From bcdeb9be566ded2eb35233aaccf38742a21e5daa Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Thu, 6 Jul 2017 19:03:53 +0200 Subject: chardev: block during sync read MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A sync read should block until all requested data is available (instead of retrying in qemu_chr_fe_read_all). Change the channel to blocking during sync_read. Signed-off-by: Marc-André Lureau Message-Id: <20170706170353.32601-1-marcandre.lureau@redhat.com> Signed-off-by: Paolo Bonzini Signed-off-by: Marc-André Lureau --- chardev/char-socket.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'chardev') diff --git a/chardev/char-socket.c b/chardev/char-socket.c index ccc499cfa1..7e6648b03a 100644 --- a/chardev/char-socket.c +++ b/chardev/char-socket.c @@ -454,7 +454,9 @@ static int tcp_chr_sync_read(Chardev *chr, const uint8_t *buf, int len) return 0; } + qio_channel_set_blocking(s->ioc, true, NULL); size = tcp_chr_recv(chr, (void *) buf, len); + qio_channel_set_blocking(s->ioc, false, NULL); if (size == 0) { /* connection closed */ tcp_chr_disconnect(chr); -- cgit v1.2.1 From 313e45b5fe45542602bfa801db7a13d485c29b04 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:48 +0300 Subject: char: move QemuOpts->ChardevBackend translation to a separate func MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit parse function will be used by the following patch Signed-off-by: Anton Nefedov Message-Id: <1499342940-56739-2-git-send-email-anton.nefedov@virtuozzo.com> Reviewed-by: Marc-André Lureau Signed-off-by: Paolo Bonzini --- chardev/char.c | 81 ++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 51 insertions(+), 30 deletions(-) (limited to 'chardev') diff --git a/chardev/char.c b/chardev/char.c index 2b679a2295..839eff6afd 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -556,17 +556,23 @@ help_string_append(const char *name, void *opaque) g_string_append_printf(str, "\n%s", name); } -Chardev *qemu_chr_new_from_opts(QemuOpts *opts, - Error **errp) +static const char *chardev_alias_translate(const char *name) +{ + int i; + for (i = 0; i < (int)ARRAY_SIZE(chardev_alias_table); i++) { + if (g_strcmp0(chardev_alias_table[i].alias, name) == 0) { + return chardev_alias_table[i].typename; + } + } + return name; +} + +static ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts, Error **errp) { Error *local_err = NULL; const ChardevClass *cc; - Chardev *chr; - int i; ChardevBackend *backend = NULL; - const char *name = qemu_opt_get(opts, "backend"); - const char *id = qemu_opts_id(opts); - char *bid = NULL; + const char *name = chardev_alias_translate(qemu_opt_get(opts, "backend")); if (name == NULL) { error_setg(errp, "chardev: \"%s\" missing backend", @@ -574,7 +580,40 @@ Chardev *qemu_chr_new_from_opts(QemuOpts *opts, return NULL; } - if (is_help_option(name)) { + cc = char_get_class(name, errp); + if (cc == NULL) { + return NULL; + } + + backend = g_new0(ChardevBackend, 1); + backend->type = CHARDEV_BACKEND_KIND_NULL; + + if (cc->parse) { + cc->parse(opts, backend, &local_err); + if (local_err) { + error_propagate(errp, local_err); + qapi_free_ChardevBackend(backend); + return NULL; + } + } else { + ChardevCommon *ccom = g_new0(ChardevCommon, 1); + qemu_chr_parse_common(opts, ccom); + backend->u.null.data = ccom; /* Any ChardevCommon member would work */ + } + + return backend; +} + +Chardev *qemu_chr_new_from_opts(QemuOpts *opts, Error **errp) +{ + const ChardevClass *cc; + Chardev *chr = NULL; + ChardevBackend *backend = NULL; + const char *name = chardev_alias_translate(qemu_opt_get(opts, "backend")); + const char *id = qemu_opts_id(opts); + char *bid = NULL; + + if (name && is_help_option(name)) { GString *str = g_string_new(""); chardev_name_foreach(help_string_append, str); @@ -589,38 +628,20 @@ Chardev *qemu_chr_new_from_opts(QemuOpts *opts, return NULL; } - for (i = 0; i < (int)ARRAY_SIZE(chardev_alias_table); i++) { - if (g_strcmp0(chardev_alias_table[i].alias, name) == 0) { - name = chardev_alias_table[i].typename; - break; - } + backend = qemu_chr_parse_opts(opts, errp); + if (backend == NULL) { + return NULL; } cc = char_get_class(name, errp); if (cc == NULL) { - return NULL; + goto out; } - backend = g_new0(ChardevBackend, 1); - backend->type = CHARDEV_BACKEND_KIND_NULL; - if (qemu_opt_get_bool(opts, "mux", 0)) { bid = g_strdup_printf("%s-base", id); } - chr = NULL; - if (cc->parse) { - cc->parse(opts, backend, &local_err); - if (local_err) { - error_propagate(errp, local_err); - goto out; - } - } else { - ChardevCommon *ccom = g_new0(ChardevCommon, 1); - qemu_chr_parse_common(opts, ccom); - backend->u.null.data = ccom; /* Any ChardevCommon member would work */ - } - chr = qemu_chardev_new(bid ? bid : id, object_class_get_name(OBJECT_CLASS(cc)), backend, errp); -- cgit v1.2.1 From 81517ba37a6cec59f92396b4722861868eb0a500 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:49 +0300 Subject: char: add backend hotswap handler MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Frontends should have an interface to setup the handler of a backend change. The interface will be used in the next commits Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Marc-André Lureau Message-Id: <1499342940-56739-3-git-send-email-anton.nefedov@virtuozzo.com> Signed-off-by: Paolo Bonzini --- chardev/char-fe.c | 4 +++- chardev/char-mux.c | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) (limited to 'chardev') diff --git a/chardev/char-fe.c b/chardev/char-fe.c index 3f90f0567c..7054863208 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -216,7 +216,7 @@ void qemu_chr_fe_deinit(CharBackend *b, bool del) assert(b); if (b->chr) { - qemu_chr_fe_set_handlers(b, NULL, NULL, NULL, NULL, NULL, true); + qemu_chr_fe_set_handlers(b, NULL, NULL, NULL, NULL, NULL, NULL, true); if (b->chr->be == b) { b->chr->be = NULL; } @@ -235,6 +235,7 @@ void qemu_chr_fe_set_handlers(CharBackend *b, IOCanReadHandler *fd_can_read, IOReadHandler *fd_read, IOEventHandler *fd_event, + BackendChangeHandler *be_change, void *opaque, GMainContext *context, bool set_open) @@ -258,6 +259,7 @@ void qemu_chr_fe_set_handlers(CharBackend *b, b->chr_can_read = fd_can_read; b->chr_read = fd_read; b->chr_event = fd_event; + b->chr_be_change = be_change; b->opaque = opaque; if (cc->chr_update_read_handler) { cc->chr_update_read_handler(s, context); diff --git a/chardev/char-mux.c b/chardev/char-mux.c index 08570b915e..4cda5e7458 100644 --- a/chardev/char-mux.c +++ b/chardev/char-mux.c @@ -278,6 +278,7 @@ void mux_chr_set_handlers(Chardev *chr, GMainContext *context) mux_chr_can_read, mux_chr_read, mux_chr_event, + NULL, chr, context, true); } -- cgit v1.2.1 From 7bb86085e61befc95551055e26645cb23c3f0b86 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:50 +0300 Subject: char: chardevice hotswap MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch adds a possibility to change a char device without a frontend removal. Ideally, it would have to happen transparently to a frontend, i.e. frontend would continue its regular operation. However, backends are not stateless and are set up by the frontends via qemu_chr_fe_<> functions, and it's not (generally) possible to replay that setup entirely in a backend code, as different chardevs respond to the setup calls differently, so do frontends work differently basing on those setup responses. Moreover, some frontend can generally get and save the backend pointer (qemu_chr_fe_get_driver()), and it will become invalid after backend change. So, a frontend which would like to support chardev hotswap has to register a "backend change" handler, and redo its backend setup there. Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <1499342940-56739-4-git-send-email-anton.nefedov@virtuozzo.com> Reviewed-by: Marc-André Lureau Signed-off-by: Paolo Bonzini --- chardev/char.c | 83 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 83 insertions(+) (limited to 'chardev') diff --git a/chardev/char.c b/chardev/char.c index 839eff6afd..d6b9d89e93 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -951,6 +951,89 @@ ChardevReturn *qmp_chardev_add(const char *id, ChardevBackend *backend, return ret; } +ChardevReturn *qmp_chardev_change(const char *id, ChardevBackend *backend, + Error **errp) +{ + CharBackend *be; + const ChardevClass *cc; + Chardev *chr, *chr_new; + bool closed_sent = false; + ChardevReturn *ret; + + chr = qemu_chr_find(id); + if (!chr) { + error_setg(errp, "Chardev '%s' does not exist", id); + return NULL; + } + + if (CHARDEV_IS_MUX(chr)) { + error_setg(errp, "Mux device hotswap not supported yet"); + return NULL; + } + + if (qemu_chr_replay(chr)) { + error_setg(errp, + "Chardev '%s' cannot be changed in record/replay mode", id); + return NULL; + } + + be = chr->be; + if (!be) { + /* easy case */ + object_unparent(OBJECT(chr)); + return qmp_chardev_add(id, backend, errp); + } + + if (!be->chr_be_change) { + error_setg(errp, "Chardev user does not support chardev hotswap"); + return NULL; + } + + cc = char_get_class(ChardevBackendKind_lookup[backend->type], errp); + if (!cc) { + return NULL; + } + + chr_new = qemu_chardev_new(NULL, object_class_get_name(OBJECT_CLASS(cc)), + backend, errp); + if (!chr_new) { + return NULL; + } + chr_new->label = g_strdup(id); + + if (chr->be_open && !chr_new->be_open) { + qemu_chr_be_event(chr, CHR_EVENT_CLOSED); + closed_sent = true; + } + + chr->be = NULL; + qemu_chr_fe_init(be, chr_new, &error_abort); + + if (be->chr_be_change(be->opaque) < 0) { + error_setg(errp, "Chardev '%s' change failed", chr_new->label); + chr_new->be = NULL; + qemu_chr_fe_init(be, chr, &error_abort); + if (closed_sent) { + qemu_chr_be_event(chr, CHR_EVENT_OPENED); + } + object_unref(OBJECT(chr_new)); + return NULL; + } + + object_unparent(OBJECT(chr)); + object_property_add_child(get_chardevs_root(), chr_new->label, + OBJECT(chr_new), &error_abort); + object_unref(OBJECT(chr_new)); + + ret = g_new0(ChardevReturn, 1); + if (CHARDEV_IS_PTY(chr_new)) { + ret->pty = g_strdup(chr_new->filename + 4); + ret->has_pty = true; + } + + return ret; +} + void qmp_chardev_remove(const char *id, Error **errp) { Chardev *chr; -- cgit v1.2.1 From 7c44a2a9d178118193febd71cfc6943dd21bdde9 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:51 +0300 Subject: char: forbid direct chardevice access for hotswap devices MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit qemu_chr_fe_get_driver() is unsafe, frontends with hotswap support should not access CharDriver ptr directly as CharDriver might change. Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Marc-André Lureau Message-Id: <1499342940-56739-5-git-send-email-anton.nefedov@virtuozzo.com> Signed-off-by: Paolo Bonzini --- chardev/char-fe.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'chardev') diff --git a/chardev/char-fe.c b/chardev/char-fe.c index 7054863208..de5ba3c119 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -179,9 +179,16 @@ void qemu_chr_fe_printf(CharBackend *be, const char *fmt, ...) Chardev *qemu_chr_fe_get_driver(CharBackend *be) { + /* this is unsafe for the users that support chardev hotswap */ + assert(be->chr_be_change == NULL); return be->chr; } +bool qemu_chr_fe_backend_connected(CharBackend *be) +{ + return !!be->chr; +} + bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp) { int tag = 0; -- cgit v1.2.1 From 3065070153ef4235659d821c0d6fa28fd0630c57 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:52 +0300 Subject: char: avoid chardevice direct access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit frontends should avoid accessing CharDriver struct where possible Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Marc-André Lureau Message-Id: <1499342940-56739-6-git-send-email-anton.nefedov@virtuozzo.com> Signed-off-by: Paolo Bonzini --- chardev/char-fe.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'chardev') diff --git a/chardev/char-fe.c b/chardev/char-fe.c index de5ba3c119..f3af6ae584 100644 --- a/chardev/char-fe.c +++ b/chardev/char-fe.c @@ -189,6 +189,11 @@ bool qemu_chr_fe_backend_connected(CharBackend *be) return !!be->chr; } +bool qemu_chr_fe_backend_open(CharBackend *be) +{ + return be->chr && be->chr->be_open; +} + bool qemu_chr_fe_init(CharBackend *b, Chardev *s, Error **errp) { int tag = 0; -- cgit v1.2.1 From 75b601602be0462acb4e0298e738df86b1de61a1 Mon Sep 17 00:00:00 2001 From: Anton Nefedov Date: Thu, 6 Jul 2017 15:08:57 +0300 Subject: hmp: add hmp analogue for qmp-chardev-change MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Anton Nefedov Reviewed-by: Vladimir Sementsov-Ogievskiy Acked-by: Dr. David Alan Gilbert Message-Id: <1499342940-56739-11-git-send-email-anton.nefedov@virtuozzo.com> Reviewed-by: Marc-André Lureau Signed-off-by: Paolo Bonzini --- chardev/char.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'chardev') diff --git a/chardev/char.c b/chardev/char.c index d6b9d89e93..c34b44abc9 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -567,7 +567,7 @@ static const char *chardev_alias_translate(const char *name) return name; } -static ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts, Error **errp) +ChardevBackend *qemu_chr_parse_opts(QemuOpts *opts, Error **errp) { Error *local_err = NULL; const ChardevClass *cc; -- cgit v1.2.1