Add documentation, signal handling, initial supervisor and semaphor functions

fb_arc_set/generator.c

@@ -38,6 +38,8 @@ int main(int argc, char *argv[]) {
         exit(EXIT_FAILURE);
     }
 
+    process_signal();
+
     /// Create a regex to check the input against
     regex_t regex;
     if(regcomp(&regex, "^[0-9]*-[0-9]*$", REG_EXTENDED|REG_NOSUB)) {
@@ -66,5 +68,10 @@ int main(int argc, char *argv[]) {
         }
     }
 
+    int buffer_shmfd = create_shmfd(BUFF_SHM_NAME);
+    circ_buffer = (buffer_t *)open_shm(buffer_shmfd, sizeof(buffer_t));
+
+    int wr_pos = 0;
+
     exit(EXIT_SUCCESS);
 }

fb_arc_set/shared/sem.c

@@ -7,16 +7,25 @@
 #include <unistd.h>
 #endif
 
+#include <errno.h>
 #include <semaphore.h> ///< For semaphores
 
 #define FREE_SEM_NAME "/11777707_free"
-#define USED_SEM_NAME "/11777707_used"
+#define USE_SEM_NAME "/11777707_used"
 #define MUTEX_NAME "/11777707_mutex"
 
 static sem_t *free_sem;
-static sem_t *used_sem;
+static sem_t *use_sem;
 static sem_t *mutex;
 
+/**
+ * @brief Function that executes sem_open(3) and does error handling.
+ * @details The function executes sem_open(3), giving it a semaphor name and size as parameters,
+ *          and handles the errors if any. The same behaviour as sem_open(3) should be expected.
+ *          Returns a new semaphore
+ * @param sem_name, sem_size
+ * @return res
+ **/
 sem_t * open_sem(char *sem_name, size_t sem_size) {
     sem_t *res = sem_open(sem_name, O_CREAT | O_EXCL, 0600, sem_size);
     if(res == SEM_FAILED) {
@@ -26,6 +35,60 @@ sem_t * open_sem(char *sem_name, size_t sem_size) {
     return res;
 }
 
+/**
+ * @brief Function that executes sem_getvalue(3) and does error handling.
+ * @details The function executes sem_getvalue(3), giving it a semaphor and size as parameters,
+ *          and handles the errors if any. The same behaviour as sem_getvalue(3) should be expected.
+ *          Writes the value of a semaphore to a chosen pointer
+ * @param sem, rem
+ * @return none
+ **/
+void getval_sem(sem_t *sem, int *res) {
+    if(sem_getvalue(sem, res) == -1) {
+        fprintf(stderr, "ERROR: Failed getting semaphore value\n");
+        exit(EXIT_FAILURE);
+    }
+}
+
+/**
+ * @brief Function that executes sem_wait(3) and does error handling.
+ * @details The function executes sem_wait(3), giving it a semaphor as a parameter,
+ *          and handles the errors if any. The same behaviour as sem_wait(3) should be expected.
+ *          If the process was terminated, the function exits
+ * @param sem
+ * @return none
+ **/
+void wait_sem(sem_t *sem) {
+    if(sem_wait(sem) == -1) {
+        if(errno == EINTR) {
+            return;
+        }
+        fprintf(stderr, "ERROR: Failed locking semaphore\n");
+        exit(EXIT_FAILURE);
+    }
+}
+
+/**
+ * @brief Function that executes sem_post(3) and does error handling.
+ * @details The function executes sem_post(3), giving it a semaphor as a parameter,
+ *          and handles the errors if any. The same behaviour as sem_post(3) should be expected.
+ * @param sem
+ * @return none
+ **/
+void post_sem(sem_t *sem) {
+    if(sem_post(sem) == -1) {
+        fprintf(stderr, "ERROR: Failed unlocking semaphore\n");
+        exit(EXIT_FAILURE);
+    }
+}
+
+/**
+ * @brief Function that executes sem_close(3) and does error handling.
+ * @details The function executes sem_close(3), giving it a semaphor as a parameter,
+ *          and handles the errors if any. The same behaviour as sem_close(3) should be expected.
+ * @param sem
+ * @return none
+ **/
 void close_sem(sem_t *sem) {
     if(sem_close(sem) < 0) {
         fprintf(stderr, "ERROR: Failed closing semaphore\n");
@@ -33,6 +96,13 @@ void close_sem(sem_t *sem) {
     }
 }
 
+/**
+ * @brief Function that executes sem_unlink(3) and does error handling.
+ * @details The function executes sem_unlink(3), giving it a semaphor name as a parameter,
+ *          and handles the errors if any. The same behaviour as sem_unlink(3) should be expected.
+ * @param sem_name
+ * @return none
+ **/
 void destroy_sem(char *sem_name) {
     if(sem_unlink(sem_name) < 0) {
         fprintf(stderr, "ERROR: Failed closing semaphore\n");

fb_arc_set/shared/shm.c

@@ -11,8 +11,16 @@
 #include <sys/mman.h>
 #include <sys/types.h>
 
-#define BUFFER_SHM_NAME "/11777707_buff"
+#define BUFF_SHM_NAME "/11777707_buff"
 
+/**
+ * @brief Function that executes shm_open(3) and does error handling.
+ * @details The function executes shm_open(3), giving it a name as a param,
+ *          and handles the errors if any. The same behaviour as shm_open(3) should be expected.
+ *          Returns a shared memory object file descriptor
+ * @param shm_name
+ * @return shmfd
+ **/
 int create_shmfd(char *shm_name) {
     int shmfd = shm_open(shm_name, O_RDWR | O_CREAT, 0600);
     if(shmfd == -1) {
@@ -22,6 +30,13 @@ int create_shmfd(char *shm_name) {
     return shmfd;
 }
 
+/**
+ * @brief Function that executes ftruncate(2) and does error handling.
+ * @details The function executes ftruncate(2), giving it a file descriptor and size as parameters,
+ *          and handles the errors if any. The same behaviour as ftruncate(2) should be expected.
+ * @param shmfd, shm_size
+ * @return none
+ **/
 void truncate_shm(int shmfd, size_t shm_size) {
     if(ftruncate(shmfd, shm_size) < 0) {
         fprintf(stderr, "ERROR: Failed truncating shared memory object\n");
@@ -29,6 +44,14 @@ void truncate_shm(int shmfd, size_t shm_size) {
     }
 }
 
+/**
+ * @brief Function that executes mmap(2) and does error handling.
+ * @details The function executes mmap(2), giving it a file descriptor and size as parameters,
+ *          and handles the errors if any. The same behaviour as mmap(2) should be expected.
+ *          Returns a mapped shared memory object
+ * @param shmfd, shm_size
+ * @return shm
+ **/
 void* open_shm(int shmfd, size_t shm_size) {
     void* shm;
     shm = mmap(NULL, shm_size, PROT_READ | PROT_WRITE, MAP_SHARED, shmfd, 0);
@@ -41,10 +64,24 @@ void* open_shm(int shmfd, size_t shm_size) {
     return shm;
 }
 
+/**
+ * @brief Function to write a value to shared memory object
+ * @details The functions copies the value of a string with a specified size to a shared memory object
+ * @param shm, message, message_size
+ * @return none
+ **/
 void write_to_shm(void* shm, char *message, size_t message_size) {
     memcpy(shm, message, message_size);
 }
 
+/**
+ * @brief Function that executes munmap(2) and does error handling.
+ * @details The function executes munmap(2), giving it a shared memory object and size as parameters,
+ *          and handles the errors if any. The same behaviour as munmap(2) should be expected.
+ *          Returns a mapped shared memory object
+ * @param shmfd, shm_size
+ * @return none
+ **/
 void close_shm(void* shm, size_t shm_size) {
     if (munmap(shm, shm_size) == -1) {
         fprintf(stderr, "ERROR: Failed unmapping shared memory object\n");
@@ -52,6 +89,14 @@ void close_shm(void* shm, size_t shm_size) {
     }
 }
 
+/**
+ * @brief Function that executes shm_unlink(3) and close(2) and does error handling.
+ * @details The function executes shm_unlink(3) and close(2), giving them a shared memory object name
+ *          and a file descriptor respectively, and handles the errors if any.
+ *          The same behaviour as shm_unlink(3) and close(2) should be expected.
+ * @param shm_name, shmfd
+ * @return none
+ **/
 void destroy_shm(char *shm_name, int shmfd) {
     if (shm_unlink(shm_name) == -1) {
         fprintf(stderr, "ERROR: Failed unlinking shared memory object\n");

fb_arc_set/shared/structs.c

@@ -1,4 +1,5 @@
 #include <stdbool.h> ///< For boolean constants
+#include <signal.h>
 
 #define BUFF_SIZE 8
 #define SET_MAX_SIZE 8
@@ -9,15 +10,44 @@ typedef struct edge {
 } edge_t;
 
 /// Struct for the feedback arc set
-typedef struct fb_set {
+typedef struct fb_arc_set {
     bool valid;
+    int edge_num;
     edge_t edges[SET_MAX_SIZE];
-} fb_set_t;
+} fb_arc_set_t;
 
 /// Struct for the circular buffer
 typedef struct buffer {
-    bool terminate;
+    bool finished;
-    fb_set_t sets[BUFF_SIZE];
+    short best_arc_len;
+    fb_arc_set_t sets[BUFF_SIZE];
 } buffer_t;
 
+static bool terminate = false;
+
+/**
+ * @brief Function to execute when the program gets a signal
+ * @details flips the terminate variable to true
+ * @param none
+ * @return none
+ **/
+static void signal_handler() {
+    terminate = true;
+}
+
+/**
+ * @brief Function to process the signals passed by the user
+ * @details creates a new sigaction structure
+ *          and changes the behaviour of the SIGINT and SIGTERM signals
+ * @param none
+ * @return none
+ **/
+static void process_signal(void){
+    struct sigaction sa;
+    memset(&sa, 0, sizeof(sa));
+    sa.sa_handler = signal_handler;
+    sigaction(SIGINT, &sa, NULL);
+    sigaction(SIGTERM, &sa, NULL);
+}
+
 static buffer_t *circ_buffer;

fb_arc_set/supervisor.c

@@ -31,27 +31,70 @@ int main(int argc, char *argv[]) {
         exit(EXIT_FAILURE);
     }
 
+    process_signal();
+
     /// Open shared memory objects
-    int buffer_shmfd = create_shmfd(BUFFER_SHM_NAME);
+    int buffer_shmfd = create_shmfd(BUFF_SHM_NAME);
     truncate_shm(buffer_shmfd, BUFF_SIZE);
     circ_buffer = (buffer_t *)open_shm(buffer_shmfd, sizeof(buffer_t));
 
     /// Open semaphores
     free_sem = open_sem(FREE_SEM_NAME, BUFF_SIZE);
-    used_sem = open_sem(USED_SEM_NAME, 0);
+    use_sem = open_sem(USE_SEM_NAME, 0);
-    mutex = open_sem(MUTEX_NAME, 1);
 
+    int free_space = 0;
+    int use_space = 0;
+    int r_pos = 0; ///< Position of the circular buffer to read from
+    circ_buffer->best_arc_len = __INT8_MAX__;
+
+    fb_arc_set_t fb_arc;
+    while(terminate == false) {
+        /// Get the values of the semaphores
+        getval_sem(free_sem, &free_space);
+        getval_sem(use_sem, &use_space);
+
+        wait_sem(use_sem);
+
+        /// Loop until we find a place that has been written to
+        while(circ_buffer->sets[r_pos].valid == false) {
+            r_pos = (r_pos + 1) % BUFF_SIZE;
+        }
+
+        /// Get the valid set and save it
+        fb_arc = circ_buffer->sets[r_pos];
+        circ_buffer->sets[r_pos].valid = false;
+
+        post_sem(free_sem); ///< Free the semaphore
+
+        r_pos = (r_pos + 1) % BUFF_SIZE; ///< Increase read position
+
+        if(fb_arc.edge_num == 0) {
+            /// If the graph is acyclic, set the terminate flag
+            puts("The graph is acyclic!");
+            signal_handler();
+        } else if(fb_arc.edge_num < circ_buffer->best_arc_len) {
+            /// Save ther best feedback arc length and print a solution
+            circ_buffer->best_arc_len = fb_arc.edge_num;
+            printf("Solution with %d edges: ", circ_buffer->best_arc_len);
+
+            for(int i=0; i < fb_arc.edge_num; i++) {
+                printf("%d-%d ", fb_arc.edges[i].u, fb_arc.edges[i].v);
+            }
+            printf("\n");
+        }
+    }
 
     /// Close and destory semaphores
     close_sem(free_sem);
-    close_sem(used_sem);
+    close_sem(use_sem);
     close_sem(mutex);
 
     destroy_sem(FREE_SEM_NAME);
-    destroy_sem(USED_SEM_NAME);
+    destroy_sem(USE_SEM_NAME);
     destroy_sem(MUTEX_NAME);
 
     /// Close and destroy shared memory objects
     close_shm(circ_buffer, sizeof(buffer_t));
-    destroy_shm(BUFFER_SHM_NAME, buffer_shmfd);
+    destroy_shm(BUFF_SHM_NAME, buffer_shmfd);
+    exit(EXIT_SUCCESS);
 }