[OpenWrt-Devel] [PATCH 2/3] [rpcd] file: add support for base64

Luka Perkov luka at openwrt.org
Sun Mar 15 17:00:51 EDT 2015


b64encode and b64decode functions were taken from zstream project which was
written by Steven Barth and John Crispin.

Signed-off-by: Luka Perkov <luka at openwrt.org>
---
 file.c | 197 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 187 insertions(+), 10 deletions(-)

diff --git a/file.c b/file.c
index 9e87a10..54f5d8a 100644
--- a/file.c
+++ b/file.c
@@ -79,14 +79,27 @@ static const struct blobmsg_policy rpc_file_r_policy[__RPC_F_R_MAX] = {
 };
 
 enum {
+	RPC_F_RB_PATH,
+	RPC_F_RB_BASE64,
+	__RPC_F_RB_MAX,
+};
+
+static const struct blobmsg_policy rpc_file_rb_policy[__RPC_F_RB_MAX] = {
+	[RPC_F_RB_PATH]   = { .name = "path",   .type = BLOBMSG_TYPE_STRING },
+	[RPC_F_RB_BASE64] = { .name = "base64", .type = BLOBMSG_TYPE_BOOL   },
+};
+
+enum {
 	RPC_F_RW_PATH,
 	RPC_F_RW_DATA,
+	RPC_F_RW_BASE64,
 	__RPC_F_RW_MAX,
 };
 
 static const struct blobmsg_policy rpc_file_rw_policy[__RPC_F_RW_MAX] = {
-	[RPC_F_RW_PATH] = { .name = "path", .type = BLOBMSG_TYPE_STRING },
-	[RPC_F_RW_DATA] = { .name = "data", .type = BLOBMSG_TYPE_STRING },
+	[RPC_F_RW_PATH]   = { .name = "path",   .type = BLOBMSG_TYPE_STRING },
+	[RPC_F_RW_DATA]   = { .name = "data",   .type = BLOBMSG_TYPE_STRING },
+	[RPC_F_RW_BASE64] = { .name = "base64", .type = BLOBMSG_TYPE_BOOL   },
 };
 
 enum {
@@ -114,6 +127,122 @@ static const char *d_types[] = {
 };
 
 
+static const unsigned char b64encode_tbl[] =
+	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static char
+*b64encode(const void *in, size_t *len)
+{
+	size_t lenout, pad, i;
+	const uint8_t *data = (const uint8_t *) in;
+
+	lenout = *len / 3;
+	lenout *= 4;
+	pad = *len % 3;
+
+	if (*len == 0) {
+		return strdup("");
+	} else if (pad) {
+		lenout += 4;
+	}
+
+	char *out = calloc(lenout + 1, sizeof(char));
+	if (!out)
+		return NULL;
+
+	uint8_t *o = (uint8_t*)out;
+	for (i = 0; i < *len; i += 3) {
+		uint32_t cv = (data[i] << 16) | (data[i+1] << 8) | data[i+2];
+		*(o+3) = b64encode_tbl[ cv        & 0x3f];
+		*(o+2) = b64encode_tbl[(cv >> 6)  & 0x3f];
+		*(o+1) = b64encode_tbl[(cv >> 12) & 0x3f];
+		*o     = b64encode_tbl[(cv >> 18) & 0x3f];
+		o += 4;
+	}
+
+	if (pad) {
+		uint32_t cv = data[*len-pad] << 16;
+		*(o-1) = '=';
+		*(o-2) = '=';
+		if (pad == 2) {
+			cv |= data[*len-pad+1] << 8;
+			*(o-2) = b64encode_tbl[(cv >> 6) & 0x3f];
+		}
+		*(o-3) = b64encode_tbl[(cv >> 12) & 0x3f];
+		*(o-4) = b64encode_tbl[(cv >> 18) & 0x3f];
+	}
+
+	out[lenout] = 0;
+	*len = lenout;
+	return out;
+}
+
+static const unsigned char b64decode_tbl[] = {
+	0x3e, 0xff, 0xff, 0xff, 0x3f, 0x34, 0x35, 0x36,
+	0x37, 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0xff,
+	0xff, 0xff, 0x00, 0xff, 0xff, 0xff, 0x00, 0x01,
+	0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
+	0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11,
+	0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
+	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x1a, 0x1b,
+	0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
+	0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
+	0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33
+};
+
+static void
+*b64decode(const char *in, size_t *len)
+{
+	size_t lenout, i;
+
+	if (*len == 0) {
+		return strdup("");
+	} else if (*len % 4) {
+		errno = EINVAL;
+		return NULL;
+	}
+
+	lenout = *len / 4 * 3;
+
+	unsigned char *out = calloc(lenout + 1, sizeof(char));
+	if (!out)
+		return NULL;
+
+	unsigned char *o = out;
+	for (i = 0; i < *len; i += 4) {
+		uint32_t cv = 0;
+		for (int j = 0; j < 4; j++) {
+			unsigned char c = in[i + j] - 43;
+			if (c > 79 || (c = b64decode_tbl[c]) == 0xff) {
+				free(out);
+				errno = EINVAL;
+				return NULL;
+			}
+
+			cv |= c;
+			if (j != 3) {
+				cv <<= 6;
+			}
+		}
+
+		*(o+2) = (unsigned char)(cv & 0xff);
+		*(o+1) = (unsigned char)((cv >>  8) & 0xff);
+		*o     = (unsigned char)((cv >> 16) & 0xff);
+		o += 3;
+	}
+
+	if (in[*len-1] == '=') {
+		lenout--;
+	}
+
+	if (in[*len-2] == '=') {
+		lenout--;
+	}
+
+	*len = lenout;
+	return out;
+}
+
 static int
 rpc_errno_status(void)
 {
@@ -162,12 +291,22 @@ rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
               struct ubus_request_data *req, const char *method,
               struct blob_attr *msg)
 {
-	int fd, rv, len;
+	static struct blob_attr *tb[__RPC_F_RB_MAX];
+	bool base64 = false;
+	int fd, rv;
+	ssize_t len;
 	char *path;
 	struct stat s;
 	char *wbuf;
 
-	if (!rpc_check_path(msg, &path, &s))
+	blobmsg_parse(rpc_file_rb_policy, __RPC_F_RB_MAX, tb, blob_data(msg), blob_len(msg));
+
+	if (!tb[RPC_F_RB_PATH])
+		return rpc_errno_status();
+
+	path = blobmsg_data(tb[RPC_F_RB_PATH]);
+
+	if (stat(path, &s))
 		return rpc_errno_status();
 
 	if (s.st_size >= RPC_FILE_MAX_SIZE)
@@ -182,7 +321,14 @@ rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
 
 	blob_buf_init(&buf, 0);
 
-	wbuf = blobmsg_alloc_string_buffer(&buf, "data", s.st_size + 1);
+	if (tb[RPC_F_RB_BASE64])
+		base64 = blobmsg_get_bool(tb[RPC_F_RB_BASE64]);
+
+	if (base64) {
+		wbuf = blobmsg_alloc_string_buffer(&buf, "data", (s.st_size / 3) * 4 + 5);
+	} else {
+		wbuf = blobmsg_alloc_string_buffer(&buf, "data", s.st_size + 1);
+	}
 
 	if (!wbuf)
 	{
@@ -196,14 +342,25 @@ rpc_file_read(struct ubus_context *ctx, struct ubus_object *obj,
 		goto out;
 	}
 
+	if (base64) {
+		void *data = b64encode(wbuf, (size_t *) &len);
+		if (!data) {
+			rv = UBUS_STATUS_UNKNOWN_ERROR;
+			goto out;
+		}
+
+		memcpy(wbuf, data, len);
+		free(data);
+	}
+
 	*(wbuf + len) = 0;
 	blobmsg_add_string_buffer(&buf);
 
 	ubus_send_reply(ctx, req, buf.head);
-	blob_buf_free(&buf);
 	rv = UBUS_STATUS_OK;
 
 out:
+	blob_buf_free(&buf);
 	close(fd);
 	return rv;
 }
@@ -213,8 +370,11 @@ rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
                struct ubus_request_data *req, const char *method,
                struct blob_attr *msg)
 {
-	int fd;
 	struct blob_attr *tb[__RPC_F_RW_MAX];
+	bool base64 = false;
+	int fd, rv = 0;
+	void *rbuf;
+	size_t rbuf_len;
 
 	blobmsg_parse(rpc_file_rw_policy, __RPC_F_RW_MAX, tb,
 	              blob_data(msg), blob_len(msg));
@@ -222,10 +382,27 @@ rpc_file_write(struct ubus_context *ctx, struct ubus_object *obj,
 	if (!tb[RPC_F_RW_PATH] || !tb[RPC_F_RW_DATA])
 		return UBUS_STATUS_INVALID_ARGUMENT;
 
-	if ((fd = open(blobmsg_data(tb[RPC_F_RW_PATH]), O_CREAT | O_TRUNC | O_WRONLY)) < 0)
+	if ((fd = open(blobmsg_data(tb[RPC_F_RW_PATH]), O_CREAT | O_WRONLY | O_TRUNC)) < 0)
 		return rpc_errno_status();
 
-	if (write(fd, blobmsg_data(tb[RPC_F_RW_DATA]), blobmsg_data_len(tb[RPC_F_RW_DATA])) < 0)
+	if (tb[RPC_F_RW_BASE64])
+		base64 = blobmsg_get_bool(tb[RPC_F_RW_BASE64]);
+
+	if (base64) {
+		rbuf_len = blobmsg_data_len(tb[RPC_F_RW_DATA]) - 1;
+		rbuf = b64decode(blobmsg_data(tb[RPC_F_RW_DATA]), &rbuf_len);
+	} else {
+		rbuf_len = blobmsg_data_len(tb[RPC_F_RW_DATA]);
+		rbuf = blobmsg_data(tb[RPC_F_RW_DATA]);
+	}
+
+	if (write(fd, rbuf, rbuf_len) < 0)
+		rv = -1;
+
+	if (base64)
+		free(rbuf);
+		
+	if (rv)
 		return rpc_errno_status();
 
 	if (fsync(fd) < 0)
@@ -643,7 +820,7 @@ static int
 rpc_file_api_init(const struct rpc_daemon_ops *o, struct ubus_context *ctx)
 {
 	static const struct ubus_method file_methods[] = {
-		UBUS_METHOD("read",    rpc_file_read,  rpc_file_r_policy),
+		UBUS_METHOD("read",    rpc_file_read,  rpc_file_rb_policy),
 		UBUS_METHOD("write",   rpc_file_write, rpc_file_rw_policy),
 		UBUS_METHOD("list",    rpc_file_list,  rpc_file_r_policy),
 		UBUS_METHOD("stat",    rpc_file_stat,  rpc_file_r_policy),
-- 
2.3.3
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