Handle SIGINT while processing commands.

With this the pgxc_ctl utility will come back to the command prompt if
interrupted in between. Unfortunately, this works only when pgxc_ctl forks a
new process to execute a command. At many places, it uses system() function to
execute a command. By specifications, when system() function is called, process
waits for the command to complete ignoring SIGINT and SIGQUIT. So we must find
some other way to handle those paths.

3 files changed, 35 insertions, 0 deletions

diff --git a/contrib/pgxc_ctl/do_command.c b/contrib/pgxc_ctl/do_command.c
index 3c6791ca7b..8a7cf0c4dc 100644
--- a/contrib/pgxc_ctl/do_command.c
+++ b/contrib/pgxc_ctl/do_command.c
@@ -2226,6 +2226,19 @@ void do_command(FILE *inf, FILE *outf)
 		read_history(histfile);
 	}
 
+	/*
+	 * Set the long jump path so that we can come out straight here in case of
+	 * an error. There is not much to reinitialize except may be freeing up the
+	 * wkline buffer and resetting the long jump buffer pointer. But if
+	 * anything else needs to reset, that should happen in the following block
+	 */
+	if (setjmp(dcJmpBufMainLoop) != 0)
+	{
+		whereToJumpMainLoop = NULL;
+		if (wkline)
+			freeAndReset(wkline);
+	}
+
 	for (;;)
 	{
 		if (wkline)
@@ -2251,7 +2264,11 @@ void do_command(FILE *inf, FILE *outf)
 		}
 		trimNl(buf);
 		writeLogOnly("PGXC %s\n", buf);
+
+		whereToJumpMainLoop = &dcJmpBufMainLoop;
 		rc = do_singleLine(buf, wkline);
+		whereToJumpMainLoop = NULL;
+
 		freeAndReset(wkline);
 		if (rc)	/* "q" command was found */
 		{
diff --git a/contrib/pgxc_ctl/do_shell.c b/contrib/pgxc_ctl/do_shell.c
index 65c6fa68f8..20c35ac96b 100644
--- a/contrib/pgxc_ctl/do_shell.c
+++ b/contrib/pgxc_ctl/do_shell.c
@@ -60,6 +60,8 @@ static void prepareStdout(cmdList_t *cmdList);
  */
 jmp_buf *whereToJumpDoShell = NULL;
 jmp_buf dcJmpBufDoShell;
+jmp_buf *whereToJumpMainLoop = NULL;
+jmp_buf dcJmpBufMainLoop;
 pqsigfunc old_HandlerDoShell = NULL;
 void do_shell_SigHandler(int signum);
 
@@ -443,6 +445,11 @@ int doCmdList(cmdList_t *cmds)
 			}
 		}
 		elog(NOTICE, "%s:%d Finish by interrupt\n", __FUNCTION__, __LINE__);
+		if (whereToJumpMainLoop)
+		{
+			elog(NOTICE, "Control reaches to the mainloop\n");
+			longjmp(*whereToJumpMainLoop, 1);
+		}
 		return 2;
 	}
 	/*
@@ -501,6 +508,12 @@ int doCmdList(cmdList_t *cmds)
 			freeAndReset(cmds->cmds[jj]->remoteStdout);
 		}
 		elog(NOTICE, "%s:%d Finish by interrupt\n", __FUNCTION__, __LINE__);
+
+		if (whereToJumpMainLoop)
+		{
+			elog(NOTICE, "Control reaches to the mainloop\n");
+			longjmp(*whereToJumpMainLoop, 1);
+		}
 		return(2);
 	}
 	signal(SIGINT, old_HandlerDoShell);
diff --git a/contrib/pgxc_ctl/do_shell.h b/contrib/pgxc_ctl/do_shell.h
index a84e8a74be..88d72d3060 100644
--- a/contrib/pgxc_ctl/do_shell.h
+++ b/contrib/pgxc_ctl/do_shell.h
@@ -11,6 +11,11 @@
 #ifndef DO_SHELL_H
 #define DO_SHELL_H
 
+#include <setjmp.h>
+
+extern jmp_buf *whereToJumpMainLoop;
+extern jmp_buf dcJmpBufMainLoop;
+
 extern void dcSigHandler(int signum);
 typedef enum FileType { STDIN, STDOUT, STDERR, GENERAL } FileType;
 typedef void (*pqsigfunc) (int);