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author | Yifeng Li <tomli@tomli.me> | 2023-02-20 10:19:19 +0000 |
---|---|---|
committer | Will Estes <westes@users.noreply.github.com> | 2023-03-09 14:45:08 -0500 |
commit | a57e165cc50265e6ca1f6e12313e3154c6a6f96c (patch) | |
tree | cc0f0d10189371eefa12d86f707df177507a3086 /src/main.c | |
parent | 74e8c880fc043b765a5b2ea7ccdfee252d38beb4 (diff) | |
download | flex-git-a57e165cc50265e6ca1f6e12313e3154c6a6f96c.tar.gz |
Fix #539 crash on Apple M1 by casting 0 to (char *) explicitly
Currently, when the NULL-terminated variadic function
filter_create_ext() is invoked, the value "0" is passed as
the last argument to act as a terminator. However, this is
an integer value, which is incompatible with the pointer
data type expected by filter_create_ext().
This is undefined behavior in C, correct operation is not
guaranteed. In fact, it causes flex to crash on Apple M1
when GCC is used - the loop is not terminated when it should,
instead, it keeps running, corrupting the argument list for
invoking m4. As a result, it creates the following error:
> flex: fatal internal error, exec of gm4 failed
This commit fixes the problem by explicitly casting the value 0 to
the correct pointer type (char *).
Signed-off-by: Yifeng Li <tomli@tomli.me>
Diffstat (limited to 'src/main.c')
-rw-r--r-- | src/main.c | 2 |
1 files changed, 1 insertions, 1 deletions
@@ -295,7 +295,7 @@ void initialize_output_filters(void) if ( !(m4 = getenv("M4"))) { m4 = M4; } - filter_create_ext(output_chain, m4, "-P", 0); + filter_create_ext(output_chain, m4, "-P", (char *) 0); filter_create_int(output_chain, filter_fix_linedirs, NULL); /* For debugging, only run the requested number of filters. */ |