diff -r 71c463a17b3b -r ce4b5303a813 hotspot/src/jdk.hotspot.agent/macosx/native/libsaproc/symtab.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/src/jdk.hotspot.agent/macosx/native/libsaproc/symtab.c Wed Dec 23 13:12:15 2015 +0300 @@ -0,0 +1,398 @@ +/* + * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code 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 + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + * + */ + +#include +#include +#include +#include +#include +#include + +#include "libproc_impl.h" +#include "symtab.h" +#ifndef __APPLE__ +#include "salibelf.h" +#endif // __APPLE__ + + +// ---------------------------------------------------- +// functions for symbol lookups +// ---------------------------------------------------- + +typedef struct symtab_symbol { + char *name; // name like __ZThread_... + uintptr_t offset; // to loaded address + uintptr_t size; // size strlen +} symtab_symbol; + +typedef struct symtab { + char *strs; // all symbols "__symbol1__'\0'__symbol2__...." + size_t num_symbols; + DB* hash_table; + symtab_symbol* symbols; +} symtab_t; + +#ifdef __APPLE__ + +void build_search_table(symtab_t *symtab) { + int i; + for (i = 0; i < symtab->num_symbols; i++) { + DBT key, value; + key.data = symtab->symbols[i].name; + key.size = strlen(key.data) + 1; + value.data = &(symtab->symbols[i]); + value.size = sizeof(symtab_symbol); + (*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0); + + // check result + if (is_debug()) { + DBT rkey, rvalue; + char* tmp = (char *)malloc(strlen(symtab->symbols[i].name) + 1); + strcpy(tmp, symtab->symbols[i].name); + rkey.data = tmp; + rkey.size = strlen(tmp) + 1; + (*symtab->hash_table->get)(symtab->hash_table, &rkey, &rvalue, 0); + // we may get a copy back so compare contents + symtab_symbol *res = (symtab_symbol *)rvalue.data; + if (strcmp(res->name, symtab->symbols[i].name) || + res->offset != symtab->symbols[i].offset || + res->size != symtab->symbols[i].size) { + print_debug("error to get hash_table value!\n"); + } + free(tmp); + } + } +} + +// read symbol table from given fd. +struct symtab* build_symtab(int fd) { + symtab_t* symtab = NULL; + int i; + mach_header_64 header; + off_t image_start; + + if (!get_arch_off(fd, CPU_TYPE_X86_64, &image_start)) { + print_debug("failed in get fat header\n"); + return NULL; + } + lseek(fd, image_start, SEEK_SET); + if (read(fd, (void *)&header, sizeof(mach_header_64)) != sizeof(mach_header_64)) { + print_debug("reading header failed!\n"); + return NULL; + } + // header + if (header.magic != MH_MAGIC_64) { + print_debug("not a valid .dylib file\n"); + return NULL; + } + + load_command lcmd; + symtab_command symtabcmd; + nlist_64 lentry; + + bool lcsymtab_exist = false; + + long filepos = ltell(fd); + for (i = 0; i < header.ncmds; i++) { + lseek(fd, filepos, SEEK_SET); + if (read(fd, (void *)&lcmd, sizeof(load_command)) != sizeof(load_command)) { + print_debug("read load_command failed for file\n"); + return NULL; + } + filepos += lcmd.cmdsize; // next command position + if (lcmd.cmd == LC_SYMTAB) { + lseek(fd, -sizeof(load_command), SEEK_CUR); + lcsymtab_exist = true; + break; + } + } + if (!lcsymtab_exist) { + print_debug("No symtab command found!\n"); + return NULL; + } + if (read(fd, (void *)&symtabcmd, sizeof(symtab_command)) != sizeof(symtab_command)) { + print_debug("read symtab_command failed for file"); + return NULL; + } + symtab = (symtab_t *)malloc(sizeof(symtab_t)); + if (symtab == NULL) { + print_debug("out of memory: allocating symtab\n"); + return NULL; + } + + // create hash table, we use berkeley db to + // manipulate the hash table. + symtab->hash_table = dbopen(NULL, O_CREAT | O_RDWR, 0600, DB_HASH, NULL); + if (symtab->hash_table == NULL) + goto quit; + + symtab->num_symbols = symtabcmd.nsyms; + symtab->symbols = (symtab_symbol *)malloc(sizeof(symtab_symbol) * symtab->num_symbols); + symtab->strs = (char *)malloc(sizeof(char) * symtabcmd.strsize); + if (symtab->symbols == NULL || symtab->strs == NULL) { + print_debug("out of memory: allocating symtab.symbol or symtab.strs\n"); + goto quit; + } + lseek(fd, image_start + symtabcmd.symoff, SEEK_SET); + for (i = 0; i < symtab->num_symbols; i++) { + if (read(fd, (void *)&lentry, sizeof(nlist_64)) != sizeof(nlist_64)) { + print_debug("read nlist_64 failed at %i\n", i); + goto quit; + } + symtab->symbols[i].offset = lentry.n_value; + symtab->symbols[i].size = lentry.n_un.n_strx; // index + } + + // string table + lseek(fd, image_start + symtabcmd.stroff, SEEK_SET); + int size = read(fd, (void *)(symtab->strs), symtabcmd.strsize * sizeof(char)); + if (size != symtabcmd.strsize * sizeof(char)) { + print_debug("reading string table failed\n"); + goto quit; + } + + for (i = 0; i < symtab->num_symbols; i++) { + symtab->symbols[i].name = symtab->strs + symtab->symbols[i].size; + if (i > 0) { + // fix size + symtab->symbols[i - 1].size = symtab->symbols[i].size - symtab->symbols[i - 1].size; + print_debug("%s size = %d\n", symtab->symbols[i - 1].name, symtab->symbols[i - 1].size); + + } + + if (i == symtab->num_symbols - 1) { + // last index + symtab->symbols[i].size = + symtabcmd.strsize - symtab->symbols[i].size; + print_debug("%s size = %d\n", symtab->symbols[i].name, symtab->symbols[i].size); + } + } + + // build a hashtable for fast query + build_search_table(symtab); + return symtab; +quit: + if (symtab) destroy_symtab(symtab); + return NULL; +} + +#else // __APPLE__ + +struct elf_section { + ELF_SHDR *c_shdr; + void *c_data; +}; + +// read symbol table from given fd. +struct symtab* build_symtab(int fd) { + ELF_EHDR ehdr; + struct symtab* symtab = NULL; + + // Reading of elf header + struct elf_section *scn_cache = NULL; + int cnt = 0; + ELF_SHDR* shbuf = NULL; + ELF_SHDR* cursct = NULL; + ELF_PHDR* phbuf = NULL; + int symtab_found = 0; + int dynsym_found = 0; + uint32_t symsection = SHT_SYMTAB; + + uintptr_t baseaddr = (uintptr_t)-1; + + lseek(fd, (off_t)0L, SEEK_SET); + if (! read_elf_header(fd, &ehdr)) { + // not an elf + return NULL; + } + + // read ELF header + if ((shbuf = read_section_header_table(fd, &ehdr)) == NULL) { + goto quit; + } + + baseaddr = find_base_address(fd, &ehdr); + + scn_cache = calloc(ehdr.e_shnum, sizeof(*scn_cache)); + if (scn_cache == NULL) { + goto quit; + } + + for (cursct = shbuf, cnt = 0; cnt < ehdr.e_shnum; cnt++) { + scn_cache[cnt].c_shdr = cursct; + if (cursct->sh_type == SHT_SYMTAB || + cursct->sh_type == SHT_STRTAB || + cursct->sh_type == SHT_DYNSYM) { + if ( (scn_cache[cnt].c_data = read_section_data(fd, &ehdr, cursct)) == NULL) { + goto quit; + } + } + + if (cursct->sh_type == SHT_SYMTAB) + symtab_found++; + + if (cursct->sh_type == SHT_DYNSYM) + dynsym_found++; + + cursct++; + } + + if (!symtab_found && dynsym_found) + symsection = SHT_DYNSYM; + + for (cnt = 1; cnt < ehdr.e_shnum; cnt++) { + ELF_SHDR *shdr = scn_cache[cnt].c_shdr; + + if (shdr->sh_type == symsection) { + ELF_SYM *syms; + int j, n; + size_t size; + + // FIXME: there could be multiple data buffers associated with the + // same ELF section. Here we can handle only one buffer. See man page + // for elf_getdata on Solaris. + + // guarantee(symtab == NULL, "multiple symtab"); + symtab = calloc(1, sizeof(*symtab)); + if (symtab == NULL) { + goto quit; + } + // the symbol table + syms = (ELF_SYM *)scn_cache[cnt].c_data; + + // number of symbols + n = shdr->sh_size / shdr->sh_entsize; + + // create hash table, we use berkeley db to + // manipulate the hash table. + symtab->hash_table = dbopen(NULL, O_CREAT | O_RDWR, 0600, DB_HASH, NULL); + // guarantee(symtab->hash_table, "unexpected failure: dbopen"); + if (symtab->hash_table == NULL) + goto bad; + + // shdr->sh_link points to the section that contains the actual strings + // for symbol names. the st_name field in ELF_SYM is just the + // string table index. we make a copy of the string table so the + // strings will not be destroyed by elf_end. + size = scn_cache[shdr->sh_link].c_shdr->sh_size; + symtab->strs = malloc(size); + if (symtab->strs == NULL) + goto bad; + memcpy(symtab->strs, scn_cache[shdr->sh_link].c_data, size); + + // allocate memory for storing symbol offset and size; + symtab->num_symbols = n; + symtab->symbols = calloc(n , sizeof(*symtab->symbols)); + if (symtab->symbols == NULL) + goto bad; + + // copy symbols info our symtab and enter them info the hash table + for (j = 0; j < n; j++, syms++) { + DBT key, value; + char *sym_name = symtab->strs + syms->st_name; + + // skip non-object and non-function symbols + int st_type = ELF_ST_TYPE(syms->st_info); + if ( st_type != STT_FUNC && st_type != STT_OBJECT) + continue; + // skip empty strings and undefined symbols + if (*sym_name == '\0' || syms->st_shndx == SHN_UNDEF) continue; + + symtab->symbols[j].name = sym_name; + symtab->symbols[j].offset = syms->st_value - baseaddr; + symtab->symbols[j].size = syms->st_size; + + key.data = sym_name; + key.size = strlen(sym_name) + 1; + value.data = &(symtab->symbols[j]); + value.size = sizeof(symtab_symbol); + (*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0); + } + } + } + goto quit; + +bad: + destroy_symtab(symtab); + symtab = NULL; + +quit: + if (shbuf) free(shbuf); + if (phbuf) free(phbuf); + if (scn_cache) { + for (cnt = 0; cnt < ehdr.e_shnum; cnt++) { + if (scn_cache[cnt].c_data != NULL) { + free(scn_cache[cnt].c_data); + } + } + free(scn_cache); + } + return symtab; +} + +#endif // __APPLE__ + +void destroy_symtab(symtab_t* symtab) { + if (!symtab) return; + free(symtab->strs); + free(symtab->symbols); + free(symtab); +} + +uintptr_t search_symbol(struct symtab* symtab, uintptr_t base, const char *sym_name, int *sym_size) { + DBT key, value; + int ret; + + // library does not have symbol table + if (!symtab || !symtab->hash_table) { + return 0; + } + + key.data = (char*)(uintptr_t)sym_name; + key.size = strlen(sym_name) + 1; + ret = (*symtab->hash_table->get)(symtab->hash_table, &key, &value, 0); + if (ret == 0) { + symtab_symbol *sym = value.data; + uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset); + if (sym_size) *sym_size = sym->size; + return rslt; + } + + return 0; +} + +const char* nearest_symbol(struct symtab* symtab, uintptr_t offset, + uintptr_t* poffset) { + int n = 0; + if (!symtab) return NULL; + for (; n < symtab->num_symbols; n++) { + symtab_symbol* sym = &(symtab->symbols[n]); + if (sym->name != NULL && + offset >= sym->offset && offset < sym->offset + sym->size) { + if (poffset) *poffset = (offset - sym->offset); + return sym->name; + } + } + return NULL; +}