Libvirtd has set SIGPIPE to ignored, and virFork resets all signal handlers to the defaults. But child process may write logs to stderr/stdout, that may generate SIGPIPE if journald has stopped. So in virExec(), set SIGPIPE to ignored before invoke virCommandMassClose, and revert it back to SIG_DFL after that. In virProcessRunInFork(), just set SIGPIPE to ignored. Signed-off-by: Wang Yechao <wang.yechao255@zte.com.cn> --- v1 patch: https://www.redhat.com/archives/libvir-list/2019-October/msg00720.html Changes in v2: - use pthread_sigmask to block SIGPIPE Changes in v3: - pass SIG_UNBLOCK(not SIG_SETMASK) to pthread_sigmask when unlock SIGPIPE Changes in v4: - don't block SIGPIPE, ignore it when invoke VIR_FORCE_CLOSE and virCommandMassClose --- src/util/vircommand.c | 16 ++++++++++++++++ src/util/virprocess.c | 10 ++++++++++ 2 files changed, 26 insertions(+) diff --git a/src/util/vircommand.c b/src/util/vircommand.c index 763bcb6..bb6e73b 100644 --- a/src/util/vircommand.c +++ b/src/util/vircommand.c @@ -653,9 +653,25 @@ virExec(virCommandPtr cmd) umask(cmd->mask); ret = EXIT_CANCELED; + memset(&waxoff, 0, sizeof(waxoff)); + waxoff.sa_handler = SIG_IGN; + sigemptyset(&waxoff.sa_mask); + memset(&waxon, 0, sizeof(waxon)); + if (sigaction(SIGPIPE, &waxoff, &waxon) < 0) { + virReportSystemError(errno, "%s", + _("Could not disable SIGPIPE")); + goto fork_error; + } + if (virCommandMassClose(cmd, childin, childout, childerr) < 0) goto fork_error; + if (sigaction(SIGPIPE, &waxon, NULL) < 0) { + virReportSystemError(errno, "%s", + _("Could not re-enable SIGPIPE")); + goto fork_error; + } + if (prepareStdFd(childin, STDIN_FILENO) < 0) { virReportSystemError(errno, "%s", _("failed to setup stdin file handle")); diff --git a/src/util/virprocess.c b/src/util/virprocess.c index e8d4ba0..da66dcf 100644 --- a/src/util/virprocess.c +++ b/src/util/virprocess.c @@ -1151,6 +1151,16 @@ virProcessRunInFork(virProcessForkCallback cb, goto cleanup; if (child == 0) { + struct sigaction waxoff; + + memset(&waxoff, 0, sizeof(waxoff)); + waxoff.sa_handler = SIG_IGN; + sigemptyset(&waxoff.sa_mask); + if (sigaction(SIGPIPE, &waxoff, NULL) < 0) { + virReportSystemError(errno, "%s", + _("Could not disable SIGPIPE")); + } + VIR_FORCE_CLOSE(errfd[0]); ret = virProcessRunInForkHelper(errfd[1], parent, cb, opaque); VIR_FORCE_CLOSE(errfd[1]); -- 1.8.3.1