2017-07-01 commit

src/loaders/Task.cpp

@@ -1,4 +1,6 @@
 #include "Task.h"
+#include <unistd.h>
+#include <stdio.h>
 
 /// Task_InvalidDataStructure - Exception thrown when a Task is defined with invalid JSON.
 class Task_InvalidDataStructure: public std::runtime_error { public:
@@ -94,8 +96,75 @@ void Task::execute( bool verbose )
         std::cout << "\t Executing target \"" << this->definition.get_target() << "\"." << std::endl;
     }
 
-    FILE * STDOUT;
-    FILE * STDERR;
+    this->do_raw_command();
+}
 
+int Task::do_raw_command( std::string command, std::string & STDOUT, std::string & STDIN );
+{
 
+    /*
+     * since pipes are unidirectional, we need two pipes. one for data to flow from parent's stdout to child's stdin and
+     * the other for child's stdout to flow to parent's stdin
+     */
+
+    #define NUM_PIPES          2
+
+    #define PARENT_WRITE_PIPE  0
+    #define PARENT_READ_PIPE   1
+
+    int pipes[NUM_PIPES][2];
+
+    /*
+     * always in a pipe[], pipe[0] is for read and pipe[1] is for write
+     */
+
+    #define READ_FD  0
+    #define WRITE_FD 1
+    #define PARENT_READ_FD  ( pipes[PARENT_READ_PIPE][READ_FD]   )
+    #define PARENT_WRITE_FD ( pipes[PARENT_WRITE_PIPE][WRITE_FD] )
+
+    #define CHILD_READ_FD   ( pipes[PARENT_WRITE_PIPE][READ_FD]  )
+    #define CHILD_WRITE_FD  ( pipes[PARENT_READ_PIPE][WRITE_FD]  )
+
+    int outfd[2];
+    int infd[2];
+
+    // pipes for parent to write and read
+    pipe(pipes[PARENT_READ_PIPE]);
+    pipe(pipes[PARENT_WRITE_PIPE]);
+
+    if(!fork()) {
+        char *argv[]={ "/usr/bin/bc", "-q", 0};
+
+        dup2(CHILD_READ_FD, STDIN_FILENO);
+        dup2(CHILD_WRITE_FD, STDOUT_FILENO);
+
+        /* Close fds not required by child. Also, we don't
+           want the exec'ed program to know these existed */
+        close(CHILD_READ_FD);
+        close(CHILD_WRITE_FD);
+        close(PARENT_READ_FD);
+        close(PARENT_WRITE_FD);
+
+        execv(argv[0], argv);
+    } else {
+        char buffer[100];
+        int count;
+
+        /* close fds not required by parent */
+        close(CHILD_READ_FD);
+        close(CHILD_WRITE_FD);
+
+        // Write to child’s stdin
+        write(PARENT_WRITE_FD, "2^32\n", 5);
+
+        // Read from child’s stdout
+        count = read(PARENT_READ_FD, buffer, sizeof(buffer)-1);
+        if (count >= 0) {
+            buffer[count] = 0;
+            printf("%s", buffer);
+        } else {
+            printf("IO Error\n");
+        }
+    }
 }