locale: Fix localedef exit code (Bug 22292)

The error and warning handling in localedef, locale, and iconv
is a bit of a mess.

We use ugly constructs like this:
      WITH_CUR_LOCALE (error (1, errno, gettext ("\
cannot read character map directory `%s'"), directory));

to issue errors, and read error_message_count directly from the
error API to detect errors. The problem with that is that the
code also uses error to print warnings, and informative messages.
All of this leads to problems where just having warnings will
produce an exit status as-if errors had been seen.

To fix this situation I have adopted the following high-level
changes:
* All errors are counted distinctly.
* All warnings are counted distinctly.
* All informative messages are not counted.
* Increasing verbosity cannot generate *more* errors, and
  it previously did for errors conditional on verbose,
  this is now fixed.
* Increasing verbosity *can* generate *more* warnings.
* Making the output quiet cannot generate *fewer* errors,
  and it previously did for errors conditional on be_quiet,
  this is now fixed.
* Each of error, warning, and informative message has it's
  own function to call defined in record-status.h, and they
  are: record_error, record_warning, and record_verbose.
* The record_error function always records an error, but
  conditional on be_quiet may not print it.
* The record_warning function always records a warning,
  but conditional on be_quiet may not print it.
* The record_verbose function only prints the verbose
  message if verbose is true and be_quiet is false.

This has allowed the following fix:
* Previously any warnings were being treated as errors
  because they incremented error_message_count, but now
  we properly return an exit status of 1 if there are
  warnings but output was generated.

All of this allows localedef to correctly decide if errors,
or warnings were present, and produce the correct exit code.

The locale and iconv programs now also use record-status.h
and we have removed the WITH_CUR_LOCALE hack, and instead
have internal push_locale/pop_locale functions centralized
in the record routines.

Signed-off-by: Carlos O'Donell <carlos@redhat.com>

1 files changed, 227 insertions, 0 deletions

diff --git a/locale/programs/record-status.h b/locale/programs/record-status.h
new file mode 100644
index 0000000000..b6bc58cddc
--- /dev/null
+++ b/locale/programs/record-status.h
@@ -0,0 +1,227 @@
+/* General definitions for recording error and warning status.
+   Copyright (C) 1998-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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; version 2 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 <http://www.gnu.org/licenses/>.  */
+
+#ifndef _RECORD_STATUS_H
+#define _RECORD_STATUS_H 1
+
+#include <stdlib.h>
+#include <stdarg.h>
+#include <error.h>
+#include <locale.h>
+#include <string.h>
+
+/* We tentatively define all of the global data we use:
+   * recorded_warning_count: Number of warnings counted.
+   * recorded_error_count: Number of errors counted.
+   * be_quiet: Should all calls be silent?
+   * verbose: Should verbose messages be printed?  */
+int recorded_warning_count;
+int recorded_error_count;
+int be_quiet;
+int verbose;
+
+/* Saved locale state.  */
+struct locale_state
+{
+   /* The current in-use locale.  */
+   char *cur_locale;
+};
+
+/* Alter the current locale to match the locale configured by the
+   user, and return the previous saved state.  */
+static struct locale_state
+push_locale (void)
+{
+  int saved_errno;
+  const char *orig;
+  char *copy = NULL;
+
+  saved_errno = errno;
+
+  orig = setlocale (LC_CTYPE, NULL);
+  if (orig == NULL)
+    error (0, 0, "failed to read locale!");
+
+  if (setlocale (LC_CTYPE, "") == NULL)
+    error (0, 0, "failed to set locale!");
+
+  errno = saved_errno;
+
+  if (orig != NULL)
+    copy = strdup (orig);
+
+  /* We will return either a valid locale or NULL if we failed
+     to save the locale.  */
+  return (struct locale_state) { .cur_locale = copy };
+}
+
+/* Use the saved state to restore the locale.  */
+static void
+pop_locale (struct locale_state ls)
+{
+  const char *set = NULL;
+  /* We might have failed to save the locale, so only attempt to
+     restore a validly saved non-NULL locale.  */
+  if (ls.cur_locale != NULL)
+    {
+      set = setlocale (LC_CTYPE, ls.cur_locale);
+      if (set == NULL)
+	error (0, 0, "failed to restore %s locale!", ls.cur_locale);
+
+      free (ls.cur_locale);
+    }
+}
+
+/* Wrapper to print verbose informative messages.
+   Verbose messages are only printed if --verbose
+   is in effect and --quiet is not.  */
+static void
+__attribute__ ((__format__ (__printf__, 2, 3), nonnull (1, 2), unused))
+record_verbose (FILE *stream, const char *format, ...)
+{
+  char *str;
+  va_list arg;
+
+  if (!verbose)
+    return;
+
+  if (!be_quiet)
+    {
+      struct locale_state ls;
+      int ret;
+
+      va_start (arg, format);
+      ls = push_locale ();
+
+      ret = vasprintf (&str, format, arg);
+      if (ret == -1)
+	abort ();
+
+      pop_locale (ls);
+      va_end (arg);
+
+      fprintf (stream, "%s\n", str);
+
+      free (str);
+    }
+}
+
+/* Wrapper to print warning messages.  We keep track of how
+   many were called because this effects our exit code.
+   Nothing is printed if --quiet is in effect, but warnings
+   are always counted.  */
+static void
+__attribute__ ((__format__ (__printf__, 1, 2), nonnull (1), unused))
+record_warning (const char *format, ...)
+{
+  char *str;
+  va_list arg;
+
+  recorded_warning_count++;
+
+  if (!be_quiet)
+    {
+      struct locale_state ls;
+      int ret;
+
+      va_start (arg, format);
+      ls = push_locale ();
+
+      ret = vasprintf (&str, format, arg);
+      if (ret == -1)
+	abort ();
+
+      pop_locale (ls);
+      va_end (arg);
+
+      fprintf (stderr, "%s\n", str);
+
+      free (str);
+    }
+}
+
+/* Wrapper to print error messages.  We keep track of how
+   many were called because this effects our exit code.
+   Nothing is printed if --quiet is in effect, but errors
+   are always counted, and fatal errors always exit the
+   program.  */
+static void
+__attribute__ ((__format__ (__printf__, 3, 4), nonnull (3), unused))
+record_error (int status, int errnum, const char *format, ...)
+{
+  char *str;
+  va_list arg;
+
+  recorded_error_count++;
+
+  /* The existing behaviour is that even if you use --quiet, a fatal
+     error is always printed and terminates the process.  */
+  if (!be_quiet || status != 0)
+    {
+      struct locale_state ls;
+      int ret;
+
+      va_start (arg, format);
+      ls = push_locale ();
+
+      ret = vasprintf (&str, format, arg);
+      if (ret == -1)
+        abort ();
+
+      pop_locale (ls);
+      va_end (arg);
+
+      error (status, errnum, "%s", str);
+
+      free (str);
+    }
+}
+/* ... likewise for error_at_line.  */
+static void
+__attribute__ ((__format__ (__printf__, 5, 6), nonnull (3, 5), unused))
+record_error_at_line (int status, int errnum, const char *filename,
+		      unsigned int linenum, const char *format, ...)
+{
+  char *str;
+  va_list arg;
+
+  recorded_error_count++;
+
+  /* The existing behaviour is that even if you use --quiet, a fatal
+     error is always printed and terminates the process.  */
+  if (!be_quiet || status != 0)
+    {
+      struct locale_state ls;
+      int ret;
+
+      va_start (arg, format);
+      ls = push_locale ();
+
+      ret = vasprintf (&str, format, arg);
+      if (ret == -1)
+        abort ();
+
+      pop_locale (ls);
+      va_end (arg);
+
+      error_at_line (status, errnum, filename, linenum, "%s", str);
+
+      free (str);
+    }
+}
+
+#endif