/* Sysprof -- Sampling, systemwide CPU profiler * Copyright 2006, 2007, Soeren Sandmann * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include #include #include #include #include "elfparser.h" typedef struct Section Section; struct ElfSym { gulong table; gulong offset; gulong address; }; struct Section { const gchar * name; gsize offset; gsize size; gboolean allocated; gulong load_address; guint type; }; struct ElfParser { gboolean is_64; const guchar * data; gsize length; int n_sections; Section ** sections; int n_symbols; ElfSym * symbols; gsize sym_strings; GMappedFile * file; char * filename; gboolean checked_build_id; char * build_id; const Section * text_section; }; /* FIXME: All of these should in principle do endian swapping, * but sysprof never has to deal with binaries of a different * endianness than sysprof itself */ #define GET_FIELD(parser, offset, struct_name, idx, field_name) \ (((parser))->is_64? \ ((Elf64_ ## struct_name *)(((parser)->data + offset)) + (idx))->field_name : \ ((Elf32_ ## struct_name *)(((parser)->data + offset)) + (idx))->field_name) #define GET_UINT32(parser, offset) \ *((uint32_t *)(parser->data + offset)) \ #define GET_SIZE(parser, struct_name) \ (((parser)->is_64? \ sizeof (Elf64_ ## struct_name) : \ sizeof (Elf32_ ## struct_name))) #define MAKE_ELF_UINT_ACCESSOR(field_name) \ static uint64_t field_name (ElfParser *parser) \ { \ return GET_FIELD (parser, 0, Ehdr, 0, field_name); \ } MAKE_ELF_UINT_ACCESSOR (e_shoff) MAKE_ELF_UINT_ACCESSOR (e_shnum) MAKE_ELF_UINT_ACCESSOR (e_shstrndx) #define MAKE_SECTION_HEADER_ACCESSOR(field_name) \ static uint64_t field_name (ElfParser *parser, int nth_section) \ { \ gsize offset = e_shoff (parser); \ \ return GET_FIELD (parser, offset, Shdr, nth_section, field_name); \ } MAKE_SECTION_HEADER_ACCESSOR (sh_name); MAKE_SECTION_HEADER_ACCESSOR (sh_type); MAKE_SECTION_HEADER_ACCESSOR (sh_flags); MAKE_SECTION_HEADER_ACCESSOR (sh_addr); MAKE_SECTION_HEADER_ACCESSOR (sh_offset); MAKE_SECTION_HEADER_ACCESSOR (sh_size); #define MAKE_SYMBOL_ACCESSOR(field_name) \ static uint64_t field_name (ElfParser *parser, gulong offset, gulong nth) \ { \ return GET_FIELD (parser, offset, Sym, nth, field_name); \ } MAKE_SYMBOL_ACCESSOR(st_name); MAKE_SYMBOL_ACCESSOR(st_info); MAKE_SYMBOL_ACCESSOR(st_value); MAKE_SYMBOL_ACCESSOR(st_size); MAKE_SYMBOL_ACCESSOR(st_shndx); static void section_free (Section *section) { g_free (section); } static const Section * find_section (ElfParser *parser, const char *name, guint type) { int i; for (i = 0; i < parser->n_sections; ++i) { Section *section = parser->sections[i]; if (strcmp (section->name, name) == 0 && section->type == type) return section; } return NULL; } static gboolean parse_elf_signature (const guchar *data, gsize length, gboolean *is_64, gboolean *is_be) { /* FIXME: this function should be able to return an error */ if (length < EI_NIDENT) { /* FIXME set error */ return FALSE; } if (data[EI_CLASS] != ELFCLASS32 && data[EI_CLASS] != ELFCLASS64) { /* FIXME set error */ return FALSE; } if (data[EI_DATA] != ELFDATA2LSB && data[EI_DATA] != ELFDATA2MSB) { /* FIXME set error */ return FALSE; } if (is_64) *is_64 = (data[EI_CLASS] == ELFCLASS64); if (is_be) *is_be = (data[EI_DATA] == ELFDATA2MSB); return TRUE; } ElfParser * elf_parser_new_from_data (const guchar *data, gsize length) { ElfParser *parser; gboolean is_64, is_big_endian; int section_names_idx; const guchar *section_names; gsize section_headers; int i; if (!parse_elf_signature (data, length, &is_64, &is_big_endian)) { /* FIXME: set error */ return NULL; } parser = g_new0 (ElfParser, 1); parser->is_64 = is_64; parser->data = data; parser->length = length; #if 0 g_print (" new parser : %p\n", parser); #endif /* Read ELF header */ parser->n_sections = e_shnum (parser); section_names_idx = e_shstrndx (parser); section_headers = e_shoff (parser); /* Read section headers */ parser->sections = g_new0 (Section *, parser->n_sections); section_names = parser->data + sh_offset (parser, section_names_idx); for (i = 0; i < parser->n_sections; ++i) { Section *section = g_new (Section, 1); section->name = (char *)(section_names + sh_name (parser, i)); section->size = sh_size (parser, i); section->offset = sh_offset (parser, i); section->allocated = !!(sh_flags (parser, i) & SHF_ALLOC); if (section->allocated) section->load_address = sh_addr (parser, i); else section->load_address = 0; section->type = sh_type (parser, i); parser->sections[i] = section; } /* Cache the text section */ parser->text_section = find_section (parser, ".text", SHT_PROGBITS); if (!parser->text_section) parser->text_section = find_section (parser, ".text", SHT_NOBITS); parser->filename = NULL; parser->build_id = NULL; return parser; } ElfParser * elf_parser_new (const char *filename, GError **err) { const guchar *data; gsize length; ElfParser *parser; GMappedFile *file = g_mapped_file_new (filename, FALSE, NULL); if (!file) return NULL; #if 0 g_print ("elf parser new : %s\n", filename); #endif data = (guchar *)g_mapped_file_get_contents (file); length = g_mapped_file_get_length (file); #if 0 g_print ("data %p: for %s\n", data, filename); #endif parser = elf_parser_new_from_data (data, length); #if 0 g_print ("Parser for %s: %p\n", filename, parser); #endif if (!parser) { g_mapped_file_free (file); return NULL; } parser->filename = g_strdup (filename); parser->file = file; #if 0 g_print ("Elf file: %s (debug: %s)\n", filename, elf_parser_get_debug_link (parser, NULL)); if (!parser->symbols) g_print ("at this point %s has no symbols\n", filename); #endif return parser; } guint32 elf_parser_get_crc32 (ElfParser *parser) { static const unsigned long crc32_table[256] = { 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d }; const guchar *data; gsize length; gulong crc; gsize i; data = parser->data; length = parser->length; crc = 0xffffffff; madvise ((char *)data, length, MADV_SEQUENTIAL); for (i = 0; i < length; ++i) crc = crc32_table[(crc ^ data[i]) & 0xff] ^ (crc >> 8); /* We just read the entire file into memory, but we only really * need the symbol table, so swap the whole thing out. * * We could be more exact here, but it's only a few minor * pagefaults. */ if (parser->file) madvise ((char *)data, length, MADV_DONTNEED); return ~crc & 0xffffffff; } void elf_parser_free (ElfParser *parser) { int i; for (i = 0; i < parser->n_sections; ++i) section_free (parser->sections[i]); g_free (parser->sections); if (parser->file) g_mapped_file_free (parser->file); g_free (parser->symbols); if (parser->filename) g_free (parser->filename); if (parser->build_id) g_free (parser->build_id); g_free (parser); } extern char *sysprof_cplus_demangle (const char *name, int options); char * elf_demangle (const char *name) { #define DMGL_PARAMS (1 << 0) /* Include function args */ #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ char *demangled = sysprof_cplus_demangle (name, DMGL_PARAMS | DMGL_ANSI); if (demangled) return demangled; else return g_strdup (name); } /* * Looking up symbols */ static int compare_sym (const void *a, const void *b) { const ElfSym *sym_a = a; const ElfSym *sym_b = b; if (sym_a->address < sym_b->address) return -1; else if (sym_a->address == sym_b->address) return 0; else return 1; } #if 0 static void dump_symbols (ElfParser *parser, ElfSym *syms, guint n_syms) { int i; for (i = 0; i < n_syms; ++i) { ElfSym *s = &(syms[i]); g_print (" %s: %lx\n", elf_parser_get_sym_name (parser, s), s->address); } } #endif static void read_table (ElfParser *parser, const Section *sym_table, const Section *str_table) { int sym_size = GET_SIZE (parser, Sym); int i, n_symbols; #if 0 g_print ("elf: Reading table for %s\n", parser->filename? parser->filename : ""); #endif parser->n_symbols = sym_table->size / sym_size; parser->symbols = g_new (ElfSym, parser->n_symbols); #if 0 g_print ("sym table offset: %d\n", sym_table->offset); #endif n_symbols = 0; #if 0 g_print ("n syms: %d\n", parser->n_symbols); #endif for (i = 0; i < parser->n_symbols; ++i) { guint info; gulong addr; gulong shndx; info = st_info (parser, sym_table->offset, i); addr = st_value (parser, sym_table->offset, i); shndx = st_shndx (parser, sym_table->offset, i); #if 0 g_print ("read symbol: %s (section: %d)\n", get_string_indirct (parser->parser, parser->sym_format, "st_name", str_table->offset), shndx); #endif if (addr != 0 && shndx < parser->n_sections && parser->sections[shndx] == parser->text_section && (info & 0xf) == STT_FUNC && ((info >> 4) == STB_GLOBAL || (info >> 4) == STB_LOCAL || (info >> 4) == STB_WEAK)) { parser->symbols[n_symbols].address = addr; parser->symbols[n_symbols].table = sym_table->offset; parser->symbols[n_symbols].offset = i; n_symbols++; #if 0 g_print (" symbol: %s: %lx\n", get_string_indirect (parser->parser, parser->sym_format, "st_name", str_table->offset), addr - parser->text_section->load_address); g_print (" sym %d in %p (info: %d:%d) (func:global %d:%d)\n", addr, parser, info & 0xf, info >> 4, STT_FUNC, STB_GLOBAL); #endif } else if (addr != 0) { #if 0 g_print (" rejecting %d in %p (info: %d:%d) (func:global %d:%d)\n", addr, parser, info & 0xf, info >> 4, STT_FUNC, STB_GLOBAL); #endif } } parser->sym_strings = str_table->offset; parser->n_symbols = n_symbols; /* Allocate space for at least one symbol, so that parser->symbols will be * non-NULL. If it ends up being NULL, we will be parsing the file over and * over. */ parser->symbols = g_renew (ElfSym, parser->symbols, parser->n_symbols + 1); qsort (parser->symbols, parser->n_symbols, sizeof (ElfSym), compare_sym); } static void read_symbols (ElfParser *parser) { const Section *symtab = find_section (parser, ".symtab", SHT_SYMTAB); const Section *strtab = find_section (parser, ".strtab", SHT_STRTAB); const Section *dynsym = find_section (parser, ".dynsym", SHT_DYNSYM); const Section *dynstr = find_section (parser, ".dynstr", SHT_STRTAB); if (symtab && strtab) { #if 0 g_print ("reading symbol table of %s\n", parser->filename); #endif read_table (parser, symtab, strtab); } else if (dynsym && dynstr) { #if 0 g_print ("reading dynamic symbol table of %s\n", parser->filename); #endif read_table (parser, dynsym, dynstr); } else { /* To make sure parser->symbols is non-NULL */ parser->n_symbols = 0; parser->symbols = g_new (ElfSym, 1); } } static ElfSym * do_lookup (ElfSym *symbols, gulong address, int first, int last) { if (address >= symbols[last].address) { return &(symbols[last]); } else if (last - first < 3) { while (last >= first) { if (address >= symbols[last].address) return &(symbols[last]); last--; } return NULL; } else { int mid = (first + last) / 2; if (symbols[mid].address > address) return do_lookup (symbols, address, first, mid); else return do_lookup (symbols, address, mid, last); } } /* Address should be given in 'offset into text segment' */ const ElfSym * elf_parser_lookup_symbol (ElfParser *parser, gulong address) { const ElfSym *result; if (!parser->symbols) { #if 0 g_print ("reading symbols at %p\n", parser); #endif read_symbols (parser); } if (parser->n_symbols == 0) return NULL; if (!parser->text_section) return NULL; address += parser->text_section->load_address; #if 0 g_print ("elf: the address we are looking up is %p\n", address); #endif result = do_lookup (parser->symbols, address, 0, parser->n_symbols - 1); #if 0 if (result) { g_print (" elf: found %s at %lx\n", elf_parser_get_sym_name (parser, result), result->address); } else { g_print ("elf: not found\n"); } #endif if (result) { gulong size = st_size (parser, result->table, result->offset); if (size > 0 && result->address + size <= address) { #if 0 g_print (" elf: ends at %lx, so rejecting\n", result->address + size); #endif result = NULL; } } if (result) { /* Reject the symbols if the address is outside the text section */ if (address > parser->text_section->load_address + parser->text_section->size) result = NULL; } return result; } gulong elf_parser_get_text_offset (ElfParser *parser) { g_return_val_if_fail (parser != NULL, (gulong)-1); if (!parser->text_section) return (gulong)-1; return parser->text_section->offset; } static gchar * make_hex_string (const guchar *data, int n_bytes) { static const char hex_digits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' }; GString *string = g_string_new (NULL); int i; for (i = 0; i < n_bytes; ++i) { char c = data[i]; g_string_append_c (string, hex_digits[(c & 0xf0) >> 4]); g_string_append_c (string, hex_digits[(c & 0x0f)]); } return g_string_free (string, FALSE); } const gchar * elf_parser_get_build_id (ElfParser *parser) { if (!parser->checked_build_id) { const Section *build_id = find_section (parser, ".note.gnu.build-id", SHT_NOTE); guint64 name_size; guint64 desc_size; guint64 type; const char *name; guint64 offset; parser->checked_build_id = TRUE; if (!build_id) return NULL; offset = build_id->offset; name_size = GET_FIELD (parser, offset, Nhdr, 0, n_namesz); desc_size = GET_FIELD (parser, offset, Nhdr, 0, n_descsz); type = GET_FIELD (parser, offset, Nhdr, 0, n_type); offset += GET_SIZE (parser, Nhdr); name = (char *)(parser->data + offset); if (strncmp (name, ELF_NOTE_GNU, name_size) != 0 || type != NT_GNU_BUILD_ID) return NULL; offset += strlen (name); offset = (offset + 3) & (~0x3); parser->build_id = make_hex_string (parser->data + offset, desc_size); } return parser->build_id; } const char * elf_parser_get_debug_link (ElfParser *parser, guint32 *crc32) { guint64 offset; const Section *debug_link = find_section (parser, ".gnu_debuglink", SHT_PROGBITS); const gchar *result; if (!debug_link) return NULL; offset = debug_link->offset; result = (char *)(parser->data + offset); if (crc32) { offset = (offset + 3) & ~0x3; *crc32 = GET_UINT32 (parser, offset); } return result; } const guchar * get_section (ElfParser *parser, const char *name) { const Section *section = find_section (parser, name, SHT_PROGBITS); if (section) return parser->data + section->offset; else return NULL; } const guchar * elf_parser_get_eh_frame (ElfParser *parser) { return get_section (parser, ".eh_frame"); } const guchar * elf_parser_get_debug_frame (ElfParser *parser) { return get_section (parser, ".debug_frame"); } const char * elf_parser_get_sym_name (ElfParser *parser, const ElfSym *sym) { g_return_val_if_fail (parser != NULL, NULL); return (char *)(parser->data + parser->sym_strings + st_name (parser, sym->table, sym->offset)); } gboolean elf_parser_owns_symbol (ElfParser *parser, const ElfSym *sym) { ElfSym *first, *last; if (!parser->n_symbols) return FALSE; first = parser->symbols; last = parser->symbols + parser->n_symbols - 1; return first <= sym && sym <= last; } gulong elf_parser_get_sym_address (ElfParser *parser, const ElfSym *sym) { return sym->address - parser->text_section->load_address; } /* * Utility functions */