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-rw-r--r--safetitle.c124
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);
+}