X-Git-Url: https://git.dlugolecki.net.pl/?a=blobdiff_plain;f=src%2Fprocess3.c;h=b1b997212be53430306b69232a3c88bd7d2f3b14;hb=f0a7f7a71896b25cc524598e5472c821f987a71c;hp=4568d97d1e3c4ee1280221fbf7f23ef1cd7f57e2;hpb=51faabd1c82aa37c43f6521ae17c47ce62272754;p=wsti_so.git diff --git a/src/process3.c b/src/process3.c index 4568d97..b1b9972 100644 --- a/src/process3.c +++ b/src/process3.c @@ -1,30 +1,115 @@ #include +/* exit.. */ +#include + /* open/read/write/close */ #include +/* Signals handling.. */ +#include + +#include + +/** Named pipe used to communicate with process2 */ +char * read_pipe = "/tmp/process2pipe"; + +/** Descriptor of input pipe */ +int read_descriptor; + + +/** + * Shared memory variables + */ +/** + * Memory key for processes. Must be same between all processes to properly + * communicate. + */ +key_t shmkey = 18912; +/** + * Id of the shared memory + */ +int shmid; + +/** + * Message shared by processes. Contains array of process IDs + */ +struct message { + pid_t pids[3]; +}; + +struct message * processes = NULL; + + +/** + * Handler for signals. + */ +void sig_handler(int signo) +{ + fprintf(stderr, "[%s] Received %s!\n", "process3", strsignal(signo)); + if (signo == SIGUSR1) { + } + else if (signo == SIGTERM) { + int i = 0; + fprintf(stderr, "[%s] > Releasing resources\n", "process3"); + close(read_descriptor); + for (; i < 3; i++) { + fprintf(stderr, "[%s] Process %d, PID: %d\n", "process3", i, processes->pids[i]); + } + exit(0); + } + else if (signo == SIGTSTP) { + fprintf(stderr, "[%s] > Closing pipe\n", "process3"); + close(read_descriptor); + raise (SIGSTOP); + } + else if (signo == SIGCONT) { + fprintf(stderr, "[%s] > Opening pipe\n", "process3"); + read_descriptor = open(read_pipe, O_RDONLY); + } +} + /** * Program grabs data (calculated number of characters) from process2 and prints * grabbed data to the standard output. */ int main(void) { - /** Named pipe used to communicate with process2 */ - char * read_pipe = "/tmp/process2pipe"; - - /** Descriptor of input pipe */ - int read_descriptor; - /** Buffer used for storing data from input pipe */ int buffer = 0; /** Stores number of bytes read from input pipe in current iteration */ ssize_t count = 0; + fprintf(stderr, "[%s] Init!\n", "process3"); + + /** + * Register signals handled by process + */ + if (signal(SIGUSR1, sig_handler) == SIG_ERR) { + fprintf(stderr, "can't catch SIGUSR1\n"); + } + if (signal(SIGTERM, sig_handler) == SIG_ERR) { + fprintf(stderr, "can't catch SIGTERM\n"); + } + if (signal(SIGTSTP, sig_handler) == SIG_ERR) { + fprintf(stderr, "can't catch SIGTSTP\n"); + } + if (signal(SIGCONT, sig_handler) == SIG_ERR) { + fprintf(stderr, "can't catch SIGCONT\n"); + } + + /* + * Register memory to share with other processes, and pass current + * process id to the array. + */ + shmid = shmget(shmkey, sizeof(struct message), IPC_CREAT | 0666); + + processes = (struct message *)shmat(shmid, NULL, 0); + processes->pids[2] = getpid(); + /* Reading from process2 */ read_descriptor = open(read_pipe, O_RDONLY); - fprintf(stderr, "[%s] Init!\n", "process3"); - while(1) { /* Read data from input pipe */ count = read(read_descriptor, &buffer, sizeof(int)); @@ -39,6 +124,7 @@ int main(void) { } } + /* Release resources in normal program flow exit. */ close(read_descriptor); return 0;