Extract process-management functionality into a new lib/process

Note that procmon does *not* go here, since procmon needs to
integrate with the event loop.

1 files changed, 0 insertions, 158 deletions

diff --git a/src/common/util_process.c b/src/common/util_process.c
deleted file mode 100644
index 321258b694..0000000000
--- a/src/common/util_process.c
+++ /dev/null
@@ -1,158 +0,0 @@
-/* Copyright (c) 2003-2004, Roger Dingledine
- * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
- * Copyright (c) 2007-2018, The Tor Project, Inc. */
-/* See LICENSE for licensing information */
-
-/**
- * \file util_process.c
- * \brief utility functions for launching processes and checking their
- *    status. These functions are kept separately from procmon so that they
- *    won't require linking against libevent.
- **/
-
-#include "orconfig.h"
-
-#ifdef HAVE_SYS_TYPES_H
-#include <sys/types.h>
-#endif
-#ifdef HAVE_SYS_WAIT_H
-#include <sys/wait.h>
-#endif
-
-#include "common/compat.h"
-#include "common/util.h"
-#include "lib/log/torlog.h"
-#include "common/util_process.h"
-#include "ht.h"
-
-/* ================================================== */
-/* Convenience structures for handlers for waitpid().
- *
- * The tor_process_monitor*() code above doesn't use them, since it is for
- * monitoring a non-child process.
- */
-
-#ifndef _WIN32
-
-/** Mapping from a PID to a userfn/userdata pair. */
-struct waitpid_callback_t {
-  HT_ENTRY(waitpid_callback_t) node;
-  pid_t pid;
-
-  void (*userfn)(int, void *userdata);
-  void *userdata;
-
-  unsigned running;
-};
-
-static inline unsigned int
-process_map_entry_hash_(const waitpid_callback_t *ent)
-{
-  return (unsigned) ent->pid;
-}
-
-static inline unsigned int
-process_map_entries_eq_(const waitpid_callback_t *a,
-                        const waitpid_callback_t *b)
-{
-  return a->pid == b->pid;
-}
-
-static HT_HEAD(process_map, waitpid_callback_t) process_map = HT_INITIALIZER();
-
-HT_PROTOTYPE(process_map, waitpid_callback_t, node, process_map_entry_hash_,
-             process_map_entries_eq_)
-HT_GENERATE2(process_map, waitpid_callback_t, node, process_map_entry_hash_,
-             process_map_entries_eq_, 0.6, tor_reallocarray_, tor_free_)
-
-/**
- * Begin monitoring the child pid <b>pid</b> to see if we get a SIGCHLD for
- * it.  If we eventually do, call <b>fn</b>, passing it the exit status (as
- * yielded by waitpid) and the pointer <b>arg</b>.
- *
- * To cancel this, or clean up after it has triggered, call
- * clear_waitpid_callback().
- */
-waitpid_callback_t *
-set_waitpid_callback(pid_t pid, void (*fn)(int, void *), void *arg)
-{
-  waitpid_callback_t *old_ent;
-  waitpid_callback_t *ent = tor_malloc_zero(sizeof(waitpid_callback_t));
-  ent->pid = pid;
-  ent->userfn = fn;
-  ent->userdata = arg;
-  ent->running = 1;
-
-  old_ent = HT_REPLACE(process_map, &process_map, ent);
-  if (old_ent) {
-    log_warn(LD_BUG, "Replaced a waitpid monitor on pid %u. That should be "
-             "impossible.", (unsigned) pid);
-    old_ent->running = 0;
-  }
-
-  return ent;
-}
-
-/**
- * Cancel a waitpid_callback_t, or clean up after one has triggered. Releases
- * all storage held by <b>ent</b>.
- */
-void
-clear_waitpid_callback(waitpid_callback_t *ent)
-{
-  waitpid_callback_t *old_ent;
-  if (ent == NULL)
-    return;
-
-  if (ent->running) {
-    old_ent = HT_REMOVE(process_map, &process_map, ent);
-    if (old_ent != ent) {
-      log_warn(LD_BUG, "Couldn't remove waitpid monitor for pid %u.",
-               (unsigned) ent->pid);
-      return;
-    }
-  }
-
-  tor_free(ent);
-}
-
-/** Helper: find the callack for <b>pid</b>; if there is one, run it,
- * reporting the exit status as <b>status</b>. */
-static void
-notify_waitpid_callback_by_pid(pid_t pid, int status)
-{
-  waitpid_callback_t search, *ent;
-
-  search.pid = pid;
-  ent = HT_REMOVE(process_map, &process_map, &search);
-  if (!ent || !ent->running) {
-    log_info(LD_GENERAL, "Child process %u has exited; no callback was "
-             "registered", (unsigned)pid);
-    return;
-  }
-
-  log_info(LD_GENERAL, "Child process %u has exited; running callback.",
-           (unsigned)pid);
-
-  ent->running = 0;
-  ent->userfn(status, ent->userdata);
-}
-
-/** Use waitpid() to wait for all children that have exited, and invoke any
- * callbacks registered for them. */
-void
-notify_pending_waitpid_callbacks(void)
-{
-  /* I was going to call this function reap_zombie_children(), but
-   * that makes it sound way more exciting than it really is. */
-  pid_t child;
-  int status = 0;
-
-  while ((child = waitpid(-1, &status, WNOHANG)) > 0) {
-    notify_waitpid_callback_by_pid(child, status);
-    status = 0; /* should be needless */
-  }
-}
-
-#endif /* !defined(_WIN32) */
-