Fall21_cs300_project

Distributed Reports Generator Print formatted reports using a record file

Git Repository for project files

All commands and code have been tested on cs-operatingsystems01.ua.edu

• Set up JAVA_HOME environment variable

export JAVA_HOME=/usr/java/latest

• Compile java files in both packages

javac edu/cs300/*java

• Create header file for System V C message functions

javac -h . edu/cs300/MessageJNI.java

• Compile C native functions into a library for use with MessageJNI

gcc -c -fPIC -I${JAVA_HOME}/include -I${JAVA_HOME}/include/linux system5_msg.c -o edu_cs300_MessageJNI.o

gcc -shared -o libsystem5msg.so edu_cs300_MessageJNI.o -lc

• Compile test send and receive functions

gcc -std=c99 -D_GNU_SOURCE msgsnd_report_record.c -o msgsnd

gcc -std=c99 -D_GNU_SOURCE msgrcv_report_request.c -o msgrcv

Commands to run sample programs

• Send a test message with a hard coded string to queue number 1 ./msgsnd

• Java program reads queue contents using native C function and creates and sends a response message via the System V msg queue

java -cp . -Djava.library.path=. edu.cs300.MessageJNI

• Retrieves a report request message from System V queue and prints it ./msgrcv

Commands to check/delete message queues

• Determine the status of your message queue via ipcs -a ------ Message Queues -------- key msqid owner perms used-bytes messages
  0x0d03bc96 0 crimson2 666 0 0
  0xffffffff 98305 crimson3 666 0 0
  0x0303fabb 65538 crimson1 666 0 0
  0x0c030904 131075 anderson 666 8 1
  ------ Shared Memory Segments -------- key shmid owner perms bytes nattch status
  ------ Semaphore Arrays -------- key semid owner perms nsems

0x0C030904 is the queue created by ./msgsnd. It has 1 message of 8 bytes.

• Removes the queue along with any messages ipcrm -Q 0x0c030904 ------ Message Queues -------- key msqid owner perms used-bytes messages
  0x0d03bc96 0 crimson2 666 0 0
  0xffffffff 98305 crimson3 666 0 0
  0x0303fabb 65538 crimson1 666 0 0

------ Shared Memory Segments -------- key shmid owner perms bytes nattch status
------ Semaphore Arrays -------- key semid owner perms nsems

Note: If your queue key is 0x0xffffffff, you must follow the directions to create the queue file in your home directory and update queue_ids.h

f21_os_project