Bug 689184 part 2 - Use the program PT_DYNAMIC segment for the MD_LINUX_DSO_DEBUG stream. r=ted

This commit is contained in:
Mike Hommey 2012-07-25 07:43:22 +02:00
parent 1a1bbdb5dc
commit 73793249ec

View File

@ -470,29 +470,9 @@ class MinidumpWriter {
}
bool Dump() {
// The dynamic linker makes information available that helps gdb find all
// DSOs loaded into the program. If we can access this information, we dump
// it to a MD_LINUX_DSO_DEBUG stream.
struct r_debug* r_debug = NULL;
uint32_t dynamic_length = 0;
#if !defined(__ANDROID__)
for (int i = 0;;) {
ElfW(Dyn) dyn;
dynamic_length += sizeof(dyn);
dumper_.CopyFromProcess(&dyn, crashing_tid_, _DYNAMIC+i++, sizeof(dyn));
if (dyn.d_tag == DT_DEBUG) {
r_debug = (struct r_debug*)dyn.d_un.d_ptr;
continue;
} else if (dyn.d_tag == DT_NULL)
break;
}
#endif
// A minidump file contains a number of tagged streams. This is the number
// of stream which we write.
unsigned kNumWriters = 12;
if (r_debug)
++kNumWriters;
unsigned kNumWriters = 13;
TypedMDRVA<MDRawHeader> header(&minidump_writer_);
TypedMDRVA<MDRawDirectory> dir(&minidump_writer_);
@ -571,12 +551,10 @@ class MinidumpWriter {
NullifyDirectoryEntry(&dirent);
dir.CopyIndex(dir_index++, &dirent);
if (r_debug) {
dirent.stream_type = MD_LINUX_DSO_DEBUG;
if (!WriteDSODebugStream(&dirent, r_debug, dynamic_length))
NullifyDirectoryEntry(&dirent);
dir.CopyIndex(dir_index++, &dirent);
}
dirent.stream_type = MD_LINUX_DSO_DEBUG;
if (!WriteDSODebugStream(&dirent))
NullifyDirectoryEntry(&dirent);
dir.CopyIndex(dir_index++, &dirent);
// If you add more directory entries, don't forget to update kNumWriters,
// above.
@ -1037,13 +1015,56 @@ class MinidumpWriter {
return true;
}
bool WriteDSODebugStream(MDRawDirectory* dirent, struct r_debug* r_debug,
uint32_t dynamic_length) {
bool WriteDSODebugStream(MDRawDirectory* dirent) {
#if defined(__ANDROID__)
return false;
#else
// The caller provided us with a pointer to "struct r_debug". We can
// look up the "r_map" field to get a linked list of all loaded DSOs.
ElfW(Phdr) *phdr = reinterpret_cast<ElfW(Phdr) *>(dumper_.auxv()[AT_PHDR]);
char *base;
int phnum = dumper_.auxv()[AT_PHNUM];
if (!phnum || !phdr)
return false;
// Assume the program base is at the beginning of the same page as the PHDR
base = reinterpret_cast<char *>(reinterpret_cast<uintptr_t>(phdr) & ~0xfff);
// Search for the program PT_DYNAMIC segment
ElfW(Addr) dyn_addr = 0;
for (; phnum >= 0; phnum--, phdr++) {
ElfW(Phdr) ph;
dumper_.CopyFromProcess(&ph, crashing_tid_, phdr, sizeof(ph));
// Adjust base address with the virtual address of the PT_LOAD segment
// corresponding to offset 0
if (ph.p_type == PT_LOAD && ph.p_offset == 0)
base -= ph.p_vaddr;
if (ph.p_type == PT_DYNAMIC)
dyn_addr = ph.p_vaddr;
}
if (!dyn_addr)
return false;
ElfW(Dyn) *dynamic = reinterpret_cast<ElfW(Dyn) *>(dyn_addr + base);
// The dynamic linker makes information available that helps gdb find all
// DSOs loaded into the program. If this information is indeed available,
// dump it to a MD_LINUX_DSO_DEBUG stream.
struct r_debug* r_debug = NULL;
uint32_t dynamic_length = 0;
for (int i = 0;;) {
ElfW(Dyn) dyn;
dynamic_length += sizeof(dyn);
dumper_.CopyFromProcess(&dyn, crashing_tid_, dynamic+i++, sizeof(dyn));
if (dyn.d_tag == DT_DEBUG) {
r_debug = reinterpret_cast<struct r_debug*>(dyn.d_un.d_ptr);
continue;
} else if (dyn.d_tag == DT_NULL) {
break;
}
}
// The "r_map" field of that r_debug struct contains a linked list of all
// loaded DSOs.
// Our list of DSOs potentially is different from the ones in the crashing
// process. So, we have to be careful to never dereference pointers
// directly. Instead, we use CopyFromProcess() everywhere.
@ -1106,10 +1127,10 @@ class MinidumpWriter {
debug.get()->dso_count = dso_count;
debug.get()->brk = (void*)debug_entry.r_brk;
debug.get()->ldbase = (void*)debug_entry.r_ldbase;
debug.get()->dynamic = (void*)&_DYNAMIC;
debug.get()->dynamic = dynamic;
char *dso_debug_data = new char[dynamic_length];
dumper_.CopyFromProcess(dso_debug_data, crashing_tid_, &_DYNAMIC,
dumper_.CopyFromProcess(dso_debug_data, crashing_tid_, dynamic,
dynamic_length);
debug.CopyIndexAfterObject(0, dso_debug_data, dynamic_length);
delete[] dso_debug_data;