Big commit: Setup outline for piping, piping has errors still, cleaned code

include/Common.h

@@ -1,11 +1,14 @@
 #ifndef COMMON_H
 #define COMMON_H
 
+const char* GetHomeDir(void);
+
 typedef struct CommandStruct {
     char* argv[100]; // Max 100 commands
     int argc;
 } CommandStruct;
 
+void CopyCommandStruct(CommandStruct* oldCommand, CommandStruct* newCommand, int start, int end);
 void ResetCommandStruct(CommandStruct* command);
 
 #endif

include/Integrated.h

@@ -3,16 +3,16 @@
 
 #include "Common.h"
 
-const char* GetHomeDir(void);
 void CheckRedirection(CommandStruct* command);
+int CheckSymbol(CommandStruct* command, char symbol, int start);
 int IntegratedCheck(CommandStruct* command);
 void GetInput(char* inputString);
 void append(char *input, char *file);
 void input(char *command);
-void ExecPipe();
+int ExecPipe(CommandStruct* commandParent, CommandStruct* commandChild, int* pipefd);
 void output(char *command);
 void SplitInput(char* inputString, CommandStruct* command);
-void ParseInput(char* inputString, CommandStruct* command, char *symbol);
-void ReadPishrc(CommandStruct* command, char* inputString);
+void ParseInput(char* inputString, CommandStruct* command, char* symbol);
+void RunChild(CommandStruct* commandChild, int* pipefd);
 void ioRedirection(CommandStruct* command);
 #endif

include/Pish.h

@@ -4,5 +4,6 @@
 #include "Common.h"
 
 void Pish(void);
+void ReadPishrc(CommandStruct* commandParent, CommandStruct *commandChild, char* inputString);
 
 #endif

src/Common.c

@@ -1,7 +1,28 @@
 #include "Common.h"
+#include <pwd.h>
 #include <string.h>
 #include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
 
+
+// Gets home directory location of user
+const char* GetHomeDir(void)
+{
+	char *homeDir = (getpwuid(getuid()))->pw_dir;
+	return homeDir;
+}
+
+// Copies a range of an old command object to new command object
+void CopyCommandStruct(CommandStruct* oldCommand, CommandStruct* newCommand, int start, int end)
+{
+    newCommand->argc = end - start;
+    for (int i = 0; i < newCommand->argc; i++)
+        newCommand->argv[i] = oldCommand->argv[i + start];
+    return;
+}
+
+// Resets entire command object
 void ResetCommandStruct(CommandStruct* command)
 {
     for (int i = 0; i < command->argc; i++)

src/Integrated.c

@@ -1,22 +1,13 @@
 #include <assert.h>
 #include <fcntl.h>
-#include <pwd.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/stat.h>
-#include <sys/types.h>
 #include <sys/wait.h>
 #include "Integrated.h"
 
-// Gets home directory location of user
-const char *GetHomeDir(void)
-{
-	char *homeDir = (getpwuid(getuid()))->pw_dir;
-	return homeDir;
-}
-
 // Checks for commands that are built into Pish
 int IntegratedCheck(CommandStruct *command)
 {
@@ -66,35 +57,23 @@ void ParseInput(char *inputString, CommandStruct *command, char *symbol)
 	}
 }
 
-// Reads ~/.pishrc and runs each command in the file
-void ReadPishrc(CommandStruct *command, char *inputString)
+// Run child process
+void RunChild(CommandStruct* commandChild, int* pipefd)
 {
-	char buffer[1];
-	int forkID;
-	int *argc = &(command->argc);
-	char* pishLocation = GetHomeDir();
-	strcat(pishLocation, "/.pishrc");
-	int fd = open(pishLocation, O_RDONLY | O_CREAT);
-	assert(fd > -1);
-	while (read(fd, buffer, 1) > 0)
-	{
-		if (buffer[0] == '\n')
-		{
-		  ParseInput(inputString, command, " ");
-			forkID = fork();
-			if (forkID == 0)
-				execvp(command->argv[0], command->argv);
-			else
-				wait(&forkID);
-			strcpy(inputString, "");
-			ResetCommandStruct(command);
-			continue;
-		}
-		strcat(inputString, buffer);
-	}
-	assert(close(fd) >= 0);
+	close(pipefd[0]);
+	dup2(pipefd[1], 1);
+	close(pipefd[1]);
+	// This is the child process
+	// Setup the child's process environment here
+	// E.g., where is standard I/O, how to handle signals?
+	// execve() is recommended, execvpe() may be better
+	execvp(commandChild->argv[0], commandChild->argv);
+	// exec does not return if it succeeds
+	printf("ERROR: Could not execute %s\n", commandChild->argv[0]);
+	exit(1);
 }
 
+
 // Splits a string separated by spaces into an array of strings
 void SplitInput(char *inputString, CommandStruct *command)
 {
@@ -114,6 +93,18 @@ void SplitInput(char *inputString, CommandStruct *command)
 	(*argc)--;
 }
 
+// Splits a command array into left and right
+// void SplitPipe(CommandStruct* commandLeft, CommandStruct* commandRight);
+
+int CheckSymbol(CommandStruct* command, char symbol, int start)
+{
+	for (int i = start; i < command->argc; i++)
+		if (command->argv[i][0] == symbol)
+			return i;
+	return -1;
+}
+
+
 // Checking redirection
 // TODO: Work on one symbol at a time
 // 		 inputString may not be useful here, only *command
@@ -188,17 +179,45 @@ void input(char *command)
 	dup2(newfd,0);
 }
 
-void ExecPipe()
+int ExecPipe(CommandStruct* commandParent, CommandStruct* commandChild, int* pipefd)
 {
-  //	;
+	char buffer[1024];
+	int forkPID;
+	int pipeLocation = 0;
+	int startArgc = 0;
+	int endArgc = commandParent->argc;
+	while (pipeLocation >= 0)
+	{
+		if (pipeLocation > 0)
+			startArgc = pipeLocation + 1;
+		pipeLocation = CheckSymbol(commandParent, '|', startArgc);
+		if (pipeLocation >= 0)
+			endArgc = pipeLocation - 1;
+		if (pipeLocation < 0)
+			endArgc = commandParent->argc;
+		CopyCommandStruct(commandParent, commandChild, startArgc, endArgc);
+		pipe(pipefd);
+		forkPID = fork();
+		if (forkPID == 0)
+			return forkPID;
+		if (forkPID != 0)
+			wait(&forkPID);
+		close(pipefd[1]);
+		while (read(pipefd[0], buffer, sizeof(buffer)) != 0)
+			printf("%s", buffer);
+        ResetCommandStruct(commandChild); // Clean command
+	}
+	return 1;
 }
 
-void append(char *input, char *file)
+void append(char* input, char* fileName)
 {
-	FILE *fp;
-	fp = fopen(file, "a+");
-	fputs(input, fp);
-	fclose(fp);
+	char buffer[4];
+	int fd = open(fileName, O_APPEND | O_CREAT);
+
+	// fp = fopen(file, "a+");
+	// fputs(input, fp);
+	// fclose(fp);
 }
 
 // check command standard input

src/Pish.c

@@ -1,46 +1,80 @@
 #include <assert.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <sys/wait.h>
 #include <string.h>
+#include "Common.h"
 #include "Integrated.h"
 #include "Pish.h"
 
+// Example command: ps aux | grep 'Z'
+// Pipe left: [ps aux]
+//      argv: [ps, aux]
+// Pipe right: [grep 'Z']
+//      argv: [grep, 'Z']
+
+// check for first pipe, split into before and after pipe,
+//      connect left and right execs
+
 // Main function for Pish program
 void Pish(void)
 {
-    CommandStruct commandObject = {"", 0};
-    CommandStruct* command = &commandObject;
+    CommandStruct commandParentObject = {"", 0};
+    CommandStruct commandChildObject = {"", 0};
+    CommandStruct* commandParent = &commandParentObject;
+    CommandStruct* commandChild = &commandChildObject;
     char inputString[1000]; // Max 1000 characters
     int forkPID;
-    ReadPishrc(command, inputString);
+    ReadPishrc(commandParent, commandChild, inputString);
     while (1)
     {
-        ResetCommandStruct(command); // Clean command
+        int pipefd[2];
+        ResetCommandStruct(commandParent); // Clean command
         strcpy(inputString, "");    // Clean inputString
         GetInput(inputString);
-        SplitInput(inputString, command);
-        if (IntegratedCheck(command))
+        SplitInput(inputString, commandParent);
+        if (IntegratedCheck(commandParent))
             continue;
+        forkPID = ExecPipe(commandParent, commandChild, pipefd);
         // CheckRedirection(inputString, command);
-        CheckRedirection(command);
+        // CheckRedirection(command);
         // ioRedirection(command);
-        forkPID = fork();
         // Child
         if (forkPID == 0)
-        {
-            // This is the child process
-            // Setup the child's process environment here
-            // E.g., where is standard I/O, how to handle signals?
-            // execve() is recommended, execvpe() may be better
-            execvp(command->argv[0], command->argv);
-            // exec does not return if it succeeds
-            printf("ERROR: Could not execute %s\n", inputString);
-            exit(1);
-        }
+            RunChild(commandChild, pipefd);
         // Parent
         // This is the parent process; Wait for the child to finish
-        wait(&forkPID);
     }
 }
+
+// Reads ~/.pishrc and runs each command in the file
+void ReadPishrc(CommandStruct *commandParent, CommandStruct *commandChild, char *inputString)
+{
+	char buffer[1];
+	int pipefd[2];
+	int forkPID;
+	int *argc = &(commandParent->argc);
+	char* pishLocation = GetHomeDir();
+	strcat(pishLocation, "/.pishrc");
+	int fd = open(pishLocation, O_RDONLY | O_CREAT);
+	assert(fd > -1);
+	while (read(fd, buffer, 1) > 0)
+	{
+		if (buffer[0] == '\n')
+		{
+		  	SplitInput(inputString, commandParent);
+			if (IntegratedCheck(commandParent))
+				continue;
+			forkPID = ExecPipe(commandParent, commandChild, pipefd);
+			if (forkPID == 0)
+				RunChild(commandChild, pipefd);
+			strcpy(inputString, "");
+			ResetCommandStruct(commandParent);
+			continue;
+		}
+		strcat(inputString, buffer);
+	}
+	assert(close(fd) >= 0);
+}