_vdso; |