[Bug 214338] [PATCH] devel/glib20: new kqueue() backend for file monitoring

[bugzilla-noreply at freebsd.org]

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214338

--- Comment #59 from lightside <lightside at gmx.com> ---
(In reply to comment #56)
> Fixed MSTOSBT macro for files/kqueue_fnm.c.
The MSTOSBT macro used in kq_fnm_create function in files/kqueue_fnm.c file as:
kfnm->rate_lim_time_init = MSTOSBT(kfnm->s.rate_limit_time_init);

where KQUEUE_MON_RATE_LIMIT_TIME_INIT defined as:
#ifndef KQUEUE_MON_RATE_LIMIT_TIME_INIT
#       define KQUEUE_MON_RATE_LIMIT_TIME_INIT          1000
#endif

and used for "kfms.rate_limit_time_init = KQUEUE_MON_RATE_LIMIT_TIME_INIT;" in
g_kqueue_file_monitor_is_supported function in files/gkqueuefilemonitor.c file
before kq_fnm_create function invocation.

If change "<" to  "<=" in "for (int64_t i = 0; i < 1000; ++i) {" for testcase
in comment #56, then possible to get result for 1000 value:
% cc --version | head -1
FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
% cc -O2 -o test test.c
% ./test && echo ok || echo not ok
<..>
998: funct = 4286377361, macro = -8589935, false
999: funct = 4290672328, macro = -4294968, false
1000: funct = 4294967295, macro = -1, false
not ok
% cc -O2 -DFIXED=1 -o test test.c
% ./test && echo ok || echo not ok
<..>
998: funct = 4286377361, macro = 4286377361, true
999: funct = 4290672328, macro = 4290672328, true
1000: funct = 4294967295, macro = 4294967295, true
ok
% clang60 --version | head -1
clang version 6.0.1 (tags/RELEASE_601/final)
% clang60 -O2 -o test test.c
% ./test && echo ok || echo not ok
<..>
998: funct = 4286377361, macro = 4286377361, true
999: funct = 4290672328, macro = 4290672328, true
1000: funct = 4294967295, macro = 4294967295, true
ok
% clang60 -O2 -DFIXED=1 -o test test.c
% ./test && echo ok || echo not ok
<..>
998: funct = 4286377361, macro = 4286377361, true
999: funct = 4290672328, macro = 4290672328, true
1000: funct = 4294967295, macro = 4294967295, true
ok

In other words, if kfnm->s.rate_limit_time_init was assigned to 1000 value,
then kfnm->rate_lim_time_init maybe assigned to -1 instead of 4294967295, if
compiled without fix for MSTOSBT macro (attachment #195598) with using Clang
3.4.1 base compiler on FreeBSD 10.4 amd64.

Sorry about long explanations.

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