core: Build offset queue + create output file

Signed-off-by: Ian Moffett <ian@mirocom.org>

src/main.c

@@ -1,7 +1,9 @@
 #define _DEFAULT_SOURCE
+#include <sys/queue.h>
 #include <sys/stat.h>
 #include <stdio.h>
 #include <stdint.h>
+#include <stdlib.h>
 #include <stddef.h>
 #include <errno.h>
 #include <unistd.h>
@@ -9,27 +11,66 @@
 #include <fcntl.h>
 #include <string.h>
 
+#define MAGIC_SIZE 5
 #define CAV_PASSES 3
 #define CAV_VERSION "0.0.1"
 
+#define CAV_OFF_INDEX(INDEX) \
+    ((INDEX) * sizeof(struct cav_offset))
+
 static const char *input_name = NULL;
 static const char *output_name = "out.cav";
 
+/* Forward declarations */
+struct cav_offdesc;
+
 /*
  * Represents the consume and vomit state machine
  *
  * @dir_fd: Input directory file descriptor
+ * @out_fd: Output file descriptor
  * @dir: Opened directory
  * @pass_count: Number of passes made in file
  * @file_count: Number of files encountered including subdirectories
  * @cur_off: Current offset tracker
+ * @offq: Offset queue
  */
 struct cav_state {
     int dir_fd;
+    int out_fd;
     DIR *dir;
     uint8_t pass_count;
     size_t file_count;
     uint32_t cur_off;
+    TAILQ_HEAD(, cav_offdesc) offq;
+};
+
+/*
+ * Represents an entry in the offset table
+ *
+ * @magic: Must be "BLUGH"
+ * @off:   Placement offset
+ * @size:  File size in bytes
+ * @link:  Queue link [XXX: must be at the end]
+ */
+struct cav_offset {
+    char magic[MAGIC_SIZE];
+    uint32_t off;
+    size_t size;
+};
+
+/*
+ * Represents an offset descriptor used before holding
+ * offset entries before it is entered into the file
+ *
+ * @path: Path of file
+ * @off: Offset entry to push
+ * @link: Queue link
+ */
+struct cav_offdesc {
+    char *path;
+    struct cav_offset off;
+    TAILQ_ENTRY(cav_offdesc) link;
 };
 
 static void
@@ -81,6 +122,26 @@ get_file_size(const char *path)
     return sb.st_size;
 }
 
+/*
+ * Allocate an offset descriptor
+ */
+static struct cav_offdesc *
+offset_alloc(void)
+{
+    struct cav_offdesc *off_desc;
+    struct cav_offset *off;
+
+    off_desc = malloc(sizeof(*off_desc));
+    if (off_desc == NULL) {
+        return NULL;
+    }
+
+    memset(off_desc, 0, sizeof(*off_desc));
+    off = &off_desc->off;
+    memcpy(off->magic, "BLUGH", MAGIC_SIZE);
+    return off_desc;
+}
+
 /*
  * Initialize the cav state machine
  *
@@ -102,12 +163,20 @@ state_init(struct cav_state *state)
         return -1;
     }
 
-    state->dir = fdopendir(state->dir_fd);
-    if (state->dir == NULL) {
+    state->out_fd = open(output_name, O_WRONLY | O_CREAT, 0600);
+    if (state->out_fd < 0) {
         close(state->dir_fd);
         return -1;
     }
 
+    state->dir = fdopendir(state->dir_fd);
+    if (state->dir == NULL) {
+        close(state->dir_fd);
+        close(state->out_fd);
+        return -1;
+    }
+
+    TAILQ_INIT(&state->offq);
     return 0;
 }
 
@@ -119,12 +188,23 @@ state_init(struct cav_state *state)
 static void
 state_destroy(struct cav_state *state)
 {
+    struct cav_offdesc *off;
+
     if (state == NULL) {
         return;
     }
 
+    off = TAILQ_FIRST(&state->offq);
+    while (off != NULL) {
+        TAILQ_REMOVE(&state->offq, off, link);
+        free(off->path);
+        free(off);
+        off = TAILQ_FIRST(&state->offq);
+    }
+
     closedir(state->dir);
     close(state->dir_fd);
+    close(state->out_fd);
 }
 
 /*
@@ -134,6 +214,8 @@ state_destroy(struct cav_state *state)
 static void
 consume_scan(const char *dir_path, struct cav_state *state, DIR *subdir)
 {
+    struct cav_offdesc *off_desc;
+    struct cav_offset *off;
     struct dirent *dirent;
     char buf[256];
     DIR *dir;
@@ -161,7 +243,20 @@ consume_scan(const char *dir_path, struct cav_state *state, DIR *subdir)
             closedir(subdir);
             break;
         default:
+            if ((off_desc = offset_alloc()) == NULL) {
+                printf("fatal: failed to allocate offset entry\n");
+                return;
+            }
+
             snprintf(buf, sizeof(buf), "%s/%s", dir_path, dirent->d_name);
+            off_desc->path = strdup(buf);
+
+            /* Initialize the offset descriptor */
+            off = &off_desc->off;
+            off->size = get_file_size(buf);
+            off->off = state->cur_off;
+            TAILQ_INSERT_TAIL(&state->offq, off_desc, link);
+
             ++state->file_count;
             state->cur_off += get_file_size(buf);
             break;
@@ -177,6 +272,8 @@ consume_scan(const char *dir_path, struct cav_state *state, DIR *subdir)
 static void
 consume_pass(struct cav_state *state)
 {
+    struct cav_offdesc *off;
+
     if (state == NULL) {
         return;
     }
@@ -190,6 +287,11 @@ consume_pass(struct cav_state *state)
             state->file_count,
             state->cur_off
         );
+
+        TAILQ_FOREACH(off, &state->offq, link) {
+            printf("[*] %s\n", off->path);
+        }
+
         break;
     }
 }