Most of assignment 3 is done now.

TODO: implement the other switch cases in gup_handler().

os/ass3/Makefile

@@ -19,18 +19,18 @@ ifdef PROFILE
 CFLAGS += -pg
 endif
 
-fishbones: fishbones.o
+fishbones: fishbones.o logger.o
 	$(CC) $(CFLAGS) $(LFLAGS) -o $@ $^
 
 clean:
-	rm -f fishbones.o fishbones $(PROG).tar.gz
+	rm -f *.o child.log* fishbones $(PROG).tar.gz
 	rm -Rf logs/
 	rm -Rf $(PROG)/
 
 tarball:
 	$(MAKE) clean
 	$(MKDIR) $(PROG)
-	$(CP) * report/report.pdf $(PROG) 2> /dev/null || true
+	$(CP) * screenrc report/report.pdf $(PROG) 2> /dev/null || true
 	$(PACK) $(PROG).tar.gz $(PROG)/*
 	$(RM) $(PROG)
 
@@ -38,3 +38,4 @@ tarball:
 	$(CC) -c $(CFLAGS) -o $@ $<
 
 fishbones.o: fishbones.c
+logger.o: logger.c

os/ass3/example.in

-f a b f c d P e g P x x q
+fabfcdPegPxxq

os/ass3/fishbones.c

@@ -6,28 +6,96 @@
 #include <errno.h>
 #include <string.h>
 
-static void gup(FILE * log1, FILE * log2, int pipefd[2], int cpid)
+#include "logger.h"
+
+#define STRING_LENGTH (512)
+
+static void
+gup( log_handler * logs, int pipefd[2], int cpid);
+
+static void
+gup_handler( char c, int kids, int pipefd[2], log_handler * logs )
+{
+	char buf[STRING_LENGTH+1], str[256];
+	
+	pid_t cpid;
+
+	switch( c )
+	{
+		case 'q':
+			(void) sprintf(str, "Child %d normal exit\n", kids);
+			write_to_all_logs(logs, str);
+			close_all_logs(logs);
+			exit(EXIT_FAILURE);
+		break;
+
+		case 'f':
+			kids++;
+
+			// When you fork, be sure to print the process id of the child
+			// (if the fork succeeds) and an error message otherwise
+			
+			cpid = fork();
+			
+			if( cpid == -1 )
+			{
+				perror("fork");
+				exit(EXIT_FAILURE);
+			}
+
+			if( cpid == 0 )
+			{
+				// Child reads from pipe
+				gup(logs, pipefd, kids);
+
+				close_all_logs(logs);
+				_exit(EXIT_SUCCESS);
+			}
+			else
+			{
+				// Parent writes buffer to child 
+				if( fgets(buf, STRING_LENGTH, stdin) )
+					if( !write(pipefd[1], buf, strlen(buf)) )
+						perror("pipe write");
+
+				// Close unused read end
+				close(pipefd[0]);
+				close(pipefd[1]);
+				
+				wait(NULL);
+
+				close_all_logs(logs);
+				exit(EXIT_SUCCESS);
+			}
+	}
+}
+
+static void
+gup(log_handler * logs, int pipefd[2], int cpid)
 {
-    FILE * log3;
-    char c;
 
     // Put any required declarations and initialisations here
+	if( !logs || !pipefd )
+		return;
 
 	// Close unused write end
     close(pipefd[1]);
 
+    // just for sure - open one more log file ...
+    // log3 is line buffered - a line of output is written 
+    // immediately on encountering an end-of-line
+	setvbuf(open_log("child.log3", "wt+", logs), NULL, _IOLBF, BUFSIZ);
+
     // Report your existence
-    fprintf(log1, "This is child number %d\n", cpid);
-    fprintf(log2, "This is child number %d\n", cpid);
+	char * str = malloc(256 * sizeof(char *));
 	
-    // just for sure - open one more log file ...
+	strcpy(str, "This is child number %d\n");
+	(void) sprintf(str, str, cpid);
+	write_to_all_logs(logs, str); 
 	
-    log3 = fopen("child.log3", "wt+");
-    setvbuf(log3, NULL, _IOLBF, BUFSIZ);
+	char * str_read = "Child %d read character %c '%x'\n";
 
-    // log3 is line buffered - a line of output is written 
-    // immediately on encountering an end-of-line
-    fprintf(log3, "This is child number %d\n", cpid);
+    char c;
 
 	while( read(pipefd[0], &c, 1) > 0 )
     {
@@ -37,55 +105,19 @@ static void gup(FILE * log1, FILE * log2, int pipefd[2], int cpid)
 		// an end-of-file (read returns zero), end your program
 		// with an exit(1)
 		
-		fprintf(log1, "Child %d read character '%x'\n", cpid, c);
-		fprintf(log2, "Child %d read character '%x'\n", cpid, c);
-		fprintf(log3, "Child %d read character '%x'\n", cpid, c);
-
-		if( write(STDOUT_FILENO, &c, 1) == -1 )
-		{
-			fprintf(stderr, "write error: %s\n", strerror(errno)); 
-			exit(EXIT_FAILURE);
-		}
+		(void) sprintf(str, str_read, cpid, c, c);
+		write_to_all_logs(logs, str); 
 		
 		// process the character here
+		gup_handler(c, cpid, pipefd, logs);
     }
-   
-   	char nl = '\n';
-
-	if( write(STDOUT_FILENO, &nl, 1) == -1 )
-	{
-		fprintf(stderr, "write error: %s\n", strerror(errno)); 
-		exit(EXIT_FAILURE);
-	}
-
-	fprintf(log1, "Child %d normal exit \n", cpid);
-    fprintf(log2, "Child %d normal exit \n", cpid);
-    fprintf(log3, "Child %d normal exit \n", cpid);
-    
-	fclose(log1);
-    fclose(log2);
-    fclose(log3);
 }
 
-#define STRING_LENGTH (512)
-
-int main(int argc, char ** argv)
+static void
+process_handler( log_handler * logs )
 {
-    FILE * log1;
-    FILE * log2;
-    
-	char buf;
-    
-	int kids = 0;
     int pipefd[2];
     
-    log1 = fopen("child.log1", "wt+");
-    log2 = fopen("child.log2", "wt+");
-    setvbuf(log2, NULL, _IONBF, BUFSIZ);
-
-    // So log1 is buffered; log2 is not buffered, which means that output
-    // to log2 is written immediately. 
-
 	// create the pipe somewhere around here (why?).
     // remember to test for success!! 
 	if( pipe(pipefd) == -1 )
@@ -94,74 +126,44 @@ int main(int argc, char ** argv)
 		exit(EXIT_FAILURE);
 	}
 	
-	pid_t cpid;
-
-    while( (buf = getchar()) )
-    {
-		// You can now choose to use only the first character in the
-		// string (inString[0]), or the entire string (how would you test
-		// that?).
-		// Anyway, read a character, echo it to both log files 
-		// and write it into the pipe (unless you have to call fork)
-	
-		printf("%c", buf);
-		fflush(stdout);
+	char * str = malloc(256 * sizeof(char)),
+	     * str_read = "Parent %d read character %c '%x'\n";
 
-		switch( buf )
-		{
-			case 'q':
-				goto close_logs;
-			break;
-
-			case 'f':
+	strcpy(str, "This is the parent process %d\n");
+	(void) sprintf(str, str, 0);
+	write_to_all_logs(logs, str); 
 
-				kids++;
-
-				// When you fork, be sure to print the process id of the child
-				// (if the fork succeeds) and an error message otherwise
+	char c; 
     
-				cpid = fork();
+	int kids = 0;
 
-				if( cpid == -1 )
+    while( (c = getchar()) )
     {
-					perror("fork");
-					exit(EXIT_FAILURE);
-				}
+		// Anyway, read a character, echo it to both log files 
+		// and write it into the pipe (unless you have to call fork)
 
-				if( cpid == 0 )
-				{
-					// Child reads from pipe u1
-					gup(log1, log2, pipefd, kids);
+		(void) sprintf(str, str_read, 0, c, c);
+		write_to_all_logs(logs, str); 
 		
-					_exit(EXIT_SUCCESS);
+		gup_handler(c, kids, pipefd, logs);
     }
-				else
-				{
-					/* Parent writes to pipe */
-					//write(pipefd[1], buf, len);
-
-					// Close unused read end
-					close(pipefd[0]);
-					close(pipefd[1]);          /* Reader will see EOF */
+}
 
-					wait(NULL);                /* Wait for child */
-					exit(EXIT_SUCCESS);
-				}
-			default:
-				printf("buf => default => exit\n");
-				//exit(EXIT_SUCCESS);
-				fflush(stdout);
-				goto close_logs;
-		}
-    }
+int
+main( void )
+{
+    // log1 is buffered; log2 is not buffered
+	// which means that output to log2 is 
+	// written immediately. 
 	
-    // normal end of program
+	log_handler * logs = create_logger();
+	(void) open_log("child.log1", "wt+", logs);
+    setvbuf(open_log("child.log2", "wt+", logs), NULL, _IONBF, BUFSIZ);
 	
-close_logs:
+	process_handler(logs);
 
     // close all open log files
-	fclose(log1);
-	fclose(log2);
+	close_all_logs(logs);
 
-    return 0;
+    return EXIT_SUCCESS;
 }

os/ass3/logger.c

+/*
+ * File logger abstraction layer
+ *
+ * Created by: Sander van Veen <sandervv@gmail.com>,
+ *             Taddeüs Kroes <taddeuskroes@gmail.com>
+ */
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "logger.h"
+
+/*
+ * Initialize a new log handler
+ */
+log_handler *
+create_logger( )
+{
+	log_handler * log = malloc(sizeof(log_handler));
+
+	log->list = NULL;
+	log->count = 0;
+
+	return log;
+}
+
+/*
+ * Open or create a log file, like fopen(), and add the opened file
+ * pointer to the log handler.
+ */
+FILE *
+open_log( const char * filename, const char * access, log_handler * log )
+{
+	if( !log )
+		return NULL;
+
+	log->list = realloc(log->list, (log->count+1) * sizeof(FILE *));
+	log->list[log->count] = fopen(filename, access);
+
+	return log->list[log->count++];
+}
+
+/*
+ * Close a specific log file, which was opened by open_log().
+ *
+ * See also:
+ *   <open_log>, <close_all_logs>
+ */
+void
+close_log( FILE * file, log_handler * log )
+{
+	if( !file || !log )
+		return;
+
+	fclose(file);
+	
+	FILE ** cur = log->list;
+
+	// Find open file in logger list
+	while( *cur != file && cur++ );
+	
+	if( cur )
+	{
+		FILE ** end = log->list + log->count;
+
+		free(*cur);
+		*cur = NULL;
+
+		for( ; cur < end; cur++ )
+			*cur = *(cur+1);
+
+		log->count--;
+	}
+}
+
+/*
+ * Close all log files, which was opened by open_log().
+ *
+ * See also:
+ *   <open_log>, <close_log>
+ */
+void
+close_all_logs( log_handler * log )
+{
+	if( !log )
+		return;
+	
+	FILE ** cur = log->list;
+	FILE ** end = cur + log->count;
+
+	for( ; cur < end; cur++ )
+	{
+		fclose(*cur);
+	}
+
+	free(log->list);
+	free(log);
+}
+
+void write_to_all_logs( log_handler * log, const char * str )
+{
+	if( !log || !str ) 
+		return;
+
+	FILE ** cur = log->list;
+	FILE ** end = cur + log->count;
+
+	for( ; cur < end; cur++ )
+		fwrite(str, strlen(str), sizeof(char), *cur);
+}

os/ass3/logger.h

+
+#include <stdio.h>
+#include <sys/types.h>
+
+typedef struct log_handler
+{
+	/*
+	 * List of opened log files.
+	 */
+	FILE ** list;
+	/*
+	 * Total count of currently opened logs.
+	 */
+	int count;
+} log_handler;
+
+log_handler * create_logger( );
+FILE * open_log( const char * filename, const char * access, log_handler * log );
+void close_log( FILE * file, log_handler * log );
+void close_all_logs( log_handler * log );
+void write_to_all_logs( log_handler * log, const char * str );

os/ass3/screenrc

+bindkey ^c at "#" kill
+
+split -v
+screen watch cat child.log1
+focus
+split -v
+screen watch cat child.log2
+focus
+screen watch cat child.log3

os/ass3/view-logs.bash

+#!/bin/bash
+
+if [ "`which screen`" = '' ]; then
+	echo "GNU screen is missing. I'll now trying to install screen using apt-get.";
+	echo "The installation of GNU screen requires sudo-rights: ";
+	sudo apt-get install screen ;
+fi;
+
+screen -c screenrc