Open channel files O_WRONLY, and improve mountlist support.

[nfs-utils.git] / utils / mountd / rmtab.c

diff --git a/utils/mountd/rmtab.c b/utils/mountd/rmtab.c
index 170d8594e4371f7373f50b7ba78cfd6d620d3a8e..844de511f48b07d76baac5b0b828b9e5520af33f 100644 (file)
--- a/utils/mountd/rmtab.c
+++ b/utils/mountd/rmtab.c
@@ -8,7 +8,9 @@
 
 #include "config.h"
 
+#include <sys/types.h>
 #include <sys/stat.h>
+#include <unistd.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netdb.h>
@@ -18,8 +20,33 @@
 #include "xio.h"
 #include "mountd.h"
 
+#include <limits.h> /* PATH_MAX */
+
+/* If new path is a link do not destroy it but place the
+ * file where the link points.
+ */
+
+static int 
+slink_safe_rename(const char * oldpath, const char * newpath)
+{
+       int r;
+       struct stat s;
+       char slink_path[PATH_MAX];
+       const char *real_newpath = newpath;
+
+       if ((lstat(newpath, &s) == 0) && S_ISLNK(s.st_mode)) {
+               /* New path is a symbolic link, do not destroy but follow */
+               if ((r = readlink(newpath, slink_path, PATH_MAX - 1)) == -1)
+                       return -1;
+               slink_path[r] = '\0';
+               real_newpath = slink_path;
+       }
+
+       return rename(oldpath, real_newpath);
+}
+
 void
-mountlist_add(nfs_export *exp, const char *path)
+mountlist_add(char *host, const char *path)
 {
        struct rmtabent xe;
        struct rmtabent *rep;
@@ -31,7 +58,7 @@ mountlist_add(nfs_export *exp, const char *path)
        setrmtabent("r+");
        while ((rep = getrmtabent(1, &pos)) != NULL) {
                if (strcmp (rep->r_client,
-                           exp->m_client->m_hostname) == 0
+                           host) == 0
                    && strcmp(rep->r_path, path) == 0) {
                        rep->r_count++;
                        putrmtabent(rep, &pos);
@@ -41,7 +68,7 @@ mountlist_add(nfs_export *exp, const char *path)
                }
        }
        endrmtabent();
-       strncpy(xe.r_client, exp->m_client->m_hostname,
+       strncpy(xe.r_client, host,
                sizeof (xe.r_client) - 1);
        xe.r_client [sizeof (xe.r_client) - 1] = '\0';
        strncpy(xe.r_path, path, sizeof (xe.r_path) - 1);
@@ -55,11 +82,10 @@ mountlist_add(nfs_export *exp, const char *path)
 }
 
 void
-mountlist_del(nfs_export *exp, const char *path)
+mountlist_del(char *hname, const char *path)
 {
        struct rmtabent *rep;
        FILE            *fp;
-       char            *hname = exp->m_client->m_hostname;
        int             lockid;
        int             match;
 
@@ -82,7 +108,7 @@ mountlist_del(nfs_export *exp, const char *path)
                if (!match || rep->r_count)
                        fputrmtabent(fp, rep, NULL);
        }
-       if (rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
+       if (slink_safe_rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
                xlog(L_ERROR, "couldn't rename %s to %s",
                                _PATH_RMTABTMP, _PATH_RMTAB);
        }
@@ -130,7 +156,7 @@ mountlist_del_all(struct sockaddr_in *sin)
                }
                fputrmtabent(fp, rep, NULL);
        }
-       if (rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
+       if (slink_safe_rename(_PATH_RMTABTMP, _PATH_RMTAB) < 0) {
                xlog(L_ERROR, "couldn't rename %s to %s",
                                _PATH_RMTABTMP, _PATH_RMTAB);
        }