| Message ID | 20240603212228.3878836-1-tavip@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] chardev: add path option for pty backend | expand |
On Tue, Jun 4, 2024 at 1:22 AM Octavian Purdila <tavip@google.com> wrote: > > Add path option to the pty char backend which will create a symbolic > link to the given path that points to the allocated PTY. > > This avoids having to make QMP or HMP monitor queries to find out what > the new PTY device path is. > > Based on patch from Paulo Neves: > > https://patchew.org/QEMU/1548509635-15776-1-git-send-email-ptsneves@gmail.com/ > > Tested with the following invocations that the link is created and > removed when qemu stops: > > qemu-system-x86_64 -nodefaults -mon chardev=compat_monitor \ > -chardev pty,path=test,id=compat_monitor0 > > qemu-system-x86_64 -nodefaults -monitor pty:test > > Also tested that when a link path is not passed invocations still work, e.g.: > > qemu-system-x86_64 -monitor pty > > Co-authored-by: Paulo Neves <ptsneves@gmail.com> > Signed-off-by: Paulo Neves <ptsneves@gmail.com> > [OP: rebase and address original patch review comments] > Signed-off-by: Octavian Purdila <tavip@google.com> Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com> > --- > Changes since v1: > > * Keep the original Signed-off-by from Paulo and add one line > description with further changes > > * Update commit message with justification for why the new > functionality is useful > > * Don't close master_fd when symlink creation fails to avoid double > close > > * Update documentation for clarity > > chardev/char-pty.c | 33 +++++++++++++++++++++++++++++++++ > chardev/char.c | 5 +++++ > qapi/char.json | 4 ++-- > qemu-options.hx | 24 ++++++++++++++++++------ > 4 files changed, 58 insertions(+), 8 deletions(-) > > diff --git a/chardev/char-pty.c b/chardev/char-pty.c > index cc2f7617fe..b5a4eb59fc 100644 > --- a/chardev/char-pty.c > +++ b/chardev/char-pty.c > @@ -29,6 +29,7 @@ > #include "qemu/sockets.h" > #include "qemu/error-report.h" > #include "qemu/module.h" > +#include "qemu/option.h" > #include "qemu/qemu-print.h" > > #include "chardev/char-io.h" > @@ -41,6 +42,7 @@ struct PtyChardev { > > int connected; > GSource *timer_src; > + char *symlink_path; > }; > typedef struct PtyChardev PtyChardev; > > @@ -204,6 +206,12 @@ static void char_pty_finalize(Object *obj) > Chardev *chr = CHARDEV(obj); > PtyChardev *s = PTY_CHARDEV(obj); > > + /* unlink symlink */ > + if (s->symlink_path) { > + unlink(s->symlink_path); > + g_free(s->symlink_path); > + } > + > pty_chr_state(chr, 0); > object_unref(OBJECT(s->ioc)); > pty_chr_timer_cancel(s); > @@ -330,6 +338,7 @@ static void char_pty_open(Chardev *chr, > int master_fd, slave_fd; > char pty_name[PATH_MAX]; > char *name; > + char *symlink_path = backend->u.pty.data->device; > > master_fd = qemu_openpty_raw(&slave_fd, pty_name); > if (master_fd < 0) { > @@ -354,12 +363,36 @@ static void char_pty_open(Chardev *chr, > g_free(name); > s->timer_src = NULL; > *be_opened = false; > + > + /* create symbolic link */ > + if (symlink_path) { > + int res = symlink(pty_name, symlink_path); > + > + if (res != 0) { > + error_setg_errno(errp, errno, "Failed to create PTY symlink"); > + } else { > + s->symlink_path = g_strdup(symlink_path); > + } > + } > +} > + > +static void char_pty_parse(QemuOpts *opts, ChardevBackend *backend, > + Error **errp) > +{ > + const char *path = qemu_opt_get(opts, "path"); > + ChardevHostdev *dev; > + > + backend->type = CHARDEV_BACKEND_KIND_PTY; > + dev = backend->u.pty.data = g_new0(ChardevHostdev, 1); > + qemu_chr_parse_common(opts, qapi_ChardevHostdev_base(dev)); > + dev->device = path ? g_strdup(path) : NULL; > } > > static void char_pty_class_init(ObjectClass *oc, void *data) > { > ChardevClass *cc = CHARDEV_CLASS(oc); > > + cc->parse = char_pty_parse; > cc->open = char_pty_open; > cc->chr_write = char_pty_chr_write; > cc->chr_update_read_handler = pty_chr_update_read_handler; > diff --git a/chardev/char.c b/chardev/char.c > index 3c43fb1278..404c6b8a4f 100644 > --- a/chardev/char.c > +++ b/chardev/char.c > @@ -428,6 +428,11 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename, > qemu_opt_set(opts, "path", p, &error_abort); > return opts; > } > + if (strstart(filename, "pty:", &p)) { > + qemu_opt_set(opts, "backend", "pty", &error_abort); > + qemu_opt_set(opts, "path", p, &error_abort); > + return opts; > + } > if (strstart(filename, "tcp:", &p) || > strstart(filename, "telnet:", &p) || > strstart(filename, "tn3270:", &p) || > diff --git a/qapi/char.json b/qapi/char.json > index 777dde55d9..4c74bfc437 100644 > --- a/qapi/char.json > +++ b/qapi/char.json > @@ -509,7 +509,7 @@ > ## > # @ChardevHostdevWrapper: > # > -# @data: Configuration info for device and pipe chardevs > +# @data: Configuration info for device, pty and pipe chardevs > # > # Since: 1.4 > ## > @@ -650,7 +650,7 @@ > 'pipe': 'ChardevHostdevWrapper', > 'socket': 'ChardevSocketWrapper', > 'udp': 'ChardevUdpWrapper', > - 'pty': 'ChardevCommonWrapper', > + 'pty': 'ChardevHostdevWrapper', > 'null': 'ChardevCommonWrapper', > 'mux': 'ChardevMuxWrapper', > 'msmouse': 'ChardevCommonWrapper', > diff --git a/qemu-options.hx b/qemu-options.hx > index 8ca7f34ef0..94ffb1a605 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -3569,7 +3569,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, > "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > #else > - "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > + "-chardev pty,id=id[,path=path][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" > #endif > #ifdef CONFIG_BRLAPI > @@ -3808,12 +3808,18 @@ The available backends are: > > ``path`` specifies the name of the serial device to open. > > -``-chardev pty,id=id`` > - Create a new pseudo-terminal on the host and connect to it. ``pty`` > - does not take any options. > +``-chardev pty,id=id[,path=path]`` > + Create a new pseudo-terminal on the host and connect to it. > > ``pty`` is not available on Windows hosts. > > + If ``path`` is specified, QEMU will create a symbolic link at > + that location which points to the new PTY device. > + > + This avoids having to make QMP or HMP monitor queries to find out > + what the new PTY device path is. > + > + > ``-chardev stdio,id=id[,signal=on|off]`` > Connect to standard input and standard output of the QEMU process. > > @@ -4171,8 +4177,14 @@ SRST > > vc:80Cx24C > > - ``pty`` > - [Linux only] Pseudo TTY (a new PTY is automatically allocated) > + ``pty[:path]`` > + [Linux only] Pseudo TTY (a new PTY is automatically allocated). > + > + If ``path`` is specified, QEMU will create a symbolic link at > + that location which points to the new PTY device. > + > + This avoids having to make QMP or HMP monitor queries to find > + out what the new PTY device path is. > > ``none`` > No device is allocated. Note that for machine types which > -- > 2.45.1.288.g0e0cd299f1-goog >
On Tue, Jun 4, 2024 at 1:22 AM Octavian Purdila <tavip@google.com> wrote: > > Add path option to the pty char backend which will create a symbolic > link to the given path that points to the allocated PTY. > > This avoids having to make QMP or HMP monitor queries to find out what > the new PTY device path is. > > Based on patch from Paulo Neves: > > https://patchew.org/QEMU/1548509635-15776-1-git-send-email-ptsneves@gmail.com/ > > Tested with the following invocations that the link is created and > removed when qemu stops: > > qemu-system-x86_64 -nodefaults -mon chardev=compat_monitor \ > -chardev pty,path=test,id=compat_monitor0 > > qemu-system-x86_64 -nodefaults -monitor pty:test > > Also tested that when a link path is not passed invocations still work, e.g.: > > qemu-system-x86_64 -monitor pty > > Co-authored-by: Paulo Neves <ptsneves@gmail.com> > Signed-off-by: Paulo Neves <ptsneves@gmail.com> > [OP: rebase and address original patch review comments] > Signed-off-by: Octavian Purdila <tavip@google.com> > --- > Changes since v1: > > * Keep the original Signed-off-by from Paulo and add one line > description with further changes > > * Update commit message with justification for why the new > functionality is useful > > * Don't close master_fd when symlink creation fails to avoid double > close > > * Update documentation for clarity > > chardev/char-pty.c | 33 +++++++++++++++++++++++++++++++++ > chardev/char.c | 5 +++++ > qapi/char.json | 4 ++-- > qemu-options.hx | 24 ++++++++++++++++++------ > 4 files changed, 58 insertions(+), 8 deletions(-) > > diff --git a/chardev/char-pty.c b/chardev/char-pty.c > index cc2f7617fe..b5a4eb59fc 100644 > --- a/chardev/char-pty.c > +++ b/chardev/char-pty.c > @@ -29,6 +29,7 @@ > #include "qemu/sockets.h" > #include "qemu/error-report.h" > #include "qemu/module.h" > +#include "qemu/option.h" > #include "qemu/qemu-print.h" > > #include "chardev/char-io.h" > @@ -41,6 +42,7 @@ struct PtyChardev { > > int connected; > GSource *timer_src; > + char *symlink_path; > }; > typedef struct PtyChardev PtyChardev; > > @@ -204,6 +206,12 @@ static void char_pty_finalize(Object *obj) > Chardev *chr = CHARDEV(obj); > PtyChardev *s = PTY_CHARDEV(obj); > > + /* unlink symlink */ > + if (s->symlink_path) { > + unlink(s->symlink_path); > + g_free(s->symlink_path); > + } > + > pty_chr_state(chr, 0); > object_unref(OBJECT(s->ioc)); > pty_chr_timer_cancel(s); > @@ -330,6 +338,7 @@ static void char_pty_open(Chardev *chr, > int master_fd, slave_fd; > char pty_name[PATH_MAX]; > char *name; > + char *symlink_path = backend->u.pty.data->device; > > master_fd = qemu_openpty_raw(&slave_fd, pty_name); > if (master_fd < 0) { > @@ -354,12 +363,36 @@ static void char_pty_open(Chardev *chr, > g_free(name); > s->timer_src = NULL; > *be_opened = false; > + > + /* create symbolic link */ > + if (symlink_path) { > + int res = symlink(pty_name, symlink_path); > + > + if (res != 0) { > + error_setg_errno(errp, errno, "Failed to create PTY symlink"); > + } else { > + s->symlink_path = g_strdup(symlink_path); > + } > + } > +} > + > +static void char_pty_parse(QemuOpts *opts, ChardevBackend *backend, > + Error **errp) > +{ > + const char *path = qemu_opt_get(opts, "path"); > + ChardevHostdev *dev; > + > + backend->type = CHARDEV_BACKEND_KIND_PTY; > + dev = backend->u.pty.data = g_new0(ChardevHostdev, 1); > + qemu_chr_parse_common(opts, qapi_ChardevHostdev_base(dev)); > + dev->device = path ? g_strdup(path) : NULL; minor nit, g_strdup(NULL) returns NULL. Get rid of "?:" if you send a v3. > } > > static void char_pty_class_init(ObjectClass *oc, void *data) > { > ChardevClass *cc = CHARDEV_CLASS(oc); > > + cc->parse = char_pty_parse; > cc->open = char_pty_open; > cc->chr_write = char_pty_chr_write; > cc->chr_update_read_handler = pty_chr_update_read_handler; > diff --git a/chardev/char.c b/chardev/char.c > index 3c43fb1278..404c6b8a4f 100644 > --- a/chardev/char.c > +++ b/chardev/char.c > @@ -428,6 +428,11 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename, > qemu_opt_set(opts, "path", p, &error_abort); > return opts; > } > + if (strstart(filename, "pty:", &p)) { > + qemu_opt_set(opts, "backend", "pty", &error_abort); > + qemu_opt_set(opts, "path", p, &error_abort); > + return opts; > + } > if (strstart(filename, "tcp:", &p) || > strstart(filename, "telnet:", &p) || > strstart(filename, "tn3270:", &p) || > diff --git a/qapi/char.json b/qapi/char.json > index 777dde55d9..4c74bfc437 100644 > --- a/qapi/char.json > +++ b/qapi/char.json > @@ -509,7 +509,7 @@ > ## > # @ChardevHostdevWrapper: > # > -# @data: Configuration info for device and pipe chardevs > +# @data: Configuration info for device, pty and pipe chardevs > # > # Since: 1.4 > ## > @@ -650,7 +650,7 @@ > 'pipe': 'ChardevHostdevWrapper', > 'socket': 'ChardevSocketWrapper', > 'udp': 'ChardevUdpWrapper', > - 'pty': 'ChardevCommonWrapper', > + 'pty': 'ChardevHostdevWrapper', > 'null': 'ChardevCommonWrapper', > 'mux': 'ChardevMuxWrapper', > 'msmouse': 'ChardevCommonWrapper', > diff --git a/qemu-options.hx b/qemu-options.hx > index 8ca7f34ef0..94ffb1a605 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -3569,7 +3569,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, > "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > #else > - "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > + "-chardev pty,id=id[,path=path][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" > #endif > #ifdef CONFIG_BRLAPI > @@ -3808,12 +3808,18 @@ The available backends are: > > ``path`` specifies the name of the serial device to open. > > -``-chardev pty,id=id`` > - Create a new pseudo-terminal on the host and connect to it. ``pty`` > - does not take any options. > +``-chardev pty,id=id[,path=path]`` > + Create a new pseudo-terminal on the host and connect to it. > > ``pty`` is not available on Windows hosts. > > + If ``path`` is specified, QEMU will create a symbolic link at > + that location which points to the new PTY device. > + > + This avoids having to make QMP or HMP monitor queries to find out > + what the new PTY device path is. > + > + > ``-chardev stdio,id=id[,signal=on|off]`` > Connect to standard input and standard output of the QEMU process. > > @@ -4171,8 +4177,14 @@ SRST > > vc:80Cx24C > > - ``pty`` > - [Linux only] Pseudo TTY (a new PTY is automatically allocated) > + ``pty[:path]`` > + [Linux only] Pseudo TTY (a new PTY is automatically allocated). > + > + If ``path`` is specified, QEMU will create a symbolic link at > + that location which points to the new PTY device. > + > + This avoids having to make QMP or HMP monitor queries to find > + out what the new PTY device path is. > > ``none`` > No device is allocated. Note that for machine types which > -- > 2.45.1.288.g0e0cd299f1-goog >
Really happy somebody found the patch useful. I forgot to look at the review comments at the time and never got it merged. @Octavian thanks for bringing it up to shape. Cheers Paulo Neves On 04/06/2024 07:50, Marc-André Lureau wrote: > On Tue, Jun 4, 2024 at 1:22 AM Octavian Purdila <tavip@google.com> wrote: >> Add path option to the pty char backend which will create a symbolic >> link to the given path that points to the allocated PTY. >> >> This avoids having to make QMP or HMP monitor queries to find out what >> the new PTY device path is. >> >> Based on patch from Paulo Neves: >> >> https://patchew.org/QEMU/1548509635-15776-1-git-send-email-ptsneves@gmail.com/ >> >> Tested with the following invocations that the link is created and >> removed when qemu stops: >> >> qemu-system-x86_64 -nodefaults -mon chardev=compat_monitor \ >> -chardev pty,path=test,id=compat_monitor0 >> >> qemu-system-x86_64 -nodefaults -monitor pty:test >> >> Also tested that when a link path is not passed invocations still work, e.g.: >> >> qemu-system-x86_64 -monitor pty >> >> Co-authored-by: Paulo Neves <ptsneves@gmail.com> >> Signed-off-by: Paulo Neves <ptsneves@gmail.com> >> [OP: rebase and address original patch review comments] >> Signed-off-by: Octavian Purdila <tavip@google.com> >> --- >> Changes since v1: >> >> * Keep the original Signed-off-by from Paulo and add one line >> description with further changes >> >> * Update commit message with justification for why the new >> functionality is useful >> >> * Don't close master_fd when symlink creation fails to avoid double >> close >> >> * Update documentation for clarity >> >> chardev/char-pty.c | 33 +++++++++++++++++++++++++++++++++ >> chardev/char.c | 5 +++++ >> qapi/char.json | 4 ++-- >> qemu-options.hx | 24 ++++++++++++++++++------ >> 4 files changed, 58 insertions(+), 8 deletions(-) >> >> diff --git a/chardev/char-pty.c b/chardev/char-pty.c >> index cc2f7617fe..b5a4eb59fc 100644 >> --- a/chardev/char-pty.c >> +++ b/chardev/char-pty.c >> @@ -29,6 +29,7 @@ >> #include "qemu/sockets.h" >> #include "qemu/error-report.h" >> #include "qemu/module.h" >> +#include "qemu/option.h" >> #include "qemu/qemu-print.h" >> >> #include "chardev/char-io.h" >> @@ -41,6 +42,7 @@ struct PtyChardev { >> >> int connected; >> GSource *timer_src; >> + char *symlink_path; >> }; >> typedef struct PtyChardev PtyChardev; >> >> @@ -204,6 +206,12 @@ static void char_pty_finalize(Object *obj) >> Chardev *chr = CHARDEV(obj); >> PtyChardev *s = PTY_CHARDEV(obj); >> >> + /* unlink symlink */ >> + if (s->symlink_path) { >> + unlink(s->symlink_path); >> + g_free(s->symlink_path); >> + } >> + >> pty_chr_state(chr, 0); >> object_unref(OBJECT(s->ioc)); >> pty_chr_timer_cancel(s); >> @@ -330,6 +338,7 @@ static void char_pty_open(Chardev *chr, >> int master_fd, slave_fd; >> char pty_name[PATH_MAX]; >> char *name; >> + char *symlink_path = backend->u.pty.data->device; >> >> master_fd = qemu_openpty_raw(&slave_fd, pty_name); >> if (master_fd < 0) { >> @@ -354,12 +363,36 @@ static void char_pty_open(Chardev *chr, >> g_free(name); >> s->timer_src = NULL; >> *be_opened = false; >> + >> + /* create symbolic link */ >> + if (symlink_path) { >> + int res = symlink(pty_name, symlink_path); >> + >> + if (res != 0) { >> + error_setg_errno(errp, errno, "Failed to create PTY symlink"); >> + } else { >> + s->symlink_path = g_strdup(symlink_path); >> + } >> + } >> +} >> + >> +static void char_pty_parse(QemuOpts *opts, ChardevBackend *backend, >> + Error **errp) >> +{ >> + const char *path = qemu_opt_get(opts, "path"); >> + ChardevHostdev *dev; >> + >> + backend->type = CHARDEV_BACKEND_KIND_PTY; >> + dev = backend->u.pty.data = g_new0(ChardevHostdev, 1); >> + qemu_chr_parse_common(opts, qapi_ChardevHostdev_base(dev)); >> + dev->device = path ? g_strdup(path) : NULL; > minor nit, g_strdup(NULL) returns NULL. Get rid of "?:" if you send a v3. Indeed the original patch did not have the ternary. >> } >> >> static void char_pty_class_init(ObjectClass *oc, void *data) >> { >> ChardevClass *cc = CHARDEV_CLASS(oc); >> >> + cc->parse = char_pty_parse; >> cc->open = char_pty_open; >> cc->chr_write = char_pty_chr_write; >> cc->chr_update_read_handler = pty_chr_update_read_handler; >> diff --git a/chardev/char.c b/chardev/char.c >> index 3c43fb1278..404c6b8a4f 100644 >> --- a/chardev/char.c >> +++ b/chardev/char.c >> @@ -428,6 +428,11 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename, >> qemu_opt_set(opts, "path", p, &error_abort); >> return opts; >> } >> + if (strstart(filename, "pty:", &p)) { >> + qemu_opt_set(opts, "backend", "pty", &error_abort); >> + qemu_opt_set(opts, "path", p, &error_abort); >> + return opts; >> + } >> if (strstart(filename, "tcp:", &p) || >> strstart(filename, "telnet:", &p) || >> strstart(filename, "tn3270:", &p) || >> diff --git a/qapi/char.json b/qapi/char.json >> index 777dde55d9..4c74bfc437 100644 >> --- a/qapi/char.json >> +++ b/qapi/char.json >> @@ -509,7 +509,7 @@ >> ## >> # @ChardevHostdevWrapper: >> # >> -# @data: Configuration info for device and pipe chardevs >> +# @data: Configuration info for device, pty and pipe chardevs >> # >> # Since: 1.4 >> ## >> @@ -650,7 +650,7 @@ >> 'pipe': 'ChardevHostdevWrapper', >> 'socket': 'ChardevSocketWrapper', >> 'udp': 'ChardevUdpWrapper', >> - 'pty': 'ChardevCommonWrapper', >> + 'pty': 'ChardevHostdevWrapper', >> 'null': 'ChardevCommonWrapper', >> 'mux': 'ChardevMuxWrapper', >> 'msmouse': 'ChardevCommonWrapper', >> diff --git a/qemu-options.hx b/qemu-options.hx >> index 8ca7f34ef0..94ffb1a605 100644 >> --- a/qemu-options.hx >> +++ b/qemu-options.hx >> @@ -3569,7 +3569,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, >> "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" >> "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" >> #else >> - "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" >> + "-chardev pty,id=id[,path=path][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" >> "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" >> #endif >> #ifdef CONFIG_BRLAPI >> @@ -3808,12 +3808,18 @@ The available backends are: >> >> ``path`` specifies the name of the serial device to open. >> >> -``-chardev pty,id=id`` >> - Create a new pseudo-terminal on the host and connect to it. ``pty`` >> - does not take any options. >> +``-chardev pty,id=id[,path=path]`` >> + Create a new pseudo-terminal on the host and connect to it. >> >> ``pty`` is not available on Windows hosts. >> >> + If ``path`` is specified, QEMU will create a symbolic link at >> + that location which points to the new PTY device. >> + >> + This avoids having to make QMP or HMP monitor queries to find out >> + what the new PTY device path is. >> + >> + >> ``-chardev stdio,id=id[,signal=on|off]`` >> Connect to standard input and standard output of the QEMU process. >> >> @@ -4171,8 +4177,14 @@ SRST >> >> vc:80Cx24C >> >> - ``pty`` >> - [Linux only] Pseudo TTY (a new PTY is automatically allocated) >> + ``pty[:path]`` >> + [Linux only] Pseudo TTY (a new PTY is automatically allocated). >> + >> + If ``path`` is specified, QEMU will create a symbolic link at >> + that location which points to the new PTY device. >> + >> + This avoids having to make QMP or HMP monitor queries to find >> + out what the new PTY device path is. >> >> ``none`` >> No device is allocated. Note that for machine types which >> -- >> 2.45.1.288.g0e0cd299f1-goog >>
diff --git a/chardev/char-pty.c b/chardev/char-pty.c index cc2f7617fe..b5a4eb59fc 100644 --- a/chardev/char-pty.c +++ b/chardev/char-pty.c @@ -29,6 +29,7 @@ #include "qemu/sockets.h" #include "qemu/error-report.h" #include "qemu/module.h" +#include "qemu/option.h" #include "qemu/qemu-print.h" #include "chardev/char-io.h" @@ -41,6 +42,7 @@ struct PtyChardev { int connected; GSource *timer_src; + char *symlink_path; }; typedef struct PtyChardev PtyChardev; @@ -204,6 +206,12 @@ static void char_pty_finalize(Object *obj) Chardev *chr = CHARDEV(obj); PtyChardev *s = PTY_CHARDEV(obj); + /* unlink symlink */ + if (s->symlink_path) { + unlink(s->symlink_path); + g_free(s->symlink_path); + } + pty_chr_state(chr, 0); object_unref(OBJECT(s->ioc)); pty_chr_timer_cancel(s); @@ -330,6 +338,7 @@ static void char_pty_open(Chardev *chr, int master_fd, slave_fd; char pty_name[PATH_MAX]; char *name; + char *symlink_path = backend->u.pty.data->device; master_fd = qemu_openpty_raw(&slave_fd, pty_name); if (master_fd < 0) { @@ -354,12 +363,36 @@ static void char_pty_open(Chardev *chr, g_free(name); s->timer_src = NULL; *be_opened = false; + + /* create symbolic link */ + if (symlink_path) { + int res = symlink(pty_name, symlink_path); + + if (res != 0) { + error_setg_errno(errp, errno, "Failed to create PTY symlink"); + } else { + s->symlink_path = g_strdup(symlink_path); + } + } +} + +static void char_pty_parse(QemuOpts *opts, ChardevBackend *backend, + Error **errp) +{ + const char *path = qemu_opt_get(opts, "path"); + ChardevHostdev *dev; + + backend->type = CHARDEV_BACKEND_KIND_PTY; + dev = backend->u.pty.data = g_new0(ChardevHostdev, 1); + qemu_chr_parse_common(opts, qapi_ChardevHostdev_base(dev)); + dev->device = path ? g_strdup(path) : NULL; } static void char_pty_class_init(ObjectClass *oc, void *data) { ChardevClass *cc = CHARDEV_CLASS(oc); + cc->parse = char_pty_parse; cc->open = char_pty_open; cc->chr_write = char_pty_chr_write; cc->chr_update_read_handler = pty_chr_update_read_handler; diff --git a/chardev/char.c b/chardev/char.c index 3c43fb1278..404c6b8a4f 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -428,6 +428,11 @@ QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename, qemu_opt_set(opts, "path", p, &error_abort); return opts; } + if (strstart(filename, "pty:", &p)) { + qemu_opt_set(opts, "backend", "pty", &error_abort); + qemu_opt_set(opts, "path", p, &error_abort); + return opts; + } if (strstart(filename, "tcp:", &p) || strstart(filename, "telnet:", &p) || strstart(filename, "tn3270:", &p) || diff --git a/qapi/char.json b/qapi/char.json index 777dde55d9..4c74bfc437 100644 --- a/qapi/char.json +++ b/qapi/char.json @@ -509,7 +509,7 @@ ## # @ChardevHostdevWrapper: # -# @data: Configuration info for device and pipe chardevs +# @data: Configuration info for device, pty and pipe chardevs # # Since: 1.4 ## @@ -650,7 +650,7 @@ 'pipe': 'ChardevHostdevWrapper', 'socket': 'ChardevSocketWrapper', 'udp': 'ChardevUdpWrapper', - 'pty': 'ChardevCommonWrapper', + 'pty': 'ChardevHostdevWrapper', 'null': 'ChardevCommonWrapper', 'mux': 'ChardevMuxWrapper', 'msmouse': 'ChardevCommonWrapper', diff --git a/qemu-options.hx b/qemu-options.hx index 8ca7f34ef0..94ffb1a605 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3569,7 +3569,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" #else - "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" + "-chardev pty,id=id[,path=path][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" #endif #ifdef CONFIG_BRLAPI @@ -3808,12 +3808,18 @@ The available backends are: ``path`` specifies the name of the serial device to open. -``-chardev pty,id=id`` - Create a new pseudo-terminal on the host and connect to it. ``pty`` - does not take any options. +``-chardev pty,id=id[,path=path]`` + Create a new pseudo-terminal on the host and connect to it. ``pty`` is not available on Windows hosts. + If ``path`` is specified, QEMU will create a symbolic link at + that location which points to the new PTY device. + + This avoids having to make QMP or HMP monitor queries to find out + what the new PTY device path is. + + ``-chardev stdio,id=id[,signal=on|off]`` Connect to standard input and standard output of the QEMU process. @@ -4171,8 +4177,14 @@ SRST vc:80Cx24C - ``pty`` - [Linux only] Pseudo TTY (a new PTY is automatically allocated) + ``pty[:path]`` + [Linux only] Pseudo TTY (a new PTY is automatically allocated). + + If ``path`` is specified, QEMU will create a symbolic link at + that location which points to the new PTY device. + + This avoids having to make QMP or HMP monitor queries to find + out what the new PTY device path is. ``none`` No device is allocated. Note that for machine types which