Fastbootd: Comments and general cleaning

Alignment fix for fastbootd gpt_mmap

Change-Id: I86482e1645672daae1c8e4a4455c6291c0805fb0
diff --git a/fastbootd/commands.c b/fastbootd/commands.c
index 5c283a8..d8a601f 100644
--- a/fastbootd/commands.c
+++ b/fastbootd/commands.c
@@ -128,7 +128,7 @@
     second_ptr = (void *)((unsigned) ramdisk_ptr + ramdisk_actual);
 
     D(INFO, "preparing to boot");
-    // Prepares boot physical addresses from header are ignored
+    // Prepares boot physical address. Addresses from header are ignored
     rv = prepare_boot_linux(hdr->kernel_addr, kernel_ptr, kernel_actual,
                             hdr->ramdisk_addr, ramdisk_ptr, ramdisk_actual,
                             hdr->second_addr, second_ptr, second_actual,
@@ -294,7 +294,7 @@
         return;
     }
 
-    // TODO: Maybe its goot idea to check whether the partition is just bootable partition
+    // TODO: Maybe its goot idea to check whether the partition is bootable
     if (!strcmp(arg, "boot") || !strcmp(arg, "recovery")) {
         if (read_data_once(data_fd, data, BOOT_MAGIC_SIZE) < BOOT_MAGIC_SIZE) {
             fastboot_fail(phandle, "incoming data read error, cannot read boot header");
@@ -329,7 +329,6 @@
 
     flash_close(partition);
     close(data_fd);
-    //TODO: check who is closing phandle->download_fd
 
     fastboot_okay(phandle, "");
 }
@@ -375,7 +374,6 @@
 
     phandle->download_fd = protocol_handle_download(phandle, len);
     if (phandle->download_fd < 0) {
-        //handle->state = STATE_ERROR;
         fastboot_fail(phandle, "download failed");
         return;
     }
@@ -386,6 +384,7 @@
 static void cmd_oem(struct protocol_handle *phandle, const char *arg) {
     const char *response = "";
 
+    //TODO: Maybe it should get download descriptor also
     if (trigger_oem_cmd(arg, &response))
         fastboot_fail(phandle, response);
     else
diff --git a/fastbootd/commands/partitions.c b/fastbootd/commands/partitions.c
index ca66c6d..de80ea3 100644
--- a/fastbootd/commands/partitions.c
+++ b/fastbootd/commands/partitions.c
@@ -61,7 +61,7 @@
     0x87, 0xc0, 0x68, 0xb6, 0xb7, 0x26, 0x99, 0xc7,
 };
 
-//TODO: If both blocks are invalid should I leave everything to vendor (through libvendor)
+//TODO: There is assumption that we are using little endian
 
 static void GPT_entry_clear(struct GPT_entry_raw *entry)
 {
@@ -83,6 +83,7 @@
         D(ERR, "the location of mapping area is outside of the device size %lld", sz);
         return 1;
     }
+    location = ALIGN_DOWN(location, PAGE_SIZE);
 
     mapping->map_ptr = mmap64(NULL, mapping->size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, location);
 
@@ -291,7 +292,7 @@
     }
     D(DEBUG, "Deleting gpt entry '%s'\n", raw->partition_guid);
 
-    // This entry can be empty in the middle
+    // Entry in the middle of table may become empty
     GPT_entry_clear(raw);
 
     return 0;
@@ -382,7 +383,6 @@
 
 struct GPT_entry_raw *GPT_get_pointer_by_name(struct GPT_entry_table *table, const char *name)
 {
-    //TODO: reverse direction
     int count = (int) table->header->entries_count;
     int current;
 
@@ -560,10 +560,9 @@
 
 void entry_set_guid(int n, uint8_t *guid)
 {
-    guid[0] = (uint8_t) (n + 1);
     int fd;
     fd = open("/dev/urandom", O_RDONLY);
-    read(fd, &guid[1], 15);
+    read(fd, guid, 16);
     close(fd);
 
     //rfc4122