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authorPaolo Bonzini <pbonzini@redhat.com>2017-07-04 11:26:37 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2017-07-04 14:39:28 +0200
commite8c2091d4c4dd78bb9b8618205a238b96c87045d (patch)
treed405300af3eb11fad1a2c37e2b1fcd16ab13f7d7
parentde5f852f38d644edf995a810c34b4d24dbfbd740 (diff)
checkpatch: should not use signal except for SIG_DFL or SIG_IGN
Using signal to establish a signal handler is not portable; on SysV systems, the signal handler would be reset to SIG_DFL after delivery, while BSD preserves the signal handler. Daniel Berrange reported that (to complicate matters further) the signal system call has SysV behavior, but glibc signal() actually calls the sigaction system call to provide BSD behavior. However, using signal() to set a signal's disposition to SIG_DFL or SIG_IGN is portable and is a relatively common occurrence in QEMU source code, so allow that. Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Reviewed-by: Richard W.M. Jones <rjones@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rwxr-xr-xscripts/checkpatch.pl4
1 files changed, 4 insertions, 0 deletions
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 45027b9281..73efc927a9 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2473,6 +2473,10 @@ sub process {
if ($line =~ /\b(strto[^kd].*?)\s*\(/) {
ERROR("consider using qemu_$1 in preference to $1\n" . $herecurr);
}
+# recommend sigaction over signal for portability, when establishing a handler
+ if ($line =~ /\bsignal\s*\(/ && !($line =~ /SIG_(?:IGN|DFL)/)) {
+ ERROR("use sigaction to establish signal handlers; signal is not portable\n" . $herecurr);
+ }
# check for module_init(), use category-specific init macros explicitly please
if ($line =~ /^module_init\s*\(/) {
ERROR("please use block_init(), type_init() etc. instead of module_init()\n" . $herecurr);