[PATCH 2/2] error: merge from glibc and with verror

[Paul Eggert]

* lib/error.c: Merge changes since 2018 from glibc.
----- The following changes are taken from glibc:
(__error_internal, __error_at_line_internal): New functions,
with most of the old error and error_at_line_internal but
with va_list and with a new trailing mode_args,
for wide character mode.
(error_tail): Add trailing arg.
(error_tail, __error_internal, __error_at_line_internal):
Redo _LIBC implementation with respect to cancelation.
[_LIBC]: Include <libc-lock.h>, not <bits/libc-lock.h>.
----- The following changes are specific to Gnulib:
(__error_internal, __error_at_line_internal, error_tail) [!_LIBC]:
Use macros to define away the new trailing arg, and to name
the internal functions to verror and verror_at_line.
(verror, verror_at_line) [!_LIBC]: Undef so that we omit
the __gl_error_call business when defining these functions.
* lib/error.in.h: Include stdarg.h.
(verror, verror_at_line): New decls and macros.
* m4/error_h.m4 ([gl_ERROR_H]): Always compile error.c if
the verror module is also present.
* modules/verror (Files, lib_SOURCES):
Remove lib/verror.h, lib/verror.c.
(Depends-on): Remove stdio, xvasprintf.
(configure.ac-early): Define gl_HAVE_MODULE_VERROR so that
the error module compiles error.c.  Not sure if this is the
standard way to do this, but it seems to work.
* modules/verror (Include), tests/test-verror.c:
Include error.h, not verror.h.
---
 ChangeLog           |  30 ++++++++
 NEWS                |   3 +
 lib/error.c         | 166 +++++++++++++++++---------------------------
 lib/error.in.h      |  31 +++++++++
 lib/verror.c        |  80 ---------------------
 lib/verror.h        |  62 -----------------
 m4/error_h.m4       |  17 +++--
 modules/verror      |  10 ++-
 tests/test-verror.c |   2 +-
 9 files changed, 143 insertions(+), 258 deletions(-)
 delete mode 100644 lib/verror.c
 delete mode 100644 lib/verror.h

diff --git a/ChangeLog b/ChangeLog
index bd5e7b1ce5..fe16aa1787 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,35 @@
 2024-08-14  Paul Eggert  <eggert@cs.ucla.edu>
 
+       error: merge from glibc and with verror
+       * lib/error.c: Merge changes since 2018 from glibc.
+       ----- The following changes are taken from glibc:
+       (__error_internal, __error_at_line_internal): New functions,
+       with most of the old error and error_at_line_internal but
+       with va_list and with a new trailing mode_args,
+       for wide character mode.
+       (error_tail): Add trailing arg.
+       (error_tail, __error_internal, __error_at_line_internal):
+       Redo _LIBC implementation with respect to cancelation.
+       [_LIBC]: Include <libc-lock.h>, not <bits/libc-lock.h>.
+       ----- The following changes are specific to Gnulib:
+       (__error_internal, __error_at_line_internal, error_tail) [!_LIBC]:
+       Use macros to define away the new trailing arg, and to name
+       the internal functions to verror and verror_at_line.
+       (verror, verror_at_line) [!_LIBC]: Undef so that we omit
+       the __gl_error_call business when defining these functions.
+       * lib/error.in.h: Include stdarg.h.
+       (verror, verror_at_line): New decls and macros.
+       * m4/error_h.m4 ([gl_ERROR_H]): Always compile error.c if
+       the verror module is also present.
+       * modules/verror (Files, lib_SOURCES):
+       Remove lib/verror.h, lib/verror.c.
+       (Depends-on): Remove stdio, xvasprintf.
+       (configure.ac-early): Define gl_HAVE_MODULE_VERROR so that
+       the error module compiles error.c.  Not sure if this is the
+       standard way to do this, but it seems to work.
+       * modules/verror (Include), tests/test-verror.c:
+       Include error.h, not verror.h.
+
        error: it’s cold
        This mimics what glibc is doing nowadays.
        * lib/error.in.h (error, error_at_line):
diff --git a/NEWS b/NEWS
index 865b86ba3c..40a8da647a 100644
--- a/NEWS
+++ b/NEWS
@@ -74,6 +74,9 @@ User visible incompatible changes
 
 Date        Modules         Changes
 
+2024-08-14  verror          The include file is changed from "verror.h"
+                            to <error.h>.
+
 2024-08-09  full-read       These modules now prefer signed types to size_t.
             full-write      The preferred types are idx_t for object sizes and
             safe-read       ptrdiff_t for values that are either a size or -1.
diff --git a/lib/error.c b/lib/error.c
index c53dfeb60d..843e19304e 100644
--- a/lib/error.c
+++ b/lib/error.c
@@ -1,25 +1,32 @@
 /* Error handler for noninteractive utilities
-   Copyright (C) 1990-1998, 2000-2007, 2009-2024 Free Software Foundation, Inc.
+   Copyright (C) 1990-2024 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
-   This file is free software: you can redistribute it and/or modify
-   it under the terms of the GNU Lesser General Public License as
-   published by the Free Software Foundation; either version 2.1 of the
-   License, or (at your option) any later version.
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
 
-   This file is distributed in the hope that it will be useful,
+   The GNU C Library 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 Lesser General Public License for more details.
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
 
-   You should have received a copy of the GNU Lesser General Public License
-   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
 
 /* Written by David MacKenzie <djm@gnu.ai.mit.edu>.  */
 
 #if !_LIBC
 # include <config.h>
 # define _GL_NO_INLINE_ERROR
+# define __error_internal(status, err, fmt, args, flags) \
+                  verror (status, err, fmt, args)
+# define __error_at_line_internal(status, err, file, line, fmt, args, flags) \
+                  verror_at_line (status, err, file, line, fmt, args)
+# define error_tail(status, err, fmt, args, flags) \
+        error_tail (status, err, fmt, args)
 #endif
 
 #include <error.h>
@@ -85,7 +92,7 @@ extern void __error_at_line (int status, int errnum, const 
char *file_name,
 # undef putc
 # define putc(c, fp) _IO_putc (c, fp)
 
-# include <bits/libc-lock.h>
+# include <libc-lock.h>
 
 #else /* not _LIBC */
 
@@ -123,6 +130,9 @@ int strerror_r (int errnum, char *buf, size_t buflen);
 # if GNULIB_STRERROR_R_POSIX || HAVE_STRERROR_R || defined strerror_r
 #  define __strerror_r strerror_r
 # endif /* GNULIB_STRERROR_R_POSIX || HAVE_STRERROR_R || defined strerror_r */
+
+# undef verror
+# undef verror_at_line
 #endif  /* not _LIBC */
 
 #if !_LIBC
@@ -202,75 +212,19 @@ print_errno_message (int errnum)
 }
 
 static void _GL_ATTRIBUTE_FORMAT_PRINTF_STANDARD (3, 0) _GL_ARG_NONNULL ((3))
-error_tail (int status, int errnum, const char *message, va_list args)
+error_tail (int status, int errnum, const char *message, va_list args,
+            unsigned int mode_flags)
 {
 #if _LIBC
-  if (_IO_fwide (stderr, 0) > 0)
-    {
-      size_t len = strlen (message) + 1;
-      wchar_t *wmessage = NULL;
-      mbstate_t st;
-      size_t res;
-      const char *tmp;
-      bool use_malloc = false;
-
-      while (1)
-        {
-          if (__libc_use_alloca (len * sizeof (wchar_t)))
-            wmessage = (wchar_t *) alloca (len * sizeof (wchar_t));
-          else
-            {
-              if (!use_malloc)
-                wmessage = NULL;
-
-              wchar_t *p = (wchar_t *) realloc (wmessage,
-                                                len * sizeof (wchar_t));
-              if (p == NULL)
-                {
-                  free (wmessage);
-                  fputws_unlocked (L"out of memory\n", stderr);
-                  return;
-                }
-              wmessage = p;
-              use_malloc = true;
-            }
-
-          memset (&st, '\0', sizeof (st));
-          tmp = message;
-
-          res = mbsrtowcs (wmessage, &tmp, len, &st);
-          if (res != len)
-            break;
-
-          if (__builtin_expect (len >= SIZE_MAX / sizeof (wchar_t) / 2, 0))
-            {
-              /* This really should not happen if everything is fine.  */
-              res = (size_t) -1;
-              break;
-            }
-
-          len *= 2;
-        }
-
-      if (res == (size_t) -1)
-        {
-          /* The string cannot be converted.  */
-          if (use_malloc)
-            {
-              free (wmessage);
-              use_malloc = false;
-            }
-          wmessage = (wchar_t *) L"???";
-        }
-
-      __vfwprintf (stderr, wmessage, args);
-
-      if (use_malloc)
-        free (wmessage);
-    }
-  else
+  int ret = __vfxprintf (stderr, message, args, mode_flags);
+  if (ret < 0 && errno == ENOMEM && _IO_fwide (stderr, 0) > 0)
+    /* Leave a trace in case the heap allocation of the message string
+       failed.  */
+    fputws_unlocked (L"out of memory\n", stderr);
+#else
+  vfprintf (stderr, message, args);
 #endif
-    vfprintf (stderr, message, args);
+  va_end (args);
 
   ++error_message_count;
   if (errnum)
@@ -291,16 +245,14 @@ error_tail (int status, int errnum, const char *message, 
va_list args)
    If ERRNUM is nonzero, print its corresponding system error message.
    Exit with status STATUS if it is nonzero.  */
 void
-error (int status, int errnum, const char *message, ...)
+__error_internal (int status, int errnum, const char *message,
+                  va_list args, unsigned int mode_flags)
 {
-  va_list args;
-
-#if defined _LIBC && defined __libc_ptf_call
+#if defined _LIBC
   /* We do not want this call to be cut short by a thread
      cancellation.  Therefore disable cancellation for now.  */
   int state = PTHREAD_CANCEL_ENABLE;
-  __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
-                   0);
+  __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
 #endif
 
   flush_stdout ();
@@ -318,28 +270,32 @@ error (int status, int errnum, const char *message, ...)
 #endif
     }
 
-  va_start (args, message);
-  error_tail (status, errnum, message, args);
-  va_end (args);
+  error_tail (status, errnum, message, args, mode_flags);
 
 #ifdef _LIBC
   _IO_funlockfile (stderr);
-# ifdef __libc_ptf_call
-  __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
-# endif
+  __pthread_setcancelstate (state, NULL);
 #endif
 }
+
+void
+error (int status, int errnum, const char *message, ...)
+{
+  va_list ap;
+  va_start (ap, message);
+  __error_internal (status, errnum, message, ap, 0);
+  va_end (ap);
+}
 
 /* Sometimes we want to have at most one error per line.  This
    variable controls whether this mode is selected or not.  */
 int error_one_per_line;
 
 void
-error_at_line (int status, int errnum, const char *file_name,
-               unsigned int line_number, const char *message, ...)
+__error_at_line_internal (int status, int errnum, const char *file_name,
+                          unsigned int line_number, const char *message,
+                          va_list args, unsigned int mode_flags)
 {
-  va_list args;
-
   if (error_one_per_line)
     {
       static const char *old_file_name;
@@ -358,12 +314,11 @@ error_at_line (int status, int errnum, const char 
*file_name,
       old_line_number = line_number;
     }
 
-#if defined _LIBC && defined __libc_ptf_call
+#if defined _LIBC
   /* We do not want this call to be cut short by a thread
      cancellation.  Therefore disable cancellation for now.  */
   int state = PTHREAD_CANCEL_ENABLE;
-  __libc_ptf_call (pthread_setcancelstate, (PTHREAD_CANCEL_DISABLE, &state),
-                   0);
+  __pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
 #endif
 
   flush_stdout ();
@@ -389,18 +344,25 @@ error_at_line (int status, int errnum, const char 
*file_name,
            file_name, line_number);
 #endif
 
-  va_start (args, message);
-  error_tail (status, errnum, message, args);
-  va_end (args);
+  error_tail (status, errnum, message, args, mode_flags);
 
 #ifdef _LIBC
   _IO_funlockfile (stderr);
-# ifdef __libc_ptf_call
-  __libc_ptf_call (pthread_setcancelstate, (state, NULL), 0);
-# endif
+  __pthread_setcancelstate (state, NULL);
 #endif
 }
 
+void
+error_at_line (int status, int errnum, const char *file_name,
+               unsigned int line_number, const char *message, ...)
+{
+  va_list ap;
+  va_start (ap, message);
+  __error_at_line_internal (status, errnum, file_name, line_number,
+                            message, ap, 0);
+  va_end (ap);
+}
+
 #ifdef _LIBC
 /* Make the weak alias.  */
 # undef error
diff --git a/lib/error.in.h b/lib/error.in.h
index d2aede7d53..82022a9362 100644
--- a/lib/error.in.h
+++ b/lib/error.in.h
@@ -36,6 +36,9 @@
  #error "Please include config.h first."
 #endif
 
+/* Get va_list.  */
+#include <stdarg.h>
+
 /* Get 'unreachable'.  */
 #include <stddef.h>
 
@@ -200,6 +203,34 @@ _gl_inline_error_at_line (int __status, int __errnum, 
const char *__filename,
 #endif
 _GL_CXXALIASWARN (error_at_line);
 
+/* Print a message with 'vfprintf (stderr, FORMAT, ARGS)';
+   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
+   If STATUS is nonzero, terminate the program with 'exit (STATUS)'.
+   Use the globals error_print_progname and error_message_count similarly
+   to error().  */
+
+extern void verror (int __status, int __errnum, const char *__format,
+                    va_list __args)
+     _GL_ATTRIBUTE_COLD
+     _GL_ATTRIBUTE_FORMAT ((_GL_ATTRIBUTE_SPEC_PRINTF_STANDARD, 3, 0));
+#define verror(status, ...) \
+   __gl_error_call (verror, status, __VA_ARGS__)
+
+/* Print a message with 'vfprintf (stderr, FORMAT, ARGS)';
+   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
+   If STATUS is nonzero, terminate the program with 'exit (STATUS)'.
+   If FNAME is not NULL, prepend the message with "FNAME:LINENO:".
+   Use the globals error_print_progname, error_message_count, and
+   error_one_per_line similarly to error_at_line().  */
+
+extern void verror_at_line (int __status, int __errnum, const char *__fname,
+                            unsigned int __lineno, const char *__format,
+                            va_list __args)
+     _GL_ATTRIBUTE_COLD
+     _GL_ATTRIBUTE_FORMAT ((_GL_ATTRIBUTE_SPEC_PRINTF_STANDARD, 5, 0));
+#define verror_at_line(status, ...) \
+   __gl_error_call (verror_at_line, status, __VA_ARGS__)
+
 /* If NULL, error will flush stdout, then print on stderr the program
    name, a colon and a space.  Otherwise, error will call this
    function without parameters instead.  */
diff --git a/lib/verror.c b/lib/verror.c
deleted file mode 100644
index 69f606c0a4..0000000000
--- a/lib/verror.c
+++ /dev/null
@@ -1,80 +0,0 @@
-/* va_list error handler for noninteractive utilities
-   Copyright (C) 2006-2007, 2009-2024 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 of the License, 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/>.  */
-
-/* Written by Eric Blake.  */
-
-#include <config.h>
-
-/* Specification.  */
-#include "verror.h"
-
-#include <errno.h>
-#include <stdarg.h>
-#include <stdlib.h>
-
-#include <error.h>
-#include "xvasprintf.h"
-
-#if ENABLE_NLS
-# include "gettext.h"
-# define _(msgid) gettext (msgid)
-#endif
-
-#ifndef _
-# define _(String) String
-#endif
-
-/* Print a message with 'vfprintf (stderr, FORMAT, ARGS)';
-   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
-   If STATUS is nonzero, terminate the program with 'exit (STATUS)'.
-   Use the globals error_print_progname and error_message_count similarly
-   to error().  */
-void
-verror (int status, int errnum, const char *format, va_list args)
-{
-  verror_at_line (status, errnum, NULL, 0, format, args);
-}
-
-/* Print a message with 'vfprintf (stderr, FORMAT, ARGS)';
-   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
-   If STATUS is nonzero, terminate the program with 'exit (STATUS)'.
-   If FNAME is not NULL, prepend the message with "FNAME:LINENO:".
-   Use the globals error_print_progname, error_message_count, and
-   error_one_per_line similarly to error_at_line().  */
-void
-verror_at_line (int status, int errnum, const char *file,
-                unsigned int line_number, const char *format, va_list args)
-{
-  char *message = xvasprintf (format, args);
-  if (message)
-    {
-      /* Until https://sourceware.org/bugzilla/show_bug.cgi?id=2997 is fixed,
-         glibc violates GNU Coding Standards when the file argument to
-         error_at_line is NULL.  */
-      if (file)
-        error_at_line (status, errnum, file, line_number, "%s", message);
-      else
-        error (status, errnum, "%s", message);
-    }
-  else
-    {
-      /* EOVERFLOW, EINVAL, and EILSEQ from xvasprintf are signs of
-         serious programmer errors.  */
-      error (0, errno, _("unable to display error message"));
-      abort ();
-    }
-  free (message);
-}
diff --git a/lib/verror.h b/lib/verror.h
deleted file mode 100644
index a951a5c3e1..0000000000
--- a/lib/verror.h
+++ /dev/null
@@ -1,62 +0,0 @@
-/* Declaration for va_list error-reporting function
-   Copyright (C) 2006-2007, 2009-2024 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 of the License, 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/>.  */
-
-#ifndef _VERROR_H
-#define _VERROR_H 1
-
-/* This file uses _GL_ATTRIBUTE_COLD, _GL_ATTRIBUTE_FORMAT.  */
-#if !_GL_CONFIG_H_INCLUDED
- #error "Please include config.h first."
-#endif
-
-#include <stdarg.h>
-
-/* Get _GL_ATTRIBUTE_SPEC_PRINTF_STANDARD.  */
-#include <stdio.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-/* Print a message with 'vfprintf (stderr, FORMAT, ARGS)';
-   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
-   If STATUS is nonzero, terminate the program with 'exit (STATUS)'.
-   Use the globals error_print_progname and error_message_count similarly
-   to error().  */
-
-extern void verror (int __status, int __errnum, const char *__format,
-                    va_list __args)
-     _GL_ATTRIBUTE_COLD
-     _GL_ATTRIBUTE_FORMAT ((_GL_ATTRIBUTE_SPEC_PRINTF_STANDARD, 3, 0));
-
-/* Print a message with 'vfprintf (stderr, FORMAT, ARGS)';
-   if ERRNUM is nonzero, follow it with ": " and strerror (ERRNUM).
-   If STATUS is nonzero, terminate the program with 'exit (STATUS)'.
-   If FNAME is not NULL, prepend the message with "FNAME:LINENO:".
-   Use the globals error_print_progname, error_message_count, and
-   error_one_per_line similarly to error_at_line().  */
-
-extern void verror_at_line (int __status, int __errnum, const char *__fname,
-                            unsigned int __lineno, const char *__format,
-                            va_list __args)
-     _GL_ATTRIBUTE_COLD
-     _GL_ATTRIBUTE_FORMAT ((_GL_ATTRIBUTE_SPEC_PRINTF_STANDARD, 5, 0));
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* verror.h */
diff --git a/m4/error_h.m4 b/m4/error_h.m4
index 050a410ce4..91a8fc6897 100644
--- a/m4/error_h.m4
+++ b/m4/error_h.m4
@@ -1,5 +1,5 @@
 # error_h.m4
-# serial 4
+# serial 5
 dnl Copyright (C) 1996-2024 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -111,12 +111,15 @@ AC_DEFUN_ONCE([gl_ERROR_H],
     esac
   fi
 
-  if test $HAVE_ERROR = 0 || test $REPLACE_ERROR = 1 \
-     || test $HAVE_ERROR_AT_LINE = 0 || test $REPLACE_ERROR_AT_LINE = 1; then
-    COMPILE_ERROR_C=1
-  else
-    COMPILE_ERROR_C=0
-  fi
+  m4_ifdef([gl_HAVE_MODULE_VERROR],
+    [COMPILE_ERROR_C=1],
+    [if test $HAVE_ERROR = 0 || test $REPLACE_ERROR = 1 \
+        || test $HAVE_ERROR_AT_LINE = 0 \
+        || test $REPLACE_ERROR_AT_LINE = 1; then
+       COMPILE_ERROR_C=1
+     else
+       COMPILE_ERROR_C=0
+     fi])
 
   AC_SUBST([HAVE_ERROR])
   AC_SUBST([HAVE_ERROR_AT_LINE])
diff --git a/modules/verror b/modules/verror
index 16ad0c5961..8fea49ad3c 100644
--- a/modules/verror
+++ b/modules/verror
@@ -2,13 +2,12 @@ Description:
 verror and verror_at_line functions: Error reporting with va_list.
 
 Files:
-lib/verror.h
-lib/verror.c
 
 Depends-on:
-stdio
 error
-xvasprintf
+
+configure.ac-early:
+AC_DEFUN([gl_HAVE_MODULE_VERROR])
 
 configure.ac:
 m4_ifdef([AM_XGETTEXT_OPTION],
@@ -16,10 +15,9 @@ m4_ifdef([AM_XGETTEXT_OPTION],
    AM_][XGETTEXT_OPTION([--flag=verror_at_line:5:c-format])])
 
 Makefile.am:
-lib_SOURCES += verror.h verror.c
 
 Include:
-"verror.h"
+<error.h>
 
 License:
 GPL
diff --git a/tests/test-verror.c b/tests/test-verror.c
index 1e9dcd9cc5..bd17cc1429 100644
--- a/tests/test-verror.c
+++ b/tests/test-verror.c
@@ -18,7 +18,7 @@
 
 #include <config.h>
 
-#include "verror.h"
+#include <error.h>
 
 #include <errno.h>
 #include <stdarg.h>
-- 
2.46.0