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 <peter.maydell@linaro.org>
---
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 = "" 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