char-file already supports distinct paths for input/output but it was
only possible to specify a distinct input through QMP. With this change,
we can also specify a distinct input with the -chardev file argument:
    qemu -chardev file,id=char1,path=/out/file,pathin=/in/file

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
---
 chardev/char-file.c | 5 +++++
 chardev/char.c      | 3 +++
 qemu-options.hx     | 7 +++++--
 3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/chardev/char-file.c b/chardev/char-file.c
index 2fd80707e5..031f2aa7d7 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 *pathin = qemu_opt_get(opts, "pathin");
     ChardevFile *file;
 
     backend->type = CHARDEV_BACKEND_KIND_FILE;
@@ -110,6 +111,10 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, ChardevBackend *backend,
     file = backend->u.file.data = g_new0(ChardevFile, 1);
     qemu_chr_parse_common(opts, qapi_ChardevFile_base(file));
     file->out = g_strdup(path);
+    if (pathin) {
+        file->has_in = true;
+        file->in = g_strdup(pathin);
+    }
 
     file->has_append = true;
     file->append = qemu_opt_get_bool(opts, "append", false);
diff --git a/chardev/char.c b/chardev/char.c
index e77564060d..97e03a8e48 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -849,6 +849,9 @@ QemuOptsList qemu_chardev_opts = {
         },{
             .name = "path",
             .type = QEMU_OPT_STRING,
+        },{
+            .name = "pathin",
+            .type = QEMU_OPT_STRING,
         },{
             .name = "host",
             .type = QEMU_OPT_STRING,
diff --git a/qemu-options.hx b/qemu-options.hx
index 292d4e7c0c..488961099b 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2938,7 +2938,7 @@ 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[,pathin=PATH][,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"
@@ -3137,13 +3137,16 @@ 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[,pathin=pathin]``
     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.
 
+    ``pathin`` specifies a separate file as the input to the chardev. If
+    ``pathin`` is omitted, ``path`` is used for both input and output
+
 ``-chardev pipe,id=id,path=path``
     Create a two-way connection to the guest. The behaviour differs
     slightly between Windows hosts and other hosts:
-- 
2.26.2

Alexander Bulekov <alxndr@bu.edu> writes:

> char-file already supports distinct paths for input/output but it was
> only possible to specify a distinct input through QMP. With this change,
> we can also specify a distinct input with the -chardev file argument:
>     qemu -chardev file,id=char1,path=/out/file,pathin=/in/file
>
> Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
> ---
>  chardev/char-file.c | 5 +++++
>  chardev/char.c      | 3 +++
>  qemu-options.hx     | 7 +++++--
>  3 files changed, 13 insertions(+), 2 deletions(-)
[...]
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 292d4e7c0c..488961099b 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2938,7 +2938,7 @@ 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[,pathin=PATH][,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"
> @@ -3137,13 +3137,16 @@ 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[,pathin=pathin]``
>      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.
>  
> +    ``pathin`` specifies a separate file as the input to the chardev. If
> +    ``pathin`` is omitted, ``path`` is used for both input and output
> +
>  ``-chardev pipe,id=id,path=path``
>      Create a two-way connection to the guest. The behaviour differs
>      slightly between Windows hosts and other hosts:

"pathin" is ugly.  What about "path-input"?

On 200515 0526, Markus Armbruster wrote:
> Alexander Bulekov <alxndr@bu.edu> writes:
> 
> >  ``-chardev pipe,id=id,path=path``
> >      Create a two-way connection to the guest. The behaviour differs
> >      slightly between Windows hosts and other hosts:
> 
> "pathin" is ugly.  What about "path-input"?

Sounds better - I'll send another version out.
-Alex