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From: | Fei Li |
Subject: | Re: [Qemu-devel] [PATCH v2] ui/vnc.c: polish vnc_init_func |
Date: | Mon, 15 Oct 2018 18:08:47 +0800 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 |
On 10/15/2018 03:58 PM, Markus Armbruster wrote:
Fei Li <address@hidden> writes:Add a new Error parameter for vnc_display_init() to handle errors in its caller: vnc_init_func(), just like vnc_display_open() does. And let its callees propagate the Error, like init_keyboard_layout(). Signed-off-by: Fei Li <address@hidden> --- include/ui/console.h | 2 +- ui/curses.c | 4 +++- ui/keymaps.c | 11 ++++++----- ui/keymaps.h | 2 +- ui/sdl.c | 4 +++- ui/vnc.c | 16 +++++++++++----- 6 files changed, 25 insertions(+), 14 deletions(-) diff --git a/include/ui/console.h b/include/ui/console.h index fb969caf70..c17803c530 100644 --- a/include/ui/console.h +++ b/include/ui/console.h @@ -453,7 +453,7 @@ void qemu_display_early_init(DisplayOptions *opts); void qemu_display_init(DisplayState *ds, DisplayOptions *opts);/* vnc.c */-void vnc_display_init(const char *id); +void vnc_display_init(const char *id, Error **errp); void vnc_display_open(const char *id, Error **errp); void vnc_display_add_client(const char *id, int csock, bool skipauth); int vnc_display_password(const char *id, const char *password); diff --git a/ui/curses.c b/ui/curses.c index 59d819fd4d..60c0962334 100644 --- a/ui/curses.c +++ b/ui/curses.c @@ -28,6 +28,7 @@ #include <termios.h> #endif+#include "qapi/error.h"#include "qemu-common.h" #include "ui/console.h" #include "ui/input.h" @@ -421,7 +422,8 @@ static void curses_keyboard_setup(void) keyboard_layout = "en-us"; #endif if(keyboard_layout) { - kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout); + kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout, + &error_fatal); if (!kbd_layout) exit(1);As Philippe pointed out, this exit() is now unreachable.
Right, should be deleted along with the below one.
Oh, sorry! My fault.. I mistook the passed errp in parse_keyboard_layout() for &error_fatal, in this case once the first fails, qemu will exit(1) directly and no second include will be read. But the truth is we use a *local_err=NULL in vnc_init_func to propagate to the &error_abort.} diff --git a/ui/keymaps.c b/ui/keymaps.c index 43fe604724..52d432e856 100644 --- a/ui/keymaps.c +++ b/ui/keymaps.c @@ -27,6 +27,7 @@ #include "sysemu/sysemu.h" #include "trace.h" #include "qemu/error-report.h" +#include "qapi/error.h"struct keysym2code {uint32_t count; @@ -81,7 +82,7 @@ static void add_keysym(char *line, int keysym, int keycode, kbd_layout_t *k)static kbd_layout_t *parse_keyboard_layout(const name2keysym_t *table,const char *language,`> - kbd_layout_t *k)+ kbd_layout_t *k, Error **errp) { FILE *f; char * filename; @@ -94,7 +95,7 @@ static kbd_layout_t *parse_keyboard_layout(const name2keysym_t *table, f = filename ? fopen(filename, "r") : NULL; g_free(filename); if (!f) { - fprintf(stderr, "Could not read keymap file: '%s'\n", language); + error_setg(errp, "could not read keymap file: '%s'", language); return NULL; }@@ -118,7 +119,7 @@ static kbd_layout_t *parse_keyboard_layout(const name2keysym_t *table,continue; } if (!strncmp(line, "include ", 8)) { - parse_keyboard_layout(table, line + 8, k); + parse_keyboard_layout(table, line + 8, k, errp);Lacks error checking. Before this patch, an error in an included file is reported to stderr, but is otherwise ignored: $ cat kbd-layout include bad include worse $ qemu-system-x86_64 -nodefaults -S -monitor stdio -display vnc=:0 -k kbd-layout QEMU 3.0.50 monitor - type 'help' for more information (qemu) Could not read keymap file: 'bad' Could not read keymap file: 'worse' Afterwards, the error gets stored in errp. If a second include fails, we attempt to store another one, which fails the error_setv()'s assertion: $ qemu-system-x86_64 -nodefaults -S -display vnc=:0 -k kbd-layout qemu-system-x86_64: /work/armbru/qemu/util/error.c:57: error_setv: Assertion `*errp == NULL' failed. Aborted (core dumped) If it's the only failed include, parse_keyboard_layout() sets an error and returns succes, which is a no-no. Callers using the return value to determine success are prone to leak the error, or run into error_setv()'s assertion. Callers using the error are prone to leak the returned kbd_layout_t.
Let's address this in a separate patch before this one. if (!parse_keyboard_layout(table, line + 8, k, errp))
Ok.I have another thought, that is pass the &error_fatal directly to vnc_display_init/open(), and exit() in the callee parse_keyboard_layout. But the side effect is drooping the obvious
error message: "Failed to init/start VNC server: ".
} else { int offset = 0; while (line[offset] != 0 && @@ -170,9 +171,9 @@ static kbd_layout_t *parse_keyboard_layout(const name2keysym_t *table,kbd_layout_t *init_keyboard_layout(const name2keysym_t *table,- const char *language) + const char *language, Error **errp) { - return parse_keyboard_layout(table, language, NULL); + return parse_keyboard_layout(table, language, NULL, errp); }diff --git a/ui/keymaps.h b/ui/keymaps.hindex 0693588225..98213a4191 100644 --- a/ui/keymaps.h +++ b/ui/keymaps.h @@ -53,7 +53,7 @@ typedef struct { typedef struct kbd_layout_t kbd_layout_t;kbd_layout_t *init_keyboard_layout(const name2keysym_t *table,- const char *language); + const char *language, Error **errp); int keysym2scancode(kbd_layout_t *k, int keysym, bool shift, bool altgr, bool ctrl); int keycode_is_keypad(kbd_layout_t *k, int keycode); diff --git a/ui/sdl.c b/ui/sdl.c index a5fd503c25..b33df70f4d 100644 --- a/ui/sdl.c +++ b/ui/sdl.c @@ -29,6 +29,7 @@ #include <SDL.h> #include <SDL_syswm.h>+#include "qapi/error.h"#include "qemu-common.h" #include "qemu/cutils.h" #include "ui/console.h" @@ -917,7 +918,8 @@ static void sdl1_display_init(DisplayState *ds, DisplayOptions *o) keyboard_layout = "en-us"; #endif if(keyboard_layout) { - kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout); + kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout, + &error_fatal); if (!kbd_layout) exit(1);Again, exit() is now unreachable.
Yes.
} diff --git a/ui/vnc.c b/ui/vnc.c index cf221c83cc..03c70b16f6 100644 --- a/ui/vnc.c +++ b/ui/vnc.c @@ -3205,7 +3205,7 @@ static const DisplayChangeListenerOps dcl_ops = { .dpy_cursor_define = vnc_dpy_cursor_define, };-void vnc_display_init(const char *id)+void vnc_display_init(const char *id, Error **errp) { VncDisplay *vd;@@ -3222,13 +3222,14 @@ void vnc_display_init(const char *id) if (keyboard_layout) {trace_vnc_key_map_init(keyboard_layout); - vd->kbd_layout = init_keyboard_layout(name2keysym, keyboard_layout); + vd->kbd_layout = init_keyboard_layout(name2keysym, + keyboard_layout, errp); } else { - vd->kbd_layout = init_keyboard_layout(name2keysym, "en-us"); + vd->kbd_layout = init_keyboard_layout(name2keysym, "en-us", errp); }if (!vd->kbd_layout) {- exit(1); + return; }vd->share_policy = VNC_SHARE_POLICY_ALLOW_EXCLUSIVE;@@ -4079,7 +4080,12 @@ int vnc_init_func(void *opaque, QemuOpts *opts, Error **errp) char *id = (char *)qemu_opts_id(opts);assert(id);- vnc_display_init(id); + vnc_display_init(id, &local_err); + if (local_err) { + error_prepend(&local_err, "Failed to init VNC server: "); + error_propagate(errp, local_err); + return -1; + }Works, but is inconsistent with the handling of vnc_display_open() errors, visible below. Let's match that, and convert both to error_propagate() in a followup patch.vnc_display_open(id, &local_err); if (local_err != NULL) { error_reportf_err(local_err, "Failed to start VNC server: ");I think the easiest way forward is for me to pick a touched up version of this patch into a v2 of my "Replace some unwise uses of error_report() & friends" series. You'll receive a copy, of course. Thanks!
Deal, that will be consistent and much easier. :) Have a nice day, thanks Fei
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