Initial import of a C portability framework and utility functions from

remctl so that the wallet client error handling can rest on a firmer
foundation.

4 files changed, 849 insertions, 0 deletions

diff --git a/util/concat.c b/util/concat.c
new file mode 100644
index 0000000..65ca04c
--- /dev/null
+++ b/util/concat.c
@@ -0,0 +1,76 @@
+/*  $Id$
+**
+**  Concatenate strings with dynamic memory allocation.
+**
+**  Written by Russ Allbery <rra@stanford.edu>
+**  This work is hereby placed in the public domain by its author.
+**
+**  Usage:
+** 
+**       string = concat(string1, string2, ..., (char *) 0);
+**       path = concatpath(base, name);
+**
+**  Dynamically allocates (using xmalloc) sufficient memory to hold all of
+**  the strings given and then concatenates them together into that
+**  allocated memory, returning a pointer to it.  Caller is responsible for
+**  freeing.  Assumes xmalloc is available.  The last argument must be a
+**  null pointer (to a char *, if you actually find a platform where it
+**  matters).
+**
+**  concatpath is similar, except that it only takes two arguments.  If the
+**  second argument begins with / or ./, a copy of it is returned;
+**  otherwise, the first argument, a slash, and the second argument are
+**  concatenated together and returned.  This is useful for building file
+**  names where names that aren't fully qualified are qualified with some
+**  particular directory.
+*/
+
+#include <config.h>
+#include <system.h>
+
+#include <util/util.h>
+
+/* Abbreviation for cleaner code. */
+#define VA_NEXT(var, type)      ((var) = (type) va_arg(args, type))
+
+/* ANSI C requires at least one named parameter. */
+char *
+concat(const char *first, ...)
+{
+    va_list args;
+    char *result, *p;
+    const char *string;
+    size_t length = 0;
+
+    /* Find the total memory required. */
+    va_start(args, first);
+    for (string = first; string != NULL; VA_NEXT(string, const char *))
+        length += strlen(string);
+    va_end(args);
+    length++;
+
+    /* Create the string.  Doing the copy ourselves avoids useless string
+       traversals of result, if using strcat, or string, if using strlen to
+       increment a pointer into result, at the cost of losing the native
+       optimization of strcat if any. */
+    result = xmalloc(length);
+    p = result;
+    va_start(args, first);
+    for (string = first; string != NULL; VA_NEXT(string, const char *))
+        while (*string != '\0')
+            *p++ = *string++;
+    va_end(args);
+    *p = '\0';
+
+    return result;
+}
+
+
+char *
+concatpath(const char *base, const char *name)
+{
+    if (name[0] == '/' || (name[0] == '.' && name[1] == '/'))
+        return xstrdup(name);
+    else
+        return concat(base != NULL ? base : ".", "/", name, (char *) 0);
+}
diff --git a/util/messages.c b/util/messages.c
new file mode 100644
index 0000000..4a975c3
--- /dev/null
+++ b/util/messages.c
@@ -0,0 +1,361 @@
+/*  $Id$
+**
+**  Message and error reporting (possibly fatal).
+**
+**  Usage:
+**
+**      extern int cleanup(void);
+**      extern void log(int, const char *, va_list, int);
+**
+**      message_fatal_cleanup = cleanup;
+**      message_program_name = argv[0];
+**
+**      warn("Something horrible happened at %lu", time);
+**      syswarn("Couldn't unlink temporary file %s", tmpfile);
+**
+**      die("Something fatal happened at %lu", time);
+**      sysdie("open of %s failed", filename);
+**
+**      debug("Some debugging message about %s", string);
+**      notice("Informational notices");
+**
+**      message_handlers_warn(1, log);
+**      warn("This now goes through our log function");
+**
+**  These functions implement message reporting through user-configurable
+**  handler functions.  debug() only does something if DEBUG is defined, and
+**  notice() and warn() just output messages as configured.  die() similarly
+**  outputs a message but then exits, normally with a status of 1.
+**
+**  The sys* versions do the same, but append a colon, a space, and the
+**  results of strerror(errno) to the end of the message.  All functions
+**  accept printf-style formatting strings and arguments.
+**
+**  If message_fatal_cleanup is non-NULL, it is called before exit by die and
+**  sysdie and its return value is used as the argument to exit.  It is a
+**  pointer to a function taking no arguments and returning an int, and can be
+**  used to call cleanup functions or to exit in some alternate fashion (such
+**  as by calling _exit).
+**
+**  If message_program_name is non-NULL, the string it points to, followed by
+**  a colon and a space, is prepended to all error messages logged through the
+**  message_log_stdout and message_log_stderr message handlers (the former is
+**  the default for notice, and the latter is the default for warn and die).
+**
+**  Honoring error_program_name and printing to stderr is just the default
+**  handler; with message_handlers_* the handlers for any message function can
+**  be changed.  By default, notice prints to stdout, warn and die print to
+**  stderr, and the others don't do anything at all.  These functions take a
+**  count of handlers and then that many function pointers, each one to a
+**  function that takes a message length (the number of characters snprintf
+**  generates given the format and arguments), a format, an argument list as a
+**  va_list, and the applicable errno value (if any).
+**
+**  Copyright (c) 2004, 2005, 2006
+**      by Internet Systems Consortium, Inc. ("ISC")
+**  Copyright (c) 1991, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+**      2002, 2003 by The Internet Software Consortium and Rich Salz
+**
+**  This code is derived from software contributed to the Internet Software
+**  Consortium by Rich Salz.
+**
+**  Permission to use, copy, modify, and distribute this software for any
+**  purpose with or without fee is hereby granted, provided that the above
+**  copyright notice and this permission notice appear in all copies.
+**
+**  THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+**  REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+**  MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY
+**  SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+**  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+**  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+**  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <config.h>
+#include <system.h>
+
+#include <errno.h>
+#include <syslog.h>
+
+#include <util/util.h>
+
+/* The default handler lists. */
+static message_handler_func stdout_handlers[2] = {
+    message_log_stdout, NULL
+};
+static message_handler_func stderr_handlers[2] = {
+    message_log_stderr, NULL
+};
+
+/* The list of logging functions currently in effect. */
+static message_handler_func *debug_handlers  = NULL;
+static message_handler_func *notice_handlers = stdout_handlers;
+static message_handler_func *warn_handlers   = stderr_handlers;
+static message_handler_func *die_handlers    = stderr_handlers;
+
+/* If non-NULL, called before exit and its return value passed to exit. */
+int (*message_fatal_cleanup)(void) = NULL;
+
+/* If non-NULL, prepended (followed by ": ") to messages. */
+const char *message_program_name = NULL;
+
+
+/*
+**  Set the handlers for a particular message function.  Takes a pointer to
+**  the handler list, the count of handlers, and the argument list.
+*/
+static void
+message_handlers(message_handler_func **list, int count, va_list args)
+{
+    int i;
+
+    if (*list != stdout_handlers && *list != stderr_handlers)
+        free(*list);
+    *list = xmalloc(sizeof(message_handler_func) * (count + 1));
+    for (i = 0; i < count; i++)
+        (*list)[i] = (message_handler_func) va_arg(args, message_handler_func);
+    (*list)[count] = NULL;
+}
+
+
+/*
+**  There's no good way of writing these handlers without a bunch of code
+**  duplication since we can't assume variadic macros, but I can at least make
+**  it easier to write and keep them consistent.
+*/
+#define HANDLER_FUNCTION(type)                                  \
+    void                                                        \
+    message_handlers_ ## type(int count, ...)                   \
+    {                                                           \
+        va_list args;                                           \
+                                                                \
+        va_start(args, count);                                  \
+        message_handlers(& type ## _handlers, count, args);     \
+        va_end(args);                                           \
+    }
+HANDLER_FUNCTION(debug)
+HANDLER_FUNCTION(notice)
+HANDLER_FUNCTION(warn)
+HANDLER_FUNCTION(die)
+
+
+/*
+**  Print a message to stdout, supporting message_program_name.
+*/
+void
+message_log_stdout(int len UNUSED, const char *fmt, va_list args, int err)
+{
+    if (message_program_name != NULL)
+        fprintf(stdout, "%s: ", message_program_name);
+    vfprintf(stdout, fmt, args);
+    if (err)
+        fprintf(stdout, ": %s", strerror(err));
+    fprintf(stdout, "\n");
+}
+
+
+/*
+**  Print a message to stderr, supporting message_program_name.  Also flush
+**  stdout so that errors and regular output occur in the right order.
+*/
+void
+message_log_stderr(int len UNUSED, const char *fmt, va_list args, int err)
+{
+    fflush(stdout);
+    if (message_program_name != NULL)
+        fprintf(stderr, "%s: ", message_program_name);
+    vfprintf(stderr, fmt, args);
+    if (err)
+        fprintf(stderr, ": %s", strerror(err));
+    fprintf(stderr, "\n");
+}
+
+
+/*
+**  Log a message to syslog.  This is a helper function used to implement all
+**  of the syslog message log handlers.  It takes the same arguments as a
+**  regular message handler function but with an additional priority
+**  argument.
+*/
+static void
+message_log_syslog(int pri, int len, const char *fmt, va_list args, int err)
+{
+    char *buffer;
+
+    buffer = malloc(len + 1);
+    if (buffer == NULL) {
+        fprintf(stderr, "failed to malloc %u bytes at %s line %d: %s",
+                len + 1, __FILE__, __LINE__, strerror(errno));
+        exit(message_fatal_cleanup ? (*message_fatal_cleanup)() : 1);
+    }
+    vsnprintf(buffer, len + 1, fmt, args);
+    if (err == 0)
+        syslog(pri, "%s", buffer);
+    else
+        syslog(pri, "%s: %s", buffer, strerror(err));
+    free(buffer);
+}
+
+
+/*
+**  Do the same sort of wrapper to generate all of the separate syslog logging
+**  functions.
+*/
+#define SYSLOG_FUNCTION(name, type)                                     \
+    void                                                                \
+    message_log_syslog_ ## name(int l, const char *f, va_list a, int e) \
+    {                                                                   \
+        message_log_syslog(LOG_ ## type, l, f, a, e);                   \
+    }
+SYSLOG_FUNCTION(debug,   DEBUG)
+SYSLOG_FUNCTION(info,    INFO)
+SYSLOG_FUNCTION(notice,  NOTICE)
+SYSLOG_FUNCTION(warning, WARNING)
+SYSLOG_FUNCTION(err,     ERR)
+SYSLOG_FUNCTION(crit,    CRIT)
+
+
+/*
+**  All of the message handlers.  There's a lot of code duplication here too,
+**  but each one is still *slightly* different and va_start has to be called
+**  multiple times, so it's hard to get rid of the duplication.
+*/
+
+void
+debug(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+
+    if (debug_handlers == NULL)
+        return;
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length < 0)
+        return;
+    for (log = debug_handlers; *log != NULL; log++) {
+        va_start(args, format);
+        (**log)(length, format, args, 0);
+        va_end(args);
+    }
+}
+
+void
+notice(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length < 0)
+        return;
+    for (log = notice_handlers; *log != NULL; log++) {
+        va_start(args, format);
+        (**log)(length, format, args, 0);
+        va_end(args);
+    }
+}
+
+void
+sysnotice(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+    int error = errno;
+
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length < 0)
+        return;
+    for (log = notice_handlers; *log != NULL; log++) {
+        va_start(args, format);
+        (**log)(length, format, args, error);
+        va_end(args);
+    }
+}
+
+void
+warn(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length < 0)
+        return;
+    for (log = warn_handlers; *log != NULL; log++) {
+        va_start(args, format);
+        (**log)(length, format, args, 0);
+        va_end(args);
+    }
+}
+
+void
+syswarn(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+    int error = errno;
+
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length < 0)
+        return;
+    for (log = warn_handlers; *log != NULL; log++) {
+        va_start(args, format);
+        (**log)(length, format, args, error);
+        va_end(args);
+    }
+}
+
+void
+die(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length >= 0)
+        for (log = die_handlers; *log != NULL; log++) {
+            va_start(args, format);
+            (**log)(length, format, args, 0);
+            va_end(args);
+        }
+    exit(message_fatal_cleanup ? (*message_fatal_cleanup)() : 1);
+}
+
+void
+sysdie(const char *format, ...)
+{
+    va_list args;
+    message_handler_func *log;
+    int length;
+    int error = errno;
+
+    va_start(args, format);
+    length = vsnprintf(NULL, 0, format, args);
+    va_end(args);
+    if (length >= 0)
+        for (log = die_handlers; *log != NULL; log++) {
+            va_start(args, format);
+            (**log)(length, format, args, error);
+            va_end(args);
+        }
+    exit(message_fatal_cleanup ? (*message_fatal_cleanup)() : 1);
+}
diff --git a/util/util.h b/util/util.h
new file mode 100644
index 0000000..e2fce86
--- /dev/null
+++ b/util/util.h
@@ -0,0 +1,174 @@
+/*  $Id$
+**
+**  Utility functions.
+**
+**  This is a variety of utility functions that are used internally by the
+**  wallet client.  Many of them came originally from INN.
+**
+**  Written by Russ Allbery <rra@stanford.edu>
+**  Copyright 2002, 2003, 2004, 2005, 2006, 2007
+**      Board of Trustees, Leland Stanford Jr. University
+**  Copyright (c) 2004, 2005, 2006, 2007
+**      by Internet Systems Consortium, Inc. ("ISC")
+**  Copyright (c) 1991, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+**      2002, 2003 by The Internet Software Consortium and Rich Salz
+**
+**  See README for licensing terms.
+*/
+
+#ifndef UTIL_UTIL_H
+#define UTIL_UTIL_H 1
+
+#include <config.h>
+#include <portable/gssapi.h>
+
+#include <stdarg.h>
+#include <sys/types.h>
+
+/* __attribute__ is available in gcc 2.5 and later, but only with gcc 2.7
+   could you use the __format__ form of the attributes, which is what we use
+   (to avoid confusion with other macros). */
+#ifndef __attribute__
+# if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 7)
+#  define __attribute__(spec)   /* empty */
+# endif
+#endif
+
+/* Used for unused parameters to silence gcc warnings. */
+#define UNUSED  __attribute__((__unused__))
+
+/* BEGIN_DECLS is used at the beginning of declarations so that C++
+   compilers don't mangle their names.  END_DECLS is used at the end. */
+#undef BEGIN_DECLS
+#undef END_DECLS
+#ifdef __cplusplus
+# define BEGIN_DECLS    extern "C" {
+# define END_DECLS      }
+#else
+# define BEGIN_DECLS    /* empty */
+# define END_DECLS      /* empty */
+#endif
+
+BEGIN_DECLS
+
+/* Forward declarations to avoid includes. */
+struct addrinfo;
+struct iovec;
+struct sockaddr;
+
+/* Concatenate NULL-terminated strings into a newly allocated string. */
+extern char *concat(const char *first, ...);
+
+/* Given a base path and a file name, create a newly allocated path string.
+   The name will be appended to base with a / between them.  Exceptionally, if
+   name begins with a slash, it will be strdup'd and returned as-is. */
+extern char *concatpath(const char *base, const char *name);
+
+/* The reporting functions.  The ones prefaced by "sys" add a colon, a space,
+   and the results of strerror(errno) to the output and are intended for
+   reporting failures of system calls. */
+extern void debug(const char *, ...)
+    __attribute__((__format__(printf, 1, 2)));
+extern void notice(const char *, ...)
+    __attribute__((__format__(printf, 1, 2)));
+extern void sysnotice(const char *, ...)
+    __attribute__((__format__(printf, 1, 2)));
+extern void warn(const char *, ...)
+    __attribute__((__format__(printf, 1, 2)));
+extern void syswarn(const char *, ...)
+    __attribute__((__format__(printf, 1, 2)));
+extern void die(const char *, ...)
+    __attribute__((__noreturn__, __format__(printf, 1, 2)));
+extern void sysdie(const char *, ...)
+    __attribute__((__noreturn__, __format__(printf, 1, 2)));
+
+/* Set the handlers for various message functions.  All of these functions
+   take a count of the number of handlers and then function pointers for each
+   of those handlers.  These functions are not thread-safe; they set global
+   variables. */
+extern void message_handlers_debug(int count, ...);
+extern void message_handlers_notice(int count, ...);
+extern void message_handlers_warn(int count, ...);
+extern void message_handlers_die(int count, ...);
+
+/* Some useful handlers, intended to be passed to message_handlers_*.  All
+   handlers take the length of the formatted message, the format, a variadic
+   argument list, and the errno setting if any. */
+extern void message_log_stdout(int, const char *, va_list, int);
+extern void message_log_stderr(int, const char *, va_list, int);
+extern void message_log_syslog_debug(int, const char *, va_list, int);
+extern void message_log_syslog_info(int, const char *, va_list, int);
+extern void message_log_syslog_notice(int, const char *, va_list, int);
+extern void message_log_syslog_warning(int, const char *, va_list, int);
+extern void message_log_syslog_err(int, const char *, va_list, int);
+extern void message_log_syslog_crit(int, const char *, va_list, int);
+
+/* The type of a message handler. */
+typedef void (*message_handler_func)(int, const char *, va_list, int);
+
+/* If non-NULL, called before exit and its return value passed to exit. */
+extern int (*message_fatal_cleanup)(void);
+
+/* If non-NULL, prepended (followed by ": ") to all messages printed by either
+   message_log_stdout or message_log_stderr. */
+extern const char *message_program_name;
+
+/* The functions are actually macros so that we can pick up the file and line
+   number information for debugging error messages without the user having to
+   pass those in every time. */
+#define xcalloc(n, size)        x_calloc((n), (size), __FILE__, __LINE__)
+#define xmalloc(size)           x_malloc((size), __FILE__, __LINE__)
+#define xrealloc(p, size)       x_realloc((p), (size), __FILE__, __LINE__)
+#define xstrdup(p)              x_strdup((p), __FILE__, __LINE__)
+#define xstrndup(p, size)       x_strndup((p), (size), __FILE__, __LINE__)
+#define xvasprintf(p, f, a)     x_vasprintf((p), (f), (a), __FILE__, __LINE__)
+
+/* asprintf is a special case since it takes variable arguments.  If we have
+   support for variadic macros, we can still pass in the file and line and
+   just need to put them somewhere else in the argument list than last.
+   Otherwise, just call x_asprintf directly.  This means that the number of
+   arguments x_asprintf takes must vary depending on whether variadic macros
+   are supported. */
+#ifdef HAVE_C99_VAMACROS
+# define xasprintf(p, f, ...) \
+    x_asprintf((p), __FILE__, __LINE__, (f), __VA_ARGS__)
+#elif HAVE_GNU_VAMACROS
+# define xasprintf(p, f, args...) \
+    x_asprintf((p), __FILE__, __LINE__, (f), args)
+#else
+# define xasprintf x_asprintf
+#endif
+
+/* Last two arguments are always file and line number.  These are internal
+   implementations that should not be called directly.  ISO C99 says that
+   identifiers beginning with _ and a lowercase letter are reserved for
+   identifiers of file scope, so while the position of libraries in the
+   standard isn't clear, it's probably not entirely kosher to use _xmalloc
+   here.  Use x_malloc instead. */
+extern void *x_calloc(size_t, size_t, const char *, int);
+extern void *x_malloc(size_t, const char *, int);
+extern void *x_realloc(void *, size_t, const char *, int);
+extern char *x_strdup(const char *, const char *, int);
+extern char *x_strndup(const char *, size_t, const char *, int);
+extern int x_vasprintf(char **, const char *, va_list, const char *, int);
+
+/* asprintf special case. */
+#if HAVE_C99_VAMACROS || HAVE_GNU_VAMACROS
+extern int x_asprintf(char **, const char *, int, const char *, ...);
+#else
+extern int x_asprintf(char **, const char *, ...);
+#endif
+
+/* Failure handler takes the function, the size, the file, and the line. */
+typedef void (*xmalloc_handler_type)(const char *, size_t, const char *, int);
+
+/* The default error handler. */
+void xmalloc_fail(const char *, size_t, const char *, int);
+
+/* Assign to this variable to choose a handler other than the default, which
+   just calls sysdie. */
+extern xmalloc_handler_type xmalloc_error_handler;
+
+END_DECLS
+
+#endif /* UTIL_UTIL_H */
diff --git a/util/xmalloc.c b/util/xmalloc.c
new file mode 100644
index 0000000..635af75
--- /dev/null
+++ b/util/xmalloc.c
@@ -0,0 +1,238 @@
+/* $Id$
+**
+**  malloc routines with failure handling.
+**
+**  Usage:
+**
+**       extern xmalloc_handler_t memory_error;
+**       extern const char *string;
+**       char *buffer;
+**       va_list args;
+**
+**       xmalloc_error_handler = memory_error;
+**       buffer = xmalloc(1024);
+**       xrealloc(buffer, 2048);
+**       free(buffer);
+**       buffer = xcalloc(1024);
+**       free(buffer);
+**       buffer = xstrdup(string);
+**       free(buffer);
+**       buffer = xstrndup(string, 25);
+**       free(buffer);
+**       xasprintf(&buffer, "%s", "some string");
+**       free(buffer);
+**       xvasprintf(&buffer, "%s", args);
+**
+**  xmalloc, xcalloc, xrealloc, and xstrdup behave exactly like their C
+**  library counterparts without the leading x except that they will never
+**  return NULL.  Instead, on error, they call xmalloc_error_handler,
+**  passing it the name of the function whose memory allocation failed, the
+**  amount of the allocation, and the file and line number where the
+**  allocation function was invoked (from __FILE__ and __LINE__).  This
+**  function may do whatever it wishes, such as some action to free up
+**  memory or a call to sleep to hope that system resources return.  If the
+**  handler returns, the interrupted memory allocation function will try its
+**  allocation again (calling the handler again if it still fails).
+**
+**  xstrndup behaves like xstrdup but only copies the given number of
+**  characters.  It allocates an additional byte over its second argument and
+**  always nul-terminates the string.
+**
+**  xasprintf and xvasprintf behave just like their GNU glibc library
+**  implementations except that they do the same checking as described above.
+**  xasprintf will only be able to provide accurate file and line information
+**  on systems that support variadic macros.
+**
+**  The default error handler, if none is set by the caller, prints an error
+**  message to stderr and exits with exit status 1.  An error handler must
+**  take a const char * (function name), size_t (bytes allocated), const
+**  char * (file), and int (line).
+**
+**  xmalloc will return a pointer to a valid memory region on an xmalloc of 0
+**  bytes, ensuring this by allocating space for one character instead of 0
+**  bytes.
+**
+**  The functions defined here are actually x_malloc, x_realloc, etc.  The
+**  header file defines macros named xmalloc, etc. that pass the file name
+**  and line number to these functions.
+**
+**  Copyright (c) 2004, 2005, 2006
+**      by Internet Systems Consortium, Inc. ("ISC")
+**  Copyright (c) 1991, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
+**      2002, 2003 by The Internet Software Consortium and Rich Salz
+**
+**  This code is derived from software contributed to the Internet Software
+**  Consortium by Rich Salz.
+**
+**  Permission to use, copy, modify, and distribute this software for any
+**  purpose with or without fee is hereby granted, provided that the above
+**  copyright notice and this permission notice appear in all copies.
+**
+**  THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
+**  REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+**  MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY
+**  SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+**  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+**  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+**  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+#include <config.h>
+#include <system.h>
+
+#include <errno.h>
+
+#include <util/util.h>
+
+/* The default error handler. */
+void
+xmalloc_fail(const char *function, size_t size, const char *file, int line)
+{
+    sysdie("failed to %s %lu bytes at %s line %d", function,
+           (unsigned long) size, file, line);
+}
+
+/* Assign to this variable to choose a handler other than the default. */
+xmalloc_handler_type xmalloc_error_handler = xmalloc_fail;
+
+void *
+x_malloc(size_t size, const char *file, int line)
+{
+    void *p;
+    size_t real_size;
+
+    real_size = (size > 0) ? size : 1;
+    p = malloc(real_size);
+    while (p == NULL) {
+        (*xmalloc_error_handler)("malloc", size, file, line);
+        p = malloc(real_size);
+    }
+    return p;
+}
+
+void *
+x_calloc(size_t n, size_t size, const char *file, int line)
+{
+    void *p;
+
+    n = (n > 0) ? n : 1;
+    size = (size > 0) ? size : 1;
+    p = calloc(n, size);
+    while (p == NULL) {
+        (*xmalloc_error_handler)("calloc", n * size, file, line);
+        p = calloc(n, size);
+    }
+    return p;
+}
+
+void *
+x_realloc(void *p, size_t size, const char *file, int line)
+{
+    void *newp;
+
+    newp = realloc(p, size);
+    while (newp == NULL && size > 0) {
+        (*xmalloc_error_handler)("realloc", size, file, line);
+        newp = realloc(p, size);
+    }
+    return newp;
+}
+
+char *
+x_strdup(const char *s, const char *file, int line)
+{
+    char *p;
+    size_t len;
+
+    len = strlen(s) + 1;
+    p = malloc(len);
+    while (p == NULL) {
+        (*xmalloc_error_handler)("strdup", len, file, line);
+        p = malloc(len);
+    }
+    memcpy(p, s, len);
+    return p;
+}
+
+char *
+x_strndup(const char *s, size_t size, const char *file, int line)
+{
+    char *p;
+
+    p = malloc(size + 1);
+    while (p == NULL) {
+        (*xmalloc_error_handler)("strndup", size + 1, file, line);
+        p = malloc(size + 1);
+    }
+    memcpy(p, s, size);
+    p[size] = '\0';
+    return p;
+}
+
+int
+x_vasprintf(char **strp, const char *fmt, va_list args, const char *file,
+            int line)
+{
+    va_list args_copy;
+    int status;
+
+    va_copy(args_copy, args);
+    status = vasprintf(strp, fmt, args_copy);
+    va_end(args_copy);
+    while (status < 0 && errno == ENOMEM) {
+        va_copy(args_copy, args);
+        status = vsnprintf(NULL, 0, fmt, args_copy);
+        va_end(args_copy);
+        (*xmalloc_error_handler)("vasprintf", status + 1, file, line);
+        va_copy(args_copy, args);
+        status = vasprintf(strp, fmt, args_copy);
+        va_end(args_copy);
+    }
+    return status;
+}
+
+#if HAVE_C99_VAMACROS || HAVE_GNU_VAMACROS
+int
+x_asprintf(char **strp, const char *file, int line, const char *fmt, ...)
+{
+    va_list args, args_copy;
+    int status;
+
+    va_start(args, fmt);
+    va_copy(args_copy, args);
+    status = vasprintf(strp, fmt, args_copy);
+    va_end(args_copy);
+    while (status < 0 && errno == ENOMEM) {
+        va_copy(args_copy, args);
+        status = vsnprintf(NULL, 0, fmt, args_copy);
+        va_end(args_copy);
+        (*xmalloc_error_handler)("asprintf", status + 1, file, line);
+        va_copy(args_copy, args);
+        status = vasprintf(strp, fmt, args_copy);
+        va_end(args_copy);
+    }
+    return status;
+}
+#else /* !(HAVE_C99_VAMACROS || HAVE_GNU_VAMACROS) */
+int
+x_asprintf(char **strp, const char *fmt, ...)
+{
+    va_list args, args_copy;
+    int status;
+
+    va_start(args, fmt);
+    va_copy(args_copy, args);
+    status = vasprintf(strp, fmt, args_copy);
+    va_end(args_copy);
+    while (status < 0 && errno == ENOMEM) {
+        va_copy(args_copy, args);
+        status = vsnprintf(NULL, 0, fmt, args_copy);
+        va_end(args_copy);
+        (*xmalloc_error_handler)("asprintf", status + 1, __FILE__, __LINE__);
+        va_copy(args_copy, args);
+        status = vasprintf(strp, fmt, args_copy);
+        va_end(args_copy);
+    }
+    return status;
+}
+#endif /* !(HAVE_C99_VAMACROS || HAVE_GNU_VAMACROS) */