clang: Reject %n for attribute((format(__freebsd_kprintf__)))
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Authored by cem on May 9 2020, 5:53 PM.

Details

Reviewers

imp
dim
emaste

Commits

rG7785cdd1f9a8: Reapply r360852 (by cem):
rS363980: Reapply r360852 (by cem):
rS360852: clang: Reject %n for __attribute__((format(__freebsd_kprintf__)))

Summary

A follow-up to r360849.

Reported by: imp

Test Plan

Seems to work:

/home/conrad/a.c:94:21: warning: invalid conversion specifier 'n' [-Wformat-invalid-specifier]
        my_kprintflike("2 %n %s\n", &loops, "not ok");
                          ~^

a.c:

extern void
my_kprintflike(const char *s, ...) __attribute__((__format__(__freebsd_kprintf__, 1, 2)));

int main(int argc, char **argv)
{
…
        my_kprintflike("1 %s\n", "ok");
        my_kprintflike("2 %n %s\n", &loops, "not ok");
}

Diff Detail

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Unit

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Build Status

Buildable 31006
Build 28712: arc lint + arc unit

Event Timeline

cem requested review of this revision.May 9 2020, 5:53 PM

cem created this revision.

Harbormaster completed remote builds in B31006: Diff 71595.May 9 2020, 5:53 PM

cem added a parent revision: D24760: remove %n support from printf(9).May 9 2020, 5:54 PM

Sounds good to me, we'll want to submit this upstream with a test case.

This revision is now accepted and ready to land.May 9 2020, 6:21 PM

cem edited the test plan for this revision. (Show Details)May 9 2020, 6:32 PM

In D24786#545386, @emaste wrote:

Sounds good to me, we'll want to submit this upstream with a test case.

Hm, unfortunately our contrib version of LLVM excludes the test subdirectories, so I can't easily add a test case here. I expect it would be easy for someone with an existing upstream relationship with LLVM to write one.

Love it. Easy to upstream.

Closed by commit rS360852: clang: Reject %n for __attribute__((format(__freebsd_kprintf__))) (authored by cem). · Explain WhyMay 9 2020, 7:27 PM

This revision was automatically updated to reflect the committed changes.

cem added a commit: rS360852: clang: Reject %n for __attribute__((format(__freebsd_kprintf__))).

dim added a commit: rS363980: Reapply r360852 (by cem):.Aug 6 2020, 7:23 PM

dim added a commit: rG7785cdd1f9a8: Reapply r360852 (by cem):.Dec 22 2021, 10:07 AM