packer: Create file view per idata descriptor

Signed-off-by: Chloe M <chloe@faracom.org>

1 files changed, 83 insertions, 0 deletions

diff --git a/core/rdar.c b/core/rdar.c
index 2cd1e66..b3a7c64 100644
--- a/core/rdar.c
+++ b/core/rdar.c
@@ -4,8 +4,11 @@
  */
 
 #define _DEFAULT_SOURCE
+#include <sys/stat.h>
+#include <sys/mman.h>
 #include <sys/queue.h>
 #include <unistd.h>
+#include <fcntl.h>
 #include <stdio.h>
 #include <stdint.h>
 #include <stddef.h>
@@ -54,6 +57,17 @@ static const char *output_path = NULL;
 static TAILQ_HEAD(, idata_desc) d_desc_table;
 
 /*
+ * Represents a file that has been mapped into memory
+ *
+ * @data:     File data
+ * @length:   Length of data
+ */
+struct file_view {
+    char *data;
+    size_t length;
+};
+
+/*
  * A data descriptor holds information about a specific
  * file along with an offset to which it is located at
  * in the offset.
@@ -75,10 +89,12 @@ struct data_desc {
  * before being flushed to the archive
  *
  * @data:  Actual data descriptor
+ * @file:  File view this descriptor references
  * @link:  TAILQ link
  */
 struct idata_desc {
     struct data_desc data;
+    struct file_view file;
     TAILQ_ENTRY(idata_desc) link;
 };
 
@@ -103,6 +119,67 @@ version(void)
 }
 
 /*
+ * Destroy a file view
+ *
+ * @view: View to destory
+ */
+static void
+view_destroy(struct file_view *view)
+{
+    munmap(view->data, view->length);
+    view->data = NULL;
+    view->length = 0;
+}
+
+/*
+ * Create a mapped file view from a file path
+ */
+static int
+view_from_path(const char *path, struct file_view *result)
+{
+    struct stat sb;
+    int fd;
+
+    if (path == NULL || result == NULL) {
+        return -1;
+    }
+
+    fd = open(path, O_RDONLY);
+    if (fd < 0) {
+        printf("fatal: failed to open '%s'\n", path);
+        perror("open");
+        return -1;
+    }
+
+    if (stat(path, &sb) < 0) {
+        printf("fatal: failed to stat '%s'\n", path);
+        perror("stat");
+        close(fd);
+        return -1;
+    }
+
+    result->data = mmap(
+        NULL,
+        sb.st_size,
+        PROT_READ,
+        MAP_SHARED,
+        fd,
+        0
+    );
+
+    if (result->data == NULL) {
+        printf("fatal: failed to map '%s'\n", path);
+        perror("mmap");
+        close(fd);
+        return -1;
+    }
+
+    result->length = sb.st_size;
+    close(fd);
+    return 0;
+}
+
+/*
  * Allocate an internal data descriptor
  *
  * @path:   Path of file
@@ -127,6 +204,11 @@ idata_from_file(const char *path)
         return NULL;
     }
 
+    if (view_from_path(path, &idata_desc->file) < 0) {
+        free(idata_desc);
+        return NULL;
+    }
+
     /* Initialize the data descriptor */
     data_desc = &idata_desc->data;
     memcpy(data_desc->magic, RDAR_MAGIC, RDAR_MAGIC_LEN);
@@ -167,6 +249,7 @@ idata_table_destroy(void)
     desc = TAILQ_FIRST(&d_desc_table);
     while (desc != NULL) {
         printf("-- %s\n", desc->data.path);
+        view_destroy(&desc->file);
 
         next = TAILQ_NEXT(desc, link);
         TAILQ_REMOVE(&d_desc_table, desc, link);