systemd: add a generator for the rpc_pipefs mountpoint

The nfs.conf has config options for the rpc_pipefs mountpoint.
Currently, changing these from the default also requires manually
overriding the systemd unit files that are hard-coded to mount the
filesystem on /var/lib/nfs/rpc_pipefs.

This patch adds a generator that creates a mount unit file for the
rpc_pipefs when a non-default value is specified in /etc/nfs.conf, as
well as a target unit file to override the dependencies for the systemd
units using the rpc_pipefs.  The blkmapd, idmapd, and gssd service unit
files have been modified to define their dependencies on the rpc_pipefs
mountpoint indirectly via the rpc_pipefs target unit file.  Since both
rpc-pipefs-generator.c and nfs-server-generator.c need to convert path
names to unit file names, that functionality has been moved to
systemd.c.

This patch also removes the dependency on the rpc_pipefs from the
rpc-svcgssd.service unit file.  rpc.svcgssd uses the sunrpc cache
mechanism to exchange data with the kernel, not the rpc_pipefs.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

1 files changed, 138 insertions, 0 deletions

diff --git a/systemd/rpc-pipefs-generator.c b/systemd/rpc-pipefs-generator.c
new file mode 100644
index 0000000..66addb9
--- /dev/null
+++ b/systemd/rpc-pipefs-generator.c
@@ -0,0 +1,138 @@
+/*
+ * rpc-pipefs-generator:
+ *   systemd generator to create ordering dependencies between
+ *   nfs services and the rpc_pipefs mountpoint
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+#include <stdio.h>
+#include <mntent.h>
+
+#include "nfslib.h"
+#include "conffile.h"
+#include "systemd.h"
+
+#define RPC_PIPEFS_DEFAULT "/var/lib/nfs/rpc_pipefs"
+char *conf_path = NFS_CONFFILE;
+
+static int generate_mount_unit(const char *pipefs_path, const char *pipefs_unit,
+			       const char *dirname)
+{
+	char	*path;
+	FILE	*f;
+
+	path = malloc(strlen(dirname) + 1 + strlen(pipefs_unit));
+	if (!path)
+		return 1;
+	sprintf(path, "%s/%s", dirname, pipefs_unit);
+	f = fopen(path, "w");
+	if (!f)
+		return 1;
+
+	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
+	fprintf(f, "Description=RPC Pipe File System\n");
+	fprintf(f, "DefaultDependencies=no\n");
+	fprintf(f, "After=systemd-tmpfiles-setup.service\n");
+	fprintf(f, "Conflicts=umount.target\n");
+	fprintf(f, "\n[Mount]\n");
+	fprintf(f, "What=sunrpc\n");
+	fprintf(f, "Where=%s\n", pipefs_path);
+	fprintf(f, "Type=rpc_pipefs\n");
+
+	fclose(f);
+	return 0;
+}
+
+static
+int generate_target(char *pipefs_path, const char *dirname)
+{
+	char	*path;
+	char	filebase[] = "/rpc_pipefs.target";
+	char	*pipefs_unit;
+	FILE	*f;
+	int 	ret = 0;
+
+	pipefs_unit = systemd_escape(pipefs_path, ".mount");
+	if (!pipefs_unit)
+		return 1;
+
+	ret = generate_mount_unit(pipefs_path, pipefs_unit, dirname);
+	if (ret)
+		return ret;
+
+	path = malloc(strlen(dirname) + 1 + sizeof(filebase));
+	if (!path)
+		return 2;
+	sprintf(path, "%s", dirname);
+	mkdir(path, 0755);
+	strcat(path, filebase);
+	f = fopen(path, "w");
+	if (!f)
+		return 1;
+
+	fprintf(f, "# Automatically generated by rpc-pipefs-generator\n\n[Unit]\n");
+	fprintf(f, "Requires=%s\n", pipefs_unit);
+	fprintf(f, "After=%s\n", pipefs_unit);
+	fclose(f);
+
+	return 0;
+}
+
+static int is_non_pipefs_mountpoint(char *path)
+{
+	FILE		*mtab;
+	struct mntent	*mnt;
+
+	mtab = setmntent("/etc/mtab", "r");
+	if (!mtab)
+		return 0;
+
+	while ((mnt = getmntent(mtab)) != NULL) {
+		if (strlen(mnt->mnt_dir) != strlen(path))
+			continue;
+		if (strncmp(mnt->mnt_dir, path, strlen(mnt->mnt_dir)))
+			continue;
+		if (strncmp(mnt->mnt_type, "rpc_pipefs", strlen(mnt->mnt_type)))
+			break;
+	}
+	fclose(mtab);
+	return mnt != NULL;
+}
+
+int main(int argc, char *argv[])
+{
+	int 	ret;
+	char	*s;
+
+	/* Avoid using any external services */
+	xlog_syslog(0);
+
+	if (argc != 4 || argv[1][0] != '/') {
+		fprintf(stderr, "rpc-pipefs-generator: create systemd dependencies for nfs services\n");
+		fprintf(stderr, "Usage: normal-dir early-dir late-dir\n");
+		exit(1);
+	}
+
+	conf_init();
+	s = conf_get_str("general", "pipefs-directory");
+	if (!s)
+		exit(0);
+	if (strlen(s) == strlen(RPC_PIPEFS_DEFAULT) &&
+			strcmp(s, RPC_PIPEFS_DEFAULT) == 0)
+		exit(0);
+
+	if (is_non_pipefs_mountpoint(s))
+		exit(1);
+
+	ret = generate_target(s, argv[1]);
+	exit(ret);
+}