posix: implement uname

Add implementation for posix uname.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>

doc/services/portability/posix.rst

@@ -353,7 +353,7 @@ process applications.
     getenv(),
     setenv(),
     sysconf(),
-    uname(),
+    uname(),yes
     unsetenv()
 
 

include/zephyr/posix/sys/utsname.h

@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2023 Meta
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef ZEPHYR_INCLUDE_POSIX_SYS_UTSNAME_H_
+#define ZEPHYR_INCLUDE_POSIX_SYS_UTSNAME_H_
+
+#include "version.h"
+
+#include <errno.h>
+#include <stdint.h>
+
+#include <zephyr/net/hostname.h>
+#include <zephyr/toolchain/common.h>
+#include <zephyr/net/hostname.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* sysname */
+#define SYS_NAMELEN sizeof("Zephyr")
+
+/* nodename */
+#ifdef CONFIG_NET_HOSTNAME_ENABLE
+#define NODE_NAMELEN NET_HOSTNAME_MAX_LEN
+#else
+#define NODE_NAMELEN SYS_NAMELEN
+#endif
+
+/* release */
+#define RELEASE_NAMELEN sizeof(KERNEL_VERSION_STRING)
+
+/* version */
+#if defined(__DATE__) && defined(__TIME__)
+#define DATETIME_LEN (sizeof(__DATE__) + sizeof(__TIME__))
+#else
+#define DATETIME_LEN 0
+#endif
+
+#ifdef BUILD_VERSION
+#define VERSION_BUILD STRINGIFY(BUILD_VERSION)
+#else
+#define VERSION_BUILD KERNEL_VERSION_STRING
+#endif
+#define VERSION_BUILD_LEN sizeof(VERSION_BUILD)
+
+/**
+ * In case anyone wondered if this length has been adjusted for '\0', it will
+ * be formatted in utsname.c as:
+ *     "%s %s %s", VERSION_BUILD, __DATE__, __TIME__
+ * the '\0' of VERSION_BUILD_LEN & __DATE__ will be used for the space that
+ * follows, '\0' of __TIME__ will be used for the \0 of the formatted VERSION
+ * string. In the end the size of the array should fit the string snugly.
+ */
+#define VERSION_NAMELEN (VERSION_BUILD_LEN + DATETIME_LEN)
+
+/* machine */
+#define MACHINE_NAMELEN sizeof(CONFIG_ARCH)
+
+struct utsname {
+	char sysname[SYS_NAMELEN];
+	char nodename[NODE_NAMELEN];
+	char release[RELEASE_NAMELEN];
+	char version[VERSION_NAMELEN];
+	char machine[MACHINE_NAMELEN];
+};
+
+int uname(struct utsname *name);
+
+#undef SYS_NAMELEN
+#undef NODE_NAMELEN
+#undef RELEASE_NAMELEN
+#undef VERSION_NAMELEN
+#undef MACHINE_NAMELEN
+#undef DATETIME_LEN
+#undef VERSION_BUILD_LEN
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_POSIX_SYS_UTSNAME_H_ */

lib/posix/CMakeLists.txt

@@ -37,6 +37,7 @@ zephyr_library_sources_ifdef(CONFIG_POSIX_MQUEUE mqueue.c)
 zephyr_library_sources_ifdef(CONFIG_POSIX_FS fs.c)
 zephyr_library_sources_ifdef(CONFIG_EVENTFD eventfd.c)
 zephyr_library_sources_ifdef(CONFIG_FNMATCH fnmatch.c)
+zephyr_library_sources_ifdef(CONFIG_POSIX_UNAME utsname.c)
 add_subdirectory_ifdef(CONFIG_GETOPT getopt)
 
 zephyr_library_include_directories(

lib/posix/Kconfig

@@ -182,3 +182,10 @@ config FNMATCH
 	help
 	  Match filenames using the the fnmatch function. For example, the pattern
 	  "*.c" matches the filename "hello.c".
+
+config POSIX_UNAME
+	bool "Support for uname"
+	default y if POSIX_API
+	help
+	  The uname() function shall store information identifying the current
+	  system in the structure pointed to by name.

lib/posix/utsname.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2023 Meta
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#include <zephyr/posix/sys/utsname.h>
+
+int uname(struct utsname *name)
+{
+	if (name == NULL) {
+		return -1;
+		errno = EINVAL;
+	}
+
+	strncpy(name->sysname, "Zephyr", sizeof(name->sysname));
+	strncpy(name->nodename, net_hostname_get(), sizeof(name->nodename));
+	strncpy(name->release, KERNEL_VERSION_STRING, sizeof(name->release));
+#if defined(__DATE__) && defined(__TIME__)
+	snprintf(name->version, sizeof(name->version), "%s %s %s", VERSION_BUILD, __DATE__,
+		 __TIME__);
+#else
+	strncpy(name->version, VERSION_BUILD, sizeof(name->version));
+#endif
+	strncpy(name->machine, CONFIG_ARCH, sizeof(name->machine));
+
+	return 0;
+}