maint: detect unnecessary inclusion of signal.h

* maint.mk (sc_prohibit_signal_without_use): New rule.

diff --git a/maint.mk b/maint.mk
index f1c1e8a..63b4c88 100644 (file)
--- a/maint.mk
+++ b/maint.mk
@@ -289,6 +289,43 @@ ctype_re = isalnum|isalpha|isascii|isblank|iscntrl|isdigit|isgraph|islower\
 sc_prohibit_c_ctype_without_use:
        @h='[<"]c-ctype.h[">]' re='\<c_($(ctype_re)) *\(' $(_header_without_use)
 
+_empty =
+_sp = $(_empty) $(_empty)
+# The following list was generated by running:
+# man signal.h|col -b|perl -ne '/bsd_signal.*;/.../sigwaitinfo.*;/ and print' \
+#   | perl -lne '/^\s+(?:int|void).*?(\w+).*/ and print $1' | fmt
+_sig_functions = \
+  bsd_signal kill killpg pthread_kill pthread_sigmask raise sigaction \
+  sigaddset sigaltstack sigdelset sigemptyset sigfillset sighold sigignore \
+  siginterrupt sigismember signal sigpause sigpending sigprocmask sigqueue \
+  sigrelse sigset sigsuspend sigtimedwait sigwait sigwaitinfo
+_sig_function_re = $(subst $(_sp),|,$(strip $(_sig_functions)))
+# The following were extracted from "man signal.h" manually.
+_sig_types_and_consts =                                                        \
+  MINSIGSTKSZ SA_NOCLDSTOP SA_NOCLDWAIT SA_NODEFER SA_ONSTACK          \
+  SA_RESETHAND SA_RESTART SA_SIGINFO SIGEV_NONE SIGEV_SIGNAL           \
+  SIGEV_THREAD SIGSTKSZ SIG_BLOCK SIG_SETMASK SIG_UNBLOCK SS_DISABLE   \
+  SS_ONSTACK mcontext_t pid_t sig_atomic_t sigevent siginfo_t sigset_t \
+  sigstack sigval stack_t ucontext_t
+# generated via this:
+# perl -lne '/^#ifdef (SIG\w+)/ and print $1' lib/sig2str.c|sort -u|fmt -70
+_sig_names =                                                           \
+  SIGABRT SIGALRM SIGALRM1 SIGBUS SIGCANCEL SIGCHLD SIGCLD SIGCONT     \
+  SIGDANGER SIGDIL SIGEMT SIGFPE SIGFREEZE SIGGRANT SIGHUP SIGILL      \
+  SIGINFO SIGINT SIGIO SIGIOT SIGKAP SIGKILL SIGKILLTHR SIGLOST SIGLWP \
+  SIGMIGRATE SIGMSG SIGPHONE SIGPIPE SIGPOLL SIGPRE SIGPROF SIGPWR     \
+  SIGQUIT SIGRETRACT SIGSAK SIGSEGV SIGSOUND SIGSTKFLT SIGSTOP SIGSYS  \
+  SIGTERM SIGTHAW SIGTRAP SIGTSTP SIGTTIN SIGTTOU SIGURG SIGUSR1       \
+  SIGUSR2 SIGVIRT SIGVTALRM SIGWAITING SIGWINCH SIGWIND SIGWINDOW      \
+  SIGXCPU SIGXFSZ
+_sig_syms_re = $(subst $(_sp),|,$(strip $(_sig_names) $(_sig_types_and_consts)))
+
+# Prohibit the inclusion of signal.h without an actual use.
+sc_prohibit_signal_without_use:
+       @h='<signal.h>'                                                 \
+       re='\<($(_sig_function_re)) *\(|\<($(_sig_syms_re))\>'          \
+         $(_header_without_use)
+
 sc_obsolete_symbols:
        @re='\<(HAVE''_FCNTL_H|O''_NDELAY)\>'                           \
        msg='do not use HAVE''_FCNTL_H or O'_NDELAY                     \