checkpoint handling

src/checkpoint.c

@@ -0,0 +1,235 @@
+/* Checkpoint management for tar.
+
+   Copyright (C) 2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 3, or (at your option) any later
+   version.
+
+   This program 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 General
+   Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+#include <system.h>
+#include "common.h"
+
+enum checkpoint_opcode
+  {
+    cop_dot,
+    cop_echo,
+    cop_sleep,
+    cop_exec
+  };
+
+struct checkpoint_action
+{
+  struct checkpoint_action *next;
+  enum checkpoint_opcode opcode;
+  union
+  {
+    time_t time;
+    char *command;
+  } v;
+};
+
+/* Checkpointing counter */
+static unsigned checkpoint;
+
+/* List of checkpoint actions */
+static struct checkpoint_action *checkpoint_action, *checkpoint_action_tail;
+
+static struct checkpoint_action *
+alloc_action (enum checkpoint_opcode opcode)
+{
+  struct checkpoint_action *p = xzalloc (sizeof *p);
+  if (checkpoint_action_tail)
+    checkpoint_action_tail->next = p;
+  else
+    checkpoint_action = p;
+  checkpoint_action_tail = p;
+  p->opcode = opcode;
+  return p;
+}
+
+static char *
+copy_string_unquote (const char *str)
+{
+  char *output = xstrdup (str);
+  size_t len = strlen (output);
+  if ((*output == '"' || *output == '\'')
+      && output[len-1] == *output)
+    {
+      memmove (output, output+1, len-2);
+      output[len-2] = 0;
+    }
+  unquote_string (output);
+  return output;
+}
+
+void
+checkpoint_compile_action (const char *str)
+{
+  struct checkpoint_action *act;
+  
+  if (strcmp (str, ".") == 0 || strcmp (str, "dot") == 0)
+    alloc_action (cop_dot);
+  else if (strcmp (str, "echo") == 0)
+    alloc_action (cop_echo);
+  else if (strncmp (str, "echo=", 5) == 0)
+    {
+      act = alloc_action (cop_echo);
+      act->v.command = copy_string_unquote (str + 5);
+    }
+  else if (strncmp (str, "exec=", 5) == 0)
+    {
+      act = alloc_action (cop_exec);
+      act->v.command = copy_string_unquote (str + 5);
+    }
+  else if (strncmp (str, "sleep=", 6) == 0)
+    {
+      char *p;
+      time_t n = strtoul (str+6, &p, 10);
+      if (*p)
+	FATAL_ERROR ((0, 0, _("%s: not a valid timeout"), str));
+      act = alloc_action (cop_sleep);
+      act->v.time = n;
+    }
+  else
+    FATAL_ERROR ((0, 0, _("%s: unknown checkpoint action"), str));
+}
+
+void
+checkpoint_finish_compile ()
+{
+  if (checkpoint_option)
+    {
+      if (!checkpoint_action)
+	/* Provide a historical default */
+	checkpoint_compile_action ("echo"); 
+    }
+  else if (checkpoint_action)
+    /* Otherwise, set default checkpoint rate */
+    checkpoint_option = DEFAULT_CHECKPOINT;
+}
+
+char *
+expand_checkpoint_string (const char *input, bool do_write, unsigned cpn)
+{
+  const char *opstr = do_write ? gettext ("write") : gettext ("read");
+  size_t opstrlen = strlen (opstr);
+  char uintbuf[UINTMAX_STRSIZE_BOUND];
+  char *cps = STRINGIFY_BIGINT (cpn, uintbuf);
+  size_t cpslen = strlen (cps);
+  const char *ip;
+  char *op;
+  char *output;
+  size_t outlen = strlen (input); /* Initial guess */
+
+  /* Fix the initial length guess */
+  for (ip = input; (ip = strchr (ip, '%')) != NULL; )
+    {
+      switch (ip[1])
+	{
+	case 'u':
+	  outlen += cpslen - 2;
+	  break;
+	  
+	case 's':
+	  outlen += opstrlen - 2;
+	}
+      ip++;
+    }
+
+  output = xmalloc (outlen + 1);
+  for (ip = input, op = output; *ip; )
+    {
+      if (*ip == '%')
+	{
+	  switch (*++ip)
+	    {
+	    case 'u':
+	      op = stpcpy (op, cps);
+	      break;
+	      
+	    case 's':
+	      op = stpcpy (op, opstr);
+	      break;
+	      
+	    default:
+	      *op++ = '%';
+	      *op++ = *ip;
+	      break;
+	    }
+	  ip++;
+	}
+      else
+	*op++ = *ip++;
+    }
+  *op = 0;
+  return output;
+}
+
+static void
+run_checkpoint_actions (bool do_write)
+{
+  struct checkpoint_action *p;
+
+  for (p = checkpoint_action; p; p = p->next)
+    {
+      switch (p->opcode)
+	{
+	case cop_dot:
+	  fputc ('.', stdlis);
+	  fflush (stdlis);
+	  break;
+	  
+	case cop_echo:
+	  {
+	    char *tmp;
+	    const char *str = p->v.command;
+	    if (!str)
+	      {
+		if (do_write)
+		  /* TRANSLATORS: This is a ``checkpoint of write operation'',
+ 		     *not* ``Writing a checkpoint''.
+		     E.g. in Spanish ``Punto de comprobaci@'on de escritura'',
+		     *not* ``Escribiendo un punto de comprobaci@'on'' */
+		  str = gettext ("Write checkpoint %u");
+		else
+		  /* TRANSLATORS: This is a ``checkpoint of read operation'',
+	             *not* ``Reading a checkpoint''.
+		     E.g. in Spanish ``Punto de comprobaci@'on de lectura'',
+		     *not* ``Leyendo un punto de comprobaci@'on'' */
+		  str = gettext ("Read checkpoint %u");
+	      }
+	    tmp = expand_checkpoint_string (str, do_write, checkpoint);
+	    WARN ((0, 0, "%s", tmp));
+	    free (tmp);
+	  }
+	  break;
+	  
+	case cop_sleep:
+	  sleep (p->v.time);
+	  break;
+	  
+	case cop_exec:
+	  sys_exec_checkpoint_script (p->v.command,
+				      archive_name_cursor[0],
+				      checkpoint);
+	  break;
+	}
+    }
+}
+
+void
+checkpoint_run (bool do_write)
+{
+  if (checkpoint_option && !(++checkpoint % checkpoint_option))
+    run_checkpoint_actions (do_write);
+}  
+