[nfs-utils PATCH v4] systemd: add a generator for the rpc_pipefs mountpoint

[Scott Mayhew <smayhew@redhat.com>]

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>
---
 .gitignore                     |   1 +
 systemd/Makefile.am            |  14 ++++-
 systemd/nfs-blkmap.service     |   4 +-
 systemd/nfs-idmapd.service     |   4 +-
 systemd/nfs-server-generator.c |  33 +---------
 systemd/rpc-gssd.service.in    |   4 +-
 systemd/rpc-pipefs-generator.c | 138 +++++++++++++++++++++++++++++++++++++++++
 systemd/rpc-svcgssd.service    |   3 +-
 systemd/rpc_pipefs.target      |   3 +
 systemd/systemd.c              | 133 +++++++++++++++++++++++++++++++++++++++
 systemd/systemd.h              |   6 ++
 11 files changed, 302 insertions(+), 41 deletions(-)
 create mode 100644 systemd/rpc-pipefs-generator.c
 create mode 100644 systemd/rpc_pipefs.target
 create mode 100644 systemd/systemd.c
 create mode 100644 systemd/systemd.h

diff --git a/.gitignore b/.gitignore
index 126d12c..941aca0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -70,6 +70,7 @@ tests/nsm_client/nlm_sm_inter_svc.c
 tests/nsm_client/nlm_sm_inter_xdr.c
 utils/nfsidmap/nfsidmap
 systemd/nfs-server-generator
+systemd/rpc-pipefs-generator
 systemd/nfs-config.service
 systemd/rpc-gssd.service
 # cscope database files
diff --git a/systemd/Makefile.am b/systemd/Makefile.am
index 0d15b9f..eef53c4 100644
--- a/systemd/Makefile.am
+++ b/systemd/Makefile.am
@@ -4,6 +4,7 @@ MAINTAINERCLEANFILES = Makefile.in
 
 unit_files =  \
     nfs-client.target \
+    rpc_pipefs.target \
     \
     nfs-mountd.service \
     nfs-server.service \
@@ -42,14 +43,23 @@ EXTRA_DIST = $(unit_files) $(man5_MANS) $(man7_MANS)
 unit_dir = /usr/lib/systemd/system
 generator_dir = /usr/lib/systemd/system-generators
 
-EXTRA_PROGRAMS	= nfs-server-generator
+EXTRA_PROGRAMS	= nfs-server-generator rpc-pipefs-generator
 genexecdir = $(generator_dir)
+
+COMMON_SRCS = systemd.c systemd.h
+
+nfs_server_generator_SOURCES = $(COMMON_SRCS) nfs-server-generator.c
+
+rpc_pipefs_generator_SOURCES = $(COMMON_SRCS) rpc-pipefs-generator.c
+
 nfs_server_generator_LDADD = ../support/export/libexport.a \
 			     ../support/nfs/libnfs.a \
 			     ../support/misc/libmisc.a
 
+rpc_pipefs_generator_LDADD = ../support/nfs/libnfs.a
+
 if INSTALL_SYSTEMD
-genexec_PROGRAMS = nfs-server-generator
+genexec_PROGRAMS = nfs-server-generator rpc-pipefs-generator
 install-data-hook: $(unit_files)
 	mkdir -p $(DESTDIR)/$(unitdir)
 	cp $(unit_files) $(DESTDIR)/$(unitdir)
diff --git a/systemd/nfs-blkmap.service b/systemd/nfs-blkmap.service
index ddc324e..2bbcee6 100644
--- a/systemd/nfs-blkmap.service
+++ b/systemd/nfs-blkmap.service
@@ -2,8 +2,8 @@
 Description=pNFS block layout mapping daemon
 DefaultDependencies=no
 Conflicts=umount.target
-After=var-lib-nfs-rpc_pipefs.mount
-Requires=var-lib-nfs-rpc_pipefs.mount
+After=rpc_pipefs.target
+Requires=rpc_pipefs.target
 
 PartOf=nfs-utils.service
 
diff --git a/systemd/nfs-idmapd.service b/systemd/nfs-idmapd.service
index acca86b..f38fe52 100644
--- a/systemd/nfs-idmapd.service
+++ b/systemd/nfs-idmapd.service
@@ -1,8 +1,8 @@
 [Unit]
 Description=NFSv4 ID-name mapping service
 DefaultDependencies=no
-Requires=var-lib-nfs-rpc_pipefs.mount
-After=var-lib-nfs-rpc_pipefs.mount local-fs.target
+Requires=rpc_pipefs.target
+After=rpc_pipefs.target local-fs.target
 
 BindsTo=nfs-server.service
 
diff --git a/systemd/nfs-server-generator.c b/systemd/nfs-server-generator.c
index 4aa6509..ce3d7fd 100644
--- a/systemd/nfs-server-generator.c
+++ b/systemd/nfs-server-generator.c
@@ -29,6 +29,7 @@
 #include "misc.h"
 #include "nfslib.h"
 #include "exportfs.h"
+#include "systemd.h"
 
 /* A simple "set of strings" to remove duplicates
  * found in /etc/exports
@@ -55,35 +56,6 @@ static int is_unique(struct list **lp, char *path)
 	return 1;
 }
 
-/* We need to convert a path name to a systemd unit
- * name.  This requires some translation ('/' -> '-')
- * and some escaping.
- */
-static void systemd_escape(FILE *f, char *path)
-{
-	while (*path == '/')
-		path++;
-	if (!*path) {
-		/* "/" becomes "-", otherwise leading "/" is ignored */
-		fputs("-", f);
-		return;
-	}
-	while (*path) {
-		char c = *path++;
-
-		if (c == '/') {
-			/* multiple non-trailing slashes become '-' */
-			while (*path == '/')
-				path++;
-			if (*path)
-				fputs("-", f);
-		} else if (isalnum(c) || c == ':' || c == '.')
-			fputc(c, f);
-		else
-			fprintf(f, "\\x%02x", c & 0xff);
-	}
-}
-
 static int has_noauto_flag(char *path)
 {
 	FILE		*fstab;
@@ -168,8 +140,7 @@ int main(int argc, char *argv[])
 		    strcmp(mnt->mnt_type, "nfs4") != 0)
 			continue;
 		fprintf(f, "Before= ");
-		systemd_escape(f, mnt->mnt_dir);
-		fprintf(f, ".mount\n");
+		fprintf(f, "%s\n", systemd_escape(mnt->mnt_dir, ".mount"));
 	}
 
 	fclose(fstab);
diff --git a/systemd/rpc-gssd.service.in b/systemd/rpc-gssd.service.in
index b353027..6807db3 100644
--- a/systemd/rpc-gssd.service.in
+++ b/systemd/rpc-gssd.service.in
@@ -2,8 +2,8 @@
 Description=RPC security service for NFS client and server
 DefaultDependencies=no
 Conflicts=umount.target
-Requires=var-lib-nfs-rpc_pipefs.mount
-After=var-lib-nfs-rpc_pipefs.mount
+Requires=rpc_pipefs.target
+After=rpc_pipefs.target
 
 ConditionPathExists=@_sysconfdir@/krb5.keytab
 
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);
+}
diff --git a/systemd/rpc-svcgssd.service b/systemd/rpc-svcgssd.service
index 7187e3c..cb2bcd4 100644
--- a/systemd/rpc-svcgssd.service
+++ b/systemd/rpc-svcgssd.service
@@ -1,8 +1,7 @@
 [Unit]
 Description=RPC security service for NFS server
 DefaultDependencies=no
-Requires=var-lib-nfs-rpc_pipefs.mount
-After=var-lib-nfs-rpc_pipefs.mount local-fs.target
+After=local-fs.target
 PartOf=nfs-server.service
 PartOf=nfs-utils.service
 
diff --git a/systemd/rpc_pipefs.target b/systemd/rpc_pipefs.target
new file mode 100644
index 0000000..01d4d27
--- /dev/null
+++ b/systemd/rpc_pipefs.target
@@ -0,0 +1,3 @@
+[Unit]
+Requires=var-lib-nfs-rpc_pipefs.mount
+After=var-lib-nfs-rpc_pipefs.mount
diff --git a/systemd/systemd.c b/systemd/systemd.c
new file mode 100644
index 0000000..e10da52
--- /dev/null
+++ b/systemd/systemd.c
@@ -0,0 +1,133 @@
+/*
+ * Helper functions for systemd generators in nfs-utils.
+ *
+ * Currently just systemd_escape().
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+
+static const char hex[16] =
+{
+  '0', '1', '2', '3', '4', '5', '6', '7',
+  '8', '9', 'a', 'b', 'c', 'd', 'e', 'f',
+};
+
+/*
+ * determine length of the string that systemd_escape() needs to allocate
+ */
+static int systemd_len(char *path)
+{
+	char *p;
+	int len = 0;
+
+	p = path;
+	while (*p == '/')
+		/* multiple leading "/" are ignored */
+		p++;
+
+	if (!*p)
+		/* root directory "/" becomes is encoded as a single "-" */
+		return 1;
+
+	if (*p == '.')
+		/*
+		 * replace "." with "\x2d" escape sequence if
+		 * it's the first character in escaped path
+		 * */
+		len += 4;
+
+	while (*p) {
+		unsigned char c = *p++;
+
+		if (c == '/') {
+			/* multiple non-trailing slashes become '-' */
+			while (*p == '/')
+				p++;
+			if (*p)
+				len++;
+		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
+			/* these characters are not replaced */
+			len++;
+		else
+			/* replace with "\x2d" escape sequence */
+			len += 4;
+	}
+
+	return len;
+}
+
+/*
+ * convert c to "\x2d" escape sequence and append to string
+ * at position p, advancing p
+ */
+static char *hexify(unsigned char c, char *p)
+{
+	*p++ = '\\';
+	*p++ = 'x';
+	*p++ = hex[c >> 4];
+	*p++ = hex[c & 0xf];
+	return p;
+}
+
+/*
+ * convert a path to a unit name according to the logic in systemd.unit(5):
+ *
+ *     Basically, given a path, "/" is replaced by "-", and all other
+ *     characters which are not ASCII alphanumerics are replaced by C-style
+ *     "\x2d" escapes (except that "_" is never replaced and "." is only
+ *     replaced when it would be the first character in the escaped path).
+ *     The root directory "/" is encoded as single dash, while otherwise the
+ *     initial and ending "/" are removed from all paths during
+ *     transformation.
+ *
+ * NB: Although the systemd.unit(5) doesn't mention it, the ':' character
+ * is not escaped.
+ */
+char *systemd_escape(char *path, char *suffix)
+{
+	char *result;
+	char *p;
+	int len;
+
+	len = systemd_len(path);
+	result = malloc(len + strlen(suffix) + 1);
+	p = result;
+	while (*path == '/')
+		/* multiple leading "/" are ignored */
+		path++;
+	if (!*path) {
+		/* root directory "/" becomes is encoded as a single "-" */
+		*p++ = '-';
+		goto out;
+	}
+	if (*path == '.')
+		/*
+		 * replace "." with "\x2d" escape sequence if
+		 * it's the first character in escaped path
+		 * */
+		p = hexify(*path++, p);
+
+	while (*path) {
+		unsigned char c = *path++;
+
+		if (c == '/') {
+			/* multiple non-trailing slashes become '-' */
+			while (*path == '/')
+				path++;
+			if (*path)
+				*p++ = '-';
+		} else if (isalnum(c) || c == ':' || c == '.' || c == '_')
+			/* these characters are not replaced */
+			*p++ = c;
+		else
+			/* replace with "\x2d" escape sequence */
+			p = hexify(c, p);
+	}
+
+out:
+	sprintf(p, suffix);
+	return result;
+}
diff --git a/systemd/systemd.h b/systemd/systemd.h
new file mode 100644
index 0000000..25235ec
--- /dev/null
+++ b/systemd/systemd.h
@@ -0,0 +1,6 @@
+#ifndef SYSTEMD_H
+#define SYSTEMD_H
+
+char *systemd_escape(char *path, char *suffix);
+
+#endif /* SYSTEMD_H */
-- 
2.9.3