Work towards support new cache in 2.5nfs-utils-1-1-0-pre11neilb-devel

3 files changed, 195 insertions, 1 deletions

diff --git a/support/export/client.c b/support/export/client.c
index 6d5d306..3db21ae 100644
--- a/support/export/client.c
+++ b/support/export/client.c
@@ -230,6 +230,104 @@ client_find(struct hostent *hp)
 }
 
 /*
+ * Find client name given an IP address
+ * This is found by gathering all known names that match that IP address,
+ * sorting them and joining them with '+'
+ *
+ */
+static char *add_name(char *old, char *add);
+
+char *
+client_compose(struct in_addr addr)
+{
+	struct hostent *he = NULL;
+	char *name = NULL;
+	int i;
+
+	if (clientlist[MCL_WILDCARD] || clientlist[MCL_NETGROUP])
+		he = get_reliable_hostbyaddr((const char*)&addr, sizeof(addr), AF_INET);
+	if (he == NULL)
+		he = get_hostent((const char*)&addr, sizeof(addr), AF_INET);
+
+	for (i = 0 ; i < MCL_MAXTYPES; i++) {
+		nfs_client	*clp;
+		for (clp = clientlist[i]; clp ; clp = clp->m_next) {
+			if (!client_check(clp, he))
+				continue;
+			name = add_name(name, clp->m_hostname);
+		}
+	}
+	return name;
+}
+
+int 
+client_member(char *client, char *name)
+{
+	/* check if "client" (a ',' separated list of names)
+	 * contains 'name' as a member 
+	 */
+	int l = strlen(name);
+	while (*client) {
+		if (strncmp(client, name, l) == 0 &&
+		    (client[l] == ',' || client[l] == '\0'))
+			return 1;
+		client = strchr(client, ',');
+		if (client == NULL)
+			return 0;
+		client++;
+	}
+	return 0;
+}
+
+
+int 
+name_cmp(char *a, char *b)
+{
+	/* compare strings a and b, but only upto ',' in a */
+	while (*a && *b && *a != ',' && *a == *b)
+		a++, b++;
+	if (!*b && (!*a || !a == ',') )
+		return 0;
+	if (!*b) return 1;
+	if (!*a || *a == ',') return -1;
+	return *a - *b;
+}
+
+static char *
+add_name(char *old, char *add)
+{
+	int len = strlen(add)+2;
+	char *new;
+	char *cp;
+	if (old) len += strlen(old);
+	
+	new = malloc(len);
+	if (!new) {
+		free(old);
+		return NULL;
+	}
+	cp = old;
+	while (cp && *cp && name_cmp(cp, add) < 0) {
+		/* step cp forward over a name */
+		char *e = strchr(cp, ',');
+		if (e)
+			cp = e+1;
+		else
+			cp = cp + strlen(cp);
+	}
+	strncpy(new, old, cp-old);
+	new[cp-old] = 0;
+	if (cp != old && !*cp)
+		strcat(new, ",");
+	strcat(new, add);
+	if (cp && *cp) {
+		strcat(new, ",");
+		strcat(new, cp);
+	}
+	return new;
+}
+
+/*
  * Match a host (given its hostent record) to a client record. This
  * is usually called from mountd.
  */
diff --git a/support/export/hostname.c b/support/export/hostname.c
index 299fe99..0378f35 100644
--- a/support/export/hostname.c
+++ b/support/export/hostname.c
@@ -16,6 +16,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <stdlib.h>
+#include <xlog.h>
 #ifdef TEST
 #define xmalloc malloc
 #else
@@ -216,6 +217,56 @@ matchhostname (const char *h1, const char *h2)
   return status;
 }
 
+
+/* Map IP to hostname, and then map back to addr to make sure it is a
+ * reliable hostname 
+ */
+struct hostent *
+get_reliable_hostbyaddr(const char *addr, int len, int type)
+{
+	struct hostent *hp;
+
+	char **sp;
+	struct hostent *forward = NULL;
+	char *tmpname;
+
+	hp = gethostbyaddr(addr, len , type);
+	if (!hp)
+		return hp;
+
+	/* must make sure the hostent is authorative. */
+
+	hp = hostent_dup (hp);
+	tmpname = xstrdup((hp)->h_name);
+	if (tmpname) {
+		forward = gethostbyname(tmpname);
+		free(tmpname);
+	}
+	if (forward) {
+		/* now make sure the "addr" is in the list */
+		for (sp = forward->h_addr_list ; *sp ; sp++) {
+			if (memcmp(*sp, addr, forward->h_length)==0)
+				break;
+		}
+		
+		if (!*sp) {
+			/* it was a FAKE */
+			xlog(L_WARNING, "Fake hostname %s for %s - forward lookup doesn't match reverse",
+			     forward->h_name, inet_ntoa(*(struct in_addr*)addr));
+			return NULL;
+		}
+		free (hp);
+		hp = hostent_dup (forward);
+	}
+	else {
+		/* never heard of it. misconfigured DNS? */
+		xlog(L_WARNING, "Fake hostname %s for %s - forward lookup doesn't exist",
+		     forward->h_name, inet_ntoa(*(struct in_addr*)addr));
+		return NULL;
+	}
+	return hp;
+}
+
 #ifdef TEST
 void
 print_host (struct hostent *hp)
diff --git a/support/export/xtab.c b/support/export/xtab.c
index 3ef3661..d9265a2 100644
--- a/support/export/xtab.c
+++ b/support/export/xtab.c
@@ -18,6 +18,8 @@
 #include "xio.h"
 #include "xlog.h"
 
+static void cond_rename(char *newfile, char *oldfile);
+
 static int
 xtab_read(char *xtab, int is_export)
 {
@@ -104,7 +106,7 @@ xtab_write(char *xtab, char *xtabtmp, int is_export)
 	}
 	endexportent();
 
-	rename(xtabtmp, xtab);
+	cond_rename(xtabtmp, xtab);
 
 	xfunlock(lockid);
 
@@ -142,3 +144,46 @@ xtab_append(nfs_export *exp)
 	exp->m_xtabent = 1;
 }
 
+/*
+ * rename newfile onto oldfile unless
+ * they are identical 
+ */
+static void cond_rename(char *newfile, char *oldfile)
+{
+	int nfd, ofd;
+	char nbuf[4096], obuf[4096];
+	int ncnt, ocnt;
+
+	nfd = open(newfile, 0);
+	if (nfd < 0)
+		return;
+	ofd = open(oldfile, 0);
+	if (ofd < 0) {
+		close(nfd);
+		rename(newfile, oldfile);
+		return;
+	}
+
+	do {
+		ncnt = read(nfd, nbuf, sizeof(nbuf));
+		if (ncnt < 0)
+			break;
+		ocnt = read(ofd, obuf, sizeof(obuf));
+		if (ocnt < 0)
+			break;
+		if (ncnt != ocnt)
+			break;
+		if (ncnt == 0) {
+			close(nfd);
+			close(ofd);
+			unlink(newfile);
+			return;
+		}
+	} while (memcmp(obuf, nbuf, ncnt) == 0);
+
+	/* some mis-match */
+	close(nfd);
+	close(ofd);
+	rename(newfile, oldfile);
+	return;
+}