[hackers] [st][PATCH] externalpipe and externalpipein

From: Christian Tenllado <ctenllado_AT_gmail.com>
Date: Sat, 18 Apr 2020 22:27:13 +0200

This patch must be applied on the externalpipe patch. It adds the
function externalpipein to redirect the standard output of the external
command to the slave size of the pty, that is, as if the external
program had been manually executed on the terminal. It can be used to
send desired escape sequences to the terminal with a shortcut.

I created the patch to make use of the dynamic-colors program
(https://github.com/sos4nt/dynamic-colors) that uses the OSC escape
sequences to change the colors of the terminal. The program keeps the
last colorscheme selected in a file, so you can use it to select the
colorscheme for all newly opened terminals from that moment on. If you
want to change the color of the background and foreground independently
from the palette, you have to merge in the patch for the OSC escape
sequences 10, 11, and 12.

This patch includes the changes of the externalpipe sigaction patch to
prevent reseting the signal handler for SIGCHLD when the proces of the
external command exits.

---
 st.c | 28 ++++++++++++++++++++++++----
 st.h |  1 +
 2 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/st.c b/st.c
index ab291ac..ac19ebf 100644
--- a/st.c
+++ b/st.c
_AT_@ -225,6 +225,7 @@ static CSIEscape csiescseq;
 static STREscape strescseq;
 static int iofd = 1;
 static int cmdfd;
+static int csdfd;
 static pid_t pid;
 
 static uchar utfbyte[UTF_SIZ + 1] = {0x80,    0, 0xC0, 0xE0, 0xF0};
_AT_@ -712,12 +713,14 @@ sigchld(int a)
 	int stat;
 	pid_t p;
 
-	if ((p = waitpid(pid, &stat, WNOHANG)) < 0)
+	if ((p = waitpid(-1, &stat, WNOHANG)) < 0)
 		die("waiting for pid %hd failed: %s\n", pid, strerror(errno));
 
 	if (pid != p)
 		return;
 
+	close(csdfd);
+
 	if (WIFEXITED(stat) && WEXITSTATUS(stat))
 		die("child exited with status %d\n", WEXITSTATUS(stat));
 	else if (WIFSIGNALED(stat))
_AT_@ -753,6 +756,7 @@ int
 ttynew(char *line, char *cmd, char *out, char **args)
 {
 	int m, s;
+	struct sigaction sa;
 
 	if (out) {
 		term.mode |= MODE_PRINT;
_AT_@ -802,9 +806,12 @@ ttynew(char *line, char *cmd, char *out, char **args)
 		if (pledge("stdio rpath tty proc", NULL) == -1)
 			die("pledge\n");
 #endif
-		close(s);
+		csdfd = s;
 		cmdfd = m;
-		signal(SIGCHLD, sigchld);
+		memset(&sa, 0, sizeof(sa));
+		sigemptyset(&sa.sa_mask);
+		sa.sa_handler = sigchld;
+		sigaction(SIGCHLD, &sa, NULL);
 		break;
 	}
 	return cmdfd;
_AT_@ -1920,7 +1927,7 @@ strparse(void)
 }
 
 void
-externalpipe(const Arg *arg)
+extpipe(const Arg *arg, int in)
 {
 	int to[2];
 	char buf[UTF_SIZ];
_AT_@ -1940,6 +1947,9 @@ externalpipe(const Arg *arg)
 		dup2(to[0], STDIN_FILENO);
 		close(to[0]);
 		close(to[1]);
+		if (in)
+			dup2(csdfd, STDOUT_FILENO);
+		close(csdfd);
 		execvp(((char **)arg->v)[0], (char **)arg->v);
 		fprintf(stderr, "st: execvp %s\n", ((char **)arg->v)[0]);
 		perror("failed");
_AT_@ -1972,6 +1982,16 @@ externalpipe(const Arg *arg)
 	signal(SIGPIPE, oldsigpipe);
 }
 
+void
+externalpipe(const Arg *arg) {
+	extpipe(arg, 0);
+}
+
+void
+externalpipein(const Arg *arg) {
+	extpipe(arg, 1);
+}
+
 void
 strdump(void)
 {
diff --git a/st.h b/st.h
index fe84fda..bbf38fa 100644
--- a/st.h
+++ b/st.h
_AT_@ -82,6 +82,7 @@ void redraw(void);
 void draw(void);
 
 void externalpipe(const Arg *);
+void externalpipein(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);
-- 
2.20.1

Received on Sat Apr 18 2020 - 22:27:13 CEST