--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.hotspot.agent/linux/native/libsaproc/symtab.c Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,584 @@
+/*
+ * Copyright (c) 2003, 2014, 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 <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;
+
+
+// Directory that contains global debuginfo files. In theory it
+// should be possible to change this, but in a Java environment there
+// is no obvious place to put a user interface to do it. Maybe this
+// could be set with an environment variable.
+static const char debug_file_directory[] = "/usr/lib/debug";
+
+/* The CRC used in gnu_debuglink, retrieved from
+ http://sourceware.org/gdb/current/onlinedocs/gdb/Separate-Debug-Files.html#Separate-Debug-Files. */
+unsigned int gnu_debuglink_crc32 (unsigned int crc,
+ unsigned char *buf, size_t len)
+{
+ static const unsigned int 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
+ };
+ unsigned char *end;
+
+ crc = ~crc & 0xffffffff;
+ for (end = buf + len; buf < end; ++buf)
+ crc = crc32_table[(crc ^ *buf) & 0xff] ^ (crc >> 8);
+ return ~crc & 0xffffffff;
+}
+
+/* Open a debuginfo file and check its CRC. If it exists and the CRC
+ matches return its fd. */
+static int
+open_debug_file (const char *pathname, unsigned int crc)
+{
+ unsigned int file_crc = 0;
+ unsigned char buffer[8 * 1024];
+
+ int fd = pathmap_open(pathname);
+
+ if (fd < 0)
+ return -1;
+
+ lseek(fd, 0, SEEK_SET);
+
+ for (;;) {
+ int len = read(fd, buffer, sizeof buffer);
+ if (len <= 0)
+ break;
+ file_crc = gnu_debuglink_crc32(file_crc, buffer, len);
+ }
+
+ if (crc == file_crc)
+ return fd;
+ else {
+ close(fd);
+ return -1;
+ }
+}
+
+/* Find an ELF section. */
+static struct elf_section *find_section_by_name(char *name,
+ int fd,
+ ELF_EHDR *ehdr,
+ struct elf_section *scn_cache)
+{
+ char *strtab;
+ int cnt;
+ int strtab_size;
+
+ // Section cache have to already contain data for e_shstrndx section.
+ // If it's not true - elf file is broken, so just bail out
+ if (scn_cache[ehdr->e_shstrndx].c_data == NULL) {
+ return NULL;
+ }
+
+ strtab = scn_cache[ehdr->e_shstrndx].c_data;
+ strtab_size = scn_cache[ehdr->e_shstrndx].c_shdr->sh_size;
+
+ for (cnt = 0; cnt < ehdr->e_shnum; ++cnt) {
+ if (scn_cache[cnt].c_shdr->sh_name < strtab_size) {
+ if (strcmp(scn_cache[cnt].c_shdr->sh_name + strtab, name) == 0) {
+ scn_cache[cnt].c_data = read_section_data(fd, ehdr, scn_cache[cnt].c_shdr);
+ return &scn_cache[cnt];
+ }
+ }
+ }
+
+ return NULL;
+}
+
+/* Look for a ".gnu_debuglink" section. If one exists, try to open a
+ suitable debuginfo file. */
+static int open_file_from_debug_link(const char *name,
+ int fd,
+ ELF_EHDR *ehdr,
+ struct elf_section *scn_cache)
+{
+ int debug_fd;
+ struct elf_section *debug_link = find_section_by_name(".gnu_debuglink", fd, ehdr,
+ scn_cache);
+ if (debug_link == NULL)
+ return -1;
+ char *debug_filename = debug_link->c_data;
+ int offset = (strlen(debug_filename) + 4) >> 2;
+ static unsigned int crc;
+ crc = ((unsigned int*)debug_link->c_data)[offset];
+ char *debug_pathname = malloc(strlen(debug_filename)
+ + strlen(name)
+ + strlen(".debug/")
+ + strlen(debug_file_directory)
+ + 2);
+ strcpy(debug_pathname, name);
+ char *last_slash = strrchr(debug_pathname, '/');
+ if (last_slash == NULL) {
+ free(debug_pathname);
+ return -1;
+ }
+
+ /* Look in the same directory as the object. */
+ strcpy(last_slash+1, debug_filename);
+ debug_fd = open_debug_file(debug_pathname, crc);
+ if (debug_fd >= 0) {
+ free(debug_pathname);
+ return debug_fd;
+ }
+
+ /* Look in a subdirectory named ".debug". */
+ strcpy(last_slash+1, ".debug/");
+ strcat(last_slash, debug_filename);
+
+ debug_fd = open_debug_file(debug_pathname, crc);
+ if (debug_fd >= 0) {
+ free(debug_pathname);
+ return debug_fd;
+ }
+
+ /* Look in /usr/lib/debug + the full pathname. */
+ strcpy(debug_pathname, debug_file_directory);
+ strcat(debug_pathname, name);
+ last_slash = strrchr(debug_pathname, '/');
+ strcpy(last_slash+1, debug_filename);
+
+ debug_fd = open_debug_file(debug_pathname, crc);
+ if (debug_fd >= 0) {
+ free(debug_pathname);
+ return debug_fd;
+ }
+
+ free(debug_pathname);
+ return -1;
+}
+
+static struct symtab* build_symtab_internal(int fd, const char *filename, bool try_debuginfo);
+
+/* Look for a ".gnu_debuglink" section. If one exists, try to open a
+ suitable debuginfo file and read a symbol table from it. */
+static struct symtab *build_symtab_from_debug_link(const char *name,
+ int fd,
+ ELF_EHDR *ehdr,
+ struct elf_section *scn_cache)
+{
+ fd = open_file_from_debug_link(name, fd, ehdr, scn_cache);
+
+ if (fd >= 0) {
+ struct symtab *symtab = build_symtab_internal(fd, NULL, /* try_debuginfo */ false);
+ close(fd);
+ return symtab;
+ }
+
+ return NULL;
+}
+
+// Given a build_id, find the associated debuginfo file
+static char *
+build_id_to_debug_filename (size_t size, unsigned char *data)
+{
+ char *filename, *s;
+
+ filename = malloc(strlen (debug_file_directory) + (sizeof "/.build-id/" - 1) + 1
+ + 2 * size + (sizeof ".debug" - 1) + 1);
+ s = filename + sprintf (filename, "%s/.build-id/", debug_file_directory);
+ if (size > 0)
+ {
+ size--;
+ s += sprintf (s, "%02x", *data++);
+ }
+ if (size > 0)
+ *s++ = '/';
+ while (size-- > 0)
+ s += sprintf (s, "%02x", *data++);
+ strcpy (s, ".debug");
+
+ return filename;
+}
+
+// Read a build ID note. Try to open any associated debuginfo file
+// and return its symtab
+static struct symtab* build_symtab_from_build_id(Elf64_Nhdr *note)
+{
+ int fd;
+ struct symtab *symtab = NULL;
+
+ unsigned char *bytes
+ = (unsigned char*)(note+1) + note->n_namesz;
+ char *filename
+ = (build_id_to_debug_filename (note->n_descsz, bytes));
+
+ fd = pathmap_open(filename);
+ if (fd >= 0) {
+ symtab = build_symtab_internal(fd, NULL, /* try_debuginfo */ false);
+ close(fd);
+ }
+ free(filename);
+
+ return symtab;
+}
+
+// read symbol table from given fd. If try_debuginfo) is true, also
+// try to open an associated debuginfo file
+static struct symtab* build_symtab_internal(int fd, const char *filename, bool try_debuginfo) {
+ ELF_EHDR ehdr;
+ char *names = NULL;
+ struct symtab* symtab = NULL;
+
+ // Reading of elf header
+ struct elf_section *scn_cache = NULL;
+#if defined(ppc64) && !defined(ABI_ELFv2)
+ // Only big endian ppc64 (i.e. ABI_ELFv1) has 'official procedure descriptors' in ELF files
+ // see: http://refspecs.linuxfoundation.org/LSB_3.1.1/LSB-Core-PPC64/LSB-Core-PPC64/specialsections.html
+ struct elf_section *opd_sect = NULL;
+ ELF_SHDR *opd = NULL;
+#endif
+ int cnt = 0;
+ ELF_SHDR* shbuf = NULL;
+ ELF_SHDR* cursct = NULL;
+ ELF_PHDR* phbuf = NULL;
+ ELF_PHDR* phdr = NULL;
+ int sym_section = SHT_DYNSYM;
+
+ 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
+ || cursct->sh_type == SHT_NOTE || 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) {
+ // Full symbol table available so use that
+ sym_section = cursct->sh_type;
+ }
+ cursct++;
+ }
+
+#if defined(ppc64) && !defined(ABI_ELFv2)
+ opd_sect = find_section_by_name(".opd", fd, &ehdr, scn_cache);
+ if (opd_sect != NULL && opd_sect->c_data != NULL && opd_sect->c_shdr != NULL) {
+ // plausibility check
+ opd = opd_sect->c_shdr;
+ }
+#endif
+
+ for (cnt = 1; cnt < ehdr.e_shnum; cnt++) {
+ ELF_SHDR *shdr = scn_cache[cnt].c_shdr;
+
+ if (shdr->sh_type == sym_section) {
+ ELF_SYM *syms;
+ int rslt;
+ size_t size, n, j, htab_sz;
+
+ // 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.
+
+ // NOTES section in the man page of hcreate_r says
+ // "Hash table implementations are usually more efficient when
+ // the table contains enough free space to minimize collisions.
+ // Typically, this means that nel should be at least 25% larger
+ // than the maximum number of elements that the caller expects
+ // to store in the table."
+ htab_sz = n*1.25;
+
+ 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;
+ uintptr_t sym_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].size = syms->st_size;
+ sym_value = syms->st_value;
+
+#if defined(ppc64) && !defined(ABI_ELFv2)
+ // see hotspot/src/share/vm/utilities/elfFuncDescTable.hpp for a detailed description
+ // of why we have to go this extra way via the '.opd' section on big endian ppc64
+ if (opd != NULL && *sym_name != '.' &&
+ (opd->sh_addr <= sym_value && sym_value <= opd->sh_addr + opd->sh_size)) {
+ sym_value = ((ELF_ADDR*)opd_sect->c_data)[(sym_value - opd->sh_addr) / sizeof(ELF_ADDR*)];
+ }
+#endif
+
+ symtab->symbols[j].offset = sym_value - baseaddr;
+ item.key = sym_name;
+ item.data = (void *)&(symtab->symbols[j]);
+ hsearch_r(item, ENTER, &ret, symtab->hash_table);
+ }
+ }
+ }
+
+#if defined(ppc64) && !defined(ABI_ELFv2)
+ // On Linux/PPC64 the debuginfo files contain an empty function descriptor
+ // section (i.e. '.opd' section) which makes the resolution of symbols
+ // with the above algorithm impossible (we would need the have both, the
+ // .opd section from the library and the symbol table from the debuginfo
+ // file which doesn't match with the current workflow.)
+ goto quit;
+#endif
+
+ // Look for a separate debuginfo file.
+ if (try_debuginfo) {
+ // We prefer a debug symtab to an object's own symtab, so look in
+ // the debuginfo file. We stash a copy of the old symtab in case
+ // there is no debuginfo.
+ struct symtab* prev_symtab = symtab;
+ symtab = NULL;
+
+#ifdef NT_GNU_BUILD_ID
+ // First we look for a Build ID
+ for (cursct = shbuf, cnt = 0;
+ symtab == NULL && cnt < ehdr.e_shnum;
+ cnt++) {
+ if (cursct->sh_type == SHT_NOTE) {
+ Elf64_Nhdr *note = (Elf64_Nhdr *)scn_cache[cnt].c_data;
+ if (note->n_type == NT_GNU_BUILD_ID) {
+ symtab = build_symtab_from_build_id(note);
+ }
+ }
+ cursct++;
+ }
+#endif
+
+ // Then, if that doesn't work, the debug link
+ if (symtab == NULL) {
+ symtab = build_symtab_from_debug_link(filename, fd, &ehdr,
+ scn_cache);
+ }
+
+ // If we still haven't found a symtab, use the object's own symtab.
+ if (symtab != NULL) {
+ if (prev_symtab != NULL)
+ destroy_symtab(prev_symtab);
+ } else {
+ symtab = prev_symtab;
+ }
+ }
+
+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;
+}
+
+struct symtab* build_symtab(int fd, const char *filename) {
+ return build_symtab_internal(fd, filename, /* try_debuginfo */ true);
+}
+
+
+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);
+ item.data = NULL;
+ 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;
+}