Make all linux ptrace dumper tests use a subprocess

Patch by Mike Hommey <mh@glandium.org>, R=ted at https://breakpad.appspot.com/550002/

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@1190 4c0a9323-5329-0410-9bdc-e9ce6186880e
This commit is contained in:
ted.mielczarek@gmail.com 2013-06-06 13:15:54 +00:00
parent 6b46d4e872
commit e10e9ac7ca

View file

@ -41,6 +41,7 @@
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/poll.h>
#include <sys/stat.h>
#include <sys/types.h>
@ -63,14 +64,60 @@ namespace {
typedef testing::Test LinuxPtraceDumperTest;
/* Fixture for running tests in a child process. */
class LinuxPtraceDumperChildTest : public testing::Test {
protected:
virtual void SetUp() {
child_pid_ = fork();
prctl(PR_SET_PTRACER, child_pid_);
}
/* Gtest is calling TestBody from this class, which sets up a child
* process in which the RealTestBody virtual member is called.
* As such, TestBody is not supposed to be overridden in derived classes.
*/
virtual void TestBody() /* final */ {
if (child_pid_ == 0) {
// child process
RealTestBody();
exit(HasFatalFailure() ? kFatalFailure :
(HasNonfatalFailure() ? kNonFatalFailure : 0));
}
ASSERT_TRUE(child_pid_ > 0);
int status;
waitpid(child_pid_, &status, 0);
if (WEXITSTATUS(status) == kFatalFailure) {
GTEST_FATAL_FAILURE_("Test failed in child process");
} else if (WEXITSTATUS(status) == kNonFatalFailure) {
GTEST_NONFATAL_FAILURE_("Test failed in child process");
}
}
/* Gtest defines TestBody functions through its macros, but classes
* derived from this one need to define RealTestBody instead.
* This is achieved by defining a TestBody macro further below.
*/
virtual void RealTestBody() = 0;
private:
static const int kFatalFailure = 1;
static const int kNonFatalFailure = 2;
pid_t child_pid_;
};
} // namespace
TEST(LinuxPtraceDumperTest, Setup) {
LinuxPtraceDumper dumper(getpid());
/* Replace TestBody declarations within TEST*() with RealTestBody
* declarations */
#define TestBody RealTestBody
TEST_F(LinuxPtraceDumperChildTest, Setup) {
LinuxPtraceDumper dumper(getppid());
}
TEST(LinuxPtraceDumperTest, FindMappings) {
LinuxPtraceDumper dumper(getpid());
TEST_F(LinuxPtraceDumperChildTest, FindMappings) {
LinuxPtraceDumper dumper(getppid());
ASSERT_TRUE(dumper.Init());
ASSERT_TRUE(dumper.FindMapping(reinterpret_cast<void*>(getpid)));
@ -78,14 +125,14 @@ TEST(LinuxPtraceDumperTest, FindMappings) {
ASSERT_FALSE(dumper.FindMapping(NULL));
}
TEST(LinuxPtraceDumperTest, ThreadList) {
LinuxPtraceDumper dumper(getpid());
TEST_F(LinuxPtraceDumperChildTest, ThreadList) {
LinuxPtraceDumper dumper(getppid());
ASSERT_TRUE(dumper.Init());
ASSERT_GE(dumper.threads().size(), (size_t)1);
bool found = false;
for (size_t i = 0; i < dumper.threads().size(); ++i) {
if (dumper.threads()[i] == getpid()) {
if (dumper.threads()[i] == getppid()) {
ASSERT_FALSE(found);
found = true;
}
@ -97,12 +144,22 @@ TEST(LinuxPtraceDumperTest, ThreadList) {
// a mmap'ed mapping.
class StackHelper {
public:
StackHelper(int fd, char* mapping, size_t size)
: fd_(fd), mapping_(mapping), size_(size) {}
StackHelper()
: fd_(-1), mapping_(NULL), size_(0) {}
~StackHelper() {
munmap(mapping_, size_);
close(fd_);
if (size_)
munmap(mapping_, size_);
if (fd_ >= 0)
close(fd_);
}
void Init(int fd, char* mapping, size_t size) {
fd_ = fd;
mapping_ = mapping;
size_ = size;
}
char* mapping() const { return mapping_; }
size_t size() const { return size_; }
private:
int fd_;
@ -110,19 +167,28 @@ class StackHelper {
size_t size_;
};
TEST(LinuxPtraceDumperTest, MergedMappings) {
string helper_path(GetHelperBinary());
if (helper_path.empty()) {
class LinuxPtraceDumperMappingsTest : public LinuxPtraceDumperChildTest {
protected:
virtual void SetUp();
string helper_path_;
size_t page_size_;
StackHelper helper_;
};
void LinuxPtraceDumperMappingsTest::SetUp() {
helper_path_ = GetHelperBinary();
if (helper_path_.empty()) {
FAIL() << "Couldn't find helper binary";
exit(1);
}
// mmap two segments out of the helper binary, one
// enclosed in the other, but with different protections.
const size_t kPageSize = sysconf(_SC_PAGESIZE);
const size_t kMappingSize = 3 * kPageSize;
int fd = open(helper_path.c_str(), O_RDONLY);
ASSERT_NE(-1, fd) << "Failed to open file: " << helper_path
page_size_ = sysconf(_SC_PAGESIZE);
const size_t kMappingSize = 3 * page_size_;
int fd = open(helper_path_.c_str(), O_RDONLY);
ASSERT_NE(-1, fd) << "Failed to open file: " << helper_path_
<< ", Error: " << strerror(errno);
char* mapping =
reinterpret_cast<char*>(mmap(NULL,
@ -133,34 +199,37 @@ TEST(LinuxPtraceDumperTest, MergedMappings) {
0));
ASSERT_TRUE(mapping);
const uintptr_t kMappingAddress = reinterpret_cast<uintptr_t>(mapping);
// Ensure that things get cleaned up.
StackHelper helper(fd, mapping, kMappingSize);
helper_.Init(fd, mapping, kMappingSize);
// Carve a page out of the first mapping with different permissions.
char* inside_mapping = reinterpret_cast<char*>(
mmap(mapping + 2 *kPageSize,
kPageSize,
mmap(mapping + 2 * page_size_,
page_size_,
PROT_NONE,
MAP_SHARED | MAP_FIXED,
fd,
// Map a different offset just to
// better test real-world conditions.
kPageSize));
page_size_));
ASSERT_TRUE(inside_mapping);
LinuxPtraceDumperChildTest::SetUp();
}
TEST_F(LinuxPtraceDumperMappingsTest, MergedMappings) {
// Now check that LinuxPtraceDumper interpreted the mappings properly.
LinuxPtraceDumper dumper(getpid());
LinuxPtraceDumper dumper(getppid());
ASSERT_TRUE(dumper.Init());
int mapping_count = 0;
for (unsigned i = 0; i < dumper.mappings().size(); ++i) {
const MappingInfo& mapping = *dumper.mappings()[i];
if (strcmp(mapping.name, helper_path.c_str()) == 0) {
if (strcmp(mapping.name, this->helper_path_.c_str()) == 0) {
// This mapping should encompass the entire original mapped
// range.
EXPECT_EQ(kMappingAddress, mapping.start_addr);
EXPECT_EQ(kMappingSize, mapping.size);
EXPECT_EQ(reinterpret_cast<uintptr_t>(this->helper_.mapping()),
mapping.start_addr);
EXPECT_EQ(this->helper_.size(), mapping.size);
EXPECT_EQ(0U, mapping.offset);
mapping_count++;
}
@ -168,6 +237,124 @@ TEST(LinuxPtraceDumperTest, MergedMappings) {
EXPECT_EQ(1, mapping_count);
}
TEST_F(LinuxPtraceDumperChildTest, BuildProcPath) {
const pid_t pid = getppid();
LinuxPtraceDumper dumper(pid);
char maps_path[NAME_MAX] = "";
char maps_path_expected[NAME_MAX];
snprintf(maps_path_expected, sizeof(maps_path_expected),
"/proc/%d/maps", pid);
EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
EXPECT_STREQ(maps_path_expected, maps_path);
EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, 0, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
char long_node[NAME_MAX];
size_t long_node_len = NAME_MAX - strlen("/proc/123") - 1;
memset(long_node, 'a', long_node_len);
long_node[long_node_len] = '\0';
EXPECT_FALSE(dumper.BuildProcPath(maps_path, 123, long_node));
}
#if !defined(__ARM_EABI__)
// Ensure that the linux-gate VDSO is included in the mapping list.
TEST_F(LinuxPtraceDumperChildTest, MappingsIncludeLinuxGate) {
LinuxPtraceDumper dumper(getppid());
ASSERT_TRUE(dumper.Init());
void* linux_gate_loc =
reinterpret_cast<void *>(dumper.auxv()[AT_SYSINFO_EHDR]);
ASSERT_TRUE(linux_gate_loc);
bool found_linux_gate = false;
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
const MappingInfo* mapping;
for (unsigned i = 0; i < mappings.size(); ++i) {
mapping = mappings[i];
if (!strcmp(mapping->name, kLinuxGateLibraryName)) {
found_linux_gate = true;
break;
}
}
EXPECT_TRUE(found_linux_gate);
EXPECT_EQ(linux_gate_loc, reinterpret_cast<void*>(mapping->start_addr));
EXPECT_EQ(0, memcmp(linux_gate_loc, ELFMAG, SELFMAG));
}
// Ensure that the linux-gate VDSO can generate a non-zeroed File ID.
TEST_F(LinuxPtraceDumperChildTest, LinuxGateMappingID) {
LinuxPtraceDumper dumper(getppid());
ASSERT_TRUE(dumper.Init());
bool found_linux_gate = false;
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
unsigned index = 0;
for (unsigned i = 0; i < mappings.size(); ++i) {
if (!strcmp(mappings[i]->name, kLinuxGateLibraryName)) {
found_linux_gate = true;
index = i;
break;
}
}
ASSERT_TRUE(found_linux_gate);
// Need to suspend the child so ptrace actually works.
ASSERT_TRUE(dumper.ThreadsSuspend());
uint8_t identifier[sizeof(MDGUID)];
ASSERT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[index],
true,
index,
identifier));
uint8_t empty_identifier[sizeof(MDGUID)];
memset(empty_identifier, 0, sizeof(empty_identifier));
EXPECT_NE(0, memcmp(empty_identifier, identifier, sizeof(identifier)));
EXPECT_TRUE(dumper.ThreadsResume());
}
#endif
TEST_F(LinuxPtraceDumperChildTest, FileIDsMatch) {
// Calculate the File ID of our binary using both
// FileID::ElfFileIdentifier and LinuxDumper::ElfFileIdentifierForMapping
// and ensure that we get the same result from both.
char exe_name[PATH_MAX];
ASSERT_TRUE(SafeReadLink("/proc/self/exe", exe_name));
LinuxPtraceDumper dumper(getppid());
ASSERT_TRUE(dumper.Init());
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
bool found_exe = false;
unsigned i;
for (i = 0; i < mappings.size(); ++i) {
const MappingInfo* mapping = mappings[i];
if (!strcmp(mapping->name, exe_name)) {
found_exe = true;
break;
}
}
ASSERT_TRUE(found_exe);
uint8_t identifier1[sizeof(MDGUID)];
uint8_t identifier2[sizeof(MDGUID)];
EXPECT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[i], true, i,
identifier1));
FileID fileid(exe_name);
EXPECT_TRUE(fileid.ElfFileIdentifier(identifier2));
char identifier_string1[37];
char identifier_string2[37];
FileID::ConvertIdentifierToString(identifier1, identifier_string1,
37);
FileID::ConvertIdentifierToString(identifier2, identifier_string2,
37);
EXPECT_STREQ(identifier_string1, identifier_string2);
}
/* Get back to normal behavior of TEST*() macros wrt TestBody. */
#undef TestBody
TEST(LinuxPtraceDumperTest, VerifyStackReadWithMultipleThreads) {
static const int kNumberOfThreadsInHelperProgram = 5;
char kNumberOfThreadsArgument[2];
@ -213,7 +400,7 @@ TEST(LinuxPtraceDumperTest, VerifyStackReadWithMultipleThreads) {
ASSERT_EQ(1, r);
ASSERT_TRUE(pfd.revents & POLLIN);
uint8_t junk;
ASSERT_EQ(read(fds[0], &junk, sizeof(junk)),
ASSERT_EQ(read(fds[0], &junk, sizeof(junk)),
static_cast<ssize_t>(sizeof(junk)));
}
close(fds[0]);
@ -239,11 +426,11 @@ TEST(LinuxPtraceDumperTest, VerifyStackReadWithMultipleThreads) {
// In the helper program, we stored a pointer to the thread id in a
// specific register. Check that we can recover its value.
#if defined(__ARM_EABI__)
pid_t *process_tid_location = (pid_t *)(one_thread.regs.uregs[3]);
pid_t* process_tid_location = (pid_t*)(one_thread.regs.uregs[3]);
#elif defined(__i386)
pid_t *process_tid_location = (pid_t *)(one_thread.regs.ecx);
pid_t* process_tid_location = (pid_t*)(one_thread.regs.ecx);
#elif defined(__x86_64)
pid_t *process_tid_location = (pid_t *)(one_thread.regs.rcx);
pid_t* process_tid_location = (pid_t*)(one_thread.regs.rcx);
#else
#error This test has not been ported to this platform.
#endif
@ -263,178 +450,3 @@ TEST(LinuxPtraceDumperTest, VerifyStackReadWithMultipleThreads) {
ASSERT_TRUE(WIFSIGNALED(status));
ASSERT_EQ(SIGKILL, WTERMSIG(status));
}
TEST(LinuxPtraceDumperTest, BuildProcPath) {
const pid_t pid = getpid();
LinuxPtraceDumper dumper(pid);
char maps_path[NAME_MAX] = "";
char maps_path_expected[NAME_MAX];
snprintf(maps_path_expected, sizeof(maps_path_expected),
"/proc/%d/maps", pid);
EXPECT_TRUE(dumper.BuildProcPath(maps_path, pid, "maps"));
EXPECT_STREQ(maps_path_expected, maps_path);
EXPECT_FALSE(dumper.BuildProcPath(NULL, pid, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, 0, "maps"));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, ""));
EXPECT_FALSE(dumper.BuildProcPath(maps_path, pid, NULL));
char long_node[NAME_MAX];
size_t long_node_len = NAME_MAX - strlen("/proc/123") - 1;
memset(long_node, 'a', long_node_len);
long_node[long_node_len] = '\0';
EXPECT_FALSE(dumper.BuildProcPath(maps_path, 123, long_node));
}
#if !defined(__ARM_EABI__)
// Ensure that the linux-gate VDSO is included in the mapping list.
TEST(LinuxPtraceDumperTest, MappingsIncludeLinuxGate) {
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
void* linux_gate_loc =
reinterpret_cast<void *>(dumper.auxv()[AT_SYSINFO_EHDR]);
ASSERT_TRUE(linux_gate_loc);
bool found_linux_gate = false;
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
const MappingInfo* mapping;
for (unsigned i = 0; i < mappings.size(); ++i) {
mapping = mappings[i];
if (!strcmp(mapping->name, kLinuxGateLibraryName)) {
found_linux_gate = true;
break;
}
}
EXPECT_TRUE(found_linux_gate);
EXPECT_EQ(linux_gate_loc, reinterpret_cast<void*>(mapping->start_addr));
EXPECT_EQ(0, memcmp(linux_gate_loc, ELFMAG, SELFMAG));
}
// Ensure that the linux-gate VDSO can generate a non-zeroed File ID.
TEST(LinuxPtraceDumperTest, LinuxGateMappingID) {
LinuxPtraceDumper dumper(getpid());
ASSERT_TRUE(dumper.Init());
bool found_linux_gate = false;
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
unsigned index = 0;
for (unsigned i = 0; i < mappings.size(); ++i) {
if (!strcmp(mappings[i]->name, kLinuxGateLibraryName)) {
found_linux_gate = true;
index = i;
break;
}
}
ASSERT_TRUE(found_linux_gate);
uint8_t identifier[sizeof(MDGUID)];
ASSERT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[index],
true,
index,
identifier));
uint8_t empty_identifier[sizeof(MDGUID)];
memset(empty_identifier, 0, sizeof(empty_identifier));
EXPECT_NE(0, memcmp(empty_identifier, identifier, sizeof(identifier)));
}
// Ensure that the linux-gate VDSO can generate a non-zeroed File ID
// from a child process.
TEST(LinuxPtraceDumperTest, LinuxGateMappingIDChild) {
int fds[2];
ASSERT_NE(-1, pipe(fds));
// Fork a child so ptrace works.
const pid_t child = fork();
if (child == 0) {
close(fds[1]);
// Now wait forever for the parent.
char b;
IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
close(fds[0]);
syscall(__NR_exit);
}
close(fds[0]);
LinuxPtraceDumper dumper(child);
ASSERT_TRUE(dumper.Init());
bool found_linux_gate = false;
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
unsigned index = 0;
for (unsigned i = 0; i < mappings.size(); ++i) {
if (!strcmp(mappings[i]->name, kLinuxGateLibraryName)) {
found_linux_gate = true;
index = i;
break;
}
}
ASSERT_TRUE(found_linux_gate);
// Need to suspend the child so ptrace actually works.
ASSERT_TRUE(dumper.ThreadsSuspend());
uint8_t identifier[sizeof(MDGUID)];
ASSERT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[index],
true,
index,
identifier));
uint8_t empty_identifier[sizeof(MDGUID)];
memset(empty_identifier, 0, sizeof(empty_identifier));
EXPECT_NE(0, memcmp(empty_identifier, identifier, sizeof(identifier)));
EXPECT_TRUE(dumper.ThreadsResume());
close(fds[1]);
}
#endif
TEST(LinuxPtraceDumperTest, FileIDsMatch) {
// Calculate the File ID of our binary using both
// FileID::ElfFileIdentifier and LinuxDumper::ElfFileIdentifierForMapping
// and ensure that we get the same result from both.
char exe_name[PATH_MAX];
ASSERT_TRUE(SafeReadLink("/proc/self/exe", exe_name));
int fds[2];
ASSERT_NE(-1, pipe(fds));
// Fork a child so ptrace works.
const pid_t child = fork();
if (child == 0) {
close(fds[1]);
// Now wait forever for the parent.
char b;
IGNORE_RET(HANDLE_EINTR(read(fds[0], &b, sizeof(b))));
close(fds[0]);
syscall(__NR_exit);
}
close(fds[0]);
LinuxPtraceDumper dumper(child);
ASSERT_TRUE(dumper.Init());
const wasteful_vector<MappingInfo*> mappings = dumper.mappings();
bool found_exe = false;
unsigned i;
for (i = 0; i < mappings.size(); ++i) {
const MappingInfo* mapping = mappings[i];
if (!strcmp(mapping->name, exe_name)) {
found_exe = true;
break;
}
}
ASSERT_TRUE(found_exe);
uint8_t identifier1[sizeof(MDGUID)];
uint8_t identifier2[sizeof(MDGUID)];
EXPECT_TRUE(dumper.ElfFileIdentifierForMapping(*mappings[i], true, i,
identifier1));
FileID fileid(exe_name);
EXPECT_TRUE(fileid.ElfFileIdentifier(identifier2));
char identifier_string1[37];
char identifier_string2[37];
FileID::ConvertIdentifierToString(identifier1, identifier_string1,
37);
FileID::ConvertIdentifierToString(identifier2, identifier_string2,
37);
EXPECT_STREQ(identifier_string1, identifier_string2);
close(fds[1]);
}