main.c

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#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
 
#include <event2/event.h>
 
#include <amxc/amxc.h>
#include <amxp/amxp_signal.h>
#include <amxp/amxp_slot.h>
#include <amxp/amxp_syssig.h>
#include <amxp/amxp_subproc.h>
 
#define UNUSED __attribute__((unused))
 
static struct event_base* base = NULL;
 
static void signal_cb(UNUSED evutil_socket_t fd,
                      UNUSED short event,
                      UNUSED void* arg) {
    amxp_syssig_read();
}
 
static void child_stdout_cb(evutil_socket_t fd,
                            UNUSED short event,
                            UNUSED void* arg) {
    char buffer[1024] = {0};
    ssize_t size = read(fd, buffer, 1023);
 
    if(size > 0) {
        buffer[size + 1] = 0;
        printf("%s", buffer);
    }
}
 
static void slot_proc_stop(const char* const sig_name,
                           const amxc_var_t* const data,
                           UNUSED void* priv) {
    int pid = amxc_var_dyncast(int64_t, amxc_var_get_key(data, "PID", AMXC_VAR_FLAG_DEFAULT));
    printf("AMX Signal recieved : %s\n", sig_name);
    printf(" => process id = %d\n", pid);
    event_base_loopbreak(base);
}
 
int main(void) {
    int ret = 0;
    int sig_fd = -1;
    struct event* sig_event = NULL;
 
    int child_stdout_fd = -1;
    struct event* child_stdout_event = NULL;
    amxp_subproc_t* proc = NULL;
    char* cmd[] = { "ls", "-la", NULL };
 
    // allocate new proc object and connect to stop signal
    if(amxp_subproc_new(&proc) != 0) {
        exit(1);
    }
    amxp_slot_connect(amxp_subproc_get_sigmngr(proc), "stop", NULL, slot_proc_stop, NULL);
 
    // allocate new eventloop
    base = event_base_new();
    if(base == NULL) {
        exit(2);
    }
 
    // add file descriptors to event loop
    // add signal fd to eventloop
    sig_fd = amxp_syssig_get_fd(); // needed for SIGCHLD
    sig_event = event_new(base, sig_fd, EV_READ | EV_PERSIST, signal_cb, NULL);
    event_add(sig_event, NULL);
    // add child proc stdout to eventloop
    child_stdout_fd = amxp_subproc_open_fd(proc, STDOUT_FILENO);
    child_stdout_event = event_new(base, child_stdout_fd, EV_READ | EV_PERSIST, child_stdout_cb, NULL);
    event_add(child_stdout_event, NULL);
 
    // launch the process
    amxp_subproc_vstart(proc, cmd);
    printf("Child process started pid = %d\n", amxp_subproc_get_pid(proc));
 
    // start the eventloop
    event_base_dispatch(base);
 
    // process is stopped, delete proc object
    amxp_subproc_delete(&proc);
 
    // cleanup event loop
    event_del(sig_event);
    event_free(sig_event);
    event_del(child_stdout_event);
    event_free(child_stdout_event);
    event_base_free(base);
 
    return ret;
}