On Thu, Apr 13, 2023 at 7:07 PM Peter Maydell <[email protected]> wrote:
> Our 'file' chardev backend supports both "output from this chardev > is written to a file" and "input from this chardev should be read > from a file" (except on Windows). However, you can only set up > the input file if you're using the QMP interface -- there is no > command line syntax to do it. > > Add command line syntax to allow specifying an input file > as well as an output file, using a new 'input-path' suboption. > > The specific use case I have is that I'd like to be able to > feed fuzzer reproducer input into qtest without having to use > '-qtest stdio' and put the input onto stdin. Being able to > use a file chardev like this: > -chardev file,id=repro,path=/dev/null,input-path=repro.txt -qtest > chardev:repro > means that stdio is free for use by gdb. > > Signed-off-by: Peter Maydell <[email protected]> > Reviewed-by: Marc-André Lureau <[email protected]> > --- > The "not on Windows" ifdeffery is because qmp_chardev_open_file() > does something similar; it seems likely to produce a nicer > error message to catch it at parse time rather than open time. > (I wonder if we could actually reduce the win32-specific code, I'll have a look eventually) --- > chardev/char-file.c | 8 ++++++++ > chardev/char.c | 3 +++ > qemu-options.hx | 10 ++++++++-- > 3 files changed, 19 insertions(+), 2 deletions(-) > > diff --git a/chardev/char-file.c b/chardev/char-file.c > index 3a7b9caf6f0..263e6da5636 100644 > --- a/chardev/char-file.c > +++ b/chardev/char-file.c > @@ -100,6 +100,7 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, > ChardevBackend *backend, > Error **errp) > { > const char *path = qemu_opt_get(opts, "path"); > + const char *inpath = qemu_opt_get(opts, "input-path"); > ChardevFile *file; > > backend->type = CHARDEV_BACKEND_KIND_FILE; > @@ -107,9 +108,16 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, > ChardevBackend *backend, > error_setg(errp, "chardev: file: no filename given"); > return; > } > +#ifdef _WIN32 > + if (inpath) { > + error_setg(errp, "chardev: file: input-path not supported on > Windows"); > + return; > + } > +#endif > file = backend->u.file.data = g_new0(ChardevFile, 1); > qemu_chr_parse_common(opts, qapi_ChardevFile_base(file)); > file->out = g_strdup(path); > + file->in = g_strdup(inpath); > > file->has_append = true; > file->append = qemu_opt_get_bool(opts, "append", false); > diff --git a/chardev/char.c b/chardev/char.c > index e69390601fc..661ad8176a9 100644 > --- a/chardev/char.c > +++ b/chardev/char.c > @@ -805,6 +805,9 @@ QemuOptsList qemu_chardev_opts = { > },{ > .name = "path", > .type = QEMU_OPT_STRING, > + },{ > + .name = "input-path", > + .type = QEMU_OPT_STRING, > },{ > .name = "host", > .type = QEMU_OPT_STRING, > diff --git a/qemu-options.hx b/qemu-options.hx > index 59bdf67a2c5..31d08c60264 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -3360,7 +3360,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, > "-chardev > vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" > " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > "-chardev > ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" > - "-chardev > file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > + "-chardev > file,id=id,path=path[,input-file=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > "-chardev > pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > #ifdef _WIN32 > "-chardev > console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" > @@ -3563,13 +3563,19 @@ The available backends are: > Create a ring buffer with fixed size ``size``. size must be a power > of two and defaults to ``64K``. > > -``-chardev file,id=id,path=path`` > +``-chardev file,id=id,path=path[,input-path=input-path]`` > Log all traffic received from the guest to a file. > > ``path`` specifies the path of the file to be opened. This file will > be created if it does not already exist, and overwritten if it does. > ``path`` is required. > > + If ``input-path`` is specified, this is the path of a second file > + which will be used for input. If ``input-path`` is not specified, > + no input will be available from the chardev. > + > + Note that ``input-path`` is not supported on Windows hosts. > + > ``-chardev pipe,id=id,path=path`` > Create a two-way connection to the guest. The behaviour differs > slightly between Windows hosts and other hosts: > -- > 2.34.1 > >
