glib/tests/spawn-test-win32-gui.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

115 lines
3.2 KiB
C

#include <windows.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#ifdef __CYGWIN__
/* For read() and write() */
#include <unistd.h>
/* Cygwin does not prototype __argc and __argv in stdlib.h */
extern int __argc;
extern char** __argv;
#endif
int _stdcall
WinMain (struct HINSTANCE__ *hInstance,
struct HINSTANCE__ *hPrevInstance,
char *lpszCmdLine,
int nCmdShow)
{
char buf[100];
if (__argc >= 2 && strcmp (__argv[1], "nop") == 0)
{
sprintf (buf, "spawn-test-win32-gui: argv[0]=\"%s\"", __argv[0]);
MessageBox (NULL, buf, lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
}
else if (__argc <= 2)
{
MessageBox (NULL, "spawn-test-win32-gui: Will write to stdout",
lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
printf ("This is stdout\n");
fflush (stdout);
MessageBox (NULL, "spawn-test-win32-gui: Will write to stderr",
lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
fprintf (stderr, "This is stderr\n");
fflush (stderr);
}
else if (__argc == 4 && strcmp (__argv[1], "pipes") == 0)
{
int infd = atoi (__argv[2]);
int outfd = atoi (__argv[3]);
int k, n;
if (infd < 0 || outfd < 0)
{
MessageBox (NULL, "spawn-test-win32-gui: illegal fds on command line",
lpszCmdLine, MB_ICONERROR|MB_SYSTEMMODAL);
exit (1);
}
MessageBox (NULL, "spawn-test-win32-gui: Will write to parent",
lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
n = strlen ("Hello there");
if (write (outfd, &n, sizeof (n)) == -1 ||
write (outfd, "Hello there", n) == -1)
{
int errsv = errno;
sprintf (buf, "spawn-test-win32-gui: Write: %s", strerror (errsv));
MessageBox (NULL, buf, lpszCmdLine, MB_ICONERROR|MB_SYSTEMMODAL);
exit (1);
}
MessageBox (NULL, "spawn-test-win32-gui: Will read from parent",
lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
if ((k = read (infd, &n, sizeof (n))) != sizeof (n))
{
sprintf (buf, "spawn-test-win32-gui: Got only %d bytes, wanted %d",
k, sizeof (n));
MessageBox (NULL, buf, lpszCmdLine, MB_ICONERROR|MB_SYSTEMMODAL);
exit (1);
}
sprintf (buf, "spawn-test-win32-gui: Parent says %d bytes to read", n);
MessageBox (NULL, buf, lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
if ((k = read (infd, buf, n)) != n)
{
int errsv = errno;
if (k == -1)
sprintf (buf, "spawn-test-win32-gui: Read: %s", strerror (errsv));
else
sprintf (buf, "spawn-test-win32-gui: Got only %d bytes", k);
MessageBox (NULL, buf, lpszCmdLine, MB_ICONERROR|MB_SYSTEMMODAL);
exit (1);
}
MessageBox (NULL, "spawn-test-win32-gui: Will write more to parent",
lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
n = strlen ("See ya");
if (write (outfd, &n, sizeof (n)) == -1 ||
write (outfd, "See ya", n) == -1)
{
int errsv = errno;
sprintf (buf, "spawn-test-win32-gui: Write: %s", strerror (errsv));
MessageBox (NULL, buf, lpszCmdLine, MB_ICONERROR|MB_SYSTEMMODAL);
exit (1);
}
}
Sleep (2000);
MessageBox (NULL, "spawn-test-win32-gui: Done, exiting.",
lpszCmdLine, MB_ICONINFORMATION|MB_SYSTEMMODAL);
return 0;
}