1 files changed, 124 insertions, 0 deletions
diff --git a/safetitle.c b/safetitle.c
new file mode 100644
index 0000000..ee37d3b
--- /dev/null
+++ b/safetitle.c
@@ -0,0 +1,124 @@
+/*
+ *  safetitle sets the title of the terminal window to the given string,
+ *  if and only if the terminal is recognized via its device attributes.
+ *
+ *  If multiple terminals are attached to the same GNU screen session,
+ *  the title is not set.  It is theoretically possible to check every
+ *  terminal too see if it is recognized and, if so, set the title --
+ *  but that would make the code more complex.
+ *
+ */
+
+#include <err.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/select.h>
+#include <termios.h>
+#include <unistd.h>
+
+#define XTERM_DA (char[]){27,91,62,52,49,59,51,51,48,59,48,99,0}
+#define SCREEN_DA (char[]){27,91,62,56,51,59,52,48,56,48,48,59,48,99,0}
+
+int
+da(int fd, char *buf, int real)
+{
+	char c;
+	fd_set fds;
+	int i, r, responses;
+	struct timeval timeout;
+
+	FD_ZERO(&fds);
+	FD_SET(fd, &fds);
+	timeout.tv_sec = 0;
+	timeout.tv_usec = 0;
+	responses = 0;
+
+	i = 0;
+	if(real) write(fd, "\033P\033[>c\033\\", 8);
+	else write(fd, "\033[>c", 4);
+
+read:
+	while(r = read(fd, &c, 1)){
+		if(!r){
+			fprintf(stderr, "bad terminal\n");
+			return -1;
+		}
+		buf[i++] = c;
+		if(c==99) break;
+	}
+	buf[i] = '\0';
+	responses++;
+
+	/* ensure there is only one real terminal */
+	if(real && select(fd+1, &fds, NULL, NULL, &timeout)>0)
+		goto read;
+	if(responses>1)
+		buf[0] = '\0';
+
+	return i;
+}
+
+int
+main(int argc, char *argv[])
+{
+	char *ap, *buf;
+	int debug, r, screen, ttyfd;
+	struct termios term, restore;
+
+	r = 1;
+
+        /* parse arguments */
+        debug = 0;
+        if(argc==2)
+                ap = argv[1];
+        else if(argc==3){
+                ap = argv[2];
+                if(strcmp(argv[1], "-d")==0) debug = 1;
+                else goto usage;
+        }
+        else goto usage;
+
+	if((ttyfd = open("/dev/tty", O_RDWR))==-1){
+		fprintf(stderr, "could not open /dev/tty\n");
+		goto end;
+	}
+	if((buf = malloc(200*sizeof(char)))==NULL){
+		fprintf(stderr, "could not allocate memory\n");
+		goto end;
+	}
+
+	/* enter "raw" terminal mode */
+	tcgetattr(ttyfd, &restore);
+	tcgetattr(ttyfd, &term);
+	term.c_lflag &= ~(ICANON|ECHO);
+	tcsetattr(ttyfd, TCSANOW, &term);
+
+	/* get device attributes for real terminal */
+	if(da(ttyfd, buf, 0)==-1) goto end;
+	if(strcmp(buf, SCREEN_DA)==0)
+		screen = 1;
+	else
+		screen = 0;
+	if(da(ttyfd, buf, screen)==-1) goto end;
+
+	/* set title */
+	if(strcmp(buf, XTERM_DA)==0){
+		if(screen) dprintf(ttyfd, "\033P\033]2;%s\007\033\\", ap);
+		else dprintf(ttyfd, "\033]2;%s\007", ap);
+	}
+	else{
+		if(debug) fprintf(stderr, "wrong type of terminal\n");
+		r = 2;
+		goto end;
+	}
+
+	r = 0;
+end:
+	tcsetattr(ttyfd, TCSANOW, &restore);
+	exit(r);
+usage:
+        fprintf(stderr, "usage: %s [-d] title\n", argv[0]);
+        exit(1);
+}