spawn:pty

Author: lws-team

READMEs/README.coding.md

@@ -1335,3 +1335,24 @@ the user-selected text message and attempts to pull in `/error.css` for styling.
 If this file exists, it can be used to style the error page.  See
 https://libwebsockets.org/git/badrepo for an example of what can be done (
 and https://libwebsockets.org/error.css for the corresponding css).
+
+@section spawn Process Spawning and PTY routing
+
+libwebsockets provides a cross-platform API for spawning child processes and
+redirecting their standard streams (stdin, stdout, stderr) into the lws event loop
+as wsi handles: `lws_spawn_piped`.
+
+It is controlled by `struct lws_spawn_piped_info`. By default, the streams are
+redirected via standard anonymous pipes.
+
+However, if you wish to run a process that expects a terminal (for example, to
+preserve ANSI color codes or other TTY-specific behaviors), you can set
+`info.pty_mode = 1` before calling `lws_spawn_piped()`.
+
+ - On POSIX systems, `pty_mode` will allocate a pseudoterminal via `posix_openpt()`
+   and securely fuse both the child's stdout and stderr into the single PTY
+   master file descriptor.
+ - On Windows (Windows 10+), `pty_mode` will attempt to dynamically instantiate a
+   `CreatePseudoConsole` (ConPTY) handle and route the standard pipes through it. If 
+   the host system does not support ConPTY, it will gracefully fall back to pipes
+   or fail cleanly.

include/libwebsockets/lws-misc.h

@@ -1411,6 +1411,7 @@ struct lws_spawn_piped_info {
 	const struct lws_role_ops	*ops; /* NULL is raw file */
 
 	uint8_t				disable_ctrlc;
+	uint8_t				pty_mode;
 
 	const char			*cgroup_name_suffix;
 	int				*p_cgroup_ret;

lib/core-net/private-lib-core-net.h

@@ -1053,6 +1053,7 @@ struct lws_spawn_piped {
 	lws_sorted_usec_list_t		sul_poll;
 	FILETIME			ft_create;
 	FILETIME			ft_exit;
+	void				*hPC; /* Pseudoconsole */
 #else
 	pid_t				child_pid;
 

lib/plat/unix/unix-spawn.c

@@ -31,6 +31,9 @@
 #include <sys/types.h>
 #include <pwd.h>
 #include <grp.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <termios.h>
 
 #if defined(__linux__)
 #include <sys/stat.h>
@@ -452,9 +455,40 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 	/* create pipes for [stdin|stdout] and [stderr] */
 
 	for (n = 0; n < 3; n++) {
-		if (pipe(lsp->pipe_fds[n]) == -1)
-			goto bail1;
-		if (lws_plat_apply_FD_CLOEXEC(lsp->pipe_fds[n][n == 0]))
+		if (i->pty_mode && n != LWS_STDIN) {
+			if (n == LWS_STDOUT) {
+				int master = posix_openpt(O_RDWR | O_NOCTTY);
+				if (master >= 0) {
+					if (grantpt(master) == 0 && unlockpt(master) == 0) {
+						char *slavename = ptsname(master);
+						if (slavename) {
+							int slave = open(slavename, O_RDWR | O_NOCTTY);
+							if (slave >= 0) {
+								struct termios t;
+								tcgetattr(slave, &t);
+								cfmakeraw(&t);
+								tcsetattr(slave, TCSANOW, &t);
+								lsp->pipe_fds[n][0] = master;
+								lsp->pipe_fds[n][1] = slave;
+							}
+						}
+					}
+				}
+				if (lsp->pipe_fds[n][0] == -1) {
+					lwsl_err("%s: posix_openpt failed\n", __func__);
+					goto bail1;
+				}
+			} else {
+				/* STDERR: fuse into STDOUT's pty */
+				lsp->pipe_fds[n][0] = -1; /* parent has no separate reader */
+				lsp->pipe_fds[n][1] = lsp->pipe_fds[LWS_STDOUT][1]; /* child dup2s this */
+			}
+		} else {
+			if (pipe(lsp->pipe_fds[n]) == -1)
+				goto bail1;
+		}
+
+		if (lsp->pipe_fds[n][0] >= 0 && lws_plat_apply_FD_CLOEXEC(lsp->pipe_fds[n][n == 0]))
 			lwsl_info("%s: FD_CLOEXEC didn't stick\n", __func__);
 	}
 
@@ -466,6 +500,9 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 	/* create wsis for each stdin/out/err fd */
 
 	for (n = 0; n < 3; n++) {
+		if (lsp->pipe_fds[n][n == 0] == -1)
+			continue;
+
 		lsp->stdwsi[n] = lws_create_stdwsi(i->vh->context, i->tsi,
 					  i->ops ? i->ops : &role_ops_raw_file);
 		if (!lsp->stdwsi[n]) {
@@ -508,6 +545,9 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 	 */
 
 	for (n = 0; n < 3; n++) {
+		if (!lsp->stdwsi[n])
+			continue;
+
 		if (context->event_loop_ops->sock_accept)
 			if (context->event_loop_ops->sock_accept(lsp->stdwsi[n]))
 				goto bail3;
@@ -528,13 +568,13 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 		goto bail3;
 	if (lws_change_pollfd(lsp->stdwsi[LWS_STDOUT], LWS_POLLOUT, LWS_POLLIN))
 		goto bail3;
-	if (lws_change_pollfd(lsp->stdwsi[LWS_STDERR], LWS_POLLOUT, LWS_POLLIN))
+	if (lsp->stdwsi[LWS_STDERR] && lws_change_pollfd(lsp->stdwsi[LWS_STDERR], LWS_POLLOUT, LWS_POLLIN))
 		goto bail3;
 
 	lwsl_info("%s: fds in %d, out %d, err %d\n", __func__,
 		   lsp->stdwsi[LWS_STDIN]->desc.sockfd,
 		   lsp->stdwsi[LWS_STDOUT]->desc.sockfd,
-		   lsp->stdwsi[LWS_STDERR]->desc.sockfd);
+		   lsp->stdwsi[LWS_STDERR] ? lsp->stdwsi[LWS_STDERR]->desc.sockfd : -1);
 
 #if defined(__linux__)
 	if (i->cgroup_name_suffix && i->cgroup_name_suffix[0]) {
@@ -616,11 +656,17 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 		 * "other" side of the pipe fds, ie, rd for stdin and wr for
 		 * stdout / stderr.
 		 */
-		for (n = 0; n < 3; n++)
+		for (n = 0; n < 3; n++) {
 			/* these guys didn't have any wsi footprint */
-			close(lsp->pipe_fds[n][n != 0]);
+			if (lsp->pipe_fds[n][n != 0] >= 0) {
+				close(lsp->pipe_fds[n][n != 0]);
+				/* if fused, prevent double close */
+				if (i->pty_mode && n == LWS_STDOUT)
+					lsp->pipe_fds[LWS_STDERR][1] = -1;
+			}
+		}
 
-		lsp->pipes_alive = 3;
+		lsp->pipes_alive = i->pty_mode ? 2 : 3;
 		lsp->created = lws_now_usecs();
 
 		lwsl_info("%s: lsp %p spawned PID %d\n", __func__, lsp,
@@ -744,7 +790,8 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 bail3:
 
 	while (--n >= 0)
-		__remove_wsi_socket_from_fds(lsp->stdwsi[n]);
+		if (lsp->stdwsi[n])
+			__remove_wsi_socket_from_fds(lsp->stdwsi[n]);
 bail2:
 	for (n = 0; n < 3; n++)
 		if (lsp->stdwsi[n])

lib/plat/windows/windows-spawn.c

@@ -29,6 +29,21 @@
 #include <strsafe.h>
 #include <Psapi.h>
 
+#ifndef EXTENDED_STARTUPINFO_PRESENT
+#define EXTENDED_STARTUPINFO_PRESENT 0x00080000
+#endif
+
+#ifndef PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE
+#define PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE 0x00020016
+#endif
+
+typedef VOID* HPCON;
+typedef HRESULT (WINAPI *PFN_CREATE_PSEUDO_CONSOLE)(COORD, HANDLE, HANDLE, DWORD, HPCON*);
+typedef VOID (WINAPI *PFN_CLOSE_PSEUDO_CONSOLE)(HPCON);
+typedef BOOL (WINAPI *PFN_INITIALIZE_PROC_THREAD_ATTRIBUTE_LIST)(LPPROC_THREAD_ATTRIBUTE_LIST, DWORD, DWORD, PSIZE_T);
+typedef BOOL (WINAPI *PFN_UPDATE_PROC_THREAD_ATTRIBUTE)(LPPROC_THREAD_ATTRIBUTE_LIST, DWORD, DWORD_PTR, PVOID, SIZE_T, PVOID, PSIZE_T);
+typedef VOID (WINAPI *PFN_DELETE_PROC_THREAD_ATTRIBUTE_LIST)(LPPROC_THREAD_ATTRIBUTE_LIST);
+
 void
 lws_spawn_timeout(struct lws_sorted_usec_list *sul)
 {
@@ -123,6 +138,17 @@ lws_spawn_piped_destroy(struct lws_spawn_piped **_lsp)
 		lsp->hJob = NULL;
 	}
 
+	if (lsp->hPC) {
+		HMODULE hKernel32 = GetModuleHandleW(L"kernel32.dll");
+		PFN_CLOSE_PSEUDO_CONSOLE pClosePseudoConsole = NULL;
+		if (hKernel32) {
+			pClosePseudoConsole = (PFN_CLOSE_PSEUDO_CONSOLE)GetProcAddress(hKernel32, "ClosePseudoConsole");
+			if (pClosePseudoConsole)
+				pClosePseudoConsole(lsp->hPC);
+		}
+		lsp->hPC = NULL;
+	}
+
 	for (n = 0; n < 3; n++) {
 		if (lsp->pipe_fds[n][!!(n == 0)]) {
 			CloseHandle(lsp->pipe_fds[n][n == 0]);
@@ -421,23 +447,28 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 	sa.lpSecurityDescriptor = NULL;
 
 	for (n = 0; n < 3; n++) {
-		DWORD waitmode = PIPE_NOWAIT;
+		if (i->pty_mode && n == LWS_STDERR) {
+			/* fuse stderr to stdout for pty */
+			lsp->pipe_fds[n][0] = NULL;
+			lsp->pipe_fds[n][1] = lsp->pipe_fds[LWS_STDOUT][1];
+		} else {
+			DWORD waitmode = PIPE_NOWAIT;
 
-		if (!CreatePipe(&lsp->pipe_fds[n][0], &lsp->pipe_fds[n][1],
-				&sa, 0)) {
-			lwsl_err("%s: CreatePipe() failed\n", __func__);
-			goto bail1;
-		}
+			if (!CreatePipe(&lsp->pipe_fds[n][0], &lsp->pipe_fds[n][1],
+					&sa, 0)) {
+				lwsl_err("%s: CreatePipe() failed\n", __func__);
+				goto bail1;
+			}
 
-		SetNamedPipeHandleState(lsp->pipe_fds[1][0], &waitmode, NULL, NULL);
-		SetNamedPipeHandleState(lsp->pipe_fds[2][0], &waitmode, NULL, NULL);
+			if (n != LWS_STDIN)
+				SetNamedPipeHandleState(lsp->pipe_fds[n][0], &waitmode, NULL, NULL);
 
-		/* don't inherit the pipe side that belongs to the parent */
+			/* don't inherit the pipe side that belongs to the parent */
 
-		if (!SetHandleInformation(&lsp->pipe_fds[n][!n],
-					  HANDLE_FLAG_INHERIT, 0)) {
-			lwsl_info("%s: SetHandleInformation() failed\n", __func__);
-			//goto bail1;
+			if (!SetHandleInformation(&lsp->pipe_fds[n][!n],
+						  HANDLE_FLAG_INHERIT, 0)) {
+				// lwsl_info("%s: SetHandleInformation() failed\n", __func__);
+			}
 		}
 	}
 
@@ -459,12 +490,15 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 		lsp->stdwsi[n]->a.protocol = pcol;
 		lsp->stdwsi[n]->a.opaque_user_data = i->opaque;
 
+		if (!lsp->pipe_fds[n][!n])
+			continue;
+
 		lsp->stdwsi[n]->desc.filefd = lsp->pipe_fds[n][!n];
 		lsp->stdwsi[n]->file_desc = 1;
 
 		lws_dll2_remove(&lsp->stdwsi[n]->pre_natal);
 
-		lwsl_debug("%s: lsp stdwsi %p: pipe idx %d -> fd %d / %d\n",
+		lwsl_debug("%s: lsp stdwsi %p: pipe idx %d -> fd %p / %p\n",
 			   __func__, lsp->stdwsi[n], n,
 			   lsp->pipe_fds[n][!!(n == 0)],
 			   lsp->pipe_fds[n][!(n == 0)]);
@@ -524,22 +558,75 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 		*(--p) = '\0';
 	// puts(cli);
 
+	STARTUPINFOEXA siex;
+	STARTUPINFOA *psi;
+	HMODULE hKernel32;
+	PFN_CREATE_PSEUDO_CONSOLE pCreatePseudoConsole = NULL;
+	PFN_INITIALIZE_PROC_THREAD_ATTRIBUTE_LIST pInitializeProcThreadAttributeList = NULL;
+	PFN_UPDATE_PROC_THREAD_ATTRIBUTE pUpdateProcThreadAttribute = NULL;
+	PFN_DELETE_PROC_THREAD_ATTRIBUTE_LIST pDeleteProcThreadAttributeList = NULL;
+	SIZE_T attr_list_size = 0;
+	DWORD creation_flags = CREATE_SUSPENDED;
+	int pty_active = 0;
+
 	memset(&pi, 0, sizeof(pi));
 	memset(&si, 0, sizeof(si));
+	memset(&siex, 0, sizeof(siex));
+
+	if (i->pty_mode) {
+		hKernel32 = GetModuleHandleW(L"kernel32.dll");
+		if (hKernel32) {
+			pCreatePseudoConsole = (PFN_CREATE_PSEUDO_CONSOLE)GetProcAddress(hKernel32, "CreatePseudoConsole");
+			pInitializeProcThreadAttributeList = (PFN_INITIALIZE_PROC_THREAD_ATTRIBUTE_LIST)GetProcAddress(hKernel32, "InitializeProcThreadAttributeList");
+			pUpdateProcThreadAttribute = (PFN_UPDATE_PROC_THREAD_ATTRIBUTE)GetProcAddress(hKernel32, "UpdateProcThreadAttribute");
+			pDeleteProcThreadAttributeList = (PFN_DELETE_PROC_THREAD_ATTRIBUTE_LIST)GetProcAddress(hKernel32, "DeleteProcThreadAttributeList");
+		}
+
+		if (pCreatePseudoConsole && pInitializeProcThreadAttributeList && pUpdateProcThreadAttribute && pDeleteProcThreadAttributeList) {
+			COORD size;
+			size.X = 80;
+			size.Y = 24;
+
+			if (pCreatePseudoConsole(size, lsp->pipe_fds[LWS_STDIN][0], lsp->pipe_fds[LWS_STDOUT][1], 0, &lsp->hPC) == S_OK) {
+				pty_active = 1;
+				siex.StartupInfo.cb = sizeof(STARTUPINFOEXA);
+				pInitializeProcThreadAttributeList(NULL, 1, 0, &attr_list_size);
+				siex.lpAttributeList = (LPPROC_THREAD_ATTRIBUTE_LIST)lws_malloc(attr_list_size, "ptyattr");
+				pInitializeProcThreadAttributeList(siex.lpAttributeList, 1, 0, &attr_list_size);
+				pUpdateProcThreadAttribute(siex.lpAttributeList, 0, PROC_THREAD_ATTRIBUTE_PSEUDOCONSOLE, lsp->hPC, sizeof(HPCON), NULL, NULL);
+			}
+		}
+	}
+
+	if (pty_active) {
+		psi = (STARTUPINFOA *)&siex;
+		creation_flags |= EXTENDED_STARTUPINFO_PRESENT;
+	} else {
+		si.cb = sizeof(STARTUPINFOA);
+		psi = (STARTUPINFOA *)&si;
+	}
 
-	si.cb		= sizeof(STARTUPINFO);
-	si.hStdInput	= lsp->pipe_fds[LWS_STDIN][0];
-	si.hStdOutput	= lsp->pipe_fds[LWS_STDOUT][1];
-	si.hStdError	= lsp->pipe_fds[LWS_STDERR][1];
-	si.dwFlags	= STARTF_USESTDHANDLES | CREATE_NO_WINDOW;
-	si.wShowWindow	= TRUE;
+	psi->hStdInput	= lsp->pipe_fds[LWS_STDIN][0];
+	psi->hStdOutput	= lsp->pipe_fds[LWS_STDOUT][1];
+	psi->hStdError	= lsp->pipe_fds[LWS_STDERR][1];
+	psi->dwFlags	= STARTF_USESTDHANDLES | CREATE_NO_WINDOW;
+	psi->wShowWindow	= TRUE;
 
-	if (!CreateProcess(NULL, cli, NULL, NULL, TRUE, CREATE_SUSPENDED, NULL, NULL, &si, &pi)) {
-		lwsl_err("%s: CreateProcess failed 0x%x\n", __func__,
+	if (!CreateProcessA(NULL, cli, NULL, NULL, TRUE, creation_flags, NULL, NULL, psi, &pi)) {
+		lwsl_err("%s: CreateProcess failed 0x%lx\n", __func__,
 				(unsigned long)GetLastError());
+		if (pty_active && siex.lpAttributeList) {
+			pDeleteProcThreadAttributeList(siex.lpAttributeList);
+			lws_free(siex.lpAttributeList);
+		}
 		goto bail3;
 	}
 
+	if (pty_active && siex.lpAttributeList) {
+		pDeleteProcThreadAttributeList(siex.lpAttributeList);
+		lws_free(siex.lpAttributeList);
+	}
+
 	lsp->child_pid = pi.hProcess;
 	lsp->hJob = CreateJobObjectW(NULL, NULL);
 	if (lsp->hJob) {
@@ -563,10 +650,12 @@ lws_spawn_piped(const struct lws_spawn_piped_info *i)
 	/*
 	 *  close:                stdin:r, stdout:w, stderr:w
 	 */
-	for (n = 0; n < 3; n++)
-		CloseHandle(lsp->pipe_fds[n][n != 0]);
+	for (n = 0; n < 3; n++) {
+		if (lsp->pipe_fds[n][n != 0] && (!i->pty_mode || n != LWS_STDERR))
+			CloseHandle(lsp->pipe_fds[n][n != 0]);
+	}
 
-	lsp->pipes_alive = 3;
+	lsp->pipes_alive = i->pty_mode ? 2 : 3;
 	lsp->created = lws_now_usecs();
 
 	if (i->owner)

lib/roles/http/server/lejp-conf.c

@@ -1319,15 +1319,20 @@ lwsws_get_config_vhosts(struct lws_context *context,
 		memset(&i, 0, sizeof(i));
 		i.vhost_name = "root-monitor-dummy";
 		i.port = CONTEXT_PORT_NO_LISTEN;
-		i.options = info->options;
+		i.options = info->options | LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT;
 		i.protocols = info->protocols;
 		i.pprotocols = info->pprotocols;
 #if defined(LWS_ROLE_WS)
 		i.extensions = info->extensions;
 #endif
-		if (!lws_create_vhost(context, &i))
+		struct lws_vhost *vh = lws_create_vhost(context, &i);
+		if (!vh)
 			return 1;
 
+		extern int lws_context_init_ssl_library(struct lws_context *cx, const struct lws_context_creation_info *info);
+		lws_context_init_ssl_library(context, &i);
+		lws_init_vhost_client_ssl(&i, vh);
+
 		return 0;
 	}
 

lib/tls/openssl/openssl-client.c

@@ -278,9 +278,9 @@ lws_ssl_client_bio_create(struct lws *wsi)
 
 	wsi->tls.ssl = SSL_new(wsi->a.vhost->tls.ssl_client_ctx);
 	if (!wsi->tls.ssl) {
-		const char *es = ERR_error_string(
-			LWS_TLS_ERR_CAST(lws_ssl_get_error(wsi, 0)), NULL);
-		lwsl_err("SSL_new failed: %s\n", es);
+		unsigned long err = ERR_get_error();
+		const char *es = ERR_error_string(LWS_TLS_ERR_CAST(err), NULL);
+		lwsl_err("SSL_new failed: %s (real error %lu)\n", es, err);
 		lws_tls_err_describe_clear();
 		return -1;
 	}