Hi Daniel, Sorry about the delay -- was out of town the past week.
On Fri, Mar 10, 2023, at 2:24 AM, Daniel P. Berrangé wrote: > 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 I think it would be better to leave this variable un-gated b/c gating it would make the later call to g_spawn_async_with_pipes() less clean. I don't think it'll trigger any unused variable warnings either since we are technically always using it. > >> 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. Ack, that looks cleaner. [...] Thanks, Daniel