# HG changeset patch # User never # Date 1268161359 28800 # Node ID 7de45b5044c3417603bb6dfddca03bc89e9a29de # Parent 51db1e4b379da94194ffa8b4dd8475ea1c1e9a92 6932270: Allow Java's ELF symtab reader to use separate debuginfo files Reviewed-by: never Contributed-by: Andrew Haley diff -r 51db1e4b379d -r 7de45b5044c3 agent/src/os/linux/libproc_impl.c --- a/agent/src/os/linux/libproc_impl.c Mon Mar 08 04:46:30 2010 -0800 +++ b/agent/src/os/linux/libproc_impl.c Tue Mar 09 11:02:39 2010 -0800 @@ -174,7 +174,7 @@ return NULL; } - newlib->symtab = build_symtab(newlib->fd); + newlib->symtab = build_symtab(newlib->fd, libname); if (newlib->symtab == NULL) { print_debug("symbol table build failed for %s\n", newlib->name); } diff -r 51db1e4b379d -r 7de45b5044c3 agent/src/os/linux/symtab.c --- a/agent/src/os/linux/symtab.c Mon Mar 08 04:46:30 2010 -0800 +++ b/agent/src/os/linux/symtab.c Tue Mar 09 11:02:39 2010 -0800 @@ -53,8 +53,274 @@ struct hsearch_data *hash_table; } symtab_t; -// read symbol table from given fd. -struct symtab* build_symtab(int fd) { + +// 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, + ELF_SHDR *shbuf, + struct elf_section *scn_cache) +{ + ELF_SHDR* cursct = NULL; + char *strtab; + int cnt; + + if (scn_cache[ehdr->e_shstrndx].c_data == NULL) { + if ((scn_cache[ehdr->e_shstrndx].c_data + = read_section_data(fd, ehdr, cursct)) == NULL) { + return NULL; + } + } + + strtab = scn_cache[ehdr->e_shstrndx].c_data; + + for (cursct = shbuf, cnt = 0; + cnt < ehdr->e_shnum; + cnt++, cursct++) { + if (strcmp(cursct->sh_name + strtab, name) == 0) { + scn_cache[cnt].c_data = read_section_data(fd, ehdr, cursct); + 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, + ELF_SHDR *shbuf, + struct elf_section *scn_cache) +{ + int debug_fd; + struct elf_section *debug_link = find_section_by_name(".gnu_debuglink", fd, ehdr, + shbuf, 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) + 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, + ELF_SHDR *shbuf, + struct elf_section *scn_cache) +{ + fd = open_file_from_debug_link(name, fd, ehdr, shbuf, 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; + unsigned 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; @@ -66,6 +332,7 @@ ELF_SHDR* cursct = NULL; ELF_PHDR* phbuf = NULL; ELF_PHDR* phdr = NULL; + int sym_section = SHT_DYNSYM; uintptr_t baseaddr = (uintptr_t)-1; @@ -90,18 +357,23 @@ 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 (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++; } for (cnt = 1; cnt < ehdr.e_shnum; cnt++) { ELF_SHDR *shdr = scn_cache[cnt].c_shdr; - if (shdr->sh_type == SHT_SYMTAB) { + if (shdr->sh_type == sym_section) { ELF_SYM *syms; int j, n, rslt; size_t size; @@ -163,6 +435,45 @@ } } + // 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, shbuf, + 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); @@ -177,6 +488,11 @@ 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); diff -r 51db1e4b379d -r 7de45b5044c3 agent/src/os/linux/symtab.h --- a/agent/src/os/linux/symtab.h Mon Mar 08 04:46:30 2010 -0800 +++ b/agent/src/os/linux/symtab.h Tue Mar 09 11:02:39 2010 -0800 @@ -32,7 +32,7 @@ struct symtab; // build symbol table for a given ELF file descriptor -struct symtab* build_symtab(int fd); +struct symtab* build_symtab(int fd, const char *filename); // destroy the symbol table void destroy_symtab(struct symtab* symtab); diff -r 51db1e4b379d -r 7de45b5044c3 make/linux/makefiles/build_vm_def.sh --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/make/linux/makefiles/build_vm_def.sh Tue Mar 09 11:02:39 2010 -0800 @@ -0,0 +1,5 @@ +#!/bin/sh + +nm --defined-only $* | awk ' + { if ($3 ~ /^_ZTV/ || $3 ~ /^gHotSpotVM/) print "\t" $3 ";" } + ' diff -r 51db1e4b379d -r 7de45b5044c3 make/linux/makefiles/mapfile-vers-debug --- a/make/linux/makefiles/mapfile-vers-debug Mon Mar 08 04:46:30 2010 -0800 +++ b/make/linux/makefiles/mapfile-vers-debug Tue Mar 09 11:02:39 2010 -0800 @@ -290,6 +290,9 @@ # This is for Forte Analyzer profiling support. AsyncGetCallTrace; + + # INSERT VTABLE SYMBOLS HERE + local: *; }; diff -r 51db1e4b379d -r 7de45b5044c3 make/linux/makefiles/mapfile-vers-product --- a/make/linux/makefiles/mapfile-vers-product Mon Mar 08 04:46:30 2010 -0800 +++ b/make/linux/makefiles/mapfile-vers-product Tue Mar 09 11:02:39 2010 -0800 @@ -285,6 +285,9 @@ # This is for Forte Analyzer profiling support. AsyncGetCallTrace; + + # INSERT VTABLE SYMBOLS HERE + local: *; }; diff -r 51db1e4b379d -r 7de45b5044c3 make/linux/makefiles/vm.make --- a/make/linux/makefiles/vm.make Mon Mar 08 04:46:30 2010 -0800 +++ b/make/linux/makefiles/vm.make Tue Mar 09 11:02:39 2010 -0800 @@ -121,14 +121,21 @@ vm_version.o: $(filter-out vm_version.o,$(JVM_OBJ_FILES)) -mapfile : $(MAPFILE) +mapfile : $(MAPFILE) vm.def rm -f $@ - cat $^ > $@ + awk '{ if ($$0 ~ "INSERT VTABLE SYMBOLS HERE") \ + { system ("cat vm.def"); } \ + else \ + { print $$0 } \ + }' > $@ < $(MAPFILE) mapfile_reorder : mapfile $(REORDERFILE) rm -f $@ cat $^ > $@ +vm.def: $(Res_Files) $(Obj_Files) + sh $(GAMMADIR)/make/linux/makefiles/build_vm_def.sh *.o > $@ + ifeq ($(ZERO_LIBARCH), ppc64) STATIC_CXX = false else