kbuild: add support for reading stdin with gen_init_cpio

Treat an argument of "-" as meaning "read stdin for cpio files" so
gen_init_cpio can be piped into.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index 8365db6cfe06..7abc07f0fcd2 100644
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -498,7 +498,9 @@ int main (int argc, char *argv[])
                 exit(1);
         }
 
-        if (! (cpio_list = fopen(argv[1], "r"))) {
+        if (!strcmp(argv[1], "-"))
+                cpio_list = stdin;
+        else if (! (cpio_list = fopen(argv[1], "r"))) {
                 fprintf(stderr, "ERROR: unable to open '%s': %s\n\n",
                         argv[1], strerror(errno));
                 usage(argv[0]);