* [PATCH v2] modpost: remove use of non-standard strsep() in HOSTCC code
@ 2020-07-01 6:18 H. Nikolaus Schaller
2020-07-01 15:50 ` Masahiro Yamada
0 siblings, 1 reply; 2+ messages in thread
From: H. Nikolaus Schaller @ 2020-07-01 6:18 UTC (permalink / raw)
To: Masahiro Yamada, Michal Marek
Cc: linux-kbuild, linux-kernel, letux-kernel, H. Nikolaus Schaller
strsep() is neither standard C nor POSIX and used outside
the kernel code here. Using it here requires that the
build host supports it out of the box which is e.g.
not true for a Darwin build host and using a cross-compiler.
This leads to:
scripts/mod/modpost.c:145:2: warning: implicit declaration of function 'strsep' [-Wimplicit-function-declaration]
return strsep(stringp, "\n");
^
and a segfault when running MODPOST.
See also: https://stackoverflow.com/a/7219504
So let's replace this by strchr() instead of using strsep().
It does not hurt kernel size or speed since this code is run
on the build host.
Fixes: ac5100f5432967 ("modpost: add read_text_file() and get_line() helpers")
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
---
scripts/mod/modpost.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 6aea65c657454..45f2ab2ec2d46 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -138,11 +138,19 @@ char *read_text_file(const char *filename)
char *get_line(char **stringp)
{
+ char *orig = *stringp, *next;
+
/* do not return the unwanted extra line at EOF */
- if (*stringp && **stringp == '\0')
+ if (!orig || *orig == '\0')
return NULL;
- return strsep(stringp, "\n");
+ next = strchr(orig, '\n');
+ if (next)
+ *next++ = '\0';
+
+ *stringp = next;
+
+ return orig;
}
/* A list of all modules we processed */
--
2.26.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] modpost: remove use of non-standard strsep() in HOSTCC code
2020-07-01 6:18 [PATCH v2] modpost: remove use of non-standard strsep() in HOSTCC code H. Nikolaus Schaller
@ 2020-07-01 15:50 ` Masahiro Yamada
0 siblings, 0 replies; 2+ messages in thread
From: Masahiro Yamada @ 2020-07-01 15:50 UTC (permalink / raw)
To: H. Nikolaus Schaller
Cc: Michal Marek, Linux Kbuild mailing list,
Linux Kernel Mailing List, Discussions about the Letux Kernel
On Wed, Jul 1, 2020 at 3:18 PM H. Nikolaus Schaller <hns@goldelico.com> wrote:
>
> strsep() is neither standard C nor POSIX and used outside
> the kernel code here. Using it here requires that the
> build host supports it out of the box which is e.g.
> not true for a Darwin build host and using a cross-compiler.
> This leads to:
>
> scripts/mod/modpost.c:145:2: warning: implicit declaration of function 'strsep' [-Wimplicit-function-declaration]
> return strsep(stringp, "\n");
> ^
>
> and a segfault when running MODPOST.
>
> See also: https://stackoverflow.com/a/7219504
>
> So let's replace this by strchr() instead of using strsep().
> It does not hurt kernel size or speed since this code is run
> on the build host.
>
> Fixes: ac5100f5432967 ("modpost: add read_text_file() and get_line() helpers")
> Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
> Signed-off-by: H. Nikolaus Schaller <hns@goldelico.com>
> ---
Applied to linux-kbuild.
Thanks.
> scripts/mod/modpost.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 6aea65c657454..45f2ab2ec2d46 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -138,11 +138,19 @@ char *read_text_file(const char *filename)
>
> char *get_line(char **stringp)
> {
> + char *orig = *stringp, *next;
> +
> /* do not return the unwanted extra line at EOF */
> - if (*stringp && **stringp == '\0')
> + if (!orig || *orig == '\0')
> return NULL;
>
> - return strsep(stringp, "\n");
> + next = strchr(orig, '\n');
> + if (next)
> + *next++ = '\0';
> +
> + *stringp = next;
> +
> + return orig;
> }
>
> /* A list of all modules we processed */
> --
> 2.26.2
>
--
Best Regards
Masahiro Yamada
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