Add logic to handle memory allocation failures.

More generically, this patch adds handling of fatal errors.
Memory allocation failures are currently the only type of
fatal error.

- New C API config_set_fatal_error_func() allowing caller
  to provide a fatal error handler.
- A default handler will write a message to stderr and then
  call abort().
- The C++ library installs an internal handler that throws
  std::bad_alloc
- Route all malloc/calloc/realloc requests through new
  wrapper functions libconfig_malloc(), libconfig_calloc(),
  libconfig_realloc(), which call the above and then check
  the return value. If it's NULL, they call the fatal error handler.
- Force the flex- and bison-generated code to call the libconfig
  alloc functions instead of their default ones.

ac_config.h.in

@@ -9,15 +9,18 @@
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
-/* Define to 1 if you have the <memory.h> header file. */
-#undef HAVE_MEMORY_H
+/* Define to 1 if you have the <minix/config.h> header file. */
+#undef HAVE_MINIX_CONFIG_H
 
 /* Define to 1 if you have the `newlocale' function. */
 #undef HAVE_NEWLOCALE
 
 /* Define to 1 if you have the <stdint.h> header file. */
 #undef HAVE_STDINT_H
 
+/* Define to 1 if you have the <stdio.h> header file. */
+#undef HAVE_STDIO_H
+
 /* Define to 1 if you have the <stdlib.h> header file. */
 #undef HAVE_STDLIB_H
 
@@ -39,6 +42,9 @@
 /* Define to 1 if you have the `uselocale' function. */
 #undef HAVE_USELOCALE
 
+/* Define to 1 if you have the <wchar.h> header file. */
+#undef HAVE_WCHAR_H
+
 /* Define to 1 if you have the <xlocale.h> header file. */
 #undef HAVE_XLOCALE_H
 
@@ -67,7 +73,9 @@
 /* Define to the version of this package. */
 #undef PACKAGE_VERSION
 
-/* Define to 1 if you have the ANSI C header files. */
+/* Define to 1 if all of the C90 standard headers exist (not just the ones
+   required in a freestanding environment). This macro is provided for
+   backward compatibility; new code need not use it. */
 #undef STDC_HEADERS
 
 /* Configured target name. */
@@ -77,21 +85,87 @@
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE
 #endif
+/* Enable general extensions on macOS.  */
+#ifndef _DARWIN_C_SOURCE
+# undef _DARWIN_C_SOURCE
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
 /* Enable GNU extensions on systems that have them.  */
 #ifndef _GNU_SOURCE
 # undef _GNU_SOURCE
 #endif
-/* Enable threading extensions on Solaris.  */
+/* Enable X/Open compliant socket functions that do not require linking
+   with -lxnet on HP-UX 11.11.  */
+#ifndef _HPUX_ALT_XOPEN_SOCKET_API
+# undef _HPUX_ALT_XOPEN_SOCKET_API
+#endif
+/* Identify the host operating system as Minix.
+   This macro does not affect the system headers' behavior.
+   A future release of Autoconf may stop defining this macro.  */
+#ifndef _MINIX
+# undef _MINIX
+#endif
+/* Enable general extensions on NetBSD.
+   Enable NetBSD compatibility extensions on Minix.  */
+#ifndef _NETBSD_SOURCE
+# undef _NETBSD_SOURCE
+#endif
+/* Enable OpenBSD compatibility extensions on NetBSD.
+   Oddly enough, this does nothing on OpenBSD.  */
+#ifndef _OPENBSD_SOURCE
+# undef _OPENBSD_SOURCE
+#endif
+/* Define to 1 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_SOURCE
+# undef _POSIX_SOURCE
+#endif
+/* Define to 2 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_1_SOURCE
+# undef _POSIX_1_SOURCE
+#endif
+/* Enable POSIX-compatible threading on Solaris.  */
 #ifndef _POSIX_PTHREAD_SEMANTICS
 # undef _POSIX_PTHREAD_SEMANTICS
 #endif
+/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
+#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+# undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
+#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+# undef __STDC_WANT_IEC_60559_BFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
+#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
+# undef __STDC_WANT_IEC_60559_DFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
+#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
+# undef __STDC_WANT_IEC_60559_FUNCS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
+#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
+# undef __STDC_WANT_IEC_60559_TYPES_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
+#ifndef __STDC_WANT_LIB_EXT2__
+# undef __STDC_WANT_LIB_EXT2__
+#endif
+/* Enable extensions specified by ISO/IEC 24747:2009.  */
+#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
+# undef __STDC_WANT_MATH_SPEC_FUNCS__
+#endif
 /* Enable extensions on HP NonStop.  */
 #ifndef _TANDEM_SOURCE
 # undef _TANDEM_SOURCE
 #endif
-/* Enable general extensions on Solaris.  */
-#ifndef __EXTENSIONS__
-# undef __EXTENSIONS__
+/* Enable X/Open extensions.  Define to 500 only if necessary
+   to make mbstate_t available.  */
+#ifndef _XOPEN_SOURCE
+# undef _XOPEN_SOURCE
 #endif
 
 
@@ -102,15 +176,5 @@
    `char[]'. */
 #undef YYTEXT_POINTER
 
-/* Define to 1 if on MINIX. */
-#undef _MINIX
-
-/* Define to 2 if the system does not provide POSIX.1 features except with
-   this defined. */
-#undef _POSIX_1_SOURCE
-
-/* Define to 1 if you need to in order for `stat' and other things to work. */
-#undef _POSIX_SOURCE
-
 /* Define to empty if `const' does not conform to ANSI C. */
 #undef const

configure.ac

@@ -1,6 +1,6 @@
 dnl Process this file with autoconf to produce a configure script.
 
-AC_INIT(libconfig, 1.7.3, [email protected], libconfig,
+AC_INIT(libconfig, 1.7.4, [email protected], libconfig,
 	[https://hyperrealm.github.io/libconfig/])
 AC_CONFIG_AUX_DIR([aux-build])
 AC_CONFIG_MACRO_DIR([m4])

debian/copyright

@@ -11,7 +11,7 @@ Upstream Author: Mark A Lindner
 	Jose Luis Tallon - Enhancements, bugfixes
 
 
-Copyright:	Copyright (C) 2005-2015  Mark A Lindner
+Copyright:	Copyright (C) 2005-2023  Mark A Lindner
 
 License:	LGPL-2.1
 

doc/libconfig.texi

@@ -6,8 +6,8 @@
 @setfilename libconfig.info
 @settitle libconfig
 
-@set edition 1.7.3
-@set update-date 20 Jun 2021
+@set edition 1.7.4
+@set update-date 22 Nov 2022
 @set subtitle-text A Library For Processing Structured Configuration Files
 @set author-text Mark A.@: Lindner
 
@@ -38,7 +38,7 @@
 
 @page
 @vskip 0pt plus 1filll
-Copyright @copyright{} 2004-2021  Mark A Lindner
+Copyright @copyright{} 2004-2023  Mark A Lindner
 
 Permission is granted to make and distribute verbatim copies of
 this manual provided the copyright notice and this permission notice
@@ -800,6 +800,42 @@ and a parsing error, respectively.
 
 @end deftypefun
 
+@deftypefun void config_set_fatal_error_func (@w{config_fatal_error_fn_t @var{func}})
+
+@b{Since @i{v1.7.4}}
+
+@cindex fatal error
+Specifies the function @var{func} to call when a fatal error is encountered.
+If @var{func} is @code{NULL}, the default fatal error handler function will
+be reinstated.
+
+@tindex config_fatal_error_fn_t
+The type @i{config_fatal_error_fn_t} is a type alias
+for a function whose signature is:
+
+@deftypefun @w{void} func (@w{const char *@var{message}})
+
+The function receives an error message @var{message}. The function is
+not expected to return to the caller; if it does, the resulting
+behavior is undefined.
+
+@end deftypefun
+
+Fatal errors are unrecoverable, and the only reasonable course of
+action is to abort the calling process. The default fatal error
+handler function writes a message to standard error and then calls
+@code{abort()}. One potential alternate implementation would be to
+call @code{exit()} with an exit status that indicates to the parent
+process (such as a watchdog process) that the current process has
+encountered an unrecoverable condition and should be respawned.
+
+In the current implementation, the only condition that will produce a
+fatal error is a memory allocation failure---that is, a @code{NULL}
+return value from @code{malloc()}, @code{calloc()}, or
+@code{realloc()}.
+
+@end deftypefun
+
 @deftypefun void config_set_include_dir (@w{config_t *@var{config}}, @w{const char *@var{include_dir}})
 @deftypefunx {const char *} config_get_include_dir (@w{const config_t *@var{config}})
 
@@ -879,8 +915,8 @@ implementations of such include functions are not included.
 
 @end deftypefun
 
-@deftypefun {unsigned short} config_get_float_precision(@w{config_t *@var{config}})
-@deftypefunx void config_set_float_precision(@w{config_t *@var{config}}, @w{unsigned short @var{digits}})
+@deftypefun {unsigned short} config_get_float_precision (@w{config_t *@var{config}})
+@deftypefunx void config_set_float_precision (@w{config_t *@var{config}}, @w{unsigned short @var{digits}})
 
 @b{Since @i{v1.6}}
 

examples/c++/example1.cpp

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2010  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c++/example2.cpp

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2010  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c++/example3.cpp

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2010  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c++/example4.cpp

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2010  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c/example1.c

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2018  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c/example2.c

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2018  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c/example3.c

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2018  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

examples/c/example4.c

@@ -1,6 +1,6 @@
 /* ----------------------------------------------------------------------------
    libconfig - A library for processing structured configuration files
-   Copyright (C) 2005-2018  Mark A Lindner
+   Copyright (C) 2005-2023  Mark A Lindner
 
    This file is part of libconfig.
 

lib/Makefile.am

@@ -18,7 +18,7 @@
 #
 # For more info see section 6.3 of the GNU Libtool Manual.
 
-VERINFO = -version-info 12:0:1
+VERINFO = -version-info 12:1:1
 
 ## Flex
 PARSER_PREFIX = libconfig_yy