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llvm-project/lldb/tools/compact-unwind/compact-unwind-dumper.c

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#include <stdint.h>
#include <mach-o/loader.h>
#include <mach-o/compact_unwind_encoding.h>
#include <mach/machine.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/mman.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <inttypes.h>
#include <stdio.h>
#include <mach-o/nlist.h>
#define EXTRACT_BITS(value, mask) \
( (value >> __builtin_ctz(mask)) & (((1 << __builtin_popcount(mask)))-1) )
// A quick sketch of a program which can parse the compact unwind info
// used on Darwin systems for exception handling. The output of
// unwinddump will be more authoritative/reliable but this program
// can dump at least the UNWIND_X86_64_MODE_RBP_FRAME format entries
// correctly.
struct symbol
{
uint64_t file_address;
const char *name;
};
int
symbol_compare (const void *a, const void *b)
{
return (int) ((struct symbol *)a)->file_address - ((struct symbol *)b)->file_address;
}
struct baton
{
cpu_type_t cputype;
uint8_t *mach_header_start; // pointer into this program's address space
uint8_t *compact_unwind_start; // pointer into this program's address space
int addr_size; // 4 or 8 bytes, the size of addresses in this file
uint64_t text_segment_vmaddr; // __TEXT segment vmaddr
uint64_t text_segment_file_offset;
uint64_t text_section_vmaddr; // __TEXT,__text section vmaddr
uint64_t text_section_file_offset;
uint64_t eh_section_file_address; // the file address of the __TEXT,__eh_frame section
uint8_t *lsda_array_start; // for the currently-being-processed first-level index
uint8_t *lsda_array_end; // the lsda_array_start for the NEXT first-level index
struct symbol *symbols;
int symbols_count;
uint64_t *function_start_addresses;
int function_start_addresses_count;
int current_index_table_number;
struct unwind_info_section_header unwind_header;
struct unwind_info_section_header_index_entry first_level_index_entry;
struct unwind_info_compressed_second_level_page_header compressed_second_level_page_header;
struct unwind_info_regular_second_level_page_header regular_second_level_page_header;
};
uint64_t
read_leb128 (uint8_t **offset)
{
uint64_t result = 0;
int shift = 0;
while (1)
{
uint8_t byte = **offset;
*offset = *offset + 1;
result |= (byte & 0x7f) << shift;
if ((byte & 0x80) == 0)
break;
shift += 7;
}
return result;
}
// step through the load commands in a thin mach-o binary,
// find the cputype and the start of the __TEXT,__unwind_info
// section, return a pointer to that section or NULL if not found.
static void
scan_macho_load_commands (struct baton *baton)
{
struct symtab_command symtab_cmd;
uint64_t linkedit_segment_vmaddr;
uint64_t linkedit_segment_file_offset;
baton->compact_unwind_start = 0;
uint32_t *magic = (uint32_t *) baton->mach_header_start;
if (*magic != MH_MAGIC && *magic != MH_MAGIC_64)
{
printf ("Unexpected magic number 0x%x in header, exiting.", *magic);
exit (1);
}
bool is_64bit = false;
if (*magic == MH_MAGIC_64)
is_64bit = true;
uint8_t *offset = baton->mach_header_start;
struct mach_header mh;
memcpy (&mh, offset, sizeof (struct mach_header));
if (is_64bit)
offset += sizeof (struct mach_header_64);
else
offset += sizeof (struct mach_header);
if (is_64bit)
baton->addr_size = 8;
else
baton->addr_size = 4;
baton->cputype = mh.cputype;
uint8_t *start_of_load_commands = offset;
uint32_t cur_cmd = 0;
while (cur_cmd < mh.ncmds && (offset - start_of_load_commands) < mh.sizeofcmds)
{
struct load_command lc;
uint32_t *lc_cmd = (uint32_t *) offset;
uint32_t *lc_cmdsize = (uint32_t *) offset + 1;
uint8_t *start_of_this_load_cmd = offset;
if (*lc_cmd == LC_SEGMENT || *lc_cmd == LC_SEGMENT_64)
{
char segment_name[17];
segment_name[0] = '\0';
uint32_t nsects = 0;
uint64_t segment_offset = 0;
uint64_t segment_vmaddr = 0;
if (*lc_cmd == LC_SEGMENT_64)
{
struct segment_command_64 seg;
memcpy (&seg, offset, sizeof (struct segment_command_64));
memcpy (&segment_name, &seg.segname, 16);
segment_name[16] = '\0';
nsects = seg.nsects;
segment_offset = seg.fileoff;
segment_vmaddr = seg.vmaddr;
offset += sizeof (struct segment_command_64);
if ((seg.flags & SG_PROTECTED_VERSION_1) == SG_PROTECTED_VERSION_1)
{
printf ("Segment '%s' is encrypted.\n", segment_name);
}
}
if (*lc_cmd == LC_SEGMENT)
{
struct segment_command seg;
memcpy (&seg, offset, sizeof (struct segment_command));
memcpy (&segment_name, &seg.segname, 16);
segment_name[16] = '\0';
nsects = seg.nsects;
segment_offset = seg.fileoff;
segment_vmaddr = seg.vmaddr;
offset += sizeof (struct segment_command);
if ((seg.flags & SG_PROTECTED_VERSION_1) == SG_PROTECTED_VERSION_1)
{
printf ("Segment '%s' is encrypted.\n", segment_name);
}
}
if (nsects != 0 && strcmp (segment_name, "__TEXT") == 0)
{
baton->text_segment_vmaddr = segment_vmaddr;
baton->text_segment_file_offset = segment_offset;
uint32_t current_sect = 0;
while (current_sect < nsects && (offset - start_of_this_load_cmd) < *lc_cmdsize)
{
char sect_name[17];
memcpy (&sect_name, offset, 16);
sect_name[16] = '\0';
if (strcmp (sect_name, "__unwind_info") == 0)
{
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->compact_unwind_start = baton->mach_header_start + sect.offset;
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->compact_unwind_start = baton->mach_header_start + sect.offset;
}
}
if (strcmp (sect_name, "__eh_frame") == 0)
{
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->eh_section_file_address = sect.addr;
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->eh_section_file_address = sect.addr;
}
}
if (strcmp (sect_name, "__text") == 0)
{
if (is_64bit)
{
struct section_64 sect;
memcpy (&sect, offset, sizeof (struct section_64));
baton->text_section_vmaddr = sect.addr;
baton->text_section_file_offset = sect.offset;
}
else
{
struct section sect;
memcpy (&sect, offset, sizeof (struct section));
baton->text_section_vmaddr = sect.addr;
}
}
if (is_64bit)
{
offset += sizeof (struct section_64);
}
else
{
offset += sizeof (struct section);
}
}
}
if (strcmp (segment_name, "__LINKEDIT") == 0)
{
linkedit_segment_vmaddr = segment_vmaddr;
linkedit_segment_file_offset = segment_offset;
}
}
if (*lc_cmd == LC_SYMTAB)
{
memcpy (&symtab_cmd, offset, sizeof (struct symtab_command));
}
if (*lc_cmd == LC_DYSYMTAB)
{
struct dysymtab_command dysymtab_cmd;
memcpy (&dysymtab_cmd, offset, sizeof (struct dysymtab_command));
int nlist_size = 12;
if (is_64bit)
nlist_size = 16;
char *string_table = (char *) (baton->mach_header_start + symtab_cmd.stroff);
uint8_t *local_syms = baton->mach_header_start + symtab_cmd.symoff + (dysymtab_cmd.ilocalsym * nlist_size);
int local_syms_count = dysymtab_cmd.nlocalsym;
uint8_t *exported_syms = baton->mach_header_start + symtab_cmd.symoff + (dysymtab_cmd.iextdefsym * nlist_size);
int exported_syms_count = dysymtab_cmd.nextdefsym;
// We're only going to create records for a small number of these symbols but to
// simplify the memory management I'll allocate enough space to store all of them.
baton->symbols = (struct symbol *) malloc (sizeof (struct symbol) * (local_syms_count + exported_syms_count));
baton->symbols_count = 0;
for (int i = 0; i < local_syms_count; i++)
{
struct nlist_64 nlist;
if (is_64bit)
{
memcpy (&nlist, local_syms + (i * nlist_size), sizeof (struct nlist_64));
}
else
{
struct nlist nlist_32;
memcpy (&nlist_32, local_syms + (i * nlist_size), sizeof (struct nlist));
nlist.n_un.n_strx = nlist_32.n_un.n_strx;
nlist.n_type = nlist_32.n_type;
nlist.n_sect = nlist_32.n_sect;
nlist.n_desc = nlist_32.n_desc;
nlist.n_value = nlist_32.n_value;
}
if ((nlist.n_type & N_STAB) == 0
&& ((nlist.n_type & N_EXT) == 1 ||
((nlist.n_type & N_TYPE) == N_TYPE && nlist.n_sect != NO_SECT))
&& nlist.n_value != 0
&& nlist.n_value != baton->text_segment_vmaddr)
{
baton->symbols[baton->symbols_count].file_address = nlist.n_value;
baton->symbols[baton->symbols_count].name = string_table + nlist.n_un.n_strx;
baton->symbols_count++;
}
}
for (int i = 0; i < exported_syms_count; i++)
{
struct nlist_64 nlist;
if (is_64bit)
{
memcpy (&nlist, exported_syms + (i * nlist_size), sizeof (struct nlist_64));
}
else
{
struct nlist nlist_32;
memcpy (&nlist_32, exported_syms + (i * nlist_size), sizeof (struct nlist));
nlist.n_un.n_strx = nlist_32.n_un.n_strx;
nlist.n_type = nlist_32.n_type;
nlist.n_sect = nlist_32.n_sect;
nlist.n_desc = nlist_32.n_desc;
nlist.n_value = nlist_32.n_value;
}
if ((nlist.n_type & N_STAB) == 0
&& ((nlist.n_type & N_EXT) == 1 ||
((nlist.n_type & N_TYPE) == N_TYPE && nlist.n_sect != NO_SECT))
&& nlist.n_value != 0
&& nlist.n_value != baton->text_segment_vmaddr)
{
baton->symbols[baton->symbols_count].file_address = nlist.n_value;
baton->symbols[baton->symbols_count].name = string_table + nlist.n_un.n_strx;
baton->symbols_count++;
}
}
qsort (baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
}
if (*lc_cmd == LC_FUNCTION_STARTS)
{
struct linkedit_data_command function_starts_cmd;
memcpy (&function_starts_cmd, offset, sizeof (struct linkedit_data_command));
uint8_t *funcstarts_offset = baton->mach_header_start + function_starts_cmd.dataoff;
uint8_t *function_end = funcstarts_offset + function_starts_cmd.datasize;
int count = 0;
while (funcstarts_offset < function_end)
{
if (read_leb128 (&funcstarts_offset) != 0)
{
count++;
}
}
baton->function_start_addresses = (uint64_t *) malloc (sizeof (uint64_t) * count);
baton->function_start_addresses_count = count;
funcstarts_offset = baton->mach_header_start + function_starts_cmd.dataoff;
uint64_t current_pc = baton->text_segment_vmaddr;
int i = 0;
while (funcstarts_offset < function_end)
{
uint64_t func_start = read_leb128 (&funcstarts_offset);
if (func_start != 0)
{
current_pc += func_start;
baton->function_start_addresses[i++] = current_pc;
}
}
}
offset = start_of_this_load_cmd + *lc_cmdsize;
cur_cmd++;
}
// Augment the symbol table with the function starts table -- adding symbol entries
// for functions that were stripped.
int unnamed_functions_to_add = 0;
for (int i = 0; i < baton->function_start_addresses_count; i++)
{
struct symbol search_key;
search_key.file_address = baton->function_start_addresses[i];
struct symbol *sym = bsearch (&search_key, baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
if (sym == NULL)
unnamed_functions_to_add++;
}
baton->symbols = (struct symbol *) realloc (baton->symbols, sizeof (struct symbol) * (baton->symbols_count + unnamed_functions_to_add));
int current_unnamed_symbol = 1;
int number_symbols_added = 0;
for (int i = 0; i < baton->function_start_addresses_count; i++)
{
struct symbol search_key;
search_key.file_address = baton->function_start_addresses[i];
struct symbol *sym = bsearch (&search_key, baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
if (sym == NULL)
{
char *name;
asprintf (&name, "unnamed function #%d", current_unnamed_symbol++);
baton->symbols[baton->symbols_count + number_symbols_added].file_address = baton->function_start_addresses[i];
baton->symbols[baton->symbols_count + number_symbols_added].name = name;
number_symbols_added++;
}
}
baton->symbols_count += number_symbols_added;
qsort (baton->symbols, baton->symbols_count, sizeof (struct symbol), symbol_compare);
// printf ("function start addresses\n");
// for (int i = 0; i < baton->function_start_addresses_count; i++)
// {
// printf ("0x%012llx\n", baton->function_start_addresses[i]);
// }
// printf ("symbol table names & addresses\n");
// for (int i = 0; i < baton->symbols_count; i++)
// {
// printf ("0x%012llx %s\n", baton->symbols[i].file_address, baton->symbols[i].name);
// }
}
void
print_encoding_x86_64 (struct baton baton, uint8_t *function_start, uint32_t encoding)
{
int mode = encoding & UNWIND_X86_64_MODE_MASK;
switch (mode)
{
case UNWIND_X86_64_MODE_RBP_FRAME:
{
printf ("frame func: CFA is rbp+%d ", 16);
printf (" rip=[CFA-8] rbp=[CFA-16]");
uint32_t saved_registers_offset = EXTRACT_BITS (encoding, UNWIND_X86_64_RBP_FRAME_OFFSET);
uint32_t saved_registers_locations = EXTRACT_BITS (encoding, UNWIND_X86_64_RBP_FRAME_REGISTERS);
saved_registers_offset += 2;
for (int i = 0; i < 5; i++)
{
switch (saved_registers_locations & 0x7)
{
case UNWIND_X86_64_REG_NONE:
break;
case UNWIND_X86_64_REG_RBX:
printf (" rbx=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R12:
printf (" r12=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R13:
printf (" r13=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R14:
printf (" r14=[CFA-%d]", saved_registers_offset * 8);
break;
case UNWIND_X86_64_REG_R15:
printf (" r15=[CFA-%d]", saved_registers_offset * 8);
break;
}
saved_registers_offset--;
saved_registers_locations >>= 3;
}
}
break;
case UNWIND_X86_64_MODE_STACK_IND:
case UNWIND_X86_64_MODE_STACK_IMMD:
{
uint32_t stack_size = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
uint32_t register_count = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_COUNT);
uint32_t permutation = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_REG_PERMUTATION);
if (mode == UNWIND_X86_64_MODE_STACK_IND && function_start)
{
uint32_t stack_adjust = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_ADJUST);
// offset into the function instructions; 0 == beginning of first instruction
uint32_t offset_to_subl_insn = EXTRACT_BITS (encoding, UNWIND_X86_64_FRAMELESS_STACK_SIZE);
stack_size = *((uint32_t*) (function_start + offset_to_subl_insn));
stack_size += stack_adjust * 8;
printf ("large stack ");
}
if (mode == UNWIND_X86_64_MODE_STACK_IND)
{
printf ("frameless function: stack size %d, register count %d ", stack_size * 8, register_count);
}
else
{
printf ("frameless function: stack size %d, register count %d ", stack_size, register_count);
}
if (register_count == 0)
{
printf (" no registers saved");
}
else
{
// We need to include (up to) 6 registers in 10 bits.
// That would be 18 bits if we just used 3 bits per reg to indicate
// the order they're saved on the stack.
//
// This is done with Lehmer code permutation, e.g. see
// http://stackoverflow.com/questions/1506078/fast-permutation-number-permutation-mapping-algorithms
int permunreg[6];
// This decodes the variable-base number in the 10 bits
// and gives us the Lehmer code sequence which can then
// be decoded.
switch (register_count)
{
case 6:
permunreg[0] = permutation/120; // 120 == 5!
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24; // 24 == 4!
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6; // 6 == 3!
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2; // 2 == 2!
permutation -= (permunreg[3]*2);
permunreg[4] = permutation; // 1 == 1!
permunreg[5] = 0;
break;
case 5:
permunreg[0] = permutation/120;
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24;
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6;
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2;
permutation -= (permunreg[3]*2);
permunreg[4] = permutation;
break;
case 4:
permunreg[0] = permutation/60;
permutation -= (permunreg[0]*60);
permunreg[1] = permutation/12;
permutation -= (permunreg[1]*12);
permunreg[2] = permutation/3;
permutation -= (permunreg[2]*3);
permunreg[3] = permutation;
break;
case 3:
permunreg[0] = permutation/20;
permutation -= (permunreg[0]*20);
permunreg[1] = permutation/4;
permutation -= (permunreg[1]*4);
permunreg[2] = permutation;
break;
case 2:
permunreg[0] = permutation/5;
permutation -= (permunreg[0]*5);
permunreg[1] = permutation;
break;
case 1:
permunreg[0] = permutation;
break;
}
// Decode the Lehmer code for this permutation of
// the registers v. http://en.wikipedia.org/wiki/Lehmer_code
int registers[6];
bool used[7] = { false, false, false, false, false, false, false };
for (int i = 0; i < register_count; i++)
{
int renum = 0;
for (int j = 1; j < 7; j++)
{
if (used[j] == false)
{
if (renum == permunreg[i])
{
registers[i] = j;
used[j] = true;
break;
}
renum++;
}
}
}
if (mode == UNWIND_X86_64_MODE_STACK_IND)
{
printf (" CFA is rsp+%d ", stack_size);
}
else
{
printf (" CFA is rsp+%d ", stack_size * 8);
}
uint32_t saved_registers_offset = 1;
printf (" rip=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
for (int i = (sizeof (registers) / sizeof (int)) - 1; i >= 0; i--)
{
switch (registers[i])
{
case UNWIND_X86_64_REG_NONE:
break;
case UNWIND_X86_64_REG_RBX:
printf (" rbx=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
break;
case UNWIND_X86_64_REG_R12:
printf (" r12=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
break;
case UNWIND_X86_64_REG_R13:
printf (" r13=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
break;
case UNWIND_X86_64_REG_R14:
printf (" r14=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
break;
case UNWIND_X86_64_REG_R15:
printf (" r15=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
break;
case UNWIND_X86_64_REG_RBP:
printf (" rbp=[CFA-%d]", saved_registers_offset * 8);
saved_registers_offset++;
break;
}
}
}
}
break;
case UNWIND_X86_64_MODE_DWARF:
{
uint32_t dwarf_offset = encoding & UNWIND_X86_DWARF_SECTION_OFFSET;
printf ("DWARF unwind instructions: FDE at offset %d (file address 0x%" PRIx64 ")",
dwarf_offset, dwarf_offset + baton.eh_section_file_address);
}
break;
case 0:
{
printf (" no unwind information");
}
break;
}
}
void
print_encoding_i386 (struct baton baton, uint8_t *function_start, uint32_t encoding)
{
int mode = encoding & UNWIND_X86_MODE_MASK;
switch (mode)
{
case UNWIND_X86_MODE_EBP_FRAME:
{
printf ("frame func: CFA is ebp+%d ", 8);
printf (" eip=[CFA-4] ebp=[CFA-8]");
uint32_t saved_registers_offset = EXTRACT_BITS (encoding, UNWIND_X86_EBP_FRAME_OFFSET);
uint32_t saved_registers_locations = EXTRACT_BITS (encoding, UNWIND_X86_EBP_FRAME_REGISTERS);
saved_registers_offset += 2;
for (int i = 0; i < 5; i++)
{
switch (saved_registers_locations & 0x7)
{
case UNWIND_X86_REG_NONE:
break;
case UNWIND_X86_REG_EBX:
printf (" ebx=[CFA-%d]", saved_registers_offset * 4);
break;
case UNWIND_X86_REG_ECX:
printf (" ecx=[CFA-%d]", saved_registers_offset * 4);
break;
case UNWIND_X86_REG_EDX:
printf (" edx=[CFA-%d]", saved_registers_offset * 4);
break;
case UNWIND_X86_REG_EDI:
printf (" edi=[CFA-%d]", saved_registers_offset * 4);
break;
case UNWIND_X86_REG_ESI:
printf (" esi=[CFA-%d]", saved_registers_offset * 4);
break;
}
saved_registers_offset--;
saved_registers_locations >>= 3;
}
}
break;
case UNWIND_X86_MODE_STACK_IND:
case UNWIND_X86_MODE_STACK_IMMD:
{
uint32_t stack_size = EXTRACT_BITS (encoding, UNWIND_X86_FRAMELESS_STACK_SIZE);
uint32_t register_count = EXTRACT_BITS (encoding, UNWIND_X86_FRAMELESS_STACK_REG_COUNT);
uint32_t permutation = EXTRACT_BITS (encoding, UNWIND_X86_FRAMELESS_STACK_REG_PERMUTATION);
if (mode == UNWIND_X86_MODE_STACK_IND && function_start)
{
uint32_t stack_adjust = EXTRACT_BITS (encoding, UNWIND_X86_FRAMELESS_STACK_ADJUST);
// offset into the function instructions; 0 == beginning of first instruction
uint32_t offset_to_subl_insn = EXTRACT_BITS (encoding, UNWIND_X86_FRAMELESS_STACK_SIZE);
stack_size = *((uint32_t*) (function_start + offset_to_subl_insn));
stack_size += stack_adjust * 4;
printf ("large stack ");
}
if (mode == UNWIND_X86_MODE_STACK_IND)
{
printf ("frameless function: stack size %d, register count %d ", stack_size, register_count);
}
else
{
printf ("frameless function: stack size %d, register count %d ", stack_size * 4, register_count);
}
if (register_count == 0)
{
printf (" no registers saved");
}
else
{
// We need to include (up to) 6 registers in 10 bits.
// That would be 18 bits if we just used 3 bits per reg to indicate
// the order they're saved on the stack.
//
// This is done with Lehmer code permutation, e.g. see
// http://stackoverflow.com/questions/1506078/fast-permutation-number-permutation-mapping-algorithms
int permunreg[6];
// This decodes the variable-base number in the 10 bits
// and gives us the Lehmer code sequence which can then
// be decoded.
switch (register_count)
{
case 6:
permunreg[0] = permutation/120; // 120 == 5!
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24; // 24 == 4!
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6; // 6 == 3!
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2; // 2 == 2!
permutation -= (permunreg[3]*2);
permunreg[4] = permutation; // 1 == 1!
permunreg[5] = 0;
break;
case 5:
permunreg[0] = permutation/120;
permutation -= (permunreg[0]*120);
permunreg[1] = permutation/24;
permutation -= (permunreg[1]*24);
permunreg[2] = permutation/6;
permutation -= (permunreg[2]*6);
permunreg[3] = permutation/2;
permutation -= (permunreg[3]*2);
permunreg[4] = permutation;
break;
case 4:
permunreg[0] = permutation/60;
permutation -= (permunreg[0]*60);
permunreg[1] = permutation/12;
permutation -= (permunreg[1]*12);
permunreg[2] = permutation/3;
permutation -= (permunreg[2]*3);
permunreg[3] = permutation;
break;
case 3:
permunreg[0] = permutation/20;
permutation -= (permunreg[0]*20);
permunreg[1] = permutation/4;
permutation -= (permunreg[1]*4);
permunreg[2] = permutation;
break;
case 2:
permunreg[0] = permutation/5;
permutation -= (permunreg[0]*5);
permunreg[1] = permutation;
break;
case 1:
permunreg[0] = permutation;
break;
}
// Decode the Lehmer code for this permutation of
// the registers v. http://en.wikipedia.org/wiki/Lehmer_code
int registers[6];
bool used[7] = { false, false, false, false, false, false, false };
for (int i = 0; i < register_count; i++)
{
int renum = 0;
for (int j = 1; j < 7; j++)
{
if (used[j] == false)
{
if (renum == permunreg[i])
{
registers[i] = j;
used[j] = true;
break;
}
renum++;
}
}
}
if (mode == UNWIND_X86_MODE_STACK_IND)
{
printf (" CFA is esp+%d ", stack_size);
}
else
{
printf (" CFA is esp+%d ", stack_size * 4);
}
uint32_t saved_registers_offset = 1;
printf (" eip=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
for (int i = (sizeof (registers) / sizeof (int)) - 1; i >= 0; i--)
{
switch (registers[i])
{
case UNWIND_X86_REG_NONE:
break;
case UNWIND_X86_REG_EBX:
printf (" ebx=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
break;
case UNWIND_X86_REG_ECX:
printf (" ecx=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
break;
case UNWIND_X86_REG_EDX:
printf (" edx=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
break;
case UNWIND_X86_REG_EDI:
printf (" edi=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
break;
case UNWIND_X86_REG_ESI:
printf (" esi=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
break;
case UNWIND_X86_REG_EBP:
printf (" ebp=[CFA-%d]", saved_registers_offset * 4);
saved_registers_offset++;
break;
}
}
}
}
break;
case UNWIND_X86_MODE_DWARF:
{
uint32_t dwarf_offset = encoding & UNWIND_X86_DWARF_SECTION_OFFSET;
printf ("DWARF unwind instructions: FDE at offset %d (file address 0x%" PRIx64 ")",
dwarf_offset, dwarf_offset + baton.eh_section_file_address);
}
break;
case 0:
{
printf (" no unwind information");
}
break;
}
}
void print_encoding (struct baton baton, uint8_t *function_start, uint32_t encoding)
{
if (baton.cputype == CPU_TYPE_X86_64)
{
print_encoding_x86_64 (baton, function_start, encoding);
}
else if (baton.cputype == CPU_TYPE_I386)
{
print_encoding_i386 (baton, function_start, encoding);
}
else
{
printf (" -- unsupported encoding arch -- ");
}
}
void
print_function_encoding (struct baton baton, uint32_t idx, uint32_t encoding, uint32_t entry_encoding_index, uint32_t entry_func_offset)
{
char *entry_encoding_index_str = "";
if (entry_encoding_index != (uint32_t) -1)
{
asprintf (&entry_encoding_index_str, ", encoding #%d", entry_encoding_index);
}
else
{
asprintf (&entry_encoding_index_str, "");
}
uint64_t file_address = baton.first_level_index_entry.functionOffset + entry_func_offset + baton.text_segment_vmaddr;
printf (" func [%d] offset %d (file addr 0x%" PRIx64 ")%s, encoding is 0x%x",
idx, entry_func_offset,
file_address,
entry_encoding_index_str,
encoding);
struct symbol *symbol = NULL;
for (int i = 0; i < baton.symbols_count; i++)
{
if (i == baton.symbols_count - 1 && baton.symbols[i].file_address <= file_address)
{
symbol = &(baton.symbols[i]);
break;
}
else
{
if (baton.symbols[i].file_address <= file_address && baton.symbols[i + 1].file_address > file_address)
{
symbol = &(baton.symbols[i]);
break;
}
}
}
printf ("\n ");
if (symbol)
{
int offset = file_address - symbol->file_address;
// FIXME this is a poor heuristic - if we're greater than 16 bytes past the
// start of the function, this is the unwind info for a stripped function.
// In reality the compact unwind entry may not line up exactly with the
// function bounds.
if (offset >= 0)
{
printf ("name: %s", symbol->name);
if (offset > 0)
{
printf (" + %d", offset);
}
}
printf ("\n ");
}
print_encoding (baton, baton.mach_header_start + baton.first_level_index_entry.functionOffset + baton.text_section_file_offset + entry_func_offset, encoding);
bool has_lsda = encoding & UNWIND_HAS_LSDA;
if (has_lsda)
{
uint32_t func_offset = entry_func_offset + baton.first_level_index_entry.functionOffset;
int lsda_entry_number = -1;
uint32_t low = 0;
uint32_t high = (baton.lsda_array_end - baton.lsda_array_start) / sizeof (struct unwind_info_section_header_lsda_index_entry);
while (low < high)
{
uint32_t mid = (low + high) / 2;
uint8_t *mid_lsda_entry_addr = (baton.lsda_array_start + (mid * sizeof (struct unwind_info_section_header_lsda_index_entry)));
struct unwind_info_section_header_lsda_index_entry mid_lsda_entry;
memcpy (&mid_lsda_entry, mid_lsda_entry_addr, sizeof (struct unwind_info_section_header_lsda_index_entry));
if (mid_lsda_entry.functionOffset == func_offset)
{
lsda_entry_number = (mid_lsda_entry_addr - baton.lsda_array_start) / sizeof (struct unwind_info_section_header_lsda_index_entry);
break;
}
else if (mid_lsda_entry.functionOffset < func_offset)
{
low = mid + 1;
}
else
{
high = mid;
}
}
if (lsda_entry_number != -1)
{
printf (", LSDA entry #%d", lsda_entry_number);
}
else
{
printf (", LSDA entry not found");
}
}
uint32_t pers_idx = EXTRACT_BITS (encoding, UNWIND_PERSONALITY_MASK);
if (pers_idx != 0)
{
pers_idx--; // Change 1-based to 0-based index
printf (", personality entry #%d", pers_idx);
}
printf ("\n");
}
void
print_second_level_index_regular (struct baton baton)
{
uint8_t *page_entries = baton.compact_unwind_start + baton.first_level_index_entry.secondLevelPagesSectionOffset + baton.regular_second_level_page_header.entryPageOffset;
uint32_t entries_count = baton.regular_second_level_page_header.entryCount;
uint8_t *offset = page_entries;
uint32_t idx = 0;
while (idx < entries_count)
{
uint32_t func_offset = *((uint32_t *) (offset));
uint32_t encoding = *((uint32_t *) (offset + 4));
// UNWIND_SECOND_LEVEL_REGULAR entries have a funcOffset which includes the
// functionOffset from the containing index table already. UNWIND_SECOND_LEVEL_COMPRESSED
// entries only have the offset from the containing index table functionOffset.
// So strip off the containing index table functionOffset value here so they can
// be treated the same at the lower layers.
print_function_encoding (baton, idx, encoding, (uint32_t) -1, func_offset - baton.first_level_index_entry.functionOffset);
idx++;
offset += 8;
}
}
void
print_second_level_index_compressed (struct baton baton)
{
uint8_t *this_index = baton.compact_unwind_start + baton.first_level_index_entry.secondLevelPagesSectionOffset;
uint8_t *start_of_entries = this_index + baton.compressed_second_level_page_header.entryPageOffset;
uint8_t *offset = start_of_entries;
for (uint16_t idx = 0; idx < baton.compressed_second_level_page_header.entryCount; idx++)
{
uint32_t entry = *((uint32_t*) offset);
offset += 4;
uint32_t encoding;
uint32_t entry_encoding_index = UNWIND_INFO_COMPRESSED_ENTRY_ENCODING_INDEX (entry);
uint32_t entry_func_offset = UNWIND_INFO_COMPRESSED_ENTRY_FUNC_OFFSET (entry);
if (entry_encoding_index < baton.unwind_header.commonEncodingsArrayCount)
{
// encoding is in common table in section header
encoding = *((uint32_t*) (baton.compact_unwind_start + baton.unwind_header.commonEncodingsArraySectionOffset + (entry_encoding_index * sizeof (uint32_t))));
}
else
{
// encoding is in page specific table
uint32_t page_encoding_index = entry_encoding_index - baton.unwind_header.commonEncodingsArrayCount;
encoding = *((uint32_t*) (this_index + baton.compressed_second_level_page_header.encodingsPageOffset + (page_encoding_index * sizeof (uint32_t))));
}
print_function_encoding (baton, idx, encoding, entry_encoding_index, entry_func_offset);
}
}
void
print_second_level_index (struct baton baton)
{
uint8_t *index_start = baton.compact_unwind_start + baton.first_level_index_entry.secondLevelPagesSectionOffset;
if ((*(uint32_t*) index_start) == UNWIND_SECOND_LEVEL_REGULAR)
{
struct unwind_info_regular_second_level_page_header header;
memcpy (&header, index_start, sizeof (struct unwind_info_regular_second_level_page_header));
printf (" UNWIND_SECOND_LEVEL_REGULAR #%d entryPageOffset %d, entryCount %d\n", baton.current_index_table_number, header.entryPageOffset, header.entryCount);
baton.regular_second_level_page_header = header;
print_second_level_index_regular (baton);
}
if ((*(uint32_t*) index_start) == UNWIND_SECOND_LEVEL_COMPRESSED)
{
struct unwind_info_compressed_second_level_page_header header;
memcpy (&header, index_start, sizeof (struct unwind_info_compressed_second_level_page_header));
printf (" UNWIND_SECOND_LEVEL_COMPRESSED #%d entryPageOffset %d, entryCount %d, encodingsPageOffset %d, encodingsCount %d\n", baton.current_index_table_number, header.entryPageOffset, header.entryCount, header.encodingsPageOffset, header.encodingsCount);
baton.compressed_second_level_page_header = header;
print_second_level_index_compressed (baton);
}
}
void
print_index_sections (struct baton baton)
{
uint8_t *index_section_offset = baton.compact_unwind_start + baton.unwind_header.indexSectionOffset;
uint32_t index_count = baton.unwind_header.indexCount;
uint32_t cur_idx = 0;
uint8_t *offset = index_section_offset;
while (cur_idx < index_count)
{
baton.current_index_table_number = cur_idx;
struct unwind_info_section_header_index_entry index_entry;
memcpy (&index_entry, offset, sizeof (struct unwind_info_section_header_index_entry));
printf ("index section #%d: functionOffset %d, secondLevelPagesSectionOffset %d, lsdaIndexArraySectionOffset %d\n", cur_idx, index_entry.functionOffset, index_entry.secondLevelPagesSectionOffset, index_entry.lsdaIndexArraySectionOffset);
// secondLevelPagesSectionOffset == 0 means this is a sentinel entry
if (index_entry.secondLevelPagesSectionOffset != 0)
{
struct unwind_info_section_header_index_entry next_index_entry;
memcpy (&next_index_entry, offset + sizeof (struct unwind_info_section_header_index_entry), sizeof (struct unwind_info_section_header_index_entry));
baton.lsda_array_start = baton.compact_unwind_start + index_entry.lsdaIndexArraySectionOffset;
baton.lsda_array_end = baton.compact_unwind_start + next_index_entry.lsdaIndexArraySectionOffset;
uint8_t *lsda_entry_offset = baton.lsda_array_start;
uint32_t lsda_count = 0;
while (lsda_entry_offset < baton.lsda_array_end)
{
struct unwind_info_section_header_lsda_index_entry lsda_entry;
memcpy (&lsda_entry, lsda_entry_offset, sizeof (struct unwind_info_section_header_lsda_index_entry));
uint64_t function_file_address = baton.first_level_index_entry.functionOffset + lsda_entry.functionOffset + baton.text_segment_vmaddr;
uint64_t lsda_file_address = lsda_entry.lsdaOffset + baton.text_segment_vmaddr;
printf (" LSDA [%d] functionOffset %d (%d) (file address 0x%" PRIx64 "), lsdaOffset %d (file address 0x%" PRIx64 ")\n",
lsda_count, lsda_entry.functionOffset,
lsda_entry.functionOffset - index_entry.functionOffset,
function_file_address,
lsda_entry.lsdaOffset, lsda_file_address);
lsda_count++;
lsda_entry_offset += sizeof (struct unwind_info_section_header_lsda_index_entry);
}
printf ("\n");
baton.first_level_index_entry = index_entry;
print_second_level_index (baton);
}
printf ("\n");
cur_idx++;
offset += sizeof (struct unwind_info_section_header_index_entry);
}
}
int main (int argc, char **argv)
{
struct stat st;
char *file = argv[0];
if (argc > 1)
file = argv[1];
int fd = open (file, O_RDONLY);
if (fd == -1)
{
printf ("Failed to open '%s'\n", file);
exit (1);
}
fstat (fd, &st);
uint8_t *file_mem = (uint8_t*) mmap (0, st.st_size, PROT_READ, MAP_PRIVATE | MAP_FILE, fd, 0);
if (file_mem == MAP_FAILED)
{
printf ("Failed to mmap() '%s'\n", file);
}
FILE *f = fopen ("a.out", "r");
struct baton baton;
baton.mach_header_start = file_mem;
baton.symbols = NULL;
baton.symbols_count = 0;
baton.function_start_addresses = NULL;
baton.function_start_addresses_count = 0;
scan_macho_load_commands (&baton);
if (baton.compact_unwind_start == NULL)
{
printf ("could not find __TEXT,__unwind_info section\n");
exit (1);
}
struct unwind_info_section_header header;
memcpy (&header, baton.compact_unwind_start, sizeof (struct unwind_info_section_header));
printf ("Header:\n");
printf (" version %u\n", header.version);
printf (" commonEncodingsArraySectionOffset is %d\n", header.commonEncodingsArraySectionOffset);
printf (" commonEncodingsArrayCount is %d\n", header.commonEncodingsArrayCount);
printf (" personalityArraySectionOffset is %d\n", header.personalityArraySectionOffset);
printf (" personalityArrayCount is %d\n", header.personalityArrayCount);
printf (" indexSectionOffset is %d\n", header.indexSectionOffset);
printf (" indexCount is %d\n", header.indexCount);
uint8_t *common_encodings = baton.compact_unwind_start + header.commonEncodingsArraySectionOffset;
uint32_t encoding_idx = 0;
while (encoding_idx < header.commonEncodingsArrayCount)
{
uint32_t encoding = *((uint32_t*) common_encodings);
printf (" Common Encoding [%d]: 0x%x ", encoding_idx, encoding);
print_encoding (baton, NULL, encoding);
printf ("\n");
common_encodings += sizeof (uint32_t);
encoding_idx++;
}
uint8_t *pers_arr = baton.compact_unwind_start + header.personalityArraySectionOffset;
uint32_t pers_idx = 0;
while (pers_idx < header.personalityArrayCount)
{
int32_t pers_delta = *((int32_t*) (baton.compact_unwind_start + header.personalityArraySectionOffset + (pers_idx * sizeof (uint32_t))));
printf (" Personality [%d]: personality function ptr @ offset %d (file address 0x%" PRIx64 ")\n", pers_idx, pers_delta, baton.text_segment_vmaddr + pers_delta);
pers_idx++;
pers_arr += sizeof (uint32_t);
}
printf ("\n");
baton.unwind_header = header;
print_index_sections (baton);
return 0;
}
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