etags: remove some arbitrary limits

etags had undefined behavior if input files, lines, tags, etc.,
had more than INT_MAX bytes.  Clean up the usage of integer types
to fix the overflow errors I found.
* admin/merge-gnulib (GNULIB_MODULES): Add mempcpy.
* lib-src/etags.c: Include inttypes.h, intprops.h.
(memcpyz): New function.  Use it to simplify several occurrences
of memcpy followed by storing a trailing '\0'.
(xnew): Use xnmalloc, to catch overflow on integer multiplication.
(xrnew): Change last arg to multiplier.  The type is not needed.
All callers changed.
(node, lineno, charno, linecharno, invalidcharno, make_tag):
(pfnote, add_node, number_len, C_symtype, lbz, Makefile_targets)
(readline):
Use intmax_t for line numbers and character positions, instead of
int or long.
(linebuffer, make_tag, pfnote, total_size_of_entries, put_entry)
(in_word_set, C_symtype, token, cstack, pushclass_above):
(popclass_above, write_classname, consider_token, C_entries)
(Ruby_functions, Makefile_targets, Lua_functions, TeX_commands)
(TeX_decode_env, erlang_func, erlang_attribute, erlang_atom)
(substitute, regex_tag_multiline, nocase_tail, readline_interval)
(readline, savenstr, concat, etags_getcwd, relative_filename)
(linebuffer_setlen):
Use ptrdiff_t for object sizes, instead of int or long or unsigned
or size_t.
(write_classname, C_entries):
Avoid sprintf, as the result could exceed INT_MAX bytes
and then behavior goes haywire.
(main): Use int, instead of unsigned, for argv counts.
(get_language_from_filename): Use bool for boolean.
(Ruby_functions): Prefer strcpy to memcpy when copying "=".
(linebuffer_setlen): Use ‘if’ instead of ‘while’.
(memory_full, xnmalloc, xnrealloc): New functions.
(xmalloc): Use memory_full, and take a ptrdiff_t instead of a size_t.
(xrealloc): Remove; no longer needed.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* lib/mempcpy.c, m4/mempcpy.m4: New files, copied from Gnulib.

2 files changed, 40 insertions, 0 deletions

diff --git a/lib/gnulib.mk.in b/lib/gnulib.mk.in
index 9a2709c22a7..8e3b569b94f 100644
--- a/lib/gnulib.mk.in
+++ b/lib/gnulib.mk.in
@@ -116,6 +116,7 @@
 #  lstat \
 #  manywarnings \
 #  memmem-simple \
+#  mempcpy \
 #  memrchr \
 #  minmax \
 #  mkostemp \
@@ -2027,6 +2028,17 @@ EXTRA_libgnu_a_SOURCES += memmem.c
 endif
 ## end   gnulib module memmem-simple
 
+## begin gnulib module mempcpy
+ifeq (,$(OMIT_GNULIB_MODULE_mempcpy))
+
+
+EXTRA_DIST += mempcpy.c
+
+EXTRA_libgnu_a_SOURCES += mempcpy.c
+
+endif
+## end   gnulib module mempcpy
+
 ## begin gnulib module memrchr
 ifeq (,$(OMIT_GNULIB_MODULE_memrchr))
 
diff --git a/lib/mempcpy.c b/lib/mempcpy.c
new file mode 100644
index 00000000000..d0220e10fb0
--- /dev/null
+++ b/lib/mempcpy.c
@@ -0,0 +1,28 @@
+/* Copy memory area and return pointer after last written byte.
+   Copyright (C) 2003, 2007, 2009-2019 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 <https://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <string.h>
+
+/* Copy N bytes of SRC to DEST, return pointer to bytes after the
+   last written byte.  */
+void *
+mempcpy (void *dest, const void *src, size_t n)
+{
+  return (char *) memcpy (dest, src, n) + n;
+}