Changed wait_process() into a simpler, yet more versatile function,

and used it in the new wait_process_with_flush() function (the old
function's new name).  Made wait_process() public.

diff --git a/main.c b/main.c
index 65f9c0e..a9418f7 100644 (file)
--- a/main.c
+++ b/main.c
@@ -81,33 +81,39 @@ static int64 total_read, total_written;
 
 static void show_malloc_stats(void);
 
-/****************************************************************************
-wait for a process to exit, calling io_flush while waiting
-****************************************************************************/
-static void wait_process(pid_t pid, int *code_ptr)
+/* Works like waitpid(), but if we already harvested the child pid in our
+ * sigchld_handler(), we succeed instead of returning an error. */
+pid_t wait_process(pid_t pid, int *status_ptr, int flags)
 {
-       pid_t waited_pid;
-       int cnt, status;
-
-       while ((waited_pid = waitpid(pid, &status, WNOHANG)) == 0) {
-               msleep(20);
-               io_flush(FULL_FLUSH);
-       }
+       pid_t waited_pid = waitpid(pid, status_ptr, flags);
 
        if (waited_pid == -1 && errno == ECHILD) {
-               /* status of requested child no longer available.
-                * check to see if it was processed by the sigchld_handler.
-                */
+               /* Status of requested child no longer available:  check to
+                * see if it was processed by sigchld_handler(). */
+               int cnt;
                for (cnt = 0;  cnt < MAXCHILDPROCS; cnt++) {
                        if (pid == pid_stat_table[cnt].pid) {
-                               waited_pid = pid;
-                               status = pid_stat_table[cnt].status;
+                               *status_ptr = pid_stat_table[cnt].status;
                                pid_stat_table[cnt].pid = 0;
-                               break;
+                               return pid;
                        }
                }
        }
 
+       return waited_pid;
+}
+
+/* Wait for a process to exit, calling io_flush while waiting. */
+static void wait_process_with_flush(pid_t pid, int *code_ptr)
+{
+       pid_t waited_pid;
+       int status;
+
+       while ((waited_pid = wait_process(pid, &status, WNOHANG)) == 0) {
+               msleep(20);
+               io_flush(FULL_FLUSH);
+       }
+
        /* TODO: If the child exited on a signal, then log an
         * appropriate error message.  Perhaps we should also accept a
         * message describing the purpose of the child.  Also indicate
@@ -618,7 +624,7 @@ static int do_recv(int f_in,int f_out,struct file_list *flist,char *local_name)
 
        set_msg_fd_in(-1);
        kill(pid, SIGUSR2);
-       wait_process(pid, &status);
+       wait_process_with_flush(pid, &status);
        return status;
 }
 
@@ -789,7 +795,7 @@ int client_run(int f_in, int f_out, pid_t pid, int argc, char *argv[])
                        if (verbose > 3)
                                rprintf(FINFO,"client_run waiting on %d\n", (int) pid);
                        io_flush(FULL_FLUSH);
-                       wait_process(pid, &status);
+                       wait_process_with_flush(pid, &status);
                }
                output_summary();
                io_flush(FULL_FLUSH);
@@ -834,7 +840,7 @@ int client_run(int f_in, int f_out, pid_t pid, int argc, char *argv[])
                if (verbose > 3)
                        rprintf(FINFO,"client_run2 waiting on %d\n", (int) pid);
                io_flush(FULL_FLUSH);
-               wait_process(pid, &status);
+               wait_process_with_flush(pid, &status);
        }
 
        return MAX(status, status2);
@@ -1023,8 +1029,7 @@ static RETSIGTYPE sigchld_handler(UNUSED(int val))
         * get him to explain why he put it in, so rather than taking it
         * out we're instead saving the child exit statuses for later use.
         * The waitpid() loop presumably eliminates all possibility of leaving
-        * zombie children, maybe that's why he did it.
-        */
+        * zombie children, maybe that's why he did it. */
        while ((pid = waitpid(-1, &status, WNOHANG)) > 0) {
                /* save the child's exit status */
                for (cnt = 0; cnt < MAXCHILDPROCS; cnt++) {
@@ -1036,6 +1041,7 @@ static RETSIGTYPE sigchld_handler(UNUSED(int val))
                }
        }
 #endif
+       signal(SIGCHLD, sigchld_handler);
 }