On Thu, Mar 09, 2023 at 03:40:57PM -0700, Daniel Xu wrote:
> Currently, any captured output (via `capture-output`) is segregated into
> separate GuestExecStatus fields (`out-data` and `err-data`). This means
> that downstream consumers have no way to reassemble the captured data
> back into the original stream.
>
> This is relevant for chatty and semi-interactive (ie. read only) CLI
> tools. Such tools may deliberately interleave stdout and stderr for
> visual effect. If segregated, the output becomes harder to visually
> understand.
>
> This commit adds a new enum variant to the GuestExecCaptureOutputMode
> qapi to merge the output streams such that consumers can have a pristine
> view of the original command output.
>
> Signed-off-by: Daniel Xu <d...@dxuuu.xyz>
> ---
> qga/commands.c | 31 +++++++++++++++++++++++++++++--
> qga/qapi-schema.json | 4 +++-
> 2 files changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/qga/commands.c b/qga/commands.c
> index 01f68b45ab..c347d434ed 100644
> --- a/qga/commands.c
> +++ b/qga/commands.c
> @@ -270,12 +270,26 @@ static void guest_exec_child_watch(GPid pid, gint
> status, gpointer data)
> g_spawn_close_pid(pid);
> }
>
> -/** Reset ignored signals back to default. */
> static void guest_exec_task_setup(gpointer data)
> {
> #if !defined(G_OS_WIN32)
> + bool has_merge = *(bool *)data;
> struct sigaction sigact;
>
> + if (has_merge) {
> + /*
> + * FIXME: When `GLIB_VERSION_MIN_REQUIRED` is bumped to 2.58+, use
> + * g_spawn_async_with_fds() to be portable on windows. The current
> + * logic does not work on windows b/c `GSpawnChildSetupFunc` is run
> + * inside the parent, not the child.
> + */
> + if (dup2(STDOUT_FILENO, STDERR_FILENO) != 0) {
> + slog("dup2() failed to merge stderr into stdout: %s",
> + strerror(errno));
> + }
> + }
> +
> + /* Reset ignored signals back to default. */
> memset(&sigact, 0, sizeof(struct sigaction));
> sigact.sa_handler = SIG_DFL;
>
> @@ -409,6 +423,7 @@ GuestExec *qmp_guest_exec(const char *path,
> GIOChannel *in_ch, *out_ch, *err_ch;
> GSpawnFlags flags;
> bool has_output = false;
> + bool has_merge = false;
Wrap in #ifndef _WIN32
> GuestExecCaptureOutputMode output_mode;
> g_autofree uint8_t *input = NULL;
> size_t ninput = 0;
> @@ -445,13 +460,25 @@ GuestExec *qmp_guest_exec(const char *path,
> case GUEST_EXEC_CAPTURE_OUTPUT_MODE_SEPARATED:
> has_output = true;
> break;
> + case GUEST_EXEC_CAPTURE_OUTPUT_MODE_MERGED:
> + has_output = true;
> + has_merge = true;
> + break;
Wrap in #ifndef _WIN32
> case GUEST_EXEC_CAPTURE_OUTPUT_MODE__MAX:
> /* Silence warning; impossible branch */
> break;
> }
>
> +#if defined(G_OS_WIN32)
> + /* FIXME: see comment in guest_exec_task_setup() */
> + if (has_merge) {
> + error_setg(errp, "merged unsupported on windows");
> + return NULL;
> + }
> +#endif
THis can be dropped, since 'has_merge' won't exist for
Win32 builds.
> +
> ret = g_spawn_async_with_pipes(NULL, argv, envp, flags,
> - guest_exec_task_setup, NULL, &pid, input_data ? &in_fd : NULL,
> + guest_exec_task_setup, &has_merge, &pid, input_data ? &in_fd :
> NULL,
> has_output ? &out_fd : NULL, has_output ? &err_fd : NULL, &gerr);
> if (!ret) {
> error_setg(errp, QERR_QGA_COMMAND_FAILED, gerr->message);
> diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
> index d1e00a4234..b4782525ae 100644
> --- a/qga/qapi-schema.json
> +++ b/qga/qapi-schema.json
> @@ -1210,11 +1210,13 @@
> # @stderr: only capture stderr
> # @separated: capture both stdout and stderr, but separated into
> # GuestExecStatus out-data and err-data, respectively
> +# @merged: capture both stdout and stderr, but merge together
> +# into out-data. not effective on windows guests.
> #
> # Since: 8.0
> ##
> { 'enum': 'GuestExecCaptureOutputMode',
> - 'data': [ 'none', 'stdout', 'stderr', 'separated' ] }
> + 'data': [ 'none', 'stdout', 'stderr', 'separated', 'merged' ] }
Actually, I've just realized we can make this conditional:
'data': [ 'none', 'stdout', 'stderr', 'separated',
{ 'name': 'merged', 'if': 'CONFIG_WIN32' } ] }
so the constant doesn't even exist in Win32 builds.
With regards,
Daniel
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