X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=src%2Flib%2Fmsgpack%2Fmsgpack.c;h=e7ff1e393cf33ac67625dbed2193edd475569cd1;hb=de34a55bebcd90795129b7c709815bdddd67ac87;hp=f3eca64a654cd5cfcfcc9cfabdaf5fca387e5f46;hpb=9b6ae9f609ebdc4708ef97e307ad2c39d9d94e5b;p=lttng-modules.git

diff --git a/src/lib/msgpack/msgpack.c b/src/lib/msgpack/msgpack.c
index f3eca64a..e7ff1e39 100644
--- a/src/lib/msgpack/msgpack.c
+++ b/src/lib/msgpack/msgpack.c
@@ -20,7 +20,6 @@
 
 #define _GNU_SOURCE
 #define _LGPL_SOURCE
-#include <stddef.h>
 
 #define MSGPACK_FIXSTR_ID_MASK		0xA0
 #define MSGPACK_FIXMAP_ID_MASK		0x80
@@ -55,8 +54,10 @@
 #include <linux/bug.h>
 #include <linux/string.h>
 #include <linux/types.h>
+#include <asm/byteorder.h>
 
 #include <lttng/msgpack.h>
+#include <lttng/probe-user.h>
 
 #define INT8_MIN		(-128)
 #define INT16_MIN		(-32767-1)
@@ -113,6 +114,33 @@ end:
 	return ret;
 }
 
+static inline int lttng_msgpack_append_user_buffer(
+		struct lttng_msgpack_writer *writer,
+		const uint8_t __user *ubuf,
+		size_t length)
+{
+	int ret = 0;
+
+	lttng_msgpack_assert(ubuf);
+
+	/* Ensure we are not trying to write after the end of the buffer. */
+	if (writer->write_pos + length > writer->end_write_pos) {
+		ret = -1;
+		goto end;
+	}
+
+	if (lttng_copy_from_user_check_nofault(writer->write_pos, ubuf, length)) {
+		/*
+		 * After a successful strlen user, a page fault on copy is handled by
+		 * considering the string as empty, returning a success.
+		 */
+		goto end;
+	}
+	writer->write_pos += length;
+end:
+	return ret;
+}
+
 static inline int lttng_msgpack_append_u8(
 		struct lttng_msgpack_writer *writer, uint8_t value)
 {
@@ -143,20 +171,6 @@ static inline int lttng_msgpack_append_u64(
 	return lttng_msgpack_append_buffer(writer, (uint8_t *) &value, sizeof(value));
 }
 
-static inline int lttng_msgpack_append_f64(
-		struct lttng_msgpack_writer *writer, double value)
-{
-
-	union {
-		double d;
-		uint64_t u;
-	} u;
-
-	u.d = value;
-
-	return lttng_msgpack_append_u64(writer, u.u);
-}
-
 static inline int lttng_msgpack_append_i8(
 		struct lttng_msgpack_writer *writer, int8_t value)
 {
@@ -181,23 +195,6 @@ static inline int lttng_msgpack_append_i64(
 	return lttng_msgpack_append_u64(writer, (uint64_t) value);
 }
 
-static inline int lttng_msgpack_encode_f64(
-		struct lttng_msgpack_writer *writer, double value)
-{
-	int ret;
-
-	ret = lttng_msgpack_append_u8(writer, MSGPACK_FLOAT64_ID);
-	if (ret)
-		goto end;
-
-	ret = lttng_msgpack_append_f64(writer, value);
-	if (ret)
-		goto end;
-
-end:
-	return ret;
-}
-
 static inline int lttng_msgpack_encode_fixmap(
 		struct lttng_msgpack_writer *writer, uint8_t count)
 {
@@ -312,6 +309,53 @@ end:
 	return ret;
 }
 
+static inline int lttng_msgpack_encode_user_fixstr(
+		struct lttng_msgpack_writer *writer,
+		const char __user *ustr,
+		uint8_t len)
+{
+	int ret;
+
+	lttng_msgpack_assert(len <= MSGPACK_FIXSTR_MAX_LENGTH);
+
+	ret = lttng_msgpack_append_u8(writer, MSGPACK_FIXSTR_ID_MASK | len);
+	if (ret)
+		goto end;
+
+	ret = lttng_msgpack_append_user_buffer(writer, (uint8_t __user *) ustr, len);
+	if (ret)
+		goto end;
+
+end:
+	return ret;
+}
+
+static inline int lttng_msgpack_encode_user_str16(
+		struct lttng_msgpack_writer *writer,
+		const char __user *ustr,
+		uint16_t len)
+{
+	int ret;
+
+	lttng_msgpack_assert(len > MSGPACK_FIXSTR_MAX_LENGTH);
+
+	ret = lttng_msgpack_append_u8(writer, MSGPACK_STR16_ID);
+	if (ret)
+		goto end;
+
+	ret = lttng_msgpack_append_u16(writer, len);
+	if (ret)
+		goto end;
+
+	ret = lttng_msgpack_append_user_buffer(writer, (uint8_t __user *) ustr, len);
+	if (ret)
+		goto end;
+
+end:
+	return ret;
+}
+
+
 int lttng_msgpack_begin_map(struct lttng_msgpack_writer *writer, size_t count)
 {
 	int ret;
@@ -385,6 +429,36 @@ end:
 	return ret;
 }
 
+/*
+ * Provide the same behavior on lttng_strlen_user_inatomic page fault as the
+ * lttng ring buffer: truncate the last string character.
+ */
+int lttng_msgpack_write_user_str(struct lttng_msgpack_writer *writer,
+		const char __user *ustr)
+{
+	int ret;
+	size_t length = max_t(size_t, lttng_strlen_user_inatomic(ustr), 1);
+
+	if (length >= (1 << 16)) {
+		ret = -1;
+		goto end;
+	}
+
+	/*
+	 * Handle empty string and strlen user page fault as empty string.
+	 */
+	if (length == 1)
+		return lttng_msgpack_write_str(writer, "");
+
+	if (length <= MSGPACK_FIXSTR_MAX_LENGTH)
+		ret = lttng_msgpack_encode_user_fixstr(writer, ustr, length);
+	else
+		ret = lttng_msgpack_encode_user_str16(writer, ustr, length);
+
+end:
+	return ret;
+}
+
 int lttng_msgpack_write_nil(struct lttng_msgpack_writer *writer)
 {
 	return lttng_msgpack_append_u8(writer, MSGPACK_NIL_ID);
@@ -493,11 +567,6 @@ end:
 	return ret;
 }
 
-int lttng_msgpack_write_double(struct lttng_msgpack_writer *writer, double value)
-{
-	return lttng_msgpack_encode_f64(writer, value);
-}
-
 void lttng_msgpack_writer_init(struct lttng_msgpack_writer *writer,
 		uint8_t *buffer, size_t size)
 {