Add option [-V|--version] to emit version string

Add the 'zfs version' and 'zpool version' subcommands to display
the version of the user space utilities and loaded zfs kernel
module.  For example:

$ zfs version
zfs-0.8.0-rc3_169_g67e0366b88
zfs-kmod-0.8.0-rc3_169_g67e0366b88

The '-V' and '--version' aliases were added to support the
common convention of using 'zfs --version` to obtain the version
information.

Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Matthew Ahrens <[email protected]>
Reviewed-by: Richard Laager <[email protected]>
Signed-off-by: TerraTech <[email protected]>
Closes #2501
Closes #8567

1 files changed, 64 insertions, 0 deletions

diff --git a/lib/libzfs/libzfs_util.c b/lib/libzfs/libzfs_util.c
index 23dcb11bd..b988d8f31 100644
--- a/lib/libzfs/libzfs_util.c
+++ b/lib/libzfs/libzfs_util.c
@@ -54,6 +54,7 @@
 #include "zfeature_common.h"
 #include <zfs_fletcher.h>
 #include <libzutil.h>
+#include <sys/zfs_sysfs.h>
 
 int
 libzfs_errno(libzfs_handle_t *hdl)
@@ -1940,3 +1941,66 @@ zprop_iter(zprop_func func, void *cb, boolean_t show_all, boolean_t ordered,
 {
 	return (zprop_iter_common(func, cb, show_all, ordered, type));
 }
+
+/*
+ * Fill given version buffer with zfs userland version
+ */
+void
+zfs_version_userland(char *version, int len)
+{
+	(void) strlcpy(version, ZFS_META_ALIAS, len);
+}
+
+/*
+ * Fill given version buffer with zfs kernel version read from ZFS_SYSFS_DIR
+ * Returns 0 on success, and -1 on error (with errno set)
+ */
+int
+zfs_version_kernel(char *version, int len)
+{
+	int _errno;
+	int fd;
+	int rlen;
+
+	if ((fd = open(ZFS_SYSFS_DIR "/version", O_RDONLY)) == -1)
+		return (-1);
+
+	if ((rlen = read(fd, version, len)) == -1) {
+		version[0] = '\0';
+		_errno = errno;
+		(void) close(fd);
+		errno = _errno;
+		return (-1);
+	}
+
+	version[rlen-1] = '\0';  /* discard '\n' */
+
+	if (close(fd) == -1)
+		return (-1);
+
+	return (0);
+}
+
+/*
+ * Prints both zfs userland and kernel versions
+ * Returns 0 on success, and -1 on error (with errno set)
+ */
+int
+zfs_version_print(void)
+{
+	char zver_userland[128];
+	char zver_kernel[128];
+
+	if (zfs_version_kernel(zver_kernel, sizeof (zver_kernel)) == -1) {
+		fprintf(stderr, "zfs_version_kernel() failed: %s\n",
+		    strerror(errno));
+		return (-1);
+	}
+
+	zfs_version_userland(zver_userland, sizeof (zver_userland));
+
+	(void) printf("%s\n", zver_userland);
+	(void) printf("zfs-kmod-%s\n", zver_kernel);
+
+	return (0);
+}