[PATCH AUTOSEL 4.19 06/11] kconfig: let 'shell' return enough output for deep path names

[PATCH AUTOSEL 4.19 06/11] kconfig: let 'shell' return enough output for deep path names

[Sasha Levin]

From: Brenda Streiff <brenda.streiff@ni.com>

[ Upstream commit 8a4c5b2a6d8ea079fa36034e8167de87ab6f8880 ]

The 'shell' built-in only returns the first 256 bytes of the command's
output. In some cases, 'shell' is used to return a path; by bumping up
the buffer size to 4096 this lets us capture up to PATH_MAX.

The specific case where I ran into this was due to commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test"). After this
change, we now use `$(shell,$(CC) -print-file-name=plugin)` to return
a path; if the gcc path is particularly long, then the path ends up
truncated at the 256 byte mark, which makes the HAVE_GCC_PLUGINS
depends test always fail.

Signed-off-by: Brenda Streiff <brenda.streiff@ni.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 scripts/kconfig/preprocess.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c
index 389814b02d06b..8c7e51a6273cc 100644
--- a/scripts/kconfig/preprocess.c
+++ b/scripts/kconfig/preprocess.c
@@ -138,7 +138,7 @@ static char *do_lineno(int argc, char *argv[])
 static char *do_shell(int argc, char *argv[])
 {
 	FILE *p;
-	char buf[256];
+	char buf[4096];
 	char *cmd;
 	size_t nread;
 	int i;
-- 
2.34.1

Re: [PATCH AUTOSEL 4.19 06/11] kconfig: let 'shell' return enough output for deep path names

[Pavel Machek]

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Hi!

> [ Upstream commit 8a4c5b2a6d8ea079fa36034e8167de87ab6f8880 ]
> 
> The 'shell' built-in only returns the first 256 bytes of the command's
> output. In some cases, 'shell' is used to return a path; by bumping up
> the buffer size to 4096 this lets us capture up to PATH_MAX.

If the idea is to support up-to PATH_MAX, perhaps open-coded 4096
should be replaced by PATH_MAX in the code, too?

Best regards,
								Pavel

> +++ b/scripts/kconfig/preprocess.c
> @@ -138,7 +138,7 @@ static char *do_lineno(int argc, char *argv[])
>  static char *do_shell(int argc, char *argv[])
>  {
>  	FILE *p;
> -	char buf[256];
> +	char buf[4096];
>  	char *cmd;
>  	size_t nread;
>  	int i;

-- 
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HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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