]> git.decadent.org.uk Git - nfs-utils.git/blobdiff - utils/mountd/rmtab.c
2002-11-27 Chip Salzenberg <chip@pobox.com>
[nfs-utils.git] / utils / mountd / rmtab.c
index 170d8594e4371f7373f50b7ba78cfd6d620d3a8e..869b5f88fd791881eee6d01951cdfe1185222b9d 100644 (file)
@@ -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>
 #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];
+       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)
 {
@@ -82,7 +109,7 @@ 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 +157,7 @@ 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);
        }