[PATCH v2] modpost: remove use of non-standard strsep() in HOSTCC code

From: H. Nikolaus Schaller
Date: Wed Jul 01 2020 - 02:18:40 EST


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@xxxxxxxxxx>
Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
---
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