// Copyright (c) 2007, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Author: Alfred Peng
#include <dirent.h>
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <sys/frame.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <algorithm>
#include <cassert>
#include <cstdio>
#include <cstdlib>
#include <functional>
#include "client/solaris/handler/solaris_lwp.h"
#include "common/solaris/message_output.h"
using namespace google_breakpad;
// This unamed namespace contains helper function.
namespace {
uintptr_t stack_base_address = 0;
static const int HEADER_MAX = 2000;
static const int MAP_MAX = 1000;
// Context information for the callbacks when validating address by listing
// modules.
struct AddressValidatingContext {
uintptr_t address;
bool is_mapped;
AddressValidatingContext() : address(0UL), is_mapped(false) {
}
};
// Convert from string to int.
static bool LocalAtoi(char *s, int *r) {
assert(s != NULL);
assert(r != NULL);
char *endptr = NULL;
int ret = strtol(s, &endptr, 10);
if (endptr == s)
return false;
*r = ret;
return true;
}
// Callback invoked for each mapped module.
// It uses the module's adderss range to validate the address.
static bool AddressNotInModuleCallback(const ModuleInfo &module_info,
void *context) {
AddressValidatingContext *addr =
reinterpret_cast<AddressValidatingContext *>(context);
if (addr->is_mapped = ((module_info.start_addr > 0) &&
(addr->address >= module_info.start_addr) &&
(addr->address <= module_info.start_addr +
module_info.size))) {
stack_base_address = module_info.start_addr + module_info.size;
}
return !addr->is_mapped;
}
static int IterateLwpAll(int pid,
CallbackParam<LwpidCallback> *callback_param) {
char lwp_path[40];
DIR *dir;
int count = 0;
snprintf(lwp_path, sizeof (lwp_path), "/proc/%d/lwp", (int)pid);
if ((dir = opendir(lwp_path)) == NULL)
return -1;
struct dirent *entry = NULL;
while ((entry = readdir(dir)) != NULL) {
if ((strcmp(entry->d_name, ".") != 0) &&
(strcmp(entry->d_name, "..") != 0)) {
int lwpid = 0;
int last_pid = 0;
if (LocalAtoi(entry->d_name, &lwpid) && last_pid != lwpid) {
last_pid = lwpid;
++count;
if (callback_param &&
!(callback_param->call_back)(lwpid, callback_param->context)) {
break;
}
}
}
}
closedir(dir);
return count;
}
#if defined(__i386) && !defined(NO_FRAME_POINTER)
void *GetNextFrame(void **last_ebp) {
void *sp = *last_ebp;
if ((unsigned long)sp == (unsigned long)last_ebp)
return NULL;
if ((unsigned long)sp & (sizeof(void *) - 1))
return NULL;
if ((unsigned long)sp - (unsigned long)last_ebp > 100000)
return NULL;
return sp;
}
#elif defined(__sparc)
void *GetNextFrame(void *last_ebp) {
return reinterpret_cast<struct frame *>(last_ebp)->fr_savfp;
}
#else
void *GetNextFrame(void **last_ebp) {
return reinterpret_cast<void*>(last_ebp);
}
#endif
class AutoCloser {
public:
AutoCloser(int fd) : fd_(fd) {}
~AutoCloser() { if (fd_) close(fd_); }
private:
int fd_;
};
// Control the execution of the lwp.
// Suspend/Resume lwp based on the value of context.
static bool ControlLwp(int lwpid, void *context) {
// The current thread is the one to handle the crash. Ignore it.
if (lwpid != pthread_self()) {
int ctlfd;
char procname[PATH_MAX];
bool suspend = *(bool *)context;
// Open the /proc/$pid/lwp/$lwpid/lwpctl files
snprintf(procname, sizeof (procname), "/proc/self/lwp/%d/lwpctl", lwpid);
if ((ctlfd = open(procname, O_WRONLY|O_EXCL)) < 0) {
print_message2(2, "failed to open %s in ControlLwp\n", procname);
return false;
}
AutoCloser autocloser(ctlfd);
long ctl[2];
ctl[0] = suspend ? PCSTOP : PCRUN;
ctl[1] = 0;
if (write(ctlfd, ctl, sizeof (ctl)) != sizeof (ctl)) {
print_message2(2, "failed in lwp %d\n", lwpid);
return false;
}
}
return true;
}
/*
* Utility function to read the contents of a file that contains a
* prheader_t at the start (/proc/$pid/lstatus or /proc/$pid/lpsinfo).
* Return true on success.
*/
static bool read_lfile(int pid, const char *lname, prheader_t *lhp) {
char lpath[PATH_MAX];
struct stat statb;
int fd;
size_t size;
snprintf(lpath, sizeof (lpath), "/proc/%d/%s", pid, lname);
if ((fd = open(lpath, O_RDONLY)) < 0) {
print_message2(2, "failed to open %s in read_lfile\n", lpath);
return false;
}
AutoCloser autocloser(fd);
if (fstat(fd, &statb) != 0)
return false;
size = statb.st_size;
if ((size / sizeof (prheader_t)) + 32 > HEADER_MAX) {
print_message1(2, "map size overflow\n");
return false;
}
if (pread(fd, lhp, size, 0) <= sizeof (prheader_t))
return false;
return true;
}
} // namespace
namespace google_breakpad {
SolarisLwp::SolarisLwp(int pid) : pid_(pid) {
}
SolarisLwp::~SolarisLwp() {
}
int SolarisLwp::ControlAllLwps(bool suspend) {
CallbackParam<LwpidCallback> callback_param(ControlLwp, &suspend);
return IterateLwpAll(pid_, &callback_param);
}
int SolarisLwp::GetLwpCount() const {
return IterateLwpAll(pid_, NULL);
}
int SolarisLwp::Lwp_iter_all(int pid,
CallbackParam<LwpCallback> *callback_param) const {
lwpstatus_t *Lsp;
lwpstatus_t *sp;
prheader_t lphp[HEADER_MAX];
prheader_t lhp[HEADER_MAX];
prheader_t *Lphp = lphp;
prheader_t *Lhp = lhp;
lwpsinfo_t *Lpsp;
long nstat;
long ninfo;
int rv = 0;
/*
* The /proc/pid/lstatus file has the array of lwpstatus_t's and the
* /proc/pid/lpsinfo file has the array of lwpsinfo_t's.
*/
if (read_lfile(pid, "lstatus", Lhp) == NULL)
return -1;
if (read_lfile(pid, "lpsinfo", Lphp) == NULL) {
return -1;
}
Lsp = (lwpstatus_t *)(uintptr_t)(Lhp + 1);
Lpsp = (lwpsinfo_t *)(uintptr_t)(Lphp + 1);
for (ninfo = Lphp->pr_nent; ninfo != 0; --ninfo) {
if (Lpsp->pr_sname != 'Z') {
sp = Lsp;
Lsp = (lwpstatus_t *)((uintptr_t)Lsp + Lhp->pr_entsize);
} else {
sp = NULL;
}
if (callback_param &&
!(callback_param->call_back)(sp, callback_param->context))
break;
++rv;
Lpsp = (lwpsinfo_t *)((uintptr_t)Lpsp + Lphp->pr_entsize);
}
return rv;
}
uintptr_t SolarisLwp::GetLwpStackBottom(uintptr_t current_esp) const {
AddressValidatingContext addr;
addr.address = current_esp;
CallbackParam<ModuleCallback> callback_param(AddressNotInModuleCallback,
&addr);
ListModules(&callback_param);
return stack_base_address;
}
int SolarisLwp::GetModuleCount() const {
return ListModules(NULL);
}
int SolarisLwp::ListModules(
CallbackParam<ModuleCallback> *callback_param) const {
const char *maps_path = "/proc/self/map";
struct stat status;
int fd = 0, num;
prmap_t map_array[MAP_MAX];
prmap_t *maps = map_array;
size_t size;
if ((fd = open(maps_path, O_RDONLY)) == -1) {
print_message2(2, "failed to open %s in ListModules\n", maps_path);
return -1;
}
AutoCloser autocloser(fd);
if (fstat(fd, &status))
return -1;
/*
* Determine number of mappings, this value must be
* larger than the actual module count
*/
size = status.st_size;
if ((num = (int)(size / sizeof (prmap_t))) > MAP_MAX) {
print_message1(2, "map size overflow\n");
return -1;
}
if (read(fd, (void *)maps, size) < 0) {
print_message2(2, "failed to read %d\n", fd);
return -1;
}
prmap_t *_maps;
int _num;
int module_count = 0;
/*
* Scan each mapping - note it is assummed that the mappings are
* presented in order. We fill holes between mappings. On intel
* the last mapping is usually the data segment of ld.so.1, after
* this comes a red zone into which non-fixed mapping won't get
* place. Thus we can simply bail from the loop after seeing the
* last mapping.
*/
for (_num = 0, _maps = maps; _num < num; ++_num, ++_maps) {
ModuleInfo module;
char *name = _maps->pr_mapname;
memset(&module, 0, sizeof (module));
module.start_addr = _maps->pr_vaddr;
module.size = _maps->pr_size;
if (strlen(name) > 0) {
int objectfd = 0;
char path[PATH_MAX];
char buf[SELFMAG];
snprintf(path, sizeof (path), "/proc/self/object/%s", name);
if ((objectfd = open(path, O_RDONLY)) < 0) {
print_message1(2, "can't open module file\n");
continue;
}
AutoCloser autocloser(objectfd);
if (read(objectfd, buf, SELFMAG) != SELFMAG) {
print_message1(2, "can't read module file\n");
continue;
}
if (buf[0] != ELFMAG0 || buf[1] != ELFMAG1 ||
buf[2] != ELFMAG2 || buf[3] != ELFMAG3) {
continue;
}
strncpy(module.name, name, sizeof (module.name) - 1);
++module_count;
}
if (callback_param &&
(!callback_param->call_back(module, callback_param->context))) {
break;
}
}
return module_count;
}
// Check if the address is a valid virtual address.
// If the address is in any of the mapped modules, we take it as valid.
// Otherwise it is invalid.
bool SolarisLwp::IsAddressMapped(uintptr_t address) const {
AddressValidatingContext addr;
addr.address = address;
CallbackParam<ModuleCallback> callback_param(AddressNotInModuleCallback,
&addr);
ListModules(&callback_param);
return addr.is_mapped;
}
// We're looking for a ucontext_t as the second parameter
// to a signal handler function call. Luckily, the ucontext_t
// has an ebp(fp on SPARC) member which should match the ebp(fp)
// pointed to by the ebp(fp) of the signal handler frame.
// The Solaris stack looks like this:
// http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/lib/libproc/common/Pstack.c#81
bool SolarisLwp::FindSigContext(uintptr_t sighandler_ebp,
ucontext_t **sig_ctx) {
uintptr_t previous_ebp;
uintptr_t sig_ebp;
const int MAX_STACK_DEPTH = 50;
int depth_counter = 0;
do {
#if TARGET_CPU_SPARC
previous_ebp = reinterpret_cast<uintptr_t>(GetNextFrame(
reinterpret_cast<void*>(sighandler_ebp)));
*sig_ctx = reinterpret_cast<ucontext_t*>(sighandler_ebp + sizeof (struct frame));
uintptr_t sig_esp = (*sig_ctx)->uc_mcontext.gregs[REG_O6];
if (sig_esp < previous_ebp && sig_esp > sighandler_ebp)
sig_ebp = (uintptr_t)(((struct frame *)sig_esp)->fr_savfp);
#elif TARGET_CPU_X86
previous_ebp = reinterpret_cast<uintptr_t>(GetNextFrame(
reinterpret_cast<void**>(sighandler_ebp)));
*sig_ctx = reinterpret_cast<ucontext_t*>(sighandler_ebp + sizeof (struct frame) +
3 * sizeof(uintptr_t));
sig_ebp = (*sig_ctx)->uc_mcontext.gregs[EBP];
#endif
sighandler_ebp = previous_ebp;
depth_counter++;
} while(previous_ebp != sig_ebp && sighandler_ebp != 0 &&
IsAddressMapped(sighandler_ebp) && depth_counter < MAX_STACK_DEPTH);
return previous_ebp == sig_ebp && previous_ebp != 0;
}
} // namespace google_breakpad