add partial reading of input file

main.c

@@ -60,6 +60,48 @@ static int firmware_fdt_read_blob(const char *filename, char **buffp, int *len)
 	return ret;
 }
 
+static int firmware_fdt_read_chunk(const char *filename, char *buf, int len, int offset)
+{
+	int fd = 0;	/* assume stdin */
+	int ret = 0;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return errno;
+
+	struct stat st;
+	stat(filename, &st);
+	size_t file_size = st.st_size;
+
+	if (file_size < offset || offset < 0)
+	{
+		printf("Bad offset: %d/%ld\n", offset, file_size);
+		return -1;
+	}
+	if (file_size < offset + len)
+		len = file_size - offset;
+
+	if (offset)
+		lseek(fd, offset, SEEK_SET);
+	/* Loop until we have read everything */
+	size_t readed = 0;
+	do {
+		ret = read(fd, buf + readed, len - readed);
+		if (ret < 0)
+		{
+			ret = errno;
+			break;
+		}
+		readed += ret;
+	} while (ret != 0 && readed < len);
+
+	/* Clean up, including closing stdin; return errno on error */
+	close(fd);
+
+	memset(buf + readed, 0, len - readed);
+	return readed;
+}
+
 int a()
 {
 	int len = 0;
@@ -89,18 +131,19 @@ int a()
 	return 0;
 }
 
-static inline const void *fdt_offset_ptr_(const void *fdt, int offset)
+static inline const void *fdt_offset_ptr_(const void *fdt, const void *buf, int buf_offset)
 {
-	return (const char *)fdt + fdt_off_dt_struct(fdt) + offset;
+	debug("fdt_offset_ptr_: %p + %d + %x\n", buf, fdt_off_dt_struct(fdt), buf_offset);
+	return (const char *)buf + fdt_off_dt_struct(fdt) + buf_offset;
 }
 
 #define FDT_ALIGN(x, a)		(((x) + (a) - 1) & ~((a) - 1))
 #define FDT_TAGALIGN(x)		(FDT_ALIGN((x), FDT_TAGSIZE))
 
 /* Do not touch any forward data, caller will validate it later */
-int guess_next_tag(char * buf, int offset)
+int guess_next_tag(char * fdt, int offset, char * buf)
 {
-	const unsigned * val = fdt_offset_ptr_(buf, offset);
+	const unsigned * val = fdt_offset_ptr_(fdt, buf, 0);
 	unsigned tag = fdt32_to_cpu(*val);
 	char * ptr = NULL;
 
@@ -157,13 +200,113 @@ int is_offset_valid(char * fdt, int offset, int len)
 	return 1;
 }
 
+#define WINDOW_SIZE 512
+
+static int fdt_dump_node_data(const char *outname, const char *filename, int offset)
+{
+	char *buf = malloc(WINDOW_SIZE);
+	int readed = firmware_fdt_read_chunk(filename, buf, WINDOW_SIZE, 0);
+	if (readed <= 0)
+		return -1;
+	char *fdt = buf;
+
+	buf = malloc(WINDOW_SIZE);
+	readed = firmware_fdt_read_chunk(filename, buf, WINDOW_SIZE, offset);
+	if (readed <= 0)
+		return -1;
+
+	char * strings = malloc(WINDOW_SIZE);
+	readed = firmware_fdt_read_chunk(filename, strings, WINDOW_SIZE, fdt_off_dt_strings(fdt));
+	if (readed <= 0)
+		return -1;
+
+	int data_offset = 0;
+	int data_len = 0;
+	do {
+		int nextoffset = guess_next_tag(fdt, offset, buf);
+		readed = firmware_fdt_read_chunk(filename, buf, WINDOW_SIZE, nextoffset);
+		debug("DUMP: Read additional %d bytes from offset %x\n", readed, nextoffset);
+		int valid = is_offset_valid(fdt, offset, nextoffset - offset);
+		if (!valid)
+		{
+			printf("DUMP: next tag is not valid! (%d %d)\n", offset, nextoffset);
+			break;
+		}
+		debug("DUMP: Offset %x is valid\n", nextoffset);
+		offset = nextoffset;
+
+		if (FDT_PROP == fdt32_to_cpu(*(int *)(fdt_offset_ptr_(fdt, buf, 0))))
+		{
+			const struct fdt_property *prop = fdt_offset_ptr_(fdt, buf, 0);
+			debug("prop->nameoff: %x (%x)\n", fdt32_to_cpu(prop->nameoff), fdt_off_dt_strings(fdt));
+			char * name = strings + fdt32_to_cpu(prop->nameoff);
+			debug("Property name: '%s'\n", name);
+
+			if (strcmp(name, "data"))
+				continue;
+			data_offset = prop->data - (char *)prop + offset;
+			data_len = fdt32_to_cpu(prop->len);
+			debug("Property \"data\" at offset %x len %d\n", data_offset, data_len);
+			break;
+		}
+	} while (FDT_END != fdt32_to_cpu(*(int *)(fdt_offset_ptr_(fdt, buf, 0))));
+
+	char * data = malloc(data_len);
+	readed = firmware_fdt_read_chunk(filename, data, data_len,
+	                                 fdt_off_dt_struct(fdt) + data_offset);
+	if (readed <= 0)
+		return -1;
+#if 1
+	int fd = 0;	/* assume stdin */
+	int ret = 0;
+
+	char out_filename[128] = "";
+	snprintf(out_filename, 128, "/tmp/%s", outname);
+	*strchr(out_filename, '@') = '_';
+	debug("Open file '%s'\n", out_filename);
+	fd = open(out_filename, O_WRONLY | O_CREAT, 0666);
+	if (fd < 0)
+	{
+		printf("Error: %d\n", errno);
+		return -errno;
+	}
+
+	size_t writed = 0;
+	do {
+		ret = write(fd, data + writed, data_len - writed);
+		if (ret < 0)
+		{
+			ret = -errno;
+			break;
+		}
+		writed += ret;
+	} while (ret != 0 && writed < data_len);
+
+	/* Clean up, including closing stdin; return errno on error */
+	close(fd);
+
+	if (ret < 0)
+		return ret;
+
+	return writed;
+#else
+	return 0;
+#endif
+}
+
 int b()
 {
 	int len = 0;
-	char *buf = NULL;
 	const char *filename = "/tmp/esr1x.firmware";
 
-	firmware_fdt_read_blob(filename, &buf, &len);
+	char *buf = malloc(WINDOW_SIZE);
+	int file_offset = 0;
+	int readed = firmware_fdt_read_chunk(filename, buf, WINDOW_SIZE, file_offset);
+	if (readed <= 0)
+		return -1;
+	char *fdt = buf;
+	buf = malloc(WINDOW_SIZE);
+	memcpy(buf, fdt, WINDOW_SIZE);
 
 	printf("B:\n");
 	int offset = 0;
@@ -173,33 +316,44 @@ int b()
 		{ "uboot-nand@1", 0 }
 	};
 	do {
-		if (FDT_BEGIN_NODE == fdt32_to_cpu(*(int *)(fdt_offset_ptr_(buf, offset))))
+		if (FDT_BEGIN_NODE == fdt32_to_cpu(*(int *)(fdt_offset_ptr_(fdt, buf, 0))))
 		{
+			debug("Search starts\n");
 			for (int i = 0; i < sizeof(node_offsets) / sizeof(*node_offsets); i++)
 			{
 				if (!strcmp(node_offsets[i].name,
-					    (char *)(fdt_offset_ptr_(buf, offset + FDT_TAGSIZE))))
+					    (char *)(fdt_offset_ptr_(fdt, buf, FDT_TAGSIZE))))
 				{
 					node_offsets[i].offset = offset;
 				}
 
 			}
+			debug("Search ends\n");
 		}
 
-		int nextoffset = guess_next_tag(buf, offset);
+		int nextoffset = guess_next_tag(fdt, offset, buf);
-		int valid = is_offset_valid(buf, offset, nextoffset - offset);
+		readed = firmware_fdt_read_chunk(filename, buf, WINDOW_SIZE, nextoffset);
+		debug("Read additional %d bytes from offset %x\n", readed, nextoffset);
+		int valid = is_offset_valid(fdt, offset, nextoffset - offset);
 		if (!valid)
 		{
 			printf("next tag is not valid! (%d %d)\n", offset, nextoffset);
 			break;
 		}
+		debug("Offset %x is valid\n", nextoffset);
 		offset = nextoffset;
-	} while (FDT_END != fdt32_to_cpu(*(int *)(fdt_offset_ptr_(buf, offset))));
+	} while (FDT_END != fdt32_to_cpu(*(int *)(fdt_offset_ptr_(fdt, buf, 0))));
 
 	debug("Yay\n");
 
 	for (int i = 0; i < sizeof(node_offsets) / sizeof(*node_offsets); i++)
+	{
 		printf("%s offset: %x\n", node_offsets[i].name, node_offsets[i].offset);
+		readed = firmware_fdt_read_chunk(filename, buf, WINDOW_SIZE,
+		                                 node_offsets[i].offset);
+		int writed = fdt_dump_node_data(node_offsets[i].name, filename, node_offsets[i].offset);
+		printf("Written %d bytes\n", writed);
+	}
 
 	return 0;
 }