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, 35 insertions, 0 deletions

diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index 625c2211665..baf9511aca7 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -118,6 +118,7 @@ AC_DEFUN([gl_EARLY],
   # Code from module malloca:
   # Code from module manywarnings:
   # Code from module memmem-simple:
+  # Code from module mempcpy:
   # Code from module memrchr:
   # Code from module minmax:
   # Code from module mkostemp:
@@ -327,6 +328,12 @@ AC_DEFUN([gl_INIT],
     AC_LIBOBJ([memmem])
   fi
   gl_STRING_MODULE_INDICATOR([memmem])
+  gl_FUNC_MEMPCPY
+  if test $HAVE_MEMPCPY = 0; then
+    AC_LIBOBJ([mempcpy])
+    gl_PREREQ_MEMPCPY
+  fi
+  gl_STRING_MODULE_INDICATOR([mempcpy])
   gl_FUNC_MEMRCHR
   if test $ac_cv_func_memrchr = no; then
     AC_LIBOBJ([memrchr])
@@ -954,6 +961,7 @@ AC_DEFUN([gl_FILE_LIST], [
   lib/md5.c
   lib/md5.h
   lib/memmem.c
+  lib/mempcpy.c
   lib/memrchr.c
   lib/minmax.h
   lib/mkostemp.c
@@ -1094,6 +1102,7 @@ AC_DEFUN([gl_FILE_LIST], [
   m4/mbstate_t.m4
   m4/md5.m4
   m4/memmem.m4
+  m4/mempcpy.m4
   m4/memrchr.m4
   m4/minmax.m4
   m4/mkostemp.m4
diff --git a/m4/mempcpy.m4 b/m4/mempcpy.m4
new file mode 100644
index 00000000000..b6090eed285
--- /dev/null
+++ b/m4/mempcpy.m4
@@ -0,0 +1,26 @@
+# mempcpy.m4 serial 11
+dnl Copyright (C) 2003-2004, 2006-2007, 2009-2019 Free Software Foundation,
+dnl Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_MEMPCPY],
+[
+  dnl Persuade glibc <string.h> to declare mempcpy().
+  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+  dnl The mempcpy() declaration in lib/string.in.h uses 'restrict'.
+  AC_REQUIRE([AC_C_RESTRICT])
+
+  AC_REQUIRE([gl_HEADER_STRING_H_DEFAULTS])
+  AC_CHECK_FUNCS([mempcpy])
+  if test $ac_cv_func_mempcpy = no; then
+    HAVE_MEMPCPY=0
+  fi
+])
+
+# Prerequisites of lib/mempcpy.c.
+AC_DEFUN([gl_PREREQ_MEMPCPY], [
+  :
+])