externalpipe: Reading and writing st's screen through a pipe.

https://st.suckless.org/patches/externalpipe/

1 files changed, 61 insertions, 2 deletions

diff --git a/st.c b/st.c
index 50997ec..84e76ce 100644
--- a/st.c
+++ b/st.c
@@ -743,8 +743,14 @@ sigchld(int a)
 	if ((p = waitpid(pid, &stat, WNOHANG)) < 0)
 		die("waiting for pid %hd failed: %s\n", pid, strerror(errno));
 
-	if (pid != p)
+	if (pid != p) {
+		if (p == 0 && wait(&stat) < 0)
+			die("wait: %s\n", strerror(errno));
+
+		/* reinstall sigchld handler */
+		signal(SIGCHLD, sigchld);
 		return;
+	}
 
 	if (WIFEXITED(stat) && WEXITSTATUS(stat))
 		die("child exited with status %d\n", WEXITSTATUS(stat));
@@ -828,7 +834,7 @@ ttynew(const char *line, char *cmd, const char *out, char **args)
 		break;
 	default:
 #ifdef __OpenBSD__
-		if (pledge("stdio rpath tty proc", NULL) == -1)
+		if (pledge("stdio rpath tty proc exec", NULL) == -1)
 			die("pledge\n");
 #endif
 		close(s);
@@ -2174,6 +2180,59 @@ strparse(void)
 }
 
 void
+externalpipe(const Arg *arg)
+{
+	int to[2];
+	char buf[UTF_SIZ];
+	void (*oldsigpipe)(int);
+	Glyph *bp, *end;
+	int lastpos, n, newline;
+
+	if (pipe(to) == -1)
+		return;
+
+	switch (fork()) {
+	case -1:
+		close(to[0]);
+		close(to[1]);
+		return;
+	case 0:
+		dup2(to[0], STDIN_FILENO);
+		close(to[0]);
+		close(to[1]);
+		execvp(((char **)arg->v)[0], (char **)arg->v);
+		fprintf(stderr, "st: execvp %s\n", ((char **)arg->v)[0]);
+		perror("failed");
+		exit(0);
+	}
+
+	close(to[0]);
+	/* ignore sigpipe for now, in case child exists early */
+	oldsigpipe = signal(SIGPIPE, SIG_IGN);
+	newline = 0;
+	for (n = 0; n < term.row; n++) {
+		bp = TLINE(n);
+		lastpos = MIN(tlinelen(n) + 1, term.col) - 1;
+		if (lastpos < 0)
+			break;
+		end = &bp[lastpos + 1];
+		for (; bp < end; ++bp)
+			if (xwrite(to[1], buf, utf8encode(bp->u, buf)) < 0)
+				break;
+		if ((newline = TLINE(n)[lastpos].mode & ATTR_WRAP))
+			continue;
+		if (xwrite(to[1], "\n", 1) < 0)
+			break;
+		newline = 0;
+	}
+	if (newline)
+		(void)xwrite(to[1], "\n", 1);
+	close(to[1]);
+	/* restore */
+	signal(SIGPIPE, oldsigpipe);
+}
+
+void
 strdump(void)
 {
 	size_t i;