From 1469f517d6825e8349bb5e41ca13e88e6de03343 Mon Sep 17 00:00:00 2001
From: Sagi Dayan <sagidayan@gmail.com>
Date: Wed, 26 Mar 2014 00:23:18 +0200
Subject: [PATCH] Writing output to file works! - need some more documentation

---
 main.c | 55 ++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 40 insertions(+), 15 deletions(-)

diff --git a/main.c b/main.c
index b71b64c..473ae75 100644
--- a/main.c
+++ b/main.c
@@ -3,8 +3,10 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <fcntl.h>
 
-
+#define	true	1
+#define	false	0
 #define LEN 512
 #define PATH "/bin/"
 #define ERROR -1
@@ -12,11 +14,12 @@
 
 int getHostName(char* host);
 int getUserName(char* name);
-int runExec(char** args);
+int runExec(char** args, int writeToFile);
 void PrintTokens (char** tokens);
-char** ReadTokens(FILE* stream) ;
+char** ReadTokens(FILE* stream, int* writeToFile) ;
 void FreeTokens(char** tokens) ;
 void checkIfQuit(char* word);
+int getFileNameIndex(char** args);
 
 
 int main()
@@ -25,6 +28,7 @@ int main()
 	char* host_n = (char *)malloc(sizeof(char));
 	char* user_n = (char *)malloc(sizeof(char));
 	char** args;
+	int writeToFile = false;
 	
 	if(getHostName(host_n) == ERROR)
 		goto quit;
@@ -34,17 +38,18 @@ int main()
 	while(1)
 	{
 		printf("%d %s@%s$ ",exitCode, user_n, host_n);
-		args = ReadTokens(stdin);
+		args = ReadTokens(stdin, &writeToFile);
 		if(args != NULL)
 		{
-			exitCode = runExec(args);
+			exitCode = runExec(args, writeToFile);
 			FreeTokens(args); //in case of error while trying to create process - this method will free the memory already
 			if(exitCode == ERROR)
 				goto quit;
 		}
+		writeToFile = false;
 	}
 
-quit:
+	quit:
 	free(host_n);
 	free(user_n);
 	return 0;
@@ -76,7 +81,7 @@ int getUserName(char* name)
  * @param  args - an array of strings that contains all the arguments from the user
  * @return  int - exit status of child
  */
- int runExec(char** args)
+ int runExec(char** args, int writeToFile)
  {
  	int status;
  	pid_t pid;
@@ -86,8 +91,6 @@ int getUserName(char* name)
  	strcpy(path, PATH);
  	strcat(path, exe);
 
- 	printf("try: %s \n",args[0]);
-
  	pid = fork();
 
  	if(pid < 0)
@@ -97,15 +100,28 @@ int getUserName(char* name)
  	}
 	else if(pid == 0) // child
 	{
-		if(execv(path, args) != 0)
+		if(writeToFile == true)
 		{
-			fprintf(stderr, "%s%s%s\n", "myTerminal: ", args[0] ,": command not found");
+			int i_lastArg = getFileNameIndex(args);
+			char* fileName = (char *)malloc(strlen(args[i_lastArg])*sizeof(char));
+			strcpy(fileName, args[i_lastArg]);
+			args[i_lastArg - 1] = NULL;
+			int fd = open(fileName, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
+			dup2(fd, 1);   // make stdout go to file
+			dup2(fd, 2);   // make stderr go to file
+			close(fd);
+
+	    }
+	    if(execv(path, args) != 0)
+	    {
+	    	fprintf(stderr, "%s%s%s\n", "myTerminal: ", args[0] ,": command not found");
 			exit(1); //child error - chield needs to be closed manually. exit code 225;
 		}
 	}
 	else //pid > 0 father
 		waitpid(pid,&status,0);
 	free(path);
+	free(exe);
 	if(status == EXIT_1) //in my computer exit(1) returns 256 - ex demands wanted 255
 		return status-1;
 	return status;
@@ -118,7 +134,7 @@ int getUserName(char* name)
  * @param  stream FILE* - in our case stdin
  * @return        if all went well , an Array of arguements from the input line.
  */
- char** ReadTokens(FILE* stream)
+ char** ReadTokens(FILE* stream, int* writeToFile)
  {
  	char** returnArr;
 	char input[LEN]; // the var to hold the line
@@ -154,16 +170,17 @@ int getUserName(char* name)
 	while (tok != NULL)
 	{
 		returnArr[i] = (char *)malloc(strlen(tok)*sizeof(char));
-		//returnArr[i] = tok;
 		strcpy(returnArr[i], tok);
 		if(wordCnt == 1)
 			checkIfQuit(tok);
+		if(i == wordCnt-2) // one before the last argument. to see if to put output into file.
+			if(strcmp(">", returnArr[i]) == 0)
+				*writeToFile = true;
 		tok = strtok(NULL, " \n");
 		i++;
 	}
 	
 	returnArr[wordCnt] = NULL; // the last index will be NULL - so we know where the end is.
-
 	return returnArr;
 }
 
@@ -175,7 +192,7 @@ int getUserName(char* name)
  */
  void checkIfQuit(char* word)
  {
- 	if(strcmp(word, "quit") == 0)
+ 	if(strcmp(word, "exit") == 0)
  		exit(0);
  }
 
@@ -211,4 +228,12 @@ int getUserName(char* name)
 	free(tokens[i]); // free the last index
 	tokens = NULL; // free the array
 	free(tokens);
+}
+
+int getFileNameIndex(char** args)
+{
+	int i = 0;
+	while(args[i] != NULL)
+		i++;
+	return i-1;
 }
\ No newline at end of file