diff: fix a bug in diffing against stdin. Closes 7784

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/editors/diff.c b/editors/diff.c
index a78a0ee28..c3ad31bf3 100644
--- a/editors/diff.c
+++ b/editors/diff.c
@@ -740,9 +740,10 @@ static int diffreg(char *file[2])
                         unlink(name);
                         if (bb_copyfd_eof(fd, fd_tmp) < 0)
                                 xfunc_die();
-                        if (fd) /* Prevents closing of stdin */
+                        if (fd != STDIN_FILENO)
                                 close(fd);
                         fd = fd_tmp;
+                        xlseek(fd, 0, SEEK_SET);
                 }
                 fp[i] = fdopen(fd, "r");
         }