--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/agent/src/os/linux/symtab.c Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,228 @@
+/*
+ * Copyright 2003-2005 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+#include <unistd.h>
+#include <sys/procfs.h>
+#include <search.h>
+#include <stdlib.h>
+#include <string.h>
+#include "symtab.h"
+#include "salibelf.h"
+
+
+// ----------------------------------------------------
+// functions for symbol lookups
+// ----------------------------------------------------
+
+struct elf_section {
+ ELF_SHDR *c_shdr;
+ void *c_data;
+};
+
+struct elf_symbol {
+ char *name;
+ uintptr_t offset;
+ uintptr_t size;
+};
+
+typedef struct symtab {
+ char *strs;
+ size_t num_symbols;
+ struct elf_symbol *symbols;
+ struct hsearch_data *hash_table;
+} symtab_t;
+
+// read symbol table from given fd.
+struct symtab* build_symtab(int fd) {
+ ELF_EHDR ehdr;
+ char *names = NULL;
+ 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;
+ ELF_PHDR* phdr = NULL;
+
+ 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 = (struct elf_section *)
+ calloc(ehdr.e_shnum * sizeof(struct elf_section), 1);
+ 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) {
+ if ( (scn_cache[cnt].c_data = read_section_data(fd, &ehdr, cursct)) == NULL) {
+ goto quit;
+ }
+ }
+ cursct++;
+ }
+
+ for (cnt = 1; cnt < ehdr.e_shnum; cnt++) {
+ ELF_SHDR *shdr = scn_cache[cnt].c_shdr;
+
+ if (shdr->sh_type == SHT_SYMTAB) {
+ ELF_SYM *syms;
+ int j, n, rslt;
+ 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 = (struct symtab*)calloc(1, sizeof(struct 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 hcreate_r, hsearch_r and hdestroy_r to
+ // manipulate the hash table.
+ symtab->hash_table = (struct hsearch_data*) calloc(1, sizeof(struct hsearch_data));
+ rslt = hcreate_r(n, symtab->hash_table);
+ // guarantee(rslt, "unexpected failure: hcreate_r");
+
+ // 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 = (char *)malloc(size);
+ 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 = (struct elf_symbol *)calloc(n , sizeof(struct elf_symbol));
+
+ // copy symbols info our symtab and enter them info the hash table
+ for (j = 0; j < n; j++, syms++) {
+ ENTRY item, *ret;
+ 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;
+
+ item.key = sym_name;
+ item.data = (void *)&(symtab->symbols[j]);
+
+ hsearch_r(item, ENTER, &ret, symtab->hash_table);
+ }
+ }
+ }
+
+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;
+}
+
+void destroy_symtab(struct symtab* symtab) {
+ if (!symtab) return;
+ if (symtab->strs) free(symtab->strs);
+ if (symtab->symbols) free(symtab->symbols);
+ if (symtab->hash_table) {
+ hdestroy_r(symtab->hash_table);
+ free(symtab->hash_table);
+ }
+ free(symtab);
+}
+
+uintptr_t search_symbol(struct symtab* symtab, uintptr_t base,
+ const char *sym_name, int *sym_size) {
+ ENTRY item;
+ ENTRY* ret = NULL;
+
+ // library does not have symbol table
+ if (!symtab || !symtab->hash_table)
+ return (uintptr_t)NULL;
+
+ item.key = (char*) strdup(sym_name);
+ hsearch_r(item, FIND, &ret, symtab->hash_table);
+ if (ret) {
+ struct elf_symbol * sym = (struct elf_symbol *)(ret->data);
+ uintptr_t rslt = (uintptr_t) ((char*)base + sym->offset);
+ if (sym_size) *sym_size = sym->size;
+ free(item.key);
+ return rslt;
+ }
+
+quit:
+ free(item.key);
+ return (uintptr_t) NULL;
+}
+
+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++) {
+ struct elf_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;
+}