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authorDenis Vlasenko2007-05-05 15:11:40 +0000
committerDenis Vlasenko2007-05-05 15:11:40 +0000
commitdd4cb2b31eabe5c69144dfb20fd08ebc625175b1 (patch)
treed074a1749ee5b1da6dea1ca4218d3c72c9f734fd /shell
parenta6c467f6d134f1fb906806f4cf3b6ca401b6a616 (diff)
downloadbusybox-dd4cb2b31eabe5c69144dfb20fd08ebc625175b1.zip
busybox-dd4cb2b31eabe5c69144dfb20fd08ebc625175b1.tar.gz
hush: stop generating extra empty pipes in parse stage.
Diffstat (limited to 'shell')
-rw-r--r--shell/hush.c28
1 files changed, 15 insertions, 13 deletions
diff --git a/shell/hush.c b/shell/hush.c
index eb6f37f..a299b01 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2685,8 +2685,8 @@ static int done_command(struct p_context *ctx)
&& child->argv == NULL
&& child->redirects == NULL
) {
- debug_printf_parse("done_command: skipping null command\n");
- return 0;
+ debug_printf_parse("done_command: skipping null cmd, num_progs=%d\n", pi->num_progs);
+ return pi->num_progs;
}
pi->num_progs++;
debug_printf_parse("done_command: ++num_progs=%d\n", pi->num_progs);
@@ -2712,26 +2712,28 @@ static int done_command(struct p_context *ctx)
ctx->child = child;
/* but ctx->pipe and ctx->list_head remain unchanged */
- return 0;
+ return pi->num_progs; /* used only for 0/nonzero check */
}
static int done_pipe(struct p_context *ctx, pipe_style type)
{
struct pipe *new_p;
+ int not_null;
debug_printf_parse("done_pipe entered, followup %d\n", type);
- done_command(ctx); /* implicit closure of previous command */
+ not_null = done_command(ctx); /* implicit closure of previous command */
ctx->pipe->followup = type;
ctx->pipe->r_mode = ctx->res_w;
- new_p = new_pipe();
- ctx->pipe->next = new_p;
- ctx->pipe = new_p;
- ctx->child = NULL;
-// TODO: even just <enter> on command line basically generates
-// tree of three NOPs (!).
-// Can we detect that previous done_command have seen "skipping null command"
-// condition and NOT create new pipe here?
- done_command(ctx); /* set up new pipe to accept commands */
+ /* Without this check, even just <enter> on command line generates
+ * tree of three NOPs (!). Which is harmless but annoying.
+ * IOW: it is safe to do it unconditionally. */
+ if (not_null) {
+ new_p = new_pipe();
+ ctx->pipe->next = new_p;
+ ctx->pipe = new_p;
+ ctx->child = NULL;
+ done_command(ctx); /* set up new pipe to accept commands */
+ }
debug_printf_parse("done_pipe return 0\n");
return 0;
}