Producer consumer Problem in Kernel Space
Testing the Modifications
Apply the Patches to the stock kernel
Run the makefile given
run the command
./p and ./c in different terminals
Kill the both the processes and run
sudo dmesg -c
p is the producer which Enqueues in the queue and c is the consumer which dequeues from the queue.
Modifying the Kernel
syscall_64.tbl
Added the name of syscalls writer and reader and their syscall numbers
sys.c
Added semaphore headerfiles
Added the definition of the syscalls writer and reader.
Added Global Variables front, rear, semaphores, circQueue pointer, size of queue.
writer
This is used by the producer to enqueue elements into the queue.
reader
This is used by the consumer to dequeue elements from the queue
Use of Semaphores
Semaphore s1 = N : Number of empty slots in buffer
Semaphore s2 = 0 : Number of slots filled
Semaphore s3 : Mutex, used to provide mutual exclusion
Random Values in Producer
refer to getRand() function defined in Producer.
Read an 8 byte number into a character buffer from /dev/urandom
Convert that character buffer to an unsigned long long using bitwise manipulation
References
https://shivammitra.com/c/producer-consumer-problem-in-c/
https://www.programiz.com/dsa/circular-queue
https://stackoverflow.com/questions/30720546/converting-8-byte-char-array-into-long