stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8247515: OSX pc_to_symbol() lookup does not work with core files

Browse Source 
Reviewed-by: sspitsyn, kevinw
This commit is contained in:
Chris Plummer 2020-07-28 09:52:07 -07:00
parent 1a5ef6606f
commit ab729d7075
4 changed files with 103 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/jdk.hotspot.agent/macosx/native/libsaproc/libproc_impl.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2020, 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
@ -208,11 +208,11 @@ void Prelease(struct ps_prochandle* ph) {
free(ph);
}
lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base) {
return add_lib_info_fd(ph, libname, -1, base);
lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base, size_t memsz) {
return add_lib_info_fd(ph, libname, -1, base, memsz);
}
lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base) {
lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd, uintptr_t base, size_t memsz) {
lib_info* newlib;
print_debug("add_lib_info_fd %s\n", libname);
@ -229,6 +229,7 @@ lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd,
strcpy(newlib->name, libname);
newlib->base = base;
newlib->memsz = memsz;
if (fd == -1) {
if ( (newlib->fd = pathmap_open(newlib->name)) < 0) {
@ -262,7 +263,7 @@ lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd,
if (newlib->symtab == NULL) {
print_debug("symbol table build failed for %s\n", newlib->name);
} else {
print_debug("built symbol table for %s\n", newlib->name);
print_debug("built symbol table for 0x%lx %s\n", newlib, newlib->name);
}
// even if symbol table building fails, we add the lib_info.
@ -305,8 +306,12 @@ uintptr_t lookup_symbol(struct ps_prochandle* ph, const char* object_name,
const char* symbol_for_pc(struct ps_prochandle* ph, uintptr_t addr, uintptr_t* poffset) {
const char* res = NULL;
lib_info* lib = ph->libs;
print_debug("symbol_for_pc: addr 0x%lx\n", addr);
while (lib) {
if (lib->symtab && addr >= lib->base) {
print_debug("symbol_for_pc: checking lib 0x%lx 0x%lx %s\n", lib->base, lib->memsz, lib->name);
if (lib->symtab && addr >= lib->base && addr < lib->base + lib->memsz) {
print_debug("symbol_for_pc: address=0x%lx offset=0x%lx found inside lib base=0x%lx memsz=0x%lx %s\n",
addr, addr - lib->base, lib->base, lib->memsz, lib->name);
res = nearest_symbol(lib->symtab, addr - lib->base, poffset);
if (res) return res;
}

11
src/jdk.hotspot.agent/macosx/native/libsaproc/libproc_impl.h
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2020, 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
@ -95,6 +95,7 @@ typedef struct lib_info {
struct symtab* symtab;
int fd; // file descriptor for lib
struct lib_info* next;
size_t memsz;
} lib_info;
// list of threads
@ -108,8 +109,8 @@ typedef struct sa_thread_info {
// list of virtual memory maps
typedef struct map_info {
int fd; // file descriptor
off_t offset; // file offset of this mapping
uintptr_t vaddr; // starting virtual address
uint64_t offset; // file offset of this mapping
uint64_t vaddr; // starting virtual address
size_t memsz; // size of the mapping
struct map_info* next;
} map_info;
@ -170,11 +171,11 @@ typedef bool (*thread_info_callback)(struct ps_prochandle* ph, pthread_t pid, lw
bool read_thread_info(struct ps_prochandle* ph, thread_info_callback cb);
// adds a new shared object to lib list, returns NULL on failure
lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base);
lib_info* add_lib_info(struct ps_prochandle* ph, const char* libname, uintptr_t base, size_t memsz);
// adds a new shared object to lib list, supply open lib file descriptor as well
lib_info* add_lib_info_fd(struct ps_prochandle* ph, const char* libname, int fd,
uintptr_t base);
uintptr_t base, size_t memsz);
sa_thread_info* add_thread_info(struct ps_prochandle* ph, pthread_t pthread_id, lwpid_t lwp_id);
// a test for ELF signature without using libelf

24
src/jdk.hotspot.agent/macosx/native/libsaproc/ps_core.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2020, 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
@ -241,6 +241,7 @@ static bool read_core_segments(struct ps_prochandle* ph) {
goto err;
}
offset += lcmd.cmdsize; // next command position
//print_debug("LC: 0x%x\n", lcmd.cmd);
if (lcmd.cmd == LC_SEGMENT_64) {
lseek(fd, -sizeof(load_command), SEEK_CUR);
if (read(fd, (void *)&segcmd, sizeof(segment_command_64)) != sizeof(segment_command_64)) {
@ -251,8 +252,9 @@ static bool read_core_segments(struct ps_prochandle* ph) {
print_debug("Failed to add map_info at i = %d\n", i);
goto err;
}
print_debug("segment added: %" PRIu64 " 0x%" PRIx64 " %d\n",
segcmd.fileoff, segcmd.vmaddr, segcmd.vmsize);
print_debug("LC_SEGMENT_64 added: nsects=%d fileoff=0x%llx vmaddr=0x%llx vmsize=0x%llx filesize=0x%llx %s\n",
segcmd.nsects, segcmd.fileoff, segcmd.vmaddr, segcmd.vmsize,
segcmd.filesize, &segcmd.segname[0]);
} else if (lcmd.cmd == LC_THREAD || lcmd.cmd == LC_UNIXTHREAD) {
typedef struct thread_fc {
uint32_t flavor;
@ -440,7 +442,7 @@ static bool read_shared_lib_info(struct ps_prochandle* ph) {
// only search core file!
continue;
}
print_debug("map_info %d: vmaddr = 0x%016" PRIx64 " fileoff = %" PRIu64 " vmsize = %" PRIu64 "\n",
print_debug("map_info %d: vmaddr = 0x%016llx fileoff = 0x%llx vmsize = 0x%lx\n",
j, iter->vaddr, iter->offset, iter->memsz);
lseek(fd, fpos, SEEK_SET);
// we assume .dylib loaded at segment address --- which is true for JVM libraries
@ -464,7 +466,7 @@ static bool read_shared_lib_info(struct ps_prochandle* ph) {
continue;
}
lseek(fd, -sizeof(uint32_t), SEEK_CUR);
// this is the file begining to core file.
// This is the begining of the mach-o file in the segment.
if (read(fd, (void *)&header, sizeof(mach_header_64)) != sizeof(mach_header_64)) {
goto err;
}
@ -497,18 +499,26 @@ static bool read_shared_lib_info(struct ps_prochandle* ph) {
if (name[j] == '\0') break;
j++;
}
print_debug("%s\n", name);
print_debug("%d %s\n", lcmd.cmd, name);
// changed name from @rpath/xxxx.dylib to real path
if (strrchr(name, '@')) {
get_real_path(ph, name);
print_debug("get_real_path returned: %s\n", name);
} else {
break; // Ignore non-relative paths, which are system libs. See JDK-8249779.
}
add_lib_info(ph, name, iter->vaddr);
add_lib_info(ph, name, iter->vaddr, iter->memsz);
break;
}
}
// done with the file, advanced to next page to search more files
#if 0
// This line is disabled due to JDK-8249779. Instead we break out of the loop
// and don't attempt to find any more mach-o files in this segment.
fpos = (ltell(fd) + pagesize - 1) / pagesize * pagesize;
#else
break;
#endif
}
}
return true;

98
src/jdk.hotspot.agent/macosx/native/libsaproc/symtab.c
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 2020, 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
@ -24,6 +24,7 @@
#include <unistd.h>
#include <search.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <db.h>
@ -57,12 +58,14 @@ typedef struct symtab {
void build_search_table(symtab_t *symtab) {
int i;
print_debug("build_search_table\n");
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);
//print_debug("build_search_table: %d 0x%x %s\n", i, symtab->symbols[i].offset, symtab->symbols[i].name);
(*symtab->hash_table->put)(symtab->hash_table, &key, &value, 0);
// check result
@ -92,10 +95,11 @@ void build_search_table(symtab_t *symtab) {
// read symbol table from given fd.
struct symtab* build_symtab(int fd) {
symtab_t* symtab = NULL;
int i;
int i, j;
mach_header_64 header;
off_t image_start;
print_debug("build_symtab\n");
if (!get_arch_off(fd, CPU_TYPE_X86_64, &image_start)) {
print_debug("failed in get fat header\n");
return NULL;
@ -151,6 +155,7 @@ struct symtab* build_symtab(int fd) {
if (symtab->hash_table == NULL)
goto quit;
// allocate the symtab
symtab->num_symbols = symtabcmd.nsyms;
symtab->symbols = (symtab_symbol *)malloc(sizeof(symtab_symbol) * symtab->num_symbols);
symtab->strs = (char *)malloc(sizeof(char) * symtabcmd.strsize);
@ -158,17 +163,8 @@ struct symtab* build_symtab(int fd) {
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
// read in the 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)) {
@ -176,21 +172,42 @@ struct symtab* build_symtab(int fd) {
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);
// read in each nlist_64 from the symbol table and use to fill in symtab->symbols
lseek(fd, image_start + symtabcmd.symoff, SEEK_SET);
i = 0;
for (j = 0; j < symtab->num_symbols; j++) {
if (read(fd, (void *)&lentry, sizeof(nlist_64)) != sizeof(nlist_64)) {
print_debug("read nlist_64 failed at %j\n", j);
goto quit;
}
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);
uintptr_t offset = lentry.n_value; // offset of the symbol code/data in the file
uintptr_t stridx = lentry.n_un.n_strx; // offset of symbol string in the symtabcmd.symoff section
if (stridx == 0 || offset == 0) {
continue; // Skip this entry. It's not a reference to code or data
}
symtab->symbols[i].offset = offset;
symtab->symbols[i].name = symtab->strs + stridx;
symtab->symbols[i].size = strlen(symtab->symbols[i].name);
if (symtab->symbols[i].size == 0) {
continue; // Skip this entry. It points to an empty string.
}
print_debug("symbol read: %d %d n_type=0x%x n_sect=0x%x n_desc=0x%x n_strx=0x%lx offset=0x%lx %s\n",
j, i, lentry.n_type, lentry.n_sect, lentry.n_desc, stridx, offset, symtab->symbols[i].name);
i++;
}
// Update symtab->num_symbols to be the actual number of symbols we added. Since the symbols
// array was allocated larger, reallocate it to the proper size.
print_debug("build_symtab: included %d of %d entries.\n", i, symtab->num_symbols);
symtab->num_symbols = i;
symtab->symbols = (symtab_symbol *)realloc(symtab->symbols, sizeof(symtab_symbol) * symtab->num_symbols);
if (symtab->symbols == NULL) {
print_debug("out of memory: reallocating symtab.symbol\n");
goto quit;
}
// build a hashtable for fast query
@ -389,14 +406,37 @@ uintptr_t search_symbol(struct symtab* symtab, uintptr_t base, const char *sym_n
const char* nearest_symbol(struct symtab* symtab, uintptr_t offset,
uintptr_t* poffset) {
int n = 0;
char* result = NULL;
ptrdiff_t lowest_offset_from_sym = -1;
if (!symtab) return NULL;
// Search the symbol table for the symbol that is closest to the specified offset, but is not under.
//
// Note we can't just use the first symbol that is >= the offset because the symbols may not be
// sorted by offset.
//
// Note this is a rather slow search that is O(n/2), and libjvm has as many as 250k symbols.
// Probably would be good to sort the array and do a binary search, or use a hash table like
// we do for name -> address lookups. However, this functionality is not used often and
// generally just involves one lookup, such as with the clhsdb "findpc" command.
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;
if (sym->size != 0 && offset >= sym->offset) {
ptrdiff_t offset_from_sym = offset - sym->offset;
if (offset_from_sym >= 0) { // ignore symbols that come after "offset"
if (lowest_offset_from_sym == -1 || offset_from_sym < lowest_offset_from_sym) {
lowest_offset_from_sym = offset_from_sym;
result = sym->name;
//print_debug("nearest_symbol: found %d %s 0x%x 0x%x 0x%x\n",
// n, sym->name, offset, sym->offset, lowest_offset_from_sym);
}
}
}
}
return NULL;
print_debug("nearest_symbol: found symbol %d file_offset=0x%lx sym_offset=0x%lx %s\n",
n, offset, lowest_offset_from_sym, result);
// Save the offset from the symbol if requested.
if (result != NULL && poffset) {
*poffset = lowest_offset_from_sym;
}
return result;
}