From: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
To: linux-ppp@vger.kernel.org
Subject: [PATCH 9/9] pppd: refactor setjmp/longjmp with pipe pair in event wait loop
Date: Thu, 26 Sep 2019 07:21:06 +0000 [thread overview]
Message-ID: <1569482466-9551-10-git-send-email-dev.kurt@vandijck-laurijssen.be> (raw)
setjmp/longjmp isn't supported by all compilers.
Having a pipe pair to wake an event wait loop from within a signal handler
is rather portable and common enough.
Signed-off-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
---
pppd/main.c | 41 +++++++++++++++++++++++++----------------
pppd/tty.c | 1 -
2 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/pppd/main.c b/pppd/main.c
index b0d772b..41be532 100644
--- a/pppd/main.c
+++ b/pppd/main.c
@@ -80,7 +80,6 @@
#include <netdb.h>
#include <utmp.h>
#include <pwd.h>
-#include <setjmp.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
@@ -180,7 +179,7 @@ int got_sighup;
static sigset_t signals_handled;
static int waiting;
-static sigjmp_buf sigjmp;
+static int sigpipe[2];
char **script_env; /* Env. variable values for scripts */
int s_env_nalloc; /* # words avail at script_env */
@@ -598,19 +597,21 @@ static void
handle_events()
{
struct timeval timo;
+ unsigned char buf[16];
kill_link = open_ccp_flag = 0;
- if (sigsetjmp(sigjmp, 1) = 0) {
- sigprocmask(SIG_BLOCK, &signals_handled, NULL);
- if (got_sighup || got_sigterm || got_sigusr2 || got_sigchld) {
- sigprocmask(SIG_UNBLOCK, &signals_handled, NULL);
- } else {
- waiting = 1;
- sigprocmask(SIG_UNBLOCK, &signals_handled, NULL);
- wait_input(timeleft(&timo));
- }
- }
+
+ /* alert via signal pipe */
+ waiting = 1;
+ /* flush signal pipe */
+ for (; read(sigpipe[0], buf, sizeof(buf)) > 0; );
+ add_fd(sigpipe[0]);
+ /* wait if necessary */
+ if (!(got_sighup || got_sigterm || got_sigusr2 || got_sigchld))
+ wait_input(timeleft(&timo));
waiting = 0;
+ remove_fd(sigpipe[0]);
+
calltimeout();
if (got_sighup) {
info("Hangup (SIGHUP)");
@@ -645,6 +646,14 @@ setup_signals()
{
struct sigaction sa;
+ /* create pipe to wake up event handler from signal handler */
+ if (pipe(sigpipe) < 0)
+ fatal("Couldn't create signal pipe: %m");
+ fcntl(sigpipe[0], F_SETFD, fcntl(sigpipe[0], F_GETFD) | FD_CLOEXEC);
+ fcntl(sigpipe[1], F_SETFD, fcntl(sigpipe[1], F_GETFD) | FD_CLOEXEC);
+ fcntl(sigpipe[0], F_SETFL, fcntl(sigpipe[0], F_GETFL) | O_NONBLOCK);
+ fcntl(sigpipe[1], F_SETFL, fcntl(sigpipe[1], F_GETFL) | O_NONBLOCK);
+
/*
* Compute mask of all interesting signals and install signal handlers
* for each. Only one signal handler may be active at a time. Therefore,
@@ -1431,7 +1440,7 @@ hup(sig)
kill_my_pg(sig);
notify(sigreceived, sig);
if (waiting)
- siglongjmp(sigjmp, 1);
+ write(sigpipe[1], &sig, sizeof(sig));
}
@@ -1452,7 +1461,7 @@ term(sig)
kill_my_pg(sig);
notify(sigreceived, sig);
if (waiting)
- siglongjmp(sigjmp, 1);
+ write(sigpipe[1], &sig, sizeof(sig));
}
@@ -1466,7 +1475,7 @@ chld(sig)
{
got_sigchld = 1;
if (waiting)
- siglongjmp(sigjmp, 1);
+ write(sigpipe[1], &sig, sizeof(sig));
}
@@ -1501,7 +1510,7 @@ open_ccp(sig)
{
got_sigusr2 = 1;
if (waiting)
- siglongjmp(sigjmp, 1);
+ write(sigpipe[1], &sig, sizeof(sig));
}
diff --git a/pppd/tty.c b/pppd/tty.c
index c9a0b33..7ece675 100644
--- a/pppd/tty.c
+++ b/pppd/tty.c
@@ -83,7 +83,6 @@
#include <netdb.h>
#include <utmp.h>
#include <pwd.h>
-#include <setjmp.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/wait.h>
--
1.8.5.rc3
reply other threads:[~2019-09-26 7:21 UTC|newest]
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