Implement 'fastboot format' command

Some filesystems (e.g. ext4) require flushing an initial
fs image, right after erasing it the partition is unusable.

Doing erase,flush emptyfs is a little bit scaring so we have a
separate command that performs it as atomic step:

 - get size of partition
 - create an empty filesystem image
 - erase the partition
 - flush empty fs to the partition

This command applicable only for ext4 filesystem and checks the
partition type before formatting it.

Change-Id: I8529bc1dc64698f1f0d91312f7c0ab1a6e5d8b44

fastboot/Android.mk

@@ -16,8 +16,9 @@ LOCAL_PATH:= $(call my-dir)
 
 include $(CLEAR_VARS)
 
-LOCAL_C_INCLUDES := $(LOCAL_PATH)/../mkbootimg
-LOCAL_SRC_FILES := protocol.c engine.c bootimg.c fastboot.c 
+LOCAL_C_INCLUDES := $(LOCAL_PATH)/../mkbootimg \
+  $(LOCAL_PATH)/../../extras/ext4_utils
+LOCAL_SRC_FILES := protocol.c engine.c bootimg.c fastboot.c
 LOCAL_MODULE := fastboot
 
 ifeq ($(HOST_OS),linux)
@@ -47,7 +48,7 @@ ifeq ($(HOST_OS),windows)
   LOCAL_C_INCLUDES += development/host/windows/usb/api
 endif
 
-LOCAL_STATIC_LIBRARIES := $(EXTRA_STATIC_LIBS) libzipfile libunz
+LOCAL_STATIC_LIBRARIES := $(EXTRA_STATIC_LIBS) libzipfile libunz libext4_utils libz
 
 include $(BUILD_HOST_EXECUTABLE)
 $(call dist-for-goals,dist_files,$(LOCAL_BUILT_MODULE))

fastboot/engine.c

@@ -26,13 +26,24 @@
  * SUCH DAMAGE.
  */
 
+#include "fastboot.h"
+#include "make_ext4fs.h"
+#include "ext4_utils.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
 #include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
 
-#include "fastboot.h"
+extern struct fs_info info;
+
+#define ARRAY_SIZE(x)           (sizeof(x)/sizeof(x[0]))
 
 double now()
 {
@@ -60,15 +71,18 @@ char *mkmsg(const char *fmt, ...)
 #define OP_COMMAND    2
 #define OP_QUERY      3
 #define OP_NOTICE     4
+#define OP_FORMAT     5
 
 typedef struct Action Action;
 
+#define CMD_SIZE 64
+
 struct Action 
 {
     unsigned op;
     Action *next;
 
-    char cmd[64];    
+    char cmd[CMD_SIZE];
     const char *prod;
     void *data;
     unsigned size;
@@ -82,6 +96,35 @@ struct Action
 static Action *action_list = 0;
 static Action *action_last = 0;
 
+
+struct image_data {
+    long long partition_size;
+    long long image_size; // real size of image file
+    void *buffer;
+};
+
+void generate_ext4_image(struct image_data *image);
+void munmap_image(struct image_data *image);
+
+struct generator {
+    char *fs_type;
+
+    /* generate image and return it as image->buffer.
+     * size of the buffer returned as image->image_size.
+     *
+     * image->partition_size specifies what is the size of the
+     * file partition we generate image for.
+     */
+    void (*generate)(struct image_data *image);
+
+    /* it cleans the buffer allocated during image creation.
+     * this function probably does free() or munmap().
+     */
+    void (*cleanup)(struct image_data *image);
+} generators[] = {
+    { "ext4", generate_ext4_image, munmap_image }
+};
+
 static int cb_default(Action *a, int status, char *resp)
 {
     if (status) {
@@ -133,6 +176,104 @@ void fb_queue_erase(const char *ptn)
     a->msg = mkmsg("erasing '%s'", ptn);
 }
 
+void munmap_image(struct image_data *image)
+{
+    munmap(image->buffer, image->image_size);
+}
+
+void generate_ext4_image(struct image_data *image)
+{
+    int fd;
+    struct stat st;
+
+    fd = fileno(tmpfile());
+    info.len = image->partition_size;
+    make_ext4fs_internal(fd, NULL, NULL, 0, 0, 1, 0, 0, 0);
+
+    fstat(fd, &st);
+    image->image_size = st.st_size;
+
+    image->buffer = mmap(NULL, image->image_size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (image->buffer == MAP_FAILED) {
+        perror("mmap");
+        image->buffer = NULL;
+    }
+
+    close(fd);
+}
+
+int fb_format(Action *a, usb_handle *usb)
+{
+    const char *partition = a->cmd;
+    char query[256];
+    char response[FB_RESPONSE_SZ+1];
+    int status = 0;
+    struct image_data image;
+    struct generator *generator = NULL;
+    int fd;
+    unsigned i;
+    char cmd[CMD_SIZE];
+
+    response[FB_RESPONSE_SZ] = '\0';
+    snprintf(query, sizeof(query), "getvar:partition-type:%s", partition);
+    status = fb_command_response(usb, query, response);
+    if (status) {
+        fprintf(stderr,"FAILED (%s)\n", fb_get_error());
+        return status;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(generators); i++) {
+        if (!strncmp(generators[i].fs_type, response, FB_RESPONSE_SZ)) {
+            generator = &generators[i];
+            break;
+        }
+    }
+    if (!generator) {
+        fprintf(stderr,"Formatting is not supported for filesystem with type '%s'.\n",
+                response);
+        return -1;
+    }
+
+    response[FB_RESPONSE_SZ] = '\0';
+    snprintf(query, sizeof(query), "getvar:partition-size:%s", partition);
+    status = fb_command_response(usb, query, response);
+    if (status) {
+        fprintf(stderr,"FAILED (%s)\n", fb_get_error());
+        return status;
+    }
+    image.partition_size = strtoll(response, (char **)NULL, 16);
+
+    generator->generate(&image);
+    if (!image.buffer) {
+        fprintf(stderr,"Cannot generate image.\n");
+        return -1;
+    }
+
+    // Following piece of code is similar to fb_queue_flash() but executes
+    // actions directly without queuing
+    fprintf(stderr, "sending '%s' (%lli KB)...\n", partition, image.image_size/1024);
+    status = fb_download_data(usb, image.buffer, image.image_size);
+    if (status) goto cleanup;
+
+    fprintf(stderr, "writing '%s'...\n", partition);
+    snprintf(cmd, CMD_SIZE, "flash:%s", partition);
+    status = fb_command(usb, cmd);
+    if (status) goto cleanup;
+
+cleanup:
+    generator->cleanup(&image);
+
+    return status;
+}
+
+void fb_queue_format(const char *partition)
+{
+    Action *a;
+
+    a = queue_action(OP_FORMAT, partition);
+    a->msg = mkmsg("formatting '%s' partition", partition);
+}
+
 void fb_queue_flash(const char *ptn, void *data, unsigned sz)
 {
     Action *a;
@@ -340,6 +481,10 @@ int fb_execute_queue(usb_handle *usb)
             if (status) break;
         } else if (a->op == OP_NOTICE) {
             fprintf(stderr,"%s\n",(char*)a->data);
+        } else if (a->op == OP_FORMAT) {
+            status = fb_format(a, usb);
+            status = a->func(a, status, status ? fb_get_error() : "");
+            if (status) break;
         } else {
             die("bogus action");
         }

fastboot/fastboot.c

@@ -222,6 +222,7 @@ void usage(void)
             "  flashall                                 flash boot + recovery + system\n"
             "  flash <partition> [ <filename> ]         write a file to a flash partition\n"
             "  erase <partition>                        erase a flash partition\n"
+            "  format <partition>                       format a flash partition \n"
             "  getvar <variable>                        display a bootloader variable\n"
             "  boot <kernel> [ <ramdisk> ]              download and boot kernel\n"
             "  flash:raw boot <kernel> [ <ramdisk> ]    create bootimage and flash it\n"
@@ -633,6 +634,10 @@ int main(int argc, char **argv)
             require(2);
             fb_queue_erase(argv[1]);
             skip(2);
+        } else if(!strcmp(*argv, "format")) {
+            require(2);
+            fb_queue_format(argv[1]);
+            skip(2);
         } else if(!strcmp(*argv, "signature")) {
             require(2);
             data = load_file(argv[1], &sz);

fastboot/fastboot.h

@@ -43,6 +43,7 @@ char *fb_get_error(void);
 /* engine.c - high level command queue engine */
 void fb_queue_flash(const char *ptn, void *data, unsigned sz);;
 void fb_queue_erase(const char *ptn);
+void fb_queue_format(const char *ptn);
 void fb_queue_require(const char *prod, const char *var, int invert,
         unsigned nvalues, const char **value);
 void fb_queue_display(const char *var, const char *prettyname);