Adding upstream version 2.8.5.upstream/2.8.5upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 266 insertions, 0 deletions

diff --git a/lib/cleanup.c b/lib/cleanup.c
new file mode 100644
index 0000000..5aa2e50
--- /dev/null
+++ b/lib/cleanup.c
@@ -0,0 +1,266 @@
+/*
+ * cleanup.c -- simple dynamic cleanup function management
+ * Copyright (C) 1995 Markus Armbruster.
+ * Copyright (C) 2007 Colin Watson.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; see the file COPYING.LIB.  If not,
+ * write to the Free Software Foundation, Inc., 51 Franklin St, Fifth
+ * Floor, Boston, MA  02110-1301  USA.
+*/
+
+#ifdef HAVE_CONFIG_H
+#  include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <stdlib.h>
+#include <stdio.h>		/* SunOS's loosing assert.h needs it */
+#include <assert.h>
+#include <signal.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "manconfig.h"		/* for FATAL */
+#include "cleanup.h"
+
+
+
+/* Dealing with signals */
+
+
+/* saved signal actions */
+static struct sigaction saved_hup_action;
+static struct sigaction saved_int_action;
+static struct sigaction saved_term_action;
+
+
+/* Run cleanups, then reraise signal with default handler. */
+static void
+sighandler (int signo)
+{
+  struct sigaction act;
+  sigset_t set;
+
+  do_cleanups_sigsafe (1);
+
+  /* set default signal action */
+  memset (&act, 0, sizeof act);
+  act.sa_handler = SIG_DFL;
+  sigemptyset (&act.sa_mask);
+  act.sa_flags = 0;
+  if (sigaction (signo, &act, NULL)) {
+    /* should not happen */
+    _exit (FATAL);		/* exit() is taboo from signal handlers! */
+  }
+
+  /* unmask signo */
+  if (   sigemptyset (&set)
+      || sigaddset (&set, signo)
+      || sigprocmask (SIG_UNBLOCK, &set, NULL)) {
+    /* shouldn't happen */
+    _exit (FATAL);		/* exit() is taboo from signal handlers! */
+  }
+
+  /* signal has now default action and is unmasked,
+     reraise it to terminate program abnormally */
+  kill (getpid(), signo);
+  abort();
+}
+
+
+/* Save signo's current action to oldact, if its handler is SIG_DFL
+   install sighandler, return 0 on success, -1 on failure. */
+static int
+trap_signal (int signo, struct sigaction *oldact)
+{
+  if (sigaction (signo, NULL, oldact)) {
+    return -1;
+  }
+
+  if (oldact->sa_handler == SIG_DFL) {
+    struct sigaction act;
+
+    memset (&act, 0, sizeof act);
+    act.sa_handler = sighandler;
+    sigemptyset (&act.sa_mask);
+    act.sa_flags = 0;
+    return sigaction (signo, &act, oldact);
+  }
+
+  return 0;
+}
+
+
+/* Trap some abnormal exits to call do_cleanups(). */
+static int
+trap_abnormal_exits (void)
+{
+  if (   trap_signal (SIGHUP, &saved_hup_action)
+      || trap_signal (SIGINT, &saved_int_action)
+      || trap_signal (SIGTERM, &saved_term_action))
+    return -1;
+  return 0;
+}
+
+
+/* Restore signo's action from oldact if its current handler is
+   sighandler, return 0 on success, -1 on failure. */
+static int
+untrap_signal (int signo, struct sigaction *oldact)
+{
+  struct sigaction act;
+  if (sigaction (signo, NULL, &act)) {
+    return -1;
+  }
+
+  if (act.sa_handler == sighandler) {
+    return sigaction (signo, oldact, NULL);
+  }
+
+  return 0;
+}
+
+
+/* Undo a previous trap_abnormal_exits(). */
+static int
+untrap_abnormal_exits (void)
+{
+  if (  untrap_signal (SIGHUP, &saved_hup_action)
+      | untrap_signal (SIGINT, &saved_int_action)
+      | untrap_signal (SIGTERM, &saved_term_action))
+    return -1;
+  return 0;
+}
+
+
+
+typedef struct {
+  cleanup_fun fun;
+  void *arg;
+  int sigsafe;
+} slot;
+
+static slot *stack = NULL;	/* stack of cleanup functions */
+static unsigned nslots = 0;	/* #slots in stack */
+static unsigned tos = 0;	/* top of stack, 0 <= tos <= nslots */
+
+/* Call cleanup functions in stack from from top to bottom,
+ * Automatically called on program termination via exit(3) or default
+ * action for SIGHUP, SIGINT or SIGTERM.
+ * Since this may be called from a signal handler, do not use free().
+ * If in_sighandler is true, cleanup functions with sigsafe=0 will not be
+ * called.
+ */
+void
+do_cleanups_sigsafe (int in_sighandler)
+{
+  unsigned i;
+
+  assert (tos <= nslots);
+  for (i = tos; i > 0; --i)
+    if (!in_sighandler || stack[i-1].sigsafe)
+      stack[i-1].fun (stack[i-1].arg);
+}
+
+/* Call cleanup functions in stack from from top to bottom,
+ * Automatically called on program termination via exit(3).
+ */
+void
+do_cleanups (void)
+{
+  do_cleanups_sigsafe (0);
+  tos = 0;
+  nslots = 0;
+  free (stack);
+  stack = NULL;
+}
+
+
+/* Push a cleanup function on the cleanup stack,
+ * return 0 on success, -1 on failure.
+ * Caution: the cleanup function may be called from signal handlers if
+ * sigsafe=1. If you just want a convenient atexit() wrapper, pass
+ * sigsafe=0.
+ */
+int
+push_cleanup (cleanup_fun fun, void *arg, int sigsafe)
+{
+  static int handler_installed = 0;
+
+  assert (tos <= nslots);
+
+  if (!handler_installed) {
+    if (atexit (do_cleanups))
+      return -1;
+    handler_installed = 1;
+  }
+
+  if (tos == nslots) {
+    /* stack is full, allocate another slot */
+    /* stack is not expected to grow much, otherwise we would double it */
+    slot *new_stack;
+
+    if (stack) {
+      new_stack = xnrealloc (stack, nslots+1, sizeof (slot));
+    } else {
+      new_stack = xnmalloc (nslots+1, sizeof (slot));
+    }
+      
+    if (!new_stack) return -1;
+    stack = new_stack;
+    ++nslots;
+  }
+
+  assert (tos < nslots);
+  stack[tos].fun = fun;
+  stack[tos].arg = arg;
+  stack[tos].sigsafe = sigsafe;
+  ++tos;
+
+
+  trap_abnormal_exits();
+
+  return 0;
+}
+
+
+/* Remove topmost cleanup function from the cleanup stack that matches the
+ * given values.
+ */
+void
+pop_cleanup (cleanup_fun fun, void *arg)
+{
+  unsigned i, j;
+
+  assert (tos > 0);
+
+  for (i = tos; i > 0; --i) {
+    if (stack[i-1].fun == fun && stack[i-1].arg == arg) {
+      for (j = i; j < tos; ++j)
+        stack[j-1] = stack[j];
+      --tos;
+      break;
+    }
+  }
+
+  if (tos == 0) untrap_abnormal_exits();
+}
+
+
+/* Pop all cleanup functions from the cleanup stack. */
+void
+pop_all_cleanups (void)
+{
+  tos = 0;
+  untrap_abnormal_exits();
+}