Add path option to the pty char backend which will create a symbolic link to the given path that points to the allocated PTY.
Based on patch from Paulo Neves: https://patchew.org/QEMU/1548509635-15776-1-git-send-email-ptsne...@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 <ptsne...@gmail.com> Signed-off-by: Octavian Purdila <ta...@google.com> --- chardev/char-pty.c | 34 ++++++++++++++++++++++++++++++++++ chardev/char.c | 5 +++++ qapi/char.json | 4 ++-- qemu-options.hx | 14 ++++++++++---- 4 files changed, 51 insertions(+), 6 deletions(-) diff --git a/chardev/char-pty.c b/chardev/char-pty.c index cc2f7617fe..7cd5d34851 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 +363,37 @@ 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"); + close(master_fd); + } 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..5eec194242 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 +3808,16 @@ The available backends are: ``path`` specifies the name of the serial device to open. -``-chardev pty,id=id`` +``-chardev pty,id=id[,path=path]`` Create a new pseudo-terminal on the host and connect to it. ``pty`` does not take any options. ``pty`` is not available on Windows hosts. + ``path`` specifies the symbolic link path to be created that + points to the pty device. + + ``-chardev stdio,id=id[,signal=on|off]`` Connect to standard input and standard output of the QEMU process. @@ -4171,8 +4175,10 @@ 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). + Optionally a path can be given to create a symbolic link to + the allocated PTY. ``none`` No device is allocated. Note that for machine types which -- 2.45.1.288.g0e0cd299f1-goog
