Revert "Clean up process spawning."

runtime/bin/process_linux.cc

Index: runtime/bin/process_linux.cc
diff --git a/runtime/bin/process_linux.cc b/runtime/bin/process_linux.cc
index 879c973c5a318b15badb764a7f365cd7c373b3f9..cd9c639b9fa6abdb9bee4784a50faa7c8e3996cd 100644
--- a/runtime/bin/process_linux.cc
+++ b/runtime/bin/process_linux.cc
@@ -23,6 +23,9 @@
 #include "bin/thread.h"
 
 
+extern char **environ;
+
+
 namespace dart {
 namespace bin {
 
@@ -150,7 +153,7 @@ class ExitCodeHandler {
 
     // Fork to wake up waitpid.
     if (TEMP_FAILURE_RETRY(fork()) == 0) {
-      _exit(0);
+      exit(0);
     }
 
     monitor_->Notify();
@@ -410,7 +413,7 @@ class ProcessStarter {
     int bytes_read = FDUtils::ReadFromBlocking(read_in_[0], &msg, sizeof(msg));
     if (bytes_read != sizeof(msg)) {
       perror("Failed receiving notification message");
-      _exit(1);
+      exit(1);
     }
     if (mode_ == kNormal) {
       ExecProcess();
@@ -439,14 +442,12 @@ class ProcessStarter {
     }
 
     if (program_environment_ != NULL) {
-      VOID_TEMP_FAILURE_RETRY(
-          execvpe(path_, const_cast<char* const*>(program_arguments_),
-                  program_environment_));
-    } else {
-      VOID_TEMP_FAILURE_RETRY(
-          execvp(path_, const_cast<char* const*>(program_arguments_)));
+      environ = program_environment_;
     }
 
+    VOID_TEMP_FAILURE_RETRY(
+        execvp(path_, const_cast<char* const*>(program_arguments_)));
+
     ReportChildError();
   }
 
@@ -498,13 +499,13 @@ class ProcessStarter {
               execvp(path_, const_cast<char* const*>(program_arguments_)));
           ReportChildError();
         } else {
-          // Exit the intermediate process.
-          _exit(0);
+          // Exit the intermeiate process.
+          exit(0);
         }
       }
     } else {
-      // Exit the intermediate process.
-      _exit(0);
+      // Exit the intermeiate process.
+      exit(0);
     }
   }
 
@@ -534,7 +535,7 @@ class ProcessStarter {
         FDUtils::ReadFromBlocking(
             exec_control_[0], &child_errno, sizeof(child_errno));
     if (bytes_read == sizeof(child_errno)) {
-      SetOSErrorMessage(child_errno);
+      ReadChildError();
       return child_errno;
     } else if (bytes_read == -1) {
       return errno;
@@ -558,7 +559,7 @@ class ProcessStarter {
     } else if (bytes_read == 2 * sizeof(int)) {
       *pid = result[0];
       child_errno = result[1];
-      SetOSErrorMessage(child_errno);
+      ReadChildError();
       return child_errno;
     } else if (bytes_read == -1) {
       return errno;
@@ -647,12 +648,21 @@ class ProcessStarter {
 
 
   void ReportChildError() {
-    // In the case of failure in the child process write the errno to the exec
-    // control pipe and exit.
+    // In the case of failure in the child process write the errno and
+    // the OS error message to the exec control pipe and exit.
     int child_errno = errno;
-    FDUtils::WriteToBlocking(
-        exec_control_[1], &child_errno, sizeof(child_errno));
-    _exit(1);
+    const int kBufferSize = 1024;
+    char error_buf[kBufferSize];
+    char* os_error_message = strerror_r(errno, error_buf, kBufferSize);
+    int bytes_written =
+        FDUtils::WriteToBlocking(
+            exec_control_[1], &child_errno, sizeof(child_errno));
+    if (bytes_written == sizeof(child_errno)) {
+      FDUtils::WriteToBlocking(
+          exec_control_[1], os_error_message, strlen(os_error_message) + 1);
+    }
+    VOID_TEMP_FAILURE_RETRY(close(exec_control_[1]));
+    exit(1);
   }
 
 
@@ -666,16 +676,16 @@ class ProcessStarter {
   }
 
 
-  void SetOSErrorMessage(int child_errno) {
+  void ReadChildError() {
     const int kMaxMessageSize = 256;
-    char* message = static_cast<char*>(calloc(kMaxMessageSize, 0));
-    char* os_error_message = strerror_r(
-        child_errno, message, kMaxMessageSize - 1);
-    if (message == os_error_message) {
+    char* message = static_cast<char*>(malloc(kMaxMessageSize));
+    if (message != NULL) {
+      FDUtils::ReadFromBlocking(exec_control_[0], message, kMaxMessageSize);
+      message[kMaxMessageSize - 1] = '\0';
       *os_error_message_ = message;
     } else {
-      free(message);
-      *os_error_message_ = strdup(os_error_message);
+      // Could not get error message. It will be NULL.
+      ASSERT(*os_error_message_ == NULL);
     }
   }