Port subprocess API from uxn11.

src/devices/console.c

@@ -1,5 +1,22 @@
+#undef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200112L
+
+#include <signal.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/select.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#ifdef __linux
+#include <pty.h>
+#include <sys/prctl.h>
+#endif
+
+#ifdef __NetBSD__
+#include <sys/ioctl.h>
+#include <util.h>
+#endif
 
 #include "../uxn.h"
 #include "console.h"
@@ -15,6 +32,164 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 WITH REGARD TO THIS SOFTWARE.
 */
 
+/* subprocess support */
+static char *fork_args[4] = {"/bin/sh", "-c", "", NULL};
+static int child_mode;
+static int to_child_fd[2];
+static int from_child_fd[2];
+static int saved_in;
+static int saved_out;
+static pid_t child_pid;
+
+/* child_mode:
+ * 0x01: writes to child's stdin
+ * 0x02: reads from child's stdout
+ * 0x04: reads from child's stderr
+ * 0x08: kill previous process (if any) but do not start
+ * (other bits ignored for now )
+ */
+
+#define CMD_LIVE 0x15 /*  0x00 not started, 0x01 running, 0xff dead */
+#define CMD_EXIT 0x16 /*  if dead, exit code of process */
+#define CMD_ADDR 0x1c /*  address to read command args from */
+#define CMD_MODE 0x1e /*  mode to execute, 0x00 to 0x07 */
+#define CMD_EXEC 0x1f /*  write to execute programs, etc */
+
+/* call after we're sure the process has exited */
+static void
+clean_after_child(void)
+{
+	child_pid = 0;
+	if(child_mode & 0x01) {
+		close(to_child_fd[1]);
+		dup2(saved_out, 1);
+	}
+	if(child_mode & (0x04 | 0x02)) {
+		close(from_child_fd[0]);
+		dup2(saved_in, 0);
+	}
+	child_mode = 0;
+	saved_in = -1;
+	saved_out = -1;
+}
+
+static void
+start_fork_pipe(void)
+{
+	fflush(stdout);
+	pid_t pid;
+	pid_t parent_pid = getpid();
+	int addr = PEEK2(&uxn.dev[CMD_ADDR]);
+	if(child_mode & 0x08) {
+		uxn.dev[CMD_EXIT] = uxn.dev[CMD_LIVE] = 0x00;
+		return;
+	}
+	if(child_mode & 0x01) {
+		/* parent writes to child's stdin */
+		if(pipe(to_child_fd) == -1) {
+			uxn.dev[CMD_EXIT] = uxn.dev[CMD_LIVE] = 0xff;
+			fprintf(stderr, "pipe error: to child\n");
+			return;
+		}
+	}
+	if(child_mode & (0x04 | 0x02)) {
+		/* parent reads from child's stdout and/or stderr */
+		if(pipe(from_child_fd) == -1) {
+			uxn.dev[CMD_EXIT] = uxn.dev[CMD_LIVE] = 0xff;
+			fprintf(stderr, "pipe error: from child\n");
+			return;
+		}
+	}
+
+	fork_args[2] = (char *)&uxn.ram[addr];
+	pid = fork();
+	if(pid < 0) { /* failure */
+		uxn.dev[CMD_EXIT] = uxn.dev[CMD_LIVE] = 0xff;
+		fprintf(stderr, "fork failure\n");
+	} else if(pid == 0) { /* child */
+
+#ifdef __linux__
+		int r = prctl(PR_SET_PDEATHSIG, SIGTERM);
+		if (r == -1) { perror(0); exit(6); }
+		/*  test in case the original parent exited just */
+		/*  before the prctl() call */
+		if (getppid() != parent_pid) exit(13);
+#endif
+
+		if(child_mode & 0x01) {
+			dup2(to_child_fd[0], 0);
+			close(to_child_fd[1]);
+		}
+		if(child_mode & (0x04 | 0x02)) {
+			if(child_mode & 0x02) dup2(from_child_fd[1], 1);
+			if(child_mode & 0x04) dup2(from_child_fd[1], 2);
+			close(from_child_fd[0]);
+		}
+		fflush(stdout);
+		execvp(fork_args[0], fork_args);
+		exit(1);
+	} else { /*parent*/
+		child_pid = pid;
+		uxn.dev[CMD_LIVE] = 0x01;
+		uxn.dev[CMD_EXIT] = 0x00;
+		if(child_mode & 0x01) {
+			saved_out = dup(1);
+			dup2(to_child_fd[1], 1);
+			close(to_child_fd[0]);
+		}
+		if(child_mode & (0x04 | 0x02)) {
+			saved_in = dup(0);
+			dup2(from_child_fd[0], 0);
+			close(from_child_fd[1]);
+		}
+	}
+}
+
+static void
+check_child(void)
+{
+	int wstatus;
+	if(child_pid) {
+		if(waitpid(child_pid, &wstatus, WNOHANG)) {
+			uxn.dev[CMD_LIVE] = 0xff;
+			uxn.dev[CMD_EXIT] = WEXITSTATUS(wstatus);
+			clean_after_child();
+		} else {
+			uxn.dev[CMD_LIVE] = 0x01;
+			uxn.dev[CMD_EXIT] = 0x00;
+		}
+	}
+}
+
+static void
+kill_child(void)
+{
+	int wstatus;
+	if(child_pid) {
+		kill(child_pid, 9);
+		if(waitpid(child_pid, &wstatus, WNOHANG)) {
+			uxn.dev[CMD_LIVE] = 0xff;
+			uxn.dev[CMD_EXIT] = WEXITSTATUS(wstatus);
+			clean_after_child();
+		}
+	}
+}
+
+static void
+start_fork(void)
+{
+	fflush(stderr);
+	kill_child();
+	child_mode = uxn.dev[CMD_MODE];
+	start_fork_pipe();
+}
+
+void
+close_console(void)
+{
+	kill_child();
+}
+
 int
 console_input(Uint8 c, int type)
 {
@@ -33,6 +208,16 @@ console_listen(int i, int argc, char **argv)
 	}
 }
 
+Uint8
+console_dei(Uint8 addr)
+{
+	switch(addr) {
+	case CMD_LIVE:
+	case CMD_EXIT: check_child(); break;
+	}
+	return uxn.dev[addr];
+}
+
 void
 console_deo(Uint8 addr)
 {
@@ -40,5 +225,6 @@ console_deo(Uint8 addr)
 	switch(addr) {
 	case 0x18: fd = stdout, fputc(uxn.dev[0x18], fd), fflush(fd); break;
 	case 0x19: fd = stderr, fputc(uxn.dev[0x19], fd), fflush(fd); break;
+	case CMD_EXEC: start_fork(); break;
 	}
 }

src/devices/console.h

@@ -18,3 +18,4 @@ int console_input(Uint8 c, int type);
 void console_listen(int i, int argc, char **argv);
 Uint8 console_dei(Uint8 addr);
 void console_deo(Uint8 addr);
+void close_console(void);

src/uxncli.c

@@ -25,6 +25,7 @@ emu_dei(Uint8 addr)
 {
 	switch(addr & 0xf0) {
 	case 0x00: return system_dei(addr);
+	case 0x10: return console_dei(addr);
 	case 0xc0: return datetime_dei(addr);
 	}
 	return uxn.dev[addr];
@@ -58,6 +59,7 @@ emu_run(void)
 static int
 emu_end(void)
 {
+	close_console();
 	free(uxn.ram);
 	return uxn.dev[0x0f] & 0x7f;
 }

src/uxnemu.c

@@ -85,6 +85,7 @@ emu_dei(Uint8 addr)
 	Uint8 p = addr & 0x0f, d = addr & 0xf0;
 	switch(d) {
 	case 0x00: return system_dei(addr);
+	case 0x10: return console_dei(addr);
 	case 0x20: return screen_dei(addr);
 	case 0x30: return audio_dei(0, &uxn.dev[d], p);
 	case 0x40: return audio_dei(1, &uxn.dev[d], p);
@@ -257,6 +258,7 @@ emu_init(void)
 static void
 emu_restart(char *rom, int soft)
 {
+	close_console();
 	screen_change(0, 0, WIDTH,HEIGHT), screen_resize(WIDTH, HEIGHT, 1);
 	screen_fill(uxn_screen.bg, 0);
 	screen_fill(uxn_screen.fg, 0);
@@ -446,6 +448,7 @@ emu_run(char *rom)
 static int
 emu_end(void)
 {
+	close_console();
 	SDL_CloseAudioDevice(audio_id);
 #ifdef _WIN32
 #pragma GCC diagnostic ignored "-Wint-to-pointer-cast"