* [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command
@ 2018-09-17 18:10 Trent Piepho
2018-09-17 19:42 ` Yann E. MORIN
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Trent Piepho @ 2018-09-17 18:10 UTC (permalink / raw)
To: buildroot
The underlying problem is that $(foreach V,1 2 3,) does not evaluate to
an empty string. It evaluates to "? ", three empty strings separated by
whitespace.
A construct of this format, with a giant list in the foreach, is part of
the printvars command. This means that "@:$(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@impinj.com>
---
Makefile | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Makefile b/Makefile
index 2c6af12989..57e776056c 100644
--- a/Makefile
+++ b/Makefile
@@ -988,7 +988,8 @@ $(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)), \
--
2.14.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command
2018-09-17 18:10 [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command Trent Piepho
@ 2018-09-17 19:42 ` Yann E. MORIN
2018-09-18 20:12 ` Thomas Petazzoni
2018-10-05 11:31 ` Peter Korsgaard
2 siblings, 0 replies; 4+ messages in thread
From: Yann E. MORIN @ 2018-09-17 19:42 UTC (permalink / raw)
To: buildroot
Trent, All,
On 2018-09-17 11:10 -0700, Trent Piepho spake thusly:
> The underlying problem is that $(foreach V,1 2 3,) does not evaluate to
> an empty string. It evaluates to "? ", three empty strings separated by
> whitespace.
>
> A construct of this format, with a giant list in the foreach, is part of
> the printvars command. This means that "@:$(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@impinj.com>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Regards,
Yann E. MORIN.
> ---
> Makefile | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/Makefile b/Makefile
> index 2c6af12989..57e776056c 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -988,7 +988,8 @@ $(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)), \
> --
> 2.14.4
>
--
.-----------------.--------------------.------------------.--------------------.
| Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: |
| +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ |
| +33 223 225 172 `------------.-------: X AGAINST | \e/ There is no |
| http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. |
'------------------------------^-------^------------------^--------------------'
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command
2018-09-17 18:10 [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command Trent Piepho
2018-09-17 19:42 ` Yann E. MORIN
@ 2018-09-18 20:12 ` Thomas Petazzoni
2018-10-05 11:31 ` Peter Korsgaard
2 siblings, 0 replies; 4+ messages in thread
From: Thomas Petazzoni @ 2018-09-18 20:12 UTC (permalink / raw)
To: buildroot
Hello,
On Mon, 17 Sep 2018 11:10:54 -0700, Trent Piepho wrote:
> The underlying problem is that $(foreach V,1 2 3,) does not evaluate to
> an empty string. It evaluates to "? ", three empty strings separated by
> whitespace.
>
> A construct of this format, with a giant list in the foreach, is part of
> the printvars command. This means that "@:$(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@impinj.com>
> ---
> Makefile | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Applied to master, thanks.
Thomas
--
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command
2018-09-17 18:10 [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command Trent Piepho
2018-09-17 19:42 ` Yann E. MORIN
2018-09-18 20:12 ` Thomas Petazzoni
@ 2018-10-05 11:31 ` Peter Korsgaard
2 siblings, 0 replies; 4+ messages in thread
From: Peter Korsgaard @ 2018-10-05 11:31 UTC (permalink / raw)
To: buildroot
>>>>> "Trent" == Trent Piepho <tpiepho@impinj.com> writes:
> The underlying problem is that $(foreach V,1 2 3,) does not evaluate to
> an empty string. It evaluates to "? ", three empty strings separated by
> whitespace.
> A construct of this format, with a giant list in the foreach, is part of
> the printvars command. This means that "@:$(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@impinj.com>
Committed to 2018.02.x, 2018.05.x and 2018.08.x, thanks.
--
Bye, Peter Korsgaard
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-09-17 18:10 [Buildroot] [PATCH v2] Fix issue with printvars executing giant shell command Trent Piepho
2018-09-17 19:42 ` Yann E. MORIN
2018-09-18 20:12 ` Thomas Petazzoni
2018-10-05 11:31 ` Peter Korsgaard
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