ksh: Ctrl+C in an exec'd interactive shell is buggy in some contexts

This bug is a regression introduced in commit 41ebb55a. From my testing it can be reproduced on Linux but not FreeBSD or Solaris. When Ctrl+C is used in an interactive shell to send SIGINT, one of the following can happen:

An erroneous ‘Interrupt’ message is printed after stopping the read builtin in a script. Reproducer:

$ exec arch/*/bin/ksh
$ cat ./reproducer.sh 
#!/bin/sh
read foo

$ ./reproducer.sh 
^C$ <Enter>
[1] + Interrupt                ../reproducer.sh

Ctrl+C fails to stop /bin/package make. Reproducer:

$ exec arch/*/bin/ksh
$ mv arch arch.old
$ bin/package make
# Press Ctrl+C multiple times

About this issue

Original URL
State: closed
Created 3 years ago
Comments: 21

Most upvoted comments

After fixing my screw-up with the following patch, I can no longer reproduce the problem. @JohnoKing and @hyenias, can you confirm?

--- a/src/cmd/ksh93/sh/jobs.c
+++ b/src/cmd/ksh93/sh/jobs.c
@@ -552,8 +552,8 @@ void job_init(Shell_t *shp, int lflag)
                 job.mypgid = shp->gd->pid;
         }
 #ifdef SIGTSTP
-	possible = (setpgid(0,job.mypgid) >= 0);
-	if(sh_isoption(SH_INTERACTIVE) && (possible || errno==EPERM))
+	possible = (setpgid(0,job.mypgid) >= 0) || errno==EPERM;
+	if(sh_isoption(SH_INTERACTIVE) && possible)
 	{
 		/* wait until we are in the foreground */
 		while((job.mytgid=tcgetpgrp(JOBTTY)) != job.mypgid)

McDutchie on Mar 7, 2021

My process works fine, no need to change it on my account. I also like being able to read the diff in the discussion, even if my C is +20 years old and I don’t necessarily understand them. 😃

posguy99 on Mar 7, 2021

I like seeing the colored diffs within the comments. More often than not, I look at the contents on screen than attempt to apply them to my git repo. Now, that I have been trained how to snip the diff contents and create a remote file.patch; I am good-to-go. I like seeing all the colors when I view the .patch file in my text editor. I bet, in time, github.com will enhance the web interface to allow us to download the embedded source text as diff or a file.

hyenias on Mar 7, 2021

Confirmed. All works now.

hyenias on Mar 7, 2021

I can no longer reproduce the bug after applying that patch.

JohnoKing on Mar 7, 2021