From f88ec4f337b2a755e975641697db2222ed42bca1 Mon Sep 17 00:00:00 2001
From: Simon Hancock <simon@linkingdrones.com>
Date: Sun, 24 Sep 2023 18:53:40 +0100
Subject: [PATCH] Mavgen C: Use strncpy instead of memcpy to pack char[n]
 fields

Uses new macros mavlink_array_assign_[type] in place of direct calls to mav_array_memcpy.
The 'char' version then uses strncpy, while others call mav_array_memcpy as before
Update _mav_put_char_array function to use strncpy
---
 generator/C/include_v0.9/protocol.h | 34 +++++++++++++++++++++++++++--
 generator/C/include_v1.0/protocol.h | 34 +++++++++++++++++++++++++++--
 generator/C/include_v2.0/protocol.h | 34 +++++++++++++++++++++++++++--
 generator/mavgen_c.py               |  8 +++----
 4 files changed, 100 insertions(+), 10 deletions(-)

diff --git a/generator/C/include_v0.9/protocol.h b/generator/C/include_v0.9/protocol.h
index 26c02ef82..0abd5f0dc 100644
--- a/generator/C/include_v0.9/protocol.h
+++ b/generator/C/include_v0.9/protocol.h
@@ -168,13 +168,43 @@ static void mav_array_memcpy(void *dest, const void *src, size_t n)
 	}
 }
 
+/*
+ * Array direct assignment, for use when fields align and no byte swapping
+ * is required. Most are directly #defined to mav_array_memcpy, except for 
+ * mav_array_assign_char, which uses strncpy instead.
+ */
+#if !MAVLINK_NEED_BYTE_SWAP && MAVLINK_ALIGNED_FIELDS
+static inline void mav_array_assign_char(char *dest, const char *src, size_t n)
+{
+	if (src == NULL) {
+		memset(dest, 0, n);
+	} else {
+		/* strncpy will zero pad dest array up to n bytes */
+		strncpy(dest, src, n);
+	}
+}
+#define mav_array_assign_uint8_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint8_t))
+#define mav_array_assign_int8_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int8_t))
+#define mav_array_assign_uint16_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint16_t))
+#define mav_array_assign_int16_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int16_t))
+#define mav_array_assign_uint32_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint32_t))
+#define mav_array_assign_int32_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int32_t))
+#define mav_array_assign_uint64_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint64_t))
+#define mav_array_assign_int64_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int64_t))
+#define mav_array_assign_float(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(float))
+#define mav_array_assign_double(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(double))
+#endif
+
 /*
  * Place a char array into a buffer
  */
 static inline void _mav_put_char_array(char *buf, uint8_t wire_offset, const char *b, uint8_t array_length)
 {
-	mav_array_memcpy(&buf[wire_offset], b, array_length);
-
+	if (b == NULL) {
+		memset(&buf[wire_offset], 0, array_length);
+	} else {
+		strncpy(&buf[wire_offset], b, array_length);
+	}
 }
 
 /*
diff --git a/generator/C/include_v1.0/protocol.h b/generator/C/include_v1.0/protocol.h
index f48d947f1..25bd94af0 100644
--- a/generator/C/include_v1.0/protocol.h
+++ b/generator/C/include_v1.0/protocol.h
@@ -186,13 +186,43 @@ static inline void mav_array_memcpy(void *dest, const void *src, size_t n)
 	}
 }
 
+/*
+ * Array direct assignment, for use when fields align and no byte swapping
+ * is required. Most are directly #defined to mav_array_memcpy, except for 
+ * mav_array_assign_char, which uses strncpy instead.
+ */
+#if !MAVLINK_NEED_BYTE_SWAP && MAVLINK_ALIGNED_FIELDS
+static inline void mav_array_assign_char(char *dest, const char *src, size_t n)
+{
+	if (src == NULL) {
+		memset(dest, 0, n);
+	} else {
+		/* strncpy will zero pad dest array up to n bytes */
+		strncpy(dest, src, n);
+	}
+}
+#define mav_array_assign_uint8_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint8_t))
+#define mav_array_assign_int8_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int8_t))
+#define mav_array_assign_uint16_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint16_t))
+#define mav_array_assign_int16_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int16_t))
+#define mav_array_assign_uint32_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint32_t))
+#define mav_array_assign_int32_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int32_t))
+#define mav_array_assign_uint64_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint64_t))
+#define mav_array_assign_int64_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int64_t))
+#define mav_array_assign_float(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(float))
+#define mav_array_assign_double(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(double))
+#endif
+
 /*
  * Place a char array into a buffer
  */
 static inline void _mav_put_char_array(char *buf, uint8_t wire_offset, const char *b, uint8_t array_length)
 {
-	mav_array_memcpy(&buf[wire_offset], b, array_length);
-
+	if (b == NULL) {
+		memset(&buf[wire_offset], 0, array_length);
+	} else {
+		strncpy(&buf[wire_offset], b, array_length);
+	}
 }
 
 /*
diff --git a/generator/C/include_v2.0/protocol.h b/generator/C/include_v2.0/protocol.h
index ec593c3ac..e14b979e7 100644
--- a/generator/C/include_v2.0/protocol.h
+++ b/generator/C/include_v2.0/protocol.h
@@ -179,13 +179,43 @@ static inline void mav_array_memcpy(void *dest, const void *src, size_t n)
 	}
 }
 
+/*
+ * Array direct assignment, for use when fields align and no byte swapping
+ * is required. Most are directly #defined to mav_array_memcpy, except for 
+ * mav_array_assign_char, which uses strncpy instead.
+ */
+#if !MAVLINK_NEED_BYTE_SWAP && MAVLINK_ALIGNED_FIELDS
+static inline void mav_array_assign_char(char *dest, const char *src, size_t n)
+{
+	if (src == NULL) {
+		memset(dest, 0, n);
+	} else {
+		/* strncpy will zero pad dest array up to n bytes */
+		strncpy(dest, src, n);
+	}
+}
+#define mav_array_assign_uint8_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint8_t))
+#define mav_array_assign_int8_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int8_t))
+#define mav_array_assign_uint16_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint16_t))
+#define mav_array_assign_int16_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int16_t))
+#define mav_array_assign_uint32_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint32_t))
+#define mav_array_assign_int32_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int32_t))
+#define mav_array_assign_uint64_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(uint64_t))
+#define mav_array_assign_int64_t(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(int64_t))
+#define mav_array_assign_float(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(float))
+#define mav_array_assign_double(DEST,SRC,N) mav_array_memcpy(DEST,SRC,N*sizeof(double))
+#endif
+
 /*
  * Place a char array into a buffer
  */
 static inline void _mav_put_char_array(char *buf, uint8_t wire_offset, const char *b, uint8_t array_length)
 {
-	mav_array_memcpy(&buf[wire_offset], b, array_length);
-
+	if (b == NULL) {
+		memset(&buf[wire_offset], 0, array_length);
+	} else {
+		strncpy(&buf[wire_offset], b, array_length);
+	}
 }
 
 /*
diff --git a/generator/mavgen_c.py b/generator/mavgen_c.py
index e7f01c2e4..3e28d8fd0 100644
--- a/generator/mavgen_c.py
+++ b/generator/mavgen_c.py
@@ -232,7 +232,7 @@ def generate_message_h(directory, m):
     mavlink_${name_lower}_t packet;
 ${{scalar_fields:    packet.${name} = ${putname};
 }}
-${{array_fields:    mav_array_memcpy(packet.${name}, ${name}, sizeof(${type})*${array_length});
+${{array_fields:    mav_array_assign_${type}(packet.${name}, ${name}, ${array_length});
 }}
         memcpy(_MAV_PAYLOAD_NON_CONST(msg), &packet, MAVLINK_MSG_ID_${name}_LEN);
 #endif
@@ -304,7 +304,7 @@ def generate_message_h(directory, m):
     mavlink_${name_lower}_t packet;
 ${{scalar_fields:    packet.${name} = ${putname};
 }}
-${{array_fields:    mav_array_memcpy(packet.${name}, ${name}, sizeof(${type})*${array_length});
+${{array_fields:    mav_array_assign_${type}(packet.${name}, ${name}, ${array_length});
 }}
         memcpy(_MAV_PAYLOAD_NON_CONST(msg), &packet, MAVLINK_MSG_ID_${name}_LEN);
 #endif
@@ -376,7 +376,7 @@ def generate_message_h(directory, m):
     mavlink_${name_lower}_t packet;
 ${{scalar_fields:    packet.${name} = ${putname};
 }}
-${{array_fields:    mav_array_memcpy(packet.${name}, ${name}, sizeof(${type})*${array_length});
+${{array_fields:    mav_array_assign_${type}(packet.${name}, ${name}, ${array_length});
 }}
     _mav_finalize_message_chan_send(chan, MAVLINK_MSG_ID_${name}, (const char *)&packet, MAVLINK_MSG_ID_${name}_MIN_LEN, MAVLINK_MSG_ID_${name}_LEN, MAVLINK_MSG_ID_${name}_CRC);
 #endif
@@ -417,7 +417,7 @@ def generate_message_h(directory, m):
     mavlink_${name_lower}_t *packet = (mavlink_${name_lower}_t *)msgbuf;
 ${{scalar_fields:    packet->${name} = ${putname};
 }}
-${{array_fields:    mav_array_memcpy(packet->${name}, ${name}, sizeof(${type})*${array_length});
+${{array_fields:    mav_array_assign_${type}(packet->${name}, ${name}, ${array_length});
 }}
     _mav_finalize_message_chan_send(chan, MAVLINK_MSG_ID_${name}, (const char *)packet, MAVLINK_MSG_ID_${name}_MIN_LEN, MAVLINK_MSG_ID_${name}_LEN, MAVLINK_MSG_ID_${name}_CRC);
 #endif