From: Jiri Horky <jiri.horky@gmail.com>
To: linux-nfs@vger.kernel.org
Cc: du@cesnet.cz, Jiri Horky <jiri.horky@gmail.com>, SteveD@redhat.com
Subject: [PATCH] libnfsidmap: implementation of client side Static translation method.
Date: Mon, 23 Jul 2012 09:20:20 +0200
Message-Id: <1343028020-10587-1-git-send-email-jiri.horky@gmail.com>
To: linux-nfs@vger.kernel.org
Sender: linux-nfs-owner@vger.kernel.org

Since the [Static] section in idmapd.conf does not distinguish between user
and group mappings we try both cases for each defined mapping. The code caches
id->name mappings in the init function

Signed-off-by: Jiri Horky <jiri.horky@gmail.com>
---
 static.c |  266 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 255 insertions(+), 11 deletions(-)

diff --git a/static.c b/static.c
index fffd458..8be87e8 100644
--- a/static.c
+++ b/static.c
@@ -40,6 +40,7 @@
 #include <grp.h>
 #include <errno.h>
 
+#include "queue.h"
 #include "cfg.h"
 #include "nfsidmap.h"
 #include "nfsidmap_internal.h"
@@ -57,6 +58,40 @@ struct pwbuf {
 	char buf[1];
 };
 
+struct grbuf {
+	struct group grbuf;
+	char buf[1];
+};
+
+struct uid_mapping {
+	LIST_ENTRY (uid_mapping) link;
+	uid_t uid;
+	char * principal;
+	char * localname;
+};
+
+struct gid_mapping {
+	LIST_ENTRY (gid_mapping) link;
+	gid_t gid;
+	char * principal;
+	char * localgroup;
+};
+
+static __inline__ u_int8_t uid_hash (uid_t uid)
+{
+	return uid % 256;
+}
+
+static __inline__ u_int8_t gid_hash (gid_t gid)
+{
+	return gid % 256;
+}
+
+//Hash tables of uid and guids to principals mappings.
+//We reuse some queue/hash functions from cfg.c.
+LIST_HEAD (uid_mappings, uid_mapping) uid_mappings[256];
+LIST_HEAD (gid_mappings, gid_mapping) gid_mappings[256];
+
 static struct passwd *static_getpwnam(const char *name, const char *domain,
 				      int *err_p)
 {
@@ -75,12 +110,9 @@ static struct passwd *static_getpwnam(const char *name, const char *domain,
 	localname = conf_get_str("Static", (char *)name);
 	if (!localname) {
 		err = ENOENT;
-		goto err;
+		goto err_free_buf;
 	}
 
-	IDMAP_LOG(4, ("static_getpwnam: name '%s' mapped to '%s'\n",
-		  name, localname));
-
 again:
 	err = getpwnam_r(localname, &buf->pwbuf, buf->buf, buflen, &pw);
 
@@ -91,12 +123,15 @@ again:
 		if (err == 0)
 			err = ENOENT;
 
-		IDMAP_LOG(0, ("static_getpwnam: name '%s' not found\n",
-			  localname));
+		IDMAP_LOG(0, ("static_getpwnam: localname '%s' for '%s' not found\n",
+		  localname, name));
 
 		goto err_free_buf;
 	}
 
+	IDMAP_LOG(4, ("static_getpwnam: name '%s' mapped to '%s'\n",
+		  name, localname));
+
 	*err_p = 0;
 	return pw;
 
@@ -107,6 +142,56 @@ err:
 	return NULL;
 }
 
+static struct group *static_getgrnam(const char *name, const char *domain,
+				      int *err_p)
+{
+	struct group *gr;
+	struct grbuf *buf;
+	size_t buflen = sysconf(_SC_GETGR_R_SIZE_MAX);
+	char *localgroup;
+	int err;
+
+	buf = malloc(sizeof(*buf) + buflen);
+	if (!buf) {
+		err = ENOMEM;
+		goto err;
+	}
+
+	localgroup = conf_get_str("Static", (char *)name);
+	if (!localgroup) {
+		err = ENOENT;
+		goto err_free_buf;
+	}
+
+again:
+	err = getgrnam_r(localgroup, &buf->grbuf, buf->buf, buflen, &gr);
+
+	if (err == EINTR)
+		goto again;
+
+	if (!gr) {
+		if (err == 0)
+			err = ENOENT;
+
+		IDMAP_LOG(0, ("static_getgrnam: local group '%s' for '%s' not found\n",
+			  localgroup, name));
+
+		goto err_free_buf;
+	}
+
+	IDMAP_LOG(4, ("static_getgrnam: group '%s' mapped to '%s'\n",
+		  name, localgroup));
+
+	*err_p = 0;
+	return gr;
+
+err_free_buf:
+	free(buf);
+err:
+	*err_p = err;
+	return NULL;
+}
+
 static int static_gss_princ_to_ids(char *secname, char *princ,
 				   uid_t *uid, uid_t *gid,
 				   extra_mapping_params **ex)
@@ -151,14 +236,173 @@ static int static_gss_princ_to_grouplist(char *secname, char *princ,
 	return -err;
 }
 
+static int static_name_to_uid(char *name, uid_t *uid)
+{
+	struct passwd *pw;
+	int err;
+
+	pw = static_getpwnam(name, NULL, &err);
+
+	if (pw) {
+		*uid = pw->pw_uid;
+		free(pw);
+	}
+
+	return -err;
+}
+
+static int static_name_to_gid(char *name, gid_t *gid)
+{
+	struct group *gr;
+	int err;
+
+	gr = static_getgrnam(name, NULL, &err);
+
+	if (gr) {
+		*gid = gr->gr_gid;
+		free(gr);
+	}
+
+	return -err;
+}
+
+static int static_uid_to_name(uid_t uid, char *domain, char *name, size_t len)
+{
+	struct passwd *pw;
+	struct uid_mapping * um;
+
+	for (um = LIST_FIRST (&uid_mappings[uid_hash (uid)]); um;
+		um = LIST_NEXT (um, link)) {
+		if (um->uid == uid) {
+			strcpy(name, um->principal);
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+static int static_gid_to_name(gid_t gid, char *domain, char *name, size_t len)
+{
+	struct group *gr;
+	struct gid_mapping * gm;
+
+	for (gm = LIST_FIRST (&gid_mappings[gid_hash (gid)]); gm;
+		gm = LIST_NEXT (gm, link)) {
+		if (gm->gid == gid) {
+			strcpy(name, gm->principal);
+			return 0;
+		}
+	}
+
+	return -ENOENT;
+}
+
+/*
+ * We buffer all UID's for which static mappings is defined in advance, so the
+ * uid_to_name functions will be fast enough.
+ */
+
+static int static_init() {	
+	int err;
+	uid_t uid;
+	struct conf_list * princ_list = NULL;
+	struct conf_list_node * cln, *next;
+	struct uid_mapping * unode;
+	struct gid_mapping * gnode;
+	struct passwd * pw = NULL;
+	struct group * gr = NULL;
+	unsigned int i;
+
+	//init hash_table first
+	for (i = 0; i < sizeof uid_mappings / sizeof uid_mappings[0]; i++)
+		LIST_INIT (&uid_mappings[i]);
+
+	//get all principals for which we have mappings
+	princ_list = conf_get_tag_list("Static");
+
+	if (!princ_list) {
+		return -ENOENT;
+	}
+
+	/* As we can not distinguish between mappings for users and groups, we try to
+	 * resolve all mappings for both cases.
+	 */
+
+	//resolve uid of localname account for all such principals and cache it
+	for (cln = TAILQ_FIRST (&princ_list->fields); cln; cln = next) 
+	{ 
+		next = TAILQ_NEXT (cln, link); 
+
+		pw = static_getpwnam(cln->field, NULL, &err);
+		if (!pw) {
+			continue;
+		}
+		
+		unode = calloc (1, sizeof *unode);
+		if (!unode)
+		{
+			warnx("static_init: calloc (1, %lu) failed",
+				(unsigned long)sizeof *unode);
+			free(pw);
+			return -ENOMEM;
+		}
+		unode->uid = pw->pw_uid;
+		unode->principal = strdup(cln->field);
+
+		unode->localname = conf_get_str("Static", cln->field);
+		if (!unode->localname) {
+			free(pw);
+			return -ENOENT;
+		}
+
+		free(pw);
+
+		LIST_INSERT_HEAD (&uid_mappings[uid_hash(unode->uid)], unode, link);
+	}
+
+	//resolve gid of localgroup accounts and cache it
+	for (cln = TAILQ_FIRST (&princ_list->fields); cln; cln = next) 
+	{ 
+		next = TAILQ_NEXT (cln, link); 
+
+		gr = static_getgrnam(cln->field, NULL, &err);
+		if (!pw) {
+			continue;
+		}
+		
+		gnode = calloc (1, sizeof *gnode);
+		if (!gnode)
+		{
+			warnx("static_init: calloc (1, %lu) failed",
+				(unsigned long)sizeof *gnode);
+			free(pw);
+			return -ENOMEM;
+		}
+		gnode->gid = pw->pw_uid;
+		gnode->principal = strdup(cln->field);
+
+		gnode->localgroup = conf_get_str("Static", cln->field);
+		if (!gnode->localgroup) {
+			free(pw);
+			return -ENOENT;
+		}
+
+		free(pw);
+
+		LIST_INSERT_HEAD (&gid_mappings[gid_hash(gnode->gid)], gnode, link);
+	}
+	return 0;
+}
+
 
 struct trans_func static_trans = {
 	.name			= "static",
-	.init			= NULL,
-	.name_to_uid		= NULL,
-	.name_to_gid		= NULL,
-	.uid_to_name		= NULL,
-	.gid_to_name		= NULL,
+	.init			= static_init,
+	.name_to_uid		= static_name_to_uid,
+	.name_to_gid		= static_name_to_gid,
+	.uid_to_name		= static_uid_to_name,
+	.gid_to_name		= static_gid_to_name,
 	.princ_to_ids		= static_gss_princ_to_ids,
 	.gss_princ_to_grouplist	= static_gss_princ_to_grouplist,
 };
-- 
1.7.3.4