glib/gio/tests/dbus-launch.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

79 lines
1.9 KiB
C

/*
* Mock version of dbus-launch, for gdbus-unix-addresses test
*
* Copyright © 2015 Collabora Ltd.
*
* 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/>.
*/
#include <glib.h>
#ifndef G_OS_UNIX
#error This is a Unix-specific test helper
#endif
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <unistd.h>
#define ME "GDBus mock version of dbus-launch"
static void
write_all (const void *ptr,
size_t len)
{
const char *p = ptr;
while (len > 0)
{
ssize_t done = write (STDOUT_FILENO, p, len);
int errsv = errno;
if (done == 0)
{
g_error ("%s: write: EOF", ME);
}
else if (done < 0)
{
if (errsv == EINTR)
continue;
g_error ("%s: write: %s", ME, g_strerror (errsv));
}
else
{
if (len < (size_t) done)
g_error ("%s: wrote too many bytes?", ME);
len -= done;
p += done;
}
}
}
int
main (int argc,
char *argv[])
{
pid_t pid = 0x2323;
long window_id = 0x42424242;
const char *addr = "hello:this=address-is-from-the,mock=dbus-launch";
write_all (addr, strlen (addr) + 1);
write_all (&pid, sizeof (pid));
write_all (&window_id, sizeof (window_id));
return 0;
}