From 4ca85630de6db829e6e9b43bb8e07f79c7ca223a Mon Sep 17 00:00:00 2001
From: oetiker <oetiker@a5681a0c-68f1-0310-ab6d-d61299d08faa>
Date: Mon, 8 Mar 2010 17:10:02 +0000
Subject: [PATCH] added --no-overwrite option to rrdtool create. It prevents
 rrdtool from clobbering existing rrd files. -- Chris - LINX

git-svn-id: svn://svn.oetiker.ch/rrdtool/branches/1.3@2028 a5681a0c-68f1-0310-ab6d-d61299d08faa
---
 program/doc/rrdcreate.pod |  5 +++++
 program/src/rrd_create.c  | 13 ++++++++++++-
 program/src/rrd_tool.c    |  1 +
 3 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/program/doc/rrdcreate.pod b/program/doc/rrdcreate.pod
index abb42fc9..d4390b90 100644
--- a/program/doc/rrdcreate.pod
+++ b/program/doc/rrdcreate.pod
@@ -7,6 +7,7 @@ rrdcreate - Set up a new Round Robin Database
 B<rrdtool> B<create> I<filename>
 S<[B<--start>|B<-b> I<start time>]>
 S<[B<--step>|B<-s> I<step>]>
+S<[B<--no-overwrite>]>
 S<[B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>]>
 S<[B<RRA:>I<CF>B<:>I<cf arguments>]>
 
@@ -36,6 +37,10 @@ I<rrdfetch> documentation for other ways to specify time.
 Specifies the base interval in seconds with which data will be fed
 into the B<RRD>.
 
+=head2 B<--no-overwrite>
+
+Do not clobber an existing file of the same name.
+
 =head2 B<DS:>I<ds-name>B<:>I<DST>B<:>I<dst arguments>
 
 A single B<RRD> can accept input from several data sources (B<DS>),
diff --git a/program/src/rrd_create.c b/program/src/rrd_create.c
index 75c3722f..4e98d53c 100644
--- a/program/src/rrd_create.c
+++ b/program/src/rrd_create.c
@@ -13,6 +13,7 @@
 #include "rrd_hw.h"
 
 #include "rrd_is_thread_safe.h"
+static int opt_no_overwrite = 0;
 
 #ifdef WIN32
 #include <fcntl.h>
@@ -42,6 +43,7 @@ int rrd_create(
     struct option long_options[] = {
         {"start", required_argument, 0, 'b'},
         {"step", required_argument, 0, 's'},
+        {"no-overwrite", no_argument, 0, 'O'},
         {0, 0, 0, 0}
     };
     int       option_index = 0;
@@ -57,7 +59,7 @@ int rrd_create(
     opterr = 0;         /* initialize getopt */
 
     while (1) {
-        opt = getopt_long(argc, argv, "b:s:", long_options, &option_index);
+        opt = getopt_long(argc, argv, "Ob:s:", long_options, &option_index);
 
         if (opt == EOF)
             break;
@@ -93,6 +95,10 @@ int rrd_create(
             pdp_step = long_tmp;
             break;
 
+        case 'O':
+            opt_no_overwrite = 1;
+	    break;
+
         case '?':
             if (optopt != 0)
                 rrd_set_error("unknown option '%c'", optopt);
@@ -687,6 +693,11 @@ int rrd_create_fn(
     flags |= O_BINARY;
 #endif
 
+    /* with O_CREAT (above) causes open to fail with EEXIST when if exists */
+    if (opt_no_overwrite) {
+      flags |= O_EXCL;
+    }
+
     if ((rrd_file = open(file_name, flags, 0666)) < 0) {
         rrd_set_error("creating '%s': %s", file_name, rrd_strerror(errno));
         rrd_free2(rrd);
diff --git a/program/src/rrd_tool.c b/program/src/rrd_tool.c
index 03b018ae..2e59b8e0 100644
--- a/program/src/rrd_tool.c
+++ b/program/src/rrd_tool.c
@@ -66,6 +66,7 @@ void PrintUsage(
         N_("* create - create a new RRD\n\n"
            "\trrdtool create filename [--start|-b start time]\n"
            "\t\t[--step|-s step]\n"
+           "\t\t[--no-overwrite|-O]\n"
            "\t\t[DS:ds-name:DST:dst arguments]\n"
            "\t\t[RRA:CF:cf arguments]\n\n");
 
-- 
2.30.2