ash: fix ctrl-c handling for pipelines

There were two flaws in the implementation of ctrl-c handling in
waitpid_child():

- processes associated with all jobs were killed;
- all processes in a pipeline were killed but only the status of
  one was updated.

As a result of the latter ctrl-c didn't reliably stop a pipeline.

1 files changed, 57 insertions, 43 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 2e3b22850..188ec0979 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -4453,12 +4453,14 @@ static BOOL WINAPI ctrl_handler(DWORD dwCtrlType)
 static pid_t
 waitpid_child(int *status, int wait_flags)
 {
+        struct job *jb;
+        struct procstat *ps;
+        int pid_nr = 0;
         pid_t *pidlist;
         HANDLE *proclist;
-        int pid_nr = 0;
-        pid_t pid;
+        pid_t pid = -1;
         DWORD win_status, idx;
-        struct job *jb;
+        int i, delay;
 
         for (jb = curjob; jb; jb = jb->prev_job) {
                 if (jb->state != JOBDONE)
@@ -4474,59 +4476,71 @@ waitpid_child(int *status, int wait_flags)
         proclist[0] = hSIGINT;
         pid_nr = 1;
         for (jb = curjob; jb; jb = jb->prev_job) {
-                struct procstat *ps, *psend;
                 if (jb->state == JOBDONE)
                         continue;
                 ps = jb->ps;
-                psend = ps + jb->nprocs;
-                while (ps < psend) {
-                        if (ps->ps_pid != -1 && ps->ps_proc != NULL) {
-                                pidlist[pid_nr] = ps->ps_pid;
-                                proclist[pid_nr++] = ps->ps_proc;
+                for (i = 0; i < jb->nprocs; ++i) {
+                        if (ps[i].ps_proc) {
+                                pidlist[pid_nr] = ps[i].ps_pid;
+                                proclist[pid_nr++] = ps[i].ps_proc;
                         }
-                        ps++;
                 }
         }
 
-        if (pid_nr == 1) {
-                free(pidlist);
-                free(proclist);
-                return -1;
-        }
+        if (pid_nr == 1)
+                goto done;
 
         idx = WaitForMultipleObjects(pid_nr, proclist, FALSE,
                                 wait_flags&WNOHANG ? 1 : INFINITE);
-        if (idx >= pid_nr) {
-                free(pidlist);
-                free(proclist);
-                return -1;
-        }
-        if (!idx) {             /* hSIGINT */
-                int i;
-                ResetEvent(hSIGINT);
-                for (i = 1; i < pid_nr; i++)
-                        kill_SIGTERM_by_handle(proclist[i], 128+SIGINT);
-                Sleep(200);
-                for (i = 1; i < pid_nr; i++) {
-                        DWORD code;
-                        if (GetExitCodeProcess(proclist[i], &code) &&
-                                        code == STILL_ACTIVE) {
-                                TerminateProcess(proclist[i], 128+SIGINT);
-                        }
-                }
-                pid = pidlist[1];
-                free(pidlist);
-                free(proclist);
-                *status = 128 + SIGINT; /* terminated by a signal */
-                if (iflag)
-                        write(STDOUT_FILENO, "^C", 2);
-                return pid;
+        if (idx < pid_nr) {
+                if (idx == 0) {         /* hSIGINT */
+                        ResetEvent(hSIGINT);
+
+                        ps = curjob->ps;
+                        for (i = 0; i < curjob->nprocs; ++i) {
+                                if (ps[i].ps_proc) {
+                                        kill_SIGTERM_by_handle(ps[i].ps_proc, 128+SIGINT);
+                                        pid = ps[i].ps_pid;     /* remember last valid pid */
+                                }
+                        }
+
+                        Sleep(200);
+                        delay = FALSE;
+                        for (i = 0; i < curjob->nprocs; ++i) {
+                                DWORD code;
+                                if (ps[i].ps_proc &&
+                                                GetExitCodeProcess(ps[i].ps_proc, &code) &&
+                                                code == STILL_ACTIVE) {
+                                        TerminateProcess(ps[i].ps_proc, 128+SIGINT);
+                                        delay = TRUE;
+                                }
+                        }
+
+                        if (delay)
+                                Sleep(200);
+                        for (i = 0; i < curjob->nprocs; ++i) {
+                                /* mark all pids dead except the one we'll return */
+                                if (ps[i].ps_pid != pid) {
+                                        ps[i].ps_status = 128 + SIGINT;
+                                        ps[i].ps_pid = -1;
+                                        CloseHandle(ps[i].ps_proc);
+                                        ps[i].ps_proc = NULL;
+                                }
+                        }
+
+                        *status = 128 + SIGINT; /* terminated by a signal */
+                        if (iflag)
+                                write(STDOUT_FILENO, "^C", 2);
+                }
+                else {          /* valid pid index */
+                        GetExitCodeProcess(proclist[idx], &win_status);
+                        *status = (int)win_status << 8;
+                        pid = pidlist[idx];
+                }
         }
-        GetExitCodeProcess(proclist[idx], &win_status);
-        pid = pidlist[idx];
+ done:
         free(pidlist);
         free(proclist);
-        *status = (int)win_status << 8;
         return pid;
 }
 #define waitpid(p, s, f) waitpid_child(s, f)