Add support for delta-source-fat-* directives

Closes #201

src/fatfs.c

@@ -425,6 +425,44 @@ int fatfs_truncate(struct block_cache *output, off_t block_offset, const char *f
     return 0;
 }
 
+/**
+ * @brief fatfs_pread Read a file
+ *
+ * @param fc the current FAT session
+ * @param filename an existing file
+ * @param offset offset inside file
+ * @param size number of bytes to read
+ * @param buffer buffer where to put read data
+ * @param br pointer to the variable that receives number of byters actually read
+ * @return 0 on success
+ */
+int fatfs_pread(struct block_cache *output, off_t block_offset, const char *filename, int offset, size_t size, void *buffer, size_t *br)
+{
+    // Check if this is the same file as a previous pwrite call
+    if (current_file_ && strcmp(current_file_, filename) != 0)
+        close_open_files();
+
+    MAYBE_MOUNT(output, block_offset);
+
+    if (!current_file_) {
+        CHECK("fat_read can't open file", filename, f_open(&fil_, filename, FA_READ));
+        CHECK_SYNC(filename, &fil_);
+
+        // Assuming it opens ok, cache the filename for future reads.
+        current_file_ = strdup(filename);
+    }
+
+    // Check if this pread requires a seek.
+    FSIZE_t desired_offset = offset;
+    if (desired_offset != f_tell(&fil_))
+        CHECK("fat_read can't seek to end of file", filename, f_lseek(&fil_, f_size(&fil_)));
+
+    CHECK("fat_read can't read", filename, f_read(&fil_, buffer, (uint)size, (uint*)br));
+    CHECK_SYNC(filename, &fil_);
+
+    return 0;
+}
+
 int fatfs_pwrite(struct block_cache *output, off_t block_offset, const char *filename, int offset, const char *buffer, off_t size)
 {
     // Check if this is the same file as a previous pwrite call
@@ -476,6 +514,37 @@ int fatfs_pwrite(struct block_cache *output, off_t block_offset, const char *fil
     return 0;
 }
 
+/**
+ * @brief fatfs_size read file size
+ * 
+ * @param fc the current FAT session
+ * @param filename an existing file
+ * @param size pointer to the variable that receives file size
+ * @return 0 on success
+ */
+int fatfs_size(struct block_cache *output, off_t block_offset, const char *filename, size_t *size)
+{
+    // Check if this is the same file as a previous size call
+    if (current_file_ && strcmp(current_file_, filename) != 0)
+        close_open_files();
+
+    MAYBE_MOUNT(output, block_offset);
+
+    if (!current_file_) {
+        CHECK("fat_size can't open file", filename, f_open(&fil_, filename, FA_READ));
+        CHECK_SYNC(filename, &fil_);
+
+        // Assuming it opens ok, cache the filename for future calls.
+        current_file_ = strdup(filename);
+    }
+
+    size = malloc(sizeof(off_t));
+    *size = (size_t)f_size(&fil_);
+    CHECK_SYNC(filename, &fil_);
+
+    return 0;
+}
+
 void fatfs_closefs()
 {
     if (output_) {

src/functions.h

@@ -66,6 +66,7 @@ struct fun_context {
     struct xdelta_state *xd;
     off_t xd_source_offset;
     size_t xd_source_count;
+    const char *xd_source_path;
 
     void *cookie;
 };

src/fwup_apply.c

@@ -253,6 +253,17 @@ static int xdelta_read_source_callback(void *cookie, void *buf, size_t count, of
     return block_cache_pread(fctx->output, buf, count, fctx->xd_source_offset + offset);
 }
 
+static int xdelta_read_fat_callback(void *cookie, void *buf, size_t count, off_t offset)
+{
+    struct fun_context *fctx = (struct fun_context *) cookie;
+    size_t br;
+
+    if (offset < 0)
+        ERR_RETURN("xdelta tried to load outside of allowed byte range (0-%" PRId64 ")", fctx->xd_source_count);
+
+    return fatfs_pread(fctx->output, fctx->xd_source_offset, fctx->xd_source_path, offset, count, buf, &br);
+}
+
 static int read_callback_xdelta(struct fun_context *fctx, const void **buffer, size_t *len, off_t *offset)
 {
     struct fwup_apply_data *p = (struct fwup_apply_data *) fctx->cookie;
@@ -387,17 +398,35 @@ static int run_task(struct fun_context *fctx, struct fwup_apply_data *pd)
         off_t expected_size_in_archive = sparse_file_data_size(&pd->sfm);
 
         if (pd->sfm.map_len == 1 && archive_entry_size_is_set(ae) && size_in_archive != expected_size_in_archive) {
+            // Size in archive is different from expected size
             const char *source_raw_offset_str = cfg_getstr(on_resource, "delta-source-raw-offset");
             int source_raw_count = cfg_getint(on_resource, "delta-source-raw-count");
+
+            const char *source_fat_offset_str = cfg_getstr(on_resource, "delta-source-fat-offset");
+            const char *source_fat_path = cfg_getstr(on_resource, "delta-source-fat-path");
+
             if (source_raw_count > 0 && source_raw_offset_str != NULL) {
+                // Found delta-source-raw-offset and delta-source-raw-count directives
                 off_t source_raw_offset = strtoul(source_raw_offset_str, NULL, 0);
 
                 fctx->xd = malloc(sizeof(struct xdelta_state));
                 xdelta_init(fctx->xd, xdelta_read_patch_callback, xdelta_read_source_callback, fctx);
                 fctx->xd_source_offset = source_raw_offset * FWUP_BLOCK_SIZE;
                 fctx->xd_source_count = source_raw_count * FWUP_BLOCK_SIZE;
+            } else if (source_fat_offset_str != NULL && source_fat_path != NULL) {
+                // Found delta-source-fat-offset and delta-source-fat-path directives
+                off_t source_fat_offset = strtoul(source_fat_offset_str, NULL, 0);
+
+                size_t size;
+                OK_OR_CLEANUP(fatfs_size(fctx->output, source_fat_offset, source_fat_path, &size));
+
+                fctx->xd = malloc(sizeof(struct xdelta_state));
+                xdelta_init(fctx->xd, xdelta_read_patch_callback, xdelta_read_fat_callback, fctx);
+                fctx->xd_source_offset = source_fat_offset;
+                fctx->xd_source_count = size;
+                fctx->xd_source_path = source_fat_path;
             } else {
-                ERR_CLEANUP_MSG("File '%s' isn't expected size (%d vs %d) and xdelta3 patch support not enabled on it. (Add delta-source-raw-offset or delta-source-raw-count at least)", resource_name, (int) size_in_archive, (int) expected_size_in_archive);
+                ERR_CLEANUP_MSG("File '%s' isn't expected size (%d vs %d) and xdelta3 patch support not enabled on it. (Add delta-source-raw-offset / delta-source-raw-count or delta-source-fat-offset / delta-source-fat-path)", resource_name, (int) size_in_archive, (int) expected_size_in_archive);
             }
         }
     }

tests/192_delta_fat_upgrade.test

@@ -0,0 +1,74 @@
+#!/bin/sh
+
+#
+# Write a firmware image and then test upgrading it with
+# an xdelta3-encoded update, on FAT-stored files.
+#
+# brew install xdelta
+#
+
+. "$(cd "$(dirname "$0")" && pwd)/common.sh"
+
+FWFILE2="${WORK}/fwup2.fw"
+
+cat >"$CONFIG" <<EOF
+define(BOOT_PART_OFFSET, 63)
+define(BOOT_PART_COUNT, 77238)
+
+file-resource 1k.cur {
+        host-path = "${TESTFILE_1K}"
+}
+file-resource 1k.new {
+        host-path = "${TESTFILE_1K}"
+}
+mbr mbr-a {
+    partition 0 {
+        block-offset = \${BOOT_PART_OFFSET}
+        block-count = \${BOOT_PART_COUNT}
+        type = 0xc # FAT32
+        boot = true
+    }
+}
+task complete {
+    on-init {
+        mbr_write(mbr-a)
+        fat_mkfs(\${BOOT_PART_OFFSET}, \${BOOT_PART_COUNT})
+    }
+    on-resource 1k.cur { fat_write(\${BOOT_PART_OFFSET}, "1k.cur") }
+}
+task upgrade {
+    on-resource 1k.new {
+        delta-source-fat-offset=\${BOOT_PART_OFFSET}
+        delta-source-fat-path="1k.cur"
+        fat_write(\${BOOT_PART_OFFSET}, "1k.new")
+    }
+}
+EOF
+
+offset_bytes=$(( 63*512 ))
+
+# Create the firmware file, then "burn it"
+$FWUP_CREATE -c -f "$CONFIG" -o "$FWFILE"
+$FWUP_APPLY -a -d "$IMGFILE" -i "$FWFILE" -t complete
+
+# Check the content of current firmware content
+mcopy -n -i "${IMGFILE}@@${offset_bytes}" ::/1k.cur "${WORK}/1k.cur"
+diff "${TESTFILE_1K}" "${WORK}/1k.cur"
+
+# Manually create the delta upgrade by replacing 1k.new
+# with the delta3 version
+mkdir -p "$WORK/data"
+xdelta3 -A -S -f -s "$TESTFILE_1K" "$TESTFILE_1K" "$WORK/data/1k.new"
+cp "$FWFILE" "$FWFILE2"
+(cd "$WORK" && zip "$FWFILE2" data/1k.new)
+
+# Now upgrade the IMGFILE file
+$FWUP_APPLY -a -d "$IMGFILE" -i "$FWFILE2" -t upgrade
+
+# Check the content of new firmware content
+mcopy -i "${IMGFILE}@@${offset_bytes}" ::/1k.new "${WORK}/1k.new"
+diff "${TESTFILE_1K}" "${WORK}/1k.new"
+
+# Check that the verify logic works on both files
+$FWUP_VERIFY -V -i "$FWFILE"
+$FWUP_VERIFY -V -i "$FWFILE2"

tests/Makefile.am

@@ -191,6 +191,7 @@ TESTS = 001_simple_fw.test \
 	188_uboot_redundant_bad_param.test \
 	189_uboot_redundant_recover.test \
 	190_one_metadata_cmdline.test \
-	191_disk_crypto_via_env.test
+	191_disk_crypto_via_env.test \
+	192_delta_fat_upgrade.test
 
 EXTRA_DIST = $(TESTS) common.sh 1K.bin 1K-corrupt.bin 150K.bin