SHA256
3
0
forked from pool/tcpd
tcpd/tcp_wrappers_7.6-fedora-sigchld.diff

88 lines
2.4 KiB
Diff

--- shell_cmd.c.orig
+++ shell_cmd.c
@@ -24,6 +24,11 @@ static char sccsid[] = "@(#) shell_cmd.c
#include <unistd.h>
#include <syslog.h>
#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/stat.h>
+#include <fcntl.h>
extern void exit();
@@ -35,13 +40,42 @@ extern void exit();
static void do_child();
+/*
+ * The sigchld handler. If there is a SIGCHLD caused by a child other than
+ * ours, we set a flag and raise the signal later.
+ */
+volatile static int foreign_sigchld;
+volatile static int our_child_pid;
+static void sigchld(int sig, siginfo_t *si, void *unused)
+{
+ if (si && si->si_pid != our_child_pid)
+ foreign_sigchld = 1;
+}
+
/* shell_cmd - execute shell command */
void shell_cmd(command)
char *command;
{
int child_pid;
- int wait_pid;
+
+ struct sigaction new_action, old_action;
+ sigset_t new_mask, old_mask, empty_mask;
+
+ new_action.sa_sigaction = &sigchld;
+ new_action.sa_flags = SA_SIGINFO;
+ sigemptyset(&new_action.sa_mask);
+ sigemptyset(&new_mask);
+ sigemptyset(&empty_mask);
+ sigaddset(&new_mask, SIGCHLD);
+
+ /*
+ * Set the variables for handler, set the handler and block the signal
+ * until we have the pid.
+ */
+ foreign_sigchld = 0; our_child_pid = 0;
+ sigprocmask(SIG_BLOCK, &new_mask, &old_mask);
+ sigaction(SIGCHLD, &new_action, &old_action);
/*
* Most of the work is done within the child process, to minimize the
@@ -53,12 +87,26 @@ char *command;
tcpd_warn("cannot fork: %m");
break;
case 00: /* child */
+ /* Clear the blocked mask for the child not to be surprised. */
+ sigprocmask(SIG_SETMASK, &empty_mask, 0);
do_child(command);
/* NOTREACHED */
default: /* parent */
- while ((wait_pid = wait((int *) 0)) != -1 && wait_pid != child_pid)
- /* void */ ;
+ our_child_pid = child_pid;
+ sigprocmask(SIG_UNBLOCK, &new_mask, 0);
+ while (waitpid(child_pid, (int *) 0, 0) == -1 && errno == EINTR);
}
+
+ /*
+ * Revert the signal mask and the SIGCHLD handler.
+ */
+ sigprocmask(SIG_SETMASK, &old_mask, 0);
+ sigaction(SIGCHLD, &old_action, 0);
+
+ /* If there was a foreign SIGCHLD, raise it after we have restored the old
+ * mask and handler. */
+ if (foreign_sigchld)
+ raise(SIGCHLD);
}
/* do_child - exec command with { stdin, stdout, stderr } to /dev/null */