Enable -Wwrite-strings

Also, fix leak from ztest_global_vars_to_zdb_args()

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #13348

lib/libzfs/os/freebsd/libzfs_zmount.c

@@ -74,7 +74,7 @@ build_iovec(struct iovec **iov, int *iovlen, const char *name, void *val,
 }
 
 static int
-do_mount_(const char *spec, const char *dir, int mflag, char *fstype,
+do_mount_(const char *spec, const char *dir, int mflag,
     char *dataptr, int datalen, char *optptr, int optlen)
 {
 	struct iovec *iov;
@@ -83,8 +83,6 @@ do_mount_(const char *spec, const char *dir, int mflag, char *fstype,
 
 	assert(spec != NULL);
 	assert(dir != NULL);
-	assert(fstype != NULL);
-	assert(strcmp(fstype, MNTTYPE_ZFS) == 0);
 	assert(dataptr == NULL), (void) dataptr;
 	assert(datalen == 0), (void) datalen;
 	assert(optptr != NULL);
@@ -99,7 +97,8 @@ do_mount_(const char *spec, const char *dir, int mflag, char *fstype,
 		build_iovec(&iov, &iovlen, "update", NULL, 0);
 	if (mflag & MS_RDONLY)
 		build_iovec(&iov, &iovlen, "ro", NULL, 0);
-	build_iovec(&iov, &iovlen, "fstype", fstype, (size_t)-1);
+	build_iovec(&iov, &iovlen, "fstype", __DECONST(char *, MNTTYPE_ZFS),
+	    (size_t)-1);
 	build_iovec(&iov, &iovlen, "fspath", __DECONST(char *, dir),
 	    (size_t)-1);
 	build_iovec(&iov, &iovlen, "from", __DECONST(char *, spec), (size_t)-1);
@@ -113,10 +112,10 @@ do_mount_(const char *spec, const char *dir, int mflag, char *fstype,
 }
 
 int
-do_mount(zfs_handle_t *zhp, const char *mntpt, char *opts, int flags)
+do_mount(zfs_handle_t *zhp, const char *mntpt, const char *opts, int flags)
 {
 
-	return (do_mount_(zfs_get_name(zhp), mntpt, flags, MNTTYPE_ZFS, NULL, 0,
+	return (do_mount_(zfs_get_name(zhp), mntpt, flags, NULL, 0,
 	    opts, sizeof (mntpt)));
 }
 

lib/libzfs/os/linux/libzfs_mount_os.c

@@ -180,7 +180,7 @@ out:
  * otherwise they are considered fatal are copied in to badopt.
  */
 int
-zfs_parse_mount_options(char *mntopts, unsigned long *mntflags,
+zfs_parse_mount_options(const char *mntopts, unsigned long *mntflags,
     unsigned long *zfsflags, int sloppy, char *badopt, char *mtabopt)
 {
 	int error = 0, quote = 0, flag = 0, count = 0;
@@ -320,7 +320,7 @@ zfs_adjust_mount_options(zfs_handle_t *zhp, const char *mntpoint,
  * make due with return value from the mount process.
  */
 int
-do_mount(zfs_handle_t *zhp, const char *mntpt, char *opts, int flags)
+do_mount(zfs_handle_t *zhp, const char *mntpt, const char *opts, int flags)
 {
 	const char *src = zfs_get_name(zhp);
 	int error = 0;
@@ -341,10 +341,10 @@ do_mount(zfs_handle_t *zhp, const char *mntpt, char *opts, int flags)
 		}
 	} else {
 		char *argv[9] = {
-		    "/bin/mount",
-		    "--no-canonicalize",
-		    "-t", MNTTYPE_ZFS,
-		    "-o", opts,
+		    (char *)"/bin/mount",
+		    (char *)"--no-canonicalize",
+		    (char *)"-t", (char *)MNTTYPE_ZFS,
+		    (char *)"-o", (char *)opts,
 		    (char *)src,
 		    (char *)mntpt,
 		    (char *)NULL };
@@ -384,23 +384,17 @@ do_unmount(zfs_handle_t *zhp, const char *mntpt, int flags)
 		return (rv < 0 ? errno : 0);
 	}
 
-	char force_opt[] = "-f";
-	char lazy_opt[] = "-l";
 	char *argv[7] = {
-	    "/bin/umount",
-	    "-t", MNTTYPE_ZFS,
+	    (char *)"/bin/umount",
+	    (char *)"-t", (char *)MNTTYPE_ZFS,
 	    NULL, NULL, NULL, NULL };
 	int rc, count = 3;
 
-	if (flags & MS_FORCE) {
-		argv[count] = force_opt;
-		count++;
-	}
+	if (flags & MS_FORCE)
+		argv[count++] = (char *)"-f";
 
-	if (flags & MS_DETACH) {
-		argv[count] = lazy_opt;
-		count++;
-	}
+	if (flags & MS_DETACH)
+		argv[count++] = (char *)"-l";
 
 	argv[count] = (char *)mntpt;
 	rc = libzfs_run_process(argv[0], argv, STDOUT_VERBOSE|STDERR_VERBOSE);

lib/libzfs/os/linux/libzfs_util_os.c

@@ -99,7 +99,7 @@ libzfs_load_module(void)
 		return (0);
 
 	if (access(ZFS_SYSFS_DIR, F_OK) != 0) {
-		char *argv[] = {"modprobe", "zfs", NULL};
+		char *argv[] = {(char *)"modprobe", (char *)"zfs", NULL};
 		if (libzfs_run_process("modprobe", argv, 0))
 			return (ENOEXEC);