@@ -0,0 +1,87 @@
+--- 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 */
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