Add initial shared memory object functions

fb_arc_set/shared/shm.c

@@ -0,0 +1,52 @@
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <string.h>
+
+#define TERMINATE_SHM "/terminate"
+#define TERMINATE_SHM_SIZE 8
+
+void* open_shm(char *shm_name, size_t shm_size) {
+    int shmfd = shm_open(shm_name, O_RDWR | O_CREAT, 0600);
+    if(shmfd == -1) {
+        fprintf(stderr, "ERROR: Failed creating shared memory object");
+        exit(EXIT_FAILURE);
+    }
+
+    if(ftruncate(shmfd, shm_size) < 0) {
+        fprintf(stderr, "ERROR: Failed truncating shared memory object");
+        exit(EXIT_FAILURE);
+    }
+
+    void* shm;
+    shm = mmap(NULL, shm_size, PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);
+
+    if(shm == MAP_FAILED) {
+        fprintf(stderr, "ERROR: Failed mapping shared memory object");
+        exit(EXIT_FAILURE);
+    }
+
+    return shm;
+}
+
+void write_to_shm(void* shm, char *message, size_t message_size) {
+    memcpy(shm, message, message_size);
+}
+
+void close_shm(void* shm, size_t shm_size) {
+    if (munmap(shm, shm_size) == -1) {
+        fprintf(stderr, "ERROR: Failed unmapping shared memory object");
+        exit(EXIT_FAILURE);
+    }
+}
+
+void destroy_shm(char *shm_name) {
+    if (shm_unlink(shm_name) == -1) {
+        fprintf(stderr, "ERROR: Failed unlinking shared memory object");
+        exit(EXIT_FAILURE);
+    }
+}