[lxc-devel] [PATCH] lxc_create: add outfile option

[Serge Hallyn]

lxc-create ... -o -

will send template output to standard output (the old default).

lxc-create ... without any -o will hide template output.

lxc-create -o /tmp/xxx will send template output to the file
/tmp/xxx.

Reported-by: "S.Çağlar Onur" <caglar at 10ur.org>
Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
---
 src/lxc/arguments.h  |    2 +-
 src/lxc/lxc_create.c |   22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/lxc/arguments.h b/src/lxc/arguments.h
index 3d1df70..6ab88fc 100644
--- a/src/lxc/arguments.h
+++ b/src/lxc/arguments.h
@@ -81,7 +81,7 @@ struct lxc_arguments {
 	char *fstype;
 	unsigned long fssize;
 	char *lvname, *vgname;
-	char *zfsroot, *lowerdir, *dir;
+	char *zfsroot, *lowerdir, *dir, *outfile;
 
 	/* remaining arguments */
 	char *const *argv;
diff --git a/src/lxc/lxc_create.c b/src/lxc/lxc_create.c
index 6d8ca01..32805f4 100644
--- a/src/lxc/lxc_create.c
+++ b/src/lxc/lxc_create.c
@@ -68,6 +68,7 @@ static int my_parser(struct lxc_arguments* args, int c, char* arg)
 	case '3': args->fssize = get_fssize(arg); break;
 	case '4': args->zfsroot = arg; break;
 	case '5': args->dir = arg; break;
+	case '6': args->outfile = arg; break;
 	}
 	return 0;
 }
@@ -82,6 +83,7 @@ static const struct option my_longopts[] = {
 	{"fssize", required_argument, 0, '3'},
 	{"zfsroot", required_argument, 0, '4'},
 	{"dir", required_argument, 0, '5'},
+	{"outfile", required_argument, 0, '6'},
 	LXC_COMMON_OPTIONS
 };
 
@@ -134,6 +136,9 @@ Options :\n\
   --fssize=SIZE     Create filesystem of size SIZE\n\
                     (Default: 1G))\n\
   --dir=DIR         Place rootfs directory under DIR\n\
+  --outfile=FILE    Print template output to FILE\n\
+                    Use '-' to indicate stdout\n\
+                    If unspecified, output is hidden\n\
   --zfsroot=PATH    Create zfs under given zfsroot\n\
                     (Default: tank/lxc))\n",
 	.options  = my_longopts,
@@ -228,6 +233,23 @@ int main(int argc, char *argv[])
 
 	if (strcmp(my_args.bdevtype, "_unset") == 0)
 		my_args.bdevtype = NULL;
+
+	/* redirect output if requested */
+	if (!my_args.outfile) {
+		close(0); close(1); close(2);
+		open("/dev/zero", O_RDONLY);
+		open("/dev/null", O_RDWR);
+		open("/dev/null", O_RDWR);
+	} else if (strcmp(my_args.outfile, "-") != 0) {
+		mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP;
+		close(0); close(1); close(2);
+		open("/dev/zero", O_RDONLY);
+		if (open(my_args.outfile, O_RDWR | O_CREAT, mode) < 0 ||
+		    open(my_args.outfile, O_RDWR) < 0) {
+			SYSERROR("Error opening %s\n", my_args.outfile);
+			exit(1);
+		}
+	}
 	if (!c->create(c, my_args.template, my_args.bdevtype, &spec, &argv[optind])) {
 		ERROR("Error creating container %s", c->name);
 		lxc_container_put(c);
-- 
1.7.9.5