[Buildroot] [git commit branch/2018.02.x] Makefile: fix issue with printvars executing giant shell command
Peter Korsgaard
peter at korsgaard.com
Fri Oct 5 11:31:25 UTC 2018
commit: https://git.buildroot.net/buildroot/commit/?id=afdf97ca768933b8deb5cc30e3b2fa61e55da9b5
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2018.02.x
The underlying problem is that $(foreach V,1 2 3,) does not evaluate to
an empty string. It evaluates to "Â ", three empty strings separated by
whitespace.
A construct of this format, with a giant list in the foreach, is part of
the printvars command. This means that "@:$(foreach ....)", which is
intended to expand to a null command, in fact expands to "@: "
with a great deal of whitespace. Make chooses to execute this command
with:
execve("/bin/sh", ["/bin/sh", "-c", ": "]
But with far more whitespace. So much that it can exceed shell command
line length limits.
This solution is to move the foreach to another step in the recipe. The
"@:" is retained as the first line so the recipe is not Empty, which
would cause a change in make behavior when make builds the target. The
2nd line, all whitespace, will be skipped by make.
Signed-off-by: Trent Piepho <tpiepho at impinj.com>
Tested-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Acked-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit b8d0aadc6d52733cfc914ba3cd6f506238bd19f7)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 5fb26c9733..dc26099fd4 100644
--- a/Makefile
+++ b/Makefile
@@ -976,7 +976,8 @@ $(BUILD_DIR)/.br2-external.in: $(BUILD_DIR)
# displayed.
.PHONY: printvars
printvars:
- @:$(foreach V, \
+ @:
+ $(foreach V, \
$(sort $(if $(VARS),$(filter $(VARS),$(.VARIABLES)),$(.VARIABLES))), \
$(if $(filter-out environment% default automatic, \
$(origin $V)), \
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