1 files changed, 92 insertions, 0 deletions
diff --git a/support/support_process_state.c b/support/support_process_state.c
new file mode 100644
index 0000000000..76dc798728
--- /dev/null
+++ b/support/support_process_state.c
@@ -0,0 +1,92 @@
+/* Wait for process state.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+
+#include <array_length.h>
+
+#include <support/process_state.h>
+#include <support/xstdio.h>
+#include <support/check.h>
+
+void
+support_process_state_wait (pid_t pid, enum support_process_state state)
+{
+#ifdef __linux__
+  /* For Linux it does a polling check on /proc/<pid>/status checking on
+     third field.  */
+
+  /* It mimics the kernel states from fs/proc/array.c  */
+  static const struct process_states
+  {
+    enum support_process_state s;
+    char v;
+  } process_states[] = {
+    { support_process_state_running,      'R' },
+    { support_process_state_sleeping,     'S' },
+    { support_process_state_disk_sleep,   'D' },
+    { support_process_state_stopped,      'T' },
+    { support_process_state_tracing_stop, 't' },
+    { support_process_state_dead,         'X' },
+    { support_process_state_zombie,       'Z' },
+    { support_process_state_parked,       'P' },
+  };
+
+  char spath[sizeof ("/proc/" + 3) * sizeof (pid_t) + sizeof ("/status") + 1];
+  snprintf (spath, sizeof (spath), "/proc/%i/status", pid);
+
+  FILE *fstatus = xfopen (spath, "r");
+  char *line = NULL;
+  size_t linesiz = 0;
+
+  for (;;)
+    {
+      char cur_state = -1;
+      while (xgetline (&line, &linesiz, fstatus) != -1)
+	if (strncmp (line, "State:", strlen ("State:")) == 0)
+	  {
+	    TEST_COMPARE (sscanf (line, "%*s %c", &cur_state), 1);
+	    break;
+	  }
+      /* Fallback to nanosleep for invalid state.  */
+      if (cur_state == -1)
+	break;
+
+      for (size_t i = 0; i < array_length (process_states); ++i)
+	if (state & process_states[i].s && cur_state == process_states[i].v)
+	  {
+	    free (line);
+	    xfclose (fstatus);
+	    return;
+	  }
+
+      rewind (fstatus);
+      fflush (fstatus);
+
+      if (nanosleep (&(struct timespec) { 0, 10000000 }, NULL) != 0)
+	FAIL_EXIT1 ("nanosleep: %m");
+    }
+
+  free (line);
+  xfclose (fstatus);
+  /* Fallback to nanosleep if an invalid state is found.  */
+#endif
+  nanosleep (&(struct timespec) { 2, 0 }, NULL);
+}