Add scoutfs recompute-xattr-total subcommand.

Wire SCOUTFS_IOC_RECOMPUTE_TOTL into the scoutfs util. Needs the
path to the mountpoint the A.B.C totl key.

Signed-off-by: Auke Kok <auke.kok@versity.com>

utils/src/recompute_xattr_total.c

@@ -0,0 +1,129 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/ioctl.h>
+#include <argp.h>
+
+#include "sparse.h"
+#include "parse.h"
+#include "util.h"
+#include "format.h"
+#include "ioctl.h"
+#include "cmd.h"
+
+struct recompute_xattr_total_args {
+	char *path;
+	u64 name[3];
+	unsigned name_set:1;
+};
+
+/* parse "<a>.<b>.<c>" into name[0..2] */
+static int parse_dotted_name(const char *s, u64 name[3])
+{
+	const char *p = s;
+	char *end;
+	int i;
+
+	for (i = 0; i < 3; i++) {
+		if (*p == '\0' || *p == '.')
+			return -1;
+		errno = 0;
+		name[i] = strtoull(p, &end, 0);
+		if (errno || end == p)
+			return -1;
+
+		if (i < 2) {
+			if (*end != '.')
+				return -1;
+			p = end + 1;
+		} else {
+			if (*end != '\0')
+				return -1;
+		}
+	}
+	return 0;
+}
+
+static int do_recompute_xattr_total(struct recompute_xattr_total_args *args)
+{
+	struct scoutfs_ioctl_recompute_totl rt;
+	int ret;
+	int fd;
+
+	fd = get_path(args->path, O_RDONLY);
+	if (fd < 0)
+		return fd;
+
+	memset(&rt, 0, sizeof(rt));
+	rt.name[0] = args->name[0];
+	rt.name[1] = args->name[1];
+	rt.name[2] = args->name[2];
+
+	ret = ioctl(fd, SCOUTFS_IOC_RECOMPUTE_TOTL, &rt);
+	if (ret < 0) {
+		ret = -errno;
+		fprintf(stderr, "recompute_xattr_total ioctl failed: %s (%d)\n",
+			strerror(errno), errno);
+	}
+
+	close(fd);
+	return ret;
+}
+
+static int parse_opt(int key, char *arg, struct argp_state *state)
+{
+	struct recompute_xattr_total_args *args = state->input;
+
+	switch (key) {
+	case 'p':
+		args->path = strdup_or_error(state, arg);
+		break;
+	case ARGP_KEY_ARG:
+		if (args->name_set)
+			argp_error(state, "more than one argument given");
+		if (parse_dotted_name(arg, args->name))
+			argp_error(state, "totl key parse error");
+		args->name_set = 1;
+		break;
+	case ARGP_KEY_FINI:
+		if (!args->name_set)
+			argp_error(state, "must provide totl key");
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static struct argp_option options[] = {
+	{ "path", 'p', "PATH", 0, "Path to ScoutFS filesystem"},
+	{ NULL }
+};
+
+static struct argp argp = {
+	options,
+	parse_opt,
+	"A.B.C",
+	"Recompute a .totl. xattr key from its contributing xattrs and repair drift"
+};
+
+static int recompute_xattr_total_cmd(int argc, char **argv)
+{
+	struct recompute_xattr_total_args args = { 0 };
+	int ret;
+
+	ret = argp_parse(&argp, argc, argv, 0, NULL, &args);
+	if (ret)
+		return ret;
+
+	return do_recompute_xattr_total(&args);
+}
+
+static void __attribute__((constructor)) recompute_xattr_total_ctor(void)
+{
+	cmd_register_argp("recompute-xattr-total", &argp, GROUP_INFO, recompute_xattr_total_cmd);
+}