glib/gio/gio-tool-cat.c
Philip Withnall 5cddde1fb2 Consistently save errno immediately after the operation setting it
Prevent the situation where errno is set by function A, then function B
is called (which is typically _(), but could be anything else) and it
overwrites errno, then errno is checked by the caller.

errno is a horrific API, and we need to be careful to save its value as
soon as a function call (which might set it) returns. i.e. Follow the
pattern:
  int errsv, ret;
  ret = some_call_which_might_set_errno ();
  errsv = errno;

  if (ret < 0)
    puts (strerror (errsv));

This patch implements that pattern throughout GLib. There might be a few
places in the test code which still use errno directly. They should be
ported as necessary. It doesn’t modify all the call sites like this:
  if (some_call_which_might_set_errno () && errno == ESOMETHING)
since the refactoring involved is probably more harmful than beneficial
there. It does, however, refactor other call sites regardless of whether
they were originally buggy.

https://bugzilla.gnome.org/show_bug.cgi?id=785577
2017-08-03 10:21:13 +01:00

173 lines
4.0 KiB
C

/*
* Copyright 2015 Red Hat, Inc.
*
* This 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 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.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* Author: Matthias Clasen <mclasen@redhat.com>
*/
#include "config.h"
#include <gio/gio.h>
#include <gi18n.h>
#include <errno.h>
#ifdef G_OS_WIN32
#include <io.h>
#endif
#ifndef STDOUT_FILENO
#define STDOUT_FILENO 1
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include "gio-tool.h"
static const GOptionEntry entries[] = {
{ NULL }
};
static gboolean
cat (GFile *file)
{
GInputStream *in;
char buffer[1024 * 8 + 1];
char *p;
gssize res;
gboolean close_res;
GError *error;
gboolean success;
error = NULL;
in = (GInputStream *) g_file_read (file, NULL, &error);
if (in == NULL)
{
print_file_error (file, error->message);
g_error_free (error);
return FALSE;
}
success = TRUE;
while (1)
{
res = g_input_stream_read (in, buffer, sizeof (buffer) - 1, NULL, &error);
if (res > 0)
{
gssize written;
p = buffer;
while (res > 0)
{
int errsv;
written = write (STDOUT_FILENO, p, res);
errsv = errno;
if (written == -1 && errsv != EINTR)
{
print_file_error (file, _("Error writing to stdout"));
success = FALSE;
goto out;
}
res -= written;
p += written;
}
}
else if (res < 0)
{
print_file_error (file, error->message);
g_error_free (error);
error = NULL;
success = FALSE;
break;
}
else if (res == 0)
break;
}
out:
close_res = g_input_stream_close (in, NULL, &error);
if (!close_res)
{
print_file_error (file, error->message);
g_error_free (error);
success = FALSE;
}
return success;
}
int
handle_cat (int argc, char *argv[], gboolean do_help)
{
GOptionContext *context;
gchar *param;
GError *error = NULL;
int i;
gboolean res;
GFile *file;
g_set_prgname ("gio cat");
/* Translators: commandline placeholder */
param = g_strdup_printf ("%s...", _("LOCATION"));
context = g_option_context_new (param);
g_free (param);
g_option_context_set_help_enabled (context, FALSE);
g_option_context_set_summary (context,
_("Concatenate files and print to standard output."));
g_option_context_set_description (context,
_("gio cat works just like the traditional cat utility, but using GIO\n"
"locations instead of local files: for example, you can use something\n"
"like smb://server/resource/file.txt as location."));
g_option_context_add_main_entries (context, entries, GETTEXT_PACKAGE);
if (do_help)
{
show_help (context, NULL);
g_option_context_free (context);
return 0;
}
if (!g_option_context_parse (context, &argc, &argv, &error))
{
show_help (context, error->message);
g_error_free (error);
g_option_context_free (context);
return 1;
}
if (argc < 2)
{
show_help (context, _("No locations given"));
g_option_context_free (context);
return 1;
}
g_option_context_free (context);
res = TRUE;
for (i = 1; i < argc; i++)
{
file = g_file_new_for_commandline_arg (argv[i]);
res &= cat (file);
g_object_unref (file);
}
return res ? 0 : 2;
}