gentoo-overlay/app-misc/tdl/files/tdl-1.5.2-main.c.patch

--- tdl-1.5.2.orig/main.c
+++ tdl-1.5.2/main.c
@@ -80,7 +80,7 @@
   return;
 }
 /*}}}*/
-static volatile void unlock_and_exit(int code)/*{{{*/
+static void unlock_and_exit(int code)/*{{{*/
 {
   unlock_database();
   exit(code);
@@ -237,22 +237,91 @@
 
 }
 /*}}}*/
-static void rename_database(char *path)/*{{{*/
+static mode_t get_mode(const char *path); /* prototype */
+/*}}}*/
+static int copy_file_contents(char *pathsrc, char *pathdest) {
+  int src, dest;
+  ssize_t rdsize = 1;
+  char buf[4096];
+
+  src = open(pathsrc, O_RDONLY);
+  if (src == -1) {
+    perror("warning, couldn't open database");
+    return 0;
+  }
+  dest = open(pathdest, O_WRONLY | O_CREAT, get_mode(pathsrc));
+  if (dest == -1) {
+    perror("warning, couldn't open/create backup database");
+    close(src);
+    return 0;
+  }
+  if (ftruncate(dest,0) != 0) {
+    perror("warning, couldn't truncate backup database");
+    close(src);
+    close(dest);
+    return 0;
+  }
+  lseek(src,0,SEEK_SET);
+  lseek(dest,0,SEEK_SET);
+  while (rdsize > 0) {
+    rdsize = read(src, buf, 4096);
+    if (rdsize == -1) {
+      perror("warning, error reading database");
+      close(src);
+      close(dest);
+      return 0;
+    }
+    if (rdsize > 0) {
+      if (write(dest, buf, rdsize) != rdsize) {
+	perror("warning, error writing to backup database");
+	close(src);
+	close(dest);
+	return 0;
+      }
+    }
+  }
+  close(src);
+  close(dest);
+  return 1;
+}
+/*}}}*/
+static int path_is_symlink(char *path) {
+  int i;
+  struct stat s;
+  i = lstat(path, &s);
+  if ((i == 0) && (S_ISLNK(s.st_mode))) {
+    return 1; /* is a symlink */
+  }
+  return 0; /* not a symlink */
+}
+/*}}}*/
+static int rename_database(char *path)/*{{{*/
 {
-  int len;
+  /* the rename_database function returns 1 if database or/and
+   * database backup file are symlinks; otherwise returns 0 */
+  int len, symlinks;
   char *pathbak;
-
+  
   len = strlen(path);
   pathbak = new_array(char, len + 5);
   strcpy(pathbak, path);
   strcat(pathbak, ".bak");
-  if (rename(path, pathbak) < 0) {
-    if (is_noisy) {
-      perror("warning, couldn't save backup database:");
+
+  symlinks = path_is_symlink(path) | path_is_symlink(pathbak);
+
+  if (symlinks) {
+    if (access(path,F_OK) == 0) {
+      copy_file_contents(path, pathbak);
+    }
+  } else {
+    if (rename(path, pathbak) < 0) {
+      if (is_noisy) {
+	perror("warning, couldn't save backup database:");
+      }
     }
   }
   free(pathbak);
-  return;
+  return symlinks;
 } 
 /*}}}*/
 static char *executable_name(char *argv0)/*{{{*/
@@ -315,7 +384,7 @@
 /*}}}*/
 static void save_database(char *path)/*{{{*/
 {
-  FILE *out;
+  FILE *out = NULL;
   int out_fd;
   mode_t database_mode;
   if (is_loaded && currently_dirty) {
@@ -324,20 +393,34 @@
     /* The next line only used to happen if the command wasn't 'create'.
      * However, it should quietly fail for create, where the existing database
      * doesn't exist */
-    rename_database(path);
-
-    /* Open database this way so that the permissions from the existing
-       database can be duplicated onto the new one in way free of race
-       conditions. */
-    out_fd = open(path, O_WRONLY | O_CREAT | O_EXCL, database_mode);
-    if (out_fd < 0) {
-      fprintf(stderr, "Could not open new database %s for writing : %s\n",
-              path, strerror(errno));
-      unlock_and_exit(1);
+    if (rename_database(path) == 0) {
+      /* database is a regular file */
+      /* Open database this way so that the permissions from the existing
+	 database can be duplicated onto the new one in way free of race
+	 conditions. */
+      out_fd = open(path, O_WRONLY | O_CREAT | O_EXCL, database_mode);
+      if (out_fd < 0) {
+	fprintf(stderr, "Could not open new database %s for writing : %s\n",
+		path, strerror(errno));
+	unlock_and_exit(1);
+      }
     } else {
-      /* Normal case */
-      out = fdopen(out_fd, "wb");
+      /* database and/or backup database are symlinks */
+      /* we should truncate existing file and write its contents */
+      out_fd = open(path, O_WRONLY | O_CREAT, database_mode);
+      if (out_fd < 0) {
+	fprintf(stderr, "Could not open database %s for writing : %s\n",
+		path, strerror(errno));
+	unlock_and_exit(1);
+      } else {
+	/* Normal case */
+	if (ftruncate(out_fd, 0) != 0) {
+	  perror("warning, couldn't truncate database:");
+	  unlock_and_exit(1);
+	}
+      }
     }
+    out = fdopen(out_fd, "wb");
     if (!out) {
       fprintf(stderr, "Cannot open database %s for writing\n", path);
       unlock_and_exit(1);
@@ -728,6 +811,11 @@
 
     if (!is_loaded && cmds[index].load_db) {
       load_database(current_database_path);
+      if (is_interactive && (!is_loaded)) {
+	fprintf(stderr, "error: could not open database. please create a "
+	        "database with 'tdl create' before using this tdl command\n");
+        unlock_and_exit(-1);
+      }
     }
 
     pp = is_tdl ? (p + 1) : p;