lib: cherry pick strncpy() usage fix

Origin:
	OpenAMP/open-amp#620

Commits:
	e233473d14654f08468595ad0dbe8f7e58acf267
	8591566382d055acd33f9d23e6826a8a4b0a1881
	1aecdc737d463b4ff1ece36847f4f2e68d4ffe4a

Status:
	Cherry pick PR that fixes the `stringop-truncation`
	compilation errors due to former usage of `strncpy()`.

Signed-off-by: Tomi Fontanilles <[email protected]>

open-amp/lib/CMakeLists.txt

@@ -10,6 +10,7 @@ collect (PROJECT_LIB_SOURCES version.c)
 add_subdirectory (virtio)
 add_subdirectory (rpmsg)
 add_subdirectory (remoteproc)
+add_subdirectory (utils)
 if (WITH_VIRTIO_MMIO_DRV)
 add_subdirectory (virtio_mmio)
 endif (WITH_VIRTIO_MMIO_DRV)
@@ -23,6 +24,7 @@ set (OPENAMP_LIB open_amp)
 
 configure_file(version.h.in ${PROJECT_BINARY_DIR}/include/generated/openamp/version_def.h)
 collect (PROJECT_INC_DIRS " ${PROJECT_BINARY_DIR}/include/generated/openamp")
+collect (PROJECT_INC_DIRS " ${PROJECT_BINARY_DIR}/include/internal")
 
 if (NOT CMAKE_INSTALL_LIBDIR)
 	set (CMAKE_INSTALL_LIBDIR "lib")

open-amp/lib/include/internal/string.h

@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2024, STMicroelectronics
+ *
+ */
+
+#include <string.h>
+
+/**
+ * @internal
+ *
+ * @brief Copies a string to a destination buffer with size limitation and returns the length of
+ *        the source string.
+ *
+ * This function copies up to `size - 1` characters from the source string `src`
+ * to the destination buffer `dest`, ensuring that the destination buffer is
+ * null-terminated. The function returns the length of the source string `src`.
+ * If the length of `src` is greater than or equal to `size`, the destination
+ * buffer will be truncated.
+ *
+ * @param dst Destination buffer where the string will be copied.
+ * @param src Source string to be copied.
+ * @param size Size of the destination buffer.
+ * @return The length of the source string `src`.
+ *
+ * @note If the size of the destination buffer is 0, the function does not copy any characters and
+ *       the destination buffer is not null-terminated.
+ * @note The function ensures that the destination buffer is always null-terminated if `size` is
+ *       greater than 0.
+ * @note: this code is inspired from the strlcpy.c file from freeBSD .
+ */
+size_t strlcpy(char *dest, const char *src, size_t size);

open-amp/lib/remoteproc/remoteproc.c

@@ -6,6 +6,7 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <internal/string.h>
 #include <metal/alloc.h>
 #include <metal/log.h>
 #include <metal/utilities.h>
@@ -300,7 +301,7 @@ void remoteproc_init_mem(struct remoteproc_mem *mem, const char *name,
 	if (!mem || !io || size == 0)
 		return;
 	if (name)
-		strncpy(mem->name, name, sizeof(mem->name));
+		(void)strlcpy(mem->name, name, sizeof(mem->name));
 	else
 		mem->name[0] = 0;
 	mem->pa = pa;

open-amp/lib/rpmsg/rpmsg.c

@@ -7,6 +7,7 @@
  * SPDX-License-Identifier: BSD-3-Clause
  */
 
+#include <internal/string.h>
 #include <openamp/rpmsg.h>
 #include <metal/alloc.h>
 
@@ -141,7 +142,7 @@ int rpmsg_send_ns_message(struct rpmsg_endpoint *ept, unsigned long flags)
 
 	ns_msg.flags = flags;
 	ns_msg.addr = ept->addr;
-	strncpy(ns_msg.name, ept->name, sizeof(ns_msg.name));
+	(void)strlcpy(ns_msg.name, ept->name, sizeof(ns_msg.name));
 	ret = rpmsg_send_offchannel_raw(ept, ept->addr,
 					RPMSG_NS_EPT_ADDR,
 					&ns_msg, sizeof(ns_msg), true);
@@ -305,7 +306,7 @@ void rpmsg_register_endpoint(struct rpmsg_device *rdev,
 			     rpmsg_ept_cb cb,
 			     rpmsg_ns_unbind_cb ns_unbind_cb, void *priv)
 {
-	strncpy(ept->name, name ? name : "", sizeof(ept->name));
+	(void)strlcpy(ept->name, name ? name : "", sizeof(ept->name));
 	ept->refcnt = 1;
 	ept->addr = src;
 	ept->dest_addr = dest;

open-amp/lib/utils/CMakeLists.txt

@@ -0,0 +1 @@
+collect (PROJECT_LIB_SOURCES string.c)

open-amp/lib/utils/string.c

@@ -0,0 +1,29 @@
+/*
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 2024, STMicroelectronics
+ *
+ */
+
+#include <internal/string.h>
+#include <metal/io.h>
+
+metal_weak size_t strlcpy(char *dst, const char *src, size_t size)
+{
+	size_t nleft = size;
+
+	/* Copy as many bytes as will fit. */
+	if (nleft != 0) {
+		while (--nleft != 0) {
+			*dst = *src++;
+			if (*dst++ == '\0')
+				break;
+		}
+	}
+
+	/* Not enough room in dst, add NUL and traverse rest of src. */
+	if (nleft == 0 && size != 0)
+		*dst = '\0';		/* NUL-terminate dst */
+
+	return strlen(src);
+}