qemu/ui
Markus Armbruster 1f51470d04 Revert "qemu-char: Print strerror message on failure" and deps
The commit's purpose is laudable:

    The only way for chardev drivers to communicate an error was to
    return a NULL pointer, which resulted in an error message that
    said _that_ something went wrong, but not _why_.

It attempts to achieve it by changing the interface to return 0/-errno
and update qemu_chr_open_opts() to use strerror() to display a more
helpful error message.  Unfortunately, it has serious flaws:

1. Backends "socket" and "udp" return bogus error codes, because
qemu_chr_open_socket() and qemu_chr_open_udp() assume that
unix_listen_opts(), unix_connect_opts(), inet_listen_opts(),
inet_connect_opts() and inet_dgram_opts() fail with errno set
appropriately.  That assumption is wrong, and the commit turns
unspecific error messages into misleading error messages.  For
instance:

    $ qemu-system-x86_64 -nodefaults -vnc :0 -chardev socket,id=bar,host=xxx
    inet_connect: host and/or port not specified
    chardev: opening backend "socket" failed: No such file or directory

ENOENT is what happens to be in my errno when the backend returns
-errno.  Let's put ERANGE there just for giggles:

    $ qemu-system-x86_64 -nodefaults -vnc :0 -chardev socket,id=bar,host=xxx -drive if=none,iops=99999999999999999999
    inet_connect: host and/or port not specified
    chardev: opening backend "socket" failed: Numerical result out of range

Worse: when errno happens to be zero, return -errno erroneously
signals success, and qemu_chr_new_from_opts() dies dereferencing
uninitialized chr.  I observe this with "-serial unix:".

2. All qemu_chr_open_opts() knows about the error is an errno error
code.  That's simply not enough for a decent message.  For instance,
when inet_dgram() can't resolve the parameter host, which errno code
should it use?  What if it can't resolve parameter localaddr?

Clue: many backends already report errors in their open methods.
Let's revert the flawed commit along with its dependencies, and fix up
the silent error paths instead.

This reverts commit 6e1db57b2a.

Conflicts:

	console.c
	hw/baum.c
	qemu-char.c

This reverts commit aad04cd024.

The parts of commit db418a0a "Add stdio char device on windows" that
depend on the reverted change fixed up.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-02-24 09:06:56 -06:00
..
cocoa.m cocoa: Close sheet after image file selection 2011-11-01 20:41:06 +01:00
curses.c Use glib memory allocation and free functions 2011-08-20 23:01:08 -05:00
curses_keys.h curses: Fix control-{@[\]^_} and ESC 2010-10-21 18:31:28 +02:00
d3des.c
d3des.h Delete useless 'extern' qualifiers for functions 2011-01-23 16:21:20 +00:00
keymaps.c ui: Plug memory leaks on parse_keyboard_layout() error path 2011-11-11 12:49:51 -06:00
keymaps.h
qemu-spice.h Revert "qemu-char: Print strerror message on failure" and deps 2012-02-24 09:06:56 -06:00
sdl.c sdl: Limit sdl_grab_end in handle_activation to Windows hosts 2012-02-01 14:45:02 -06:00
sdl_keysym.h
sdl_zoom.c
sdl_zoom.h
sdl_zoom_template.h
spice-core.c spice: support ipv6 channel address in monitor events and in spice info 2012-02-21 10:36:05 +01:00
spice-display.c Drop unneeded pthread.h inclusions 2011-09-21 10:49:16 +01:00
spice-display.h Replace the VMSTOP macros with a proper state type 2011-09-15 16:39:32 -03:00
spice-input.c Use glib memory allocation and free functions 2011-08-20 23:01:08 -05:00
vnc-auth-sasl.c ui/vnc: Convert sasl.mechlist to g_malloc() & friends 2011-11-10 12:29:50 +00:00
vnc-auth-sasl.h
vnc-auth-vencrypt.c Store VNC auth scheme per-client as well as per-server 2011-07-23 11:19:02 -05:00
vnc-auth-vencrypt.h
vnc-enc-hextile-template.h
vnc-enc-hextile.c ui/vnc: Fix use of free() instead of g_free() 2011-11-01 16:52:05 -05:00
vnc-enc-tight.c Use glib memory allocation and free functions 2011-08-20 23:01:08 -05:00
vnc-enc-tight.h vnc: tight add PNG encoding 2010-07-26 17:36:14 -05:00
vnc-enc-zlib.c Use glib memory allocation and free functions 2011-08-20 23:01:08 -05:00
vnc-enc-zrle-template.c vnc: Add ZRLE and ZYWRLE encodings. 2011-02-23 16:28:28 -06:00
vnc-enc-zrle.c vnc: fix uint8_t comparisons with negative values 2011-02-23 16:28:28 -06:00
vnc-enc-zrle.h vnc: Add ZRLE and ZYWRLE encodings. 2011-02-23 16:28:28 -06:00
vnc-enc-zywrle-template.c Fix spelling in comments, documentation and messages 2011-12-14 11:09:44 +00:00
vnc-enc-zywrle.h Fix spelling in comments, documentation and messages 2011-12-14 11:09:44 +00:00
vnc-jobs-async.c qemu-thread: add API for joinable threads 2011-12-12 17:06:22 -06:00
vnc-jobs-sync.c vnc: threaded VNC server 2010-07-26 17:36:14 -05:00
vnc-jobs.h vnc: threaded VNC server 2010-07-26 17:36:14 -05:00
vnc-palette.c Use glib memory allocation and free functions 2011-08-20 23:01:08 -05:00
vnc-palette.h vnc: palette: and fill and color calls. 2011-02-23 16:28:28 -06:00
vnc-tls.c ui/vnc: Fix use of free() instead of g_free() 2011-11-01 16:52:05 -05:00
vnc-tls.h
vnc.c vnc: Don't demote authentication scheme when changing password/disabling login 2012-02-17 09:58:21 -06:00
vnc.h vnc: implement shared flag handling. 2012-02-10 09:58:33 +01:00
vnc_keysym.h vnc: added missing name->keysym pairs for Polish national characters 2011-04-01 22:29:27 +02:00
x_keymap.c
x_keymap.h Delete useless 'extern' qualifiers for functions 2011-01-23 16:21:20 +00:00