Mac: Add support for in-process crash reporting

common/mac/launch_reporter.cc

Index: common/mac/launch_reporter.cc
diff --git a/common/linux/crc32.cc b/common/mac/launch_reporter.cc
similarity index 55%
copy from common/linux/crc32.cc
copy to common/mac/launch_reporter.cc
index 8df636ce4d73c7d5751d4ea3a68332ebe0d27bd3..245be82659521d0e6fa54430c8bb12d38842efff 100644
--- a/common/linux/crc32.cc
+++ b/common/mac/launch_reporter.cc
@@ -1,4 +1,4 @@
-// Copyright 2014 Google Inc.
+// Copyright (c) 2014, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -27,44 +27,58 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#include "common/linux/crc32.h"
+#include <stdio.h>
+#include <sys/wait.h>
+#include <unistd.h>
 
 namespace google_breakpad {
 
-// This implementation is based on the sample implementation in RFC 1952.
+void LaunchReporter(const char *reporter_executable_path,
+                    const char *config_file_path) {
+  const char* argv[] = { reporter_executable_path, config_file_path, NULL };
 
-// CRC32 polynomial, in reversed form.
-// See RFC 1952, or http://en.wikipedia.org/wiki/Cyclic_redundancy_check
-static const uint32_t kCrc32Polynomial = 0xEDB88320;
-static uint32_t kCrc32Table[256] = { 0 };
+  // Launch the reporter
+  pid_t pid = fork();
 
-#define arraysize(f) (sizeof(f) / sizeof(*f))
+  if (pid == -1) {
+    perror("fork");
+    fprintf(stderr, "Failed to fork reporter process\n");
+    return;
+  }
 
-static void EnsureCrc32TableInited() {
-  if (kCrc32Table[arraysize(kCrc32Table) - 1])
-    return;  // already inited
-  for (uint32_t i = 0; i < arraysize(kCrc32Table); ++i) {
-    uint32_t c = i;
-    for (size_t j = 0; j < 8; ++j) {
-      if (c & 1) {
-        c = kCrc32Polynomial ^ (c >> 1);
-      } else {
-        c >>= 1;
-      }
-    }
-    kCrc32Table[i] = c;
+  // If we're in the child, load in our new executable and run.
+  // The parent will not wait for the child to complete.
+  if (pid == 0) {
+    execv(argv[0], (char* const*)argv);
+    perror("exec");
+    fprintf(stderr,
+            "Failed to launch reporter process from path %s\n",
+            reporter_executable_path);
+    unlink(config_file_path);  // launch failed - get rid of config file
+    _exit(1);
   }
-}
 
-uint32_t UpdateCrc32(uint32_t start, const void* buf, size_t len) {
-  EnsureCrc32TableInited();
+  // Wait until the Reporter child process exits.
+  //
 
-  uint32_t c = start ^ 0xFFFFFFFF;
-  const uint8_t* u = static_cast<const uint8_t*>(buf);
-  for (size_t i = 0; i < len; ++i) {
-    c = kCrc32Table[(c ^ u[i]) & 0xFF] ^ (c >> 8);
+  // We'll use a timeout of one minute.
+  int timeout_count = 60;   // 60 seconds
+
+  while (timeout_count-- > 0) {
+    int status;
+    pid_t result = waitpid(pid, &status, WNOHANG);
+
+    if (result == 0) {
+      // The child has not yet finished.
+      sleep(1);
+    } else if (result == -1) {
+      // error occurred.
+      break;
+    } else {
+      // child has finished
+      break;
+    }
   }
-  return c ^ 0xFFFFFFFF;
 }
 
 }  // namespace google_breakpad