[compiler-rt] r201150 - [Sanitizer] External symbolizer refactoring: split protocol for communicating with
Alexey Samsonov
samsonov at google.com
Tue Feb 11 05:03:09 PST 2014
Author: samsonov
Date: Tue Feb 11 07:03:09 2014
New Revision: 201150
URL: http://llvm.org/viewvc/llvm-project?rev=201150&view=rev
Log:
[Sanitizer] External symbolizer refactoring: split protocol for communicating with
llvm-symbolizer binary and external process handling into separate classes.
No functionality change.
Modified:
compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc?rev=201150&r1=201149&r2=201150&view=diff
==============================================================================
--- compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc (original)
+++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc Tue Feb 11 07:03:09 2014
@@ -54,107 +54,6 @@ static const char *DemangleCXXABI(const
return name;
}
-#if defined(__x86_64__)
-static const char* const kSymbolizerArch = "--default-arch=x86_64";
-#elif defined(__i386__)
-static const char* const kSymbolizerArch = "--default-arch=i386";
-#elif defined(__powerpc64__)
-static const char* const kSymbolizerArch = "--default-arch=powerpc64";
-#else
-static const char* const kSymbolizerArch = "--default-arch=unknown";
-#endif
-
-static const int kSymbolizerStartupTimeMillis = 10;
-
-// Creates external symbolizer connected via pipe, user should write
-// to output_fd and read from input_fd.
-static bool StartSymbolizerSubprocess(const char *path_to_symbolizer,
- int *input_fd, int *output_fd) {
- if (!FileExists(path_to_symbolizer)) {
- Report("WARNING: invalid path to external symbolizer!\n");
- return false;
- }
-
- int *infd = NULL;
- int *outfd = NULL;
- // The client program may close its stdin and/or stdout and/or stderr
- // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
- // In this case the communication between the forked processes may be
- // broken if either the parent or the child tries to close or duplicate
- // these descriptors. The loop below produces two pairs of file
- // descriptors, each greater than 2 (stderr).
- int sock_pair[5][2];
- for (int i = 0; i < 5; i++) {
- if (pipe(sock_pair[i]) == -1) {
- for (int j = 0; j < i; j++) {
- internal_close(sock_pair[j][0]);
- internal_close(sock_pair[j][1]);
- }
- Report("WARNING: Can't create a socket pair to start "
- "external symbolizer (errno: %d)\n", errno);
- return false;
- } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
- if (infd == NULL) {
- infd = sock_pair[i];
- } else {
- outfd = sock_pair[i];
- for (int j = 0; j < i; j++) {
- if (sock_pair[j] == infd) continue;
- internal_close(sock_pair[j][0]);
- internal_close(sock_pair[j][1]);
- }
- break;
- }
- }
- }
- CHECK(infd);
- CHECK(outfd);
-
- int pid = fork();
- if (pid == -1) {
- // Fork() failed.
- internal_close(infd[0]);
- internal_close(infd[1]);
- internal_close(outfd[0]);
- internal_close(outfd[1]);
- Report("WARNING: failed to fork external symbolizer "
- " (errno: %d)\n", errno);
- return false;
- } else if (pid == 0) {
- // Child subprocess.
- internal_close(STDOUT_FILENO);
- internal_close(STDIN_FILENO);
- internal_dup2(outfd[0], STDIN_FILENO);
- internal_dup2(infd[1], STDOUT_FILENO);
- internal_close(outfd[0]);
- internal_close(outfd[1]);
- internal_close(infd[0]);
- internal_close(infd[1]);
- for (int fd = getdtablesize(); fd > 2; fd--)
- internal_close(fd);
- execl(path_to_symbolizer, path_to_symbolizer, kSymbolizerArch, (char*)0);
- internal__exit(1);
- }
-
- // Continue execution in parent process.
- internal_close(outfd[0]);
- internal_close(infd[1]);
- *input_fd = infd[0];
- *output_fd = outfd[1];
-
- // Check that symbolizer subprocess started successfully.
- int pid_status;
- SleepForMillis(kSymbolizerStartupTimeMillis);
- int exited_pid = waitpid(pid, &pid_status, WNOHANG);
- if (exited_pid != 0) {
- // Either waitpid failed, or child has already exited.
- Report("WARNING: external symbolizer didn't start up correctly!\n");
- return false;
- }
-
- return true;
-}
-
// Extracts the prefix of "str" that consists of any characters not
// present in "delims" string, and copies this prefix to "result", allocating
// space for it.
@@ -194,29 +93,20 @@ static const char *ExtractUptr(const cha
return ret;
}
-// ExternalSymbolizer encapsulates communication between the tool and
-// external symbolizer program, running in a different subprocess,
-// For now we assume the following protocol:
-// For each request of the form
-// <module_name> <module_offset>
-// passed to STDIN, external symbolizer prints to STDOUT response:
-// <function_name>
-// <file_name>:<line_number>:<column_number>
-// <function_name>
-// <file_name>:<line_number>:<column_number>
-// ...
-// <empty line>
-// ExternalSymbolizer may not be used from two threads simultaneously.
-class ExternalSymbolizer {
+// SymbolizerProcess encapsulates communication between the tool and
+// external symbolizer program, running in a different subprocess.
+// SymbolizerProcess may not be used from two threads simultaneously.
+class SymbolizerProcess {
public:
- explicit ExternalSymbolizer(const char *path)
+ explicit SymbolizerProcess(const char *path)
: path_(path),
input_fd_(kInvalidFd),
output_fd_(kInvalidFd),
times_restarted_(0),
- failed_to_start_(false) {
+ failed_to_start_(false),
+ reported_invalid_path_(false) {
CHECK(path_);
- CHECK_NE(path[0], '\0');
+ CHECK_NE(path_[0], '\0');
}
char *SendCommand(bool is_data, const char *module_name, uptr module_offset) {
@@ -239,7 +129,7 @@ class ExternalSymbolizer {
internal_close(input_fd_);
if (output_fd_ != kInvalidFd)
internal_close(output_fd_);
- return StartSymbolizerSubprocess(path_, &input_fd_, &output_fd_);
+ return StartSymbolizerSubprocess();
}
char *SendCommandImpl(bool is_data, const char *module_name,
@@ -247,8 +137,9 @@ class ExternalSymbolizer {
if (input_fd_ == kInvalidFd || output_fd_ == kInvalidFd)
return 0;
CHECK(module_name);
- internal_snprintf(buffer_, kBufferSize, "%s\"%s\" 0x%zx\n",
- is_data ? "DATA " : "", module_name, module_offset);
+ if (!RenderInputCommand(buffer_, kBufferSize, is_data, module_name,
+ module_offset))
+ return 0;
if (!writeToSymbolizer(buffer_, internal_strlen(buffer_)))
return 0;
if (!readFromSymbolizer(buffer_, kBufferSize))
@@ -270,11 +161,8 @@ class ExternalSymbolizer {
return false;
}
read_len += just_read;
- // Empty line marks the end of symbolizer output.
- if (read_len >= 2 && buffer[read_len - 1] == '\n' &&
- buffer[read_len - 2] == '\n') {
+ if (ReachedEndOfOutput(buffer, read_len))
break;
- }
}
return true;
}
@@ -290,6 +178,109 @@ class ExternalSymbolizer {
return true;
}
+ bool StartSymbolizerSubprocess() {
+ if (!FileExists(path_)) {
+ if (!reported_invalid_path_) {
+ Report("WARNING: invalid path to external symbolizer!\n");
+ reported_invalid_path_ = true;
+ }
+ return false;
+ }
+
+ int *infd = NULL;
+ int *outfd = NULL;
+ // The client program may close its stdin and/or stdout and/or stderr
+ // thus allowing socketpair to reuse file descriptors 0, 1 or 2.
+ // In this case the communication between the forked processes may be
+ // broken if either the parent or the child tries to close or duplicate
+ // these descriptors. The loop below produces two pairs of file
+ // descriptors, each greater than 2 (stderr).
+ int sock_pair[5][2];
+ for (int i = 0; i < 5; i++) {
+ if (pipe(sock_pair[i]) == -1) {
+ for (int j = 0; j < i; j++) {
+ internal_close(sock_pair[j][0]);
+ internal_close(sock_pair[j][1]);
+ }
+ Report("WARNING: Can't create a socket pair to start "
+ "external symbolizer (errno: %d)\n", errno);
+ return false;
+ } else if (sock_pair[i][0] > 2 && sock_pair[i][1] > 2) {
+ if (infd == NULL) {
+ infd = sock_pair[i];
+ } else {
+ outfd = sock_pair[i];
+ for (int j = 0; j < i; j++) {
+ if (sock_pair[j] == infd) continue;
+ internal_close(sock_pair[j][0]);
+ internal_close(sock_pair[j][1]);
+ }
+ break;
+ }
+ }
+ }
+ CHECK(infd);
+ CHECK(outfd);
+
+ int pid = fork();
+ if (pid == -1) {
+ // Fork() failed.
+ internal_close(infd[0]);
+ internal_close(infd[1]);
+ internal_close(outfd[0]);
+ internal_close(outfd[1]);
+ Report("WARNING: failed to fork external symbolizer "
+ " (errno: %d)\n", errno);
+ return false;
+ } else if (pid == 0) {
+ // Child subprocess.
+ internal_close(STDOUT_FILENO);
+ internal_close(STDIN_FILENO);
+ internal_dup2(outfd[0], STDIN_FILENO);
+ internal_dup2(infd[1], STDOUT_FILENO);
+ internal_close(outfd[0]);
+ internal_close(outfd[1]);
+ internal_close(infd[0]);
+ internal_close(infd[1]);
+ for (int fd = getdtablesize(); fd > 2; fd--)
+ internal_close(fd);
+ ExecuteWithDefaultArgs(path_);
+ internal__exit(1);
+ }
+
+ // Continue execution in parent process.
+ internal_close(outfd[0]);
+ internal_close(infd[1]);
+ input_fd_ = infd[0];
+ output_fd_ = outfd[1];
+
+ // Check that symbolizer subprocess started successfully.
+ int pid_status;
+ SleepForMillis(kSymbolizerStartupTimeMillis);
+ int exited_pid = waitpid(pid, &pid_status, WNOHANG);
+ if (exited_pid != 0) {
+ // Either waitpid failed, or child has already exited.
+ Report("WARNING: external symbolizer didn't start up correctly!\n");
+ return false;
+ }
+
+ return true;
+ }
+
+ virtual bool RenderInputCommand(char *buffer, uptr max_length, bool is_data,
+ const char *module_name,
+ uptr module_offset) const {
+ UNIMPLEMENTED();
+ }
+
+ virtual bool ReachedEndOfOutput(const char *buffer, uptr length) const {
+ UNIMPLEMENTED();
+ }
+
+ virtual void ExecuteWithDefaultArgs(const char *path_to_binary) const {
+ UNIMPLEMENTED();
+ }
+
const char *path_;
int input_fd_;
int output_fd_;
@@ -298,8 +289,52 @@ class ExternalSymbolizer {
char buffer_[kBufferSize];
static const uptr kMaxTimesRestarted = 5;
+ static const int kSymbolizerStartupTimeMillis = 10;
uptr times_restarted_;
bool failed_to_start_;
+ bool reported_invalid_path_;
+};
+
+// For now we assume the following protocol:
+// For each request of the form
+// <module_name> <module_offset>
+// passed to STDIN, external symbolizer prints to STDOUT response:
+// <function_name>
+// <file_name>:<line_number>:<column_number>
+// <function_name>
+// <file_name>:<line_number>:<column_number>
+// ...
+// <empty line>
+class LLVMSymbolizerProcess : public SymbolizerProcess {
+ public:
+ explicit LLVMSymbolizerProcess(const char *path) : SymbolizerProcess(path) {}
+
+ private:
+ bool RenderInputCommand(char *buffer, uptr max_length, bool is_data,
+ const char *module_name, uptr module_offset) const {
+ internal_snprintf(buffer, max_length, "%s\"%s\" 0x%zx\n",
+ is_data ? "DATA " : "", module_name, module_offset);
+ return true;
+ }
+
+ bool ReachedEndOfOutput(const char *buffer, uptr length) const {
+ // Empty line marks the end of llvm-symbolizer output.
+ return length >= 2 && buffer[length - 1] == '\n' &&
+ buffer[length - 2] == '\n';
+ }
+
+ void ExecuteWithDefaultArgs(const char *path_to_binary) const {
+#if defined(__x86_64__)
+ const char* const kSymbolizerArch = "--default-arch=x86_64";
+#elif defined(__i386__)
+ const char* const kSymbolizerArch = "--default-arch=i386";
+#elif defined(__powerpc64__)
+ const char* const kSymbolizerArch = "--default-arch=powerpc64";
+#else
+ const char* const kSymbolizerArch = "--default-arch=unknown";
+#endif
+ execl(path_to_binary, path_to_binary, kSymbolizerArch, (char *)0);
+ }
};
#if SANITIZER_SUPPORTS_WEAK_HOOKS
@@ -383,7 +418,7 @@ class InternalSymbolizer {
class POSIXSymbolizer : public Symbolizer {
public:
- POSIXSymbolizer(ExternalSymbolizer *external_symbolizer,
+ POSIXSymbolizer(SymbolizerProcess *external_symbolizer,
InternalSymbolizer *internal_symbolizer,
LibbacktraceSymbolizer *libbacktrace_symbolizer)
: Symbolizer(),
@@ -595,7 +630,7 @@ class POSIXSymbolizer : public Symbolize
bool modules_fresh_;
BlockingMutex mu_;
- ExternalSymbolizer *external_symbolizer_; // Leaked.
+ SymbolizerProcess *external_symbolizer_; // Leaked.
InternalSymbolizer *const internal_symbolizer_; // Leaked.
LibbacktraceSymbolizer *libbacktrace_symbolizer_; // Leaked.
};
@@ -603,7 +638,7 @@ class POSIXSymbolizer : public Symbolize
Symbolizer *Symbolizer::PlatformInit(const char *path_to_external) {
InternalSymbolizer* internal_symbolizer =
InternalSymbolizer::get(&symbolizer_allocator_);
- ExternalSymbolizer *external_symbolizer = 0;
+ SymbolizerProcess *external_symbolizer = 0;
LibbacktraceSymbolizer *libbacktrace_symbolizer = 0;
if (!internal_symbolizer) {
@@ -615,7 +650,7 @@ Symbolizer *Symbolizer::PlatformInit(con
path_to_external = FindPathToBinary("llvm-symbolizer");
if (path_to_external && path_to_external[0] != '\0')
external_symbolizer = new(symbolizer_allocator_)
- ExternalSymbolizer(path_to_external);
+ LLVMSymbolizerProcess(path_to_external);
}
}
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