Fix locking error in spawn implementation

McDutchie · McDutchie · commit 6d1352699e05 · 2021-01-27T05:32:24.000Z
This applies a patch from OpenSUSE. Source: https://build.opensuse.org/package/view_file/shells/ksh/ksh93-spawnlock.dif | Wed Oct 12 13:23:14 CEST 2016 - mls@suse.de | | - fix locking error in spawn implementation [bnc#988213] | new patch: ksh93-spawnlock.dif Unfortunately the bug report is not currently public: https://bugzilla.opensuse.org/show_bug.cgi?id=988213 but this one seems sensible enough and is in production use, so I'll take it on faith.
diff --git a/src/cmd/ksh93/sh/jobs.c b/src/cmd/ksh93/sh/jobs.c
@@ -1947,6 +1947,10 @@ void job_fork(pid_t parent)
 		job_lock();
 		jobfork++;
 		break;
+	case -2:
+		jobfork--;
+		job_unlock();
+		break;
 	case 0:
 		jobfork=0;
 		job_unlock();
diff --git a/src/cmd/ksh93/sh/xec.c b/src/cmd/ksh93/sh/xec.c
@@ -3631,6 +3631,7 @@ static pid_t sh_ntfork(Shell_t *shp,const Shnode_t *t,char *argv[],int *jobid,in
 #   endif /* !_lib_fork */
 	sh_pushcontext(shp,buffp,SH_JMPCMD);
 	errorpush(&buffp->err,ERROR_SILENT);
+	job_lock();		/* errormsg will unlock */
 	jmpval = sigsetjmp(buffp->buff,0);
 	if(jmpval == 0)
 	{
@@ -3732,14 +3733,15 @@ static pid_t sh_ntfork(Shell_t *shp,const Shnode_t *t,char *argv[],int *jobid,in
 		}
 	fail:
 		if(jobfork && spawnpid<0) 
-			job_fork(0);
+			job_fork(-2);
 		if(spawnpid < 0) switch(errno=shp->path_err)
 		{
 		    case ENOENT:
 			errormsg(SH_DICT,ERROR_system(ERROR_NOENT),e_found+4);
 		    default:
 			errormsg(SH_DICT,ERROR_system(ERROR_NOEXEC),e_exec+4);
 		}
+		job_unlock();
 	}
 	else
 		exitset();

Original file line number	Diff line number	Diff line change
`@@ -3631,6 +3631,7 @@ static pid_t sh_ntfork(Shell_t shp,const Shnode_t t,char argv[],int jobid,in`
`3631`	`3631`	`# endif /* !_lib_fork */`
`3632`	`3632`	`sh_pushcontext(shp,buffp,SH_JMPCMD);`
`3633`	`3633`	`errorpush(&buffp->err,ERROR_SILENT);`
	`3634`	`+ job_lock(); /* errormsg will unlock */`
`3634`	`3635`	`jmpval = sigsetjmp(buffp->buff,0);`
`3635`	`3636`	`if(jmpval == 0)`
`3636`	`3637`	`{`
`@@ -3732,14 +3733,15 @@ static pid_t sh_ntfork(Shell_t shp,const Shnode_t t,char argv[],int jobid,in`
`3732`	`3733`	`}`
`3733`	`3734`	`fail:`
`3734`	`3735`	`if(jobfork && spawnpid<0)`
`3735`		`- job_fork(0);`
	`3736`	`+ job_fork(-2);`
`3736`	`3737`	`if(spawnpid < 0) switch(errno=shp->path_err)`
`3737`	`3738`	`{`
`3738`	`3739`	`case ENOENT:`
`3739`	`3740`	`errormsg(SH_DICT,ERROR_system(ERROR_NOENT),e_found+4);`
`3740`	`3741`	`default:`
`3741`	`3742`	`errormsg(SH_DICT,ERROR_system(ERROR_NOEXEC),e_exec+4);`
`3742`	`3743`	`}`
	`3744`	`+ job_unlock();`
`3743`	`3745`	`}`
`3744`	`3746`	`else`
`3745`	`3747`	`exitset();`