From: Juergen Perlinger <perlinger@ntp.org>
Date: Sat, 28 Nov 2015 18:09:53 +0000 (+0100)
Subject: Bug 2971 - ntpq bails on ^C: select fails: Interrupted system call
X-Git-Tag: NTP_4_3_85~2^2^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0fd9376b197e1dd97b455804d37e5b345d096dab;p=thirdparty%2Fntp.git

Bug 2971 - ntpq bails on ^C: select fails: Interrupted system call
 - changed stacked/nested handling of CTRL-C.

bk: 5659edf14gdulYozwy2PmJ1TsnHQ_A
---

diff --git a/ChangeLog b/ChangeLog
index a787d4306..bd0e8233e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -22,6 +22,8 @@
 * [Bug 2965] Local clock didn't work since 4.2.8p4.  Martin Burnicki.
 * [Bug 2969]  Seg fault from ntpq/mrulist when looking at server with
               lots of clients. perlinger@ntp.org
+* [Bug 2971] ntpq bails on ^C: select fails: Interrupted system call
+  - changed stacked/nested handling of CTRL-C. perlinger@ntp.org
 * Unity cleanup for FreeBSD-6.4.  Harlan Stenn.
 * Unity test cleanup.  Harlan Stenn.
 * Libevent autoconf pthread fixes for FreeBSD-10.  Harlan Stenn.
diff --git a/ntpq/ntpq-subs.c b/ntpq/ntpq-subs.c
index b81dc379c..438c7ca58 100644
--- a/ntpq/ntpq-subs.c
+++ b/ntpq/ntpq-subs.c
@@ -343,7 +343,7 @@ typedef struct var_display_collection_tag {
 /*
  * other local function prototypes
  */
-void		mrulist_ctrl_c_hook(void);
+static int	mrulist_ctrl_c_hook(void);
 static mru *	add_mru(mru *);
 static int	collect_mru_list(const char *, l_fp *);
 static int	fetch_nonce(char *, size_t);
@@ -2422,10 +2422,11 @@ add_mru(
 	} while (0)
 
 
-void
+int
 mrulist_ctrl_c_hook(void)
 {
 	mrulist_interrupted = TRUE;
+	return TRUE;
 }
 
 
@@ -2496,11 +2497,6 @@ collect_mru_list(
 	mon = emalloc_zero(cb);
 	ZERO(*pnow);
 	ZERO(last_older);
-	mrulist_interrupted = FALSE;
-	set_ctrl_c_hook(&mrulist_ctrl_c_hook);
-	fprintf(stderr,
-		"Ctrl-C will stop MRU retrieval and display partial results.\n");
-	fflush(stderr);
 	next_report = time(NULL) + MRU_REPORT_SECS;
 
 	limit = min(3 * MAXFRAGS, ntpd_row_limit);
@@ -2872,7 +2868,6 @@ collect_mru_list(
 		}
 	}
 
-	set_ctrl_c_hook(NULL);
 	c_mru_l_rc = TRUE;
 	goto retain_hash_table;
 
@@ -3082,6 +3077,12 @@ mrulist(
 	int lstint;
 	size_t i;
 
+	mrulist_interrupted = FALSE;
+	push_ctrl_c_handler(&mrulist_ctrl_c_hook);
+	fprintf(stderr,
+		"Ctrl-C will stop MRU retrieval and display partial results.\n");
+	fflush(stderr);
+
 	order = MRUSORT_DEF;
 	parms_buf[0] = '\0';
 	parms = parms_buf;
@@ -3222,6 +3223,8 @@ cleanup_return:
 	free(hash_table);
 	hash_table = NULL;
 	INIT_DLIST(mru_list, mlink);
+
+	pop_ctrl_c_handler(&mrulist_ctrl_c_hook);
 }
 
 
diff --git a/ntpq/ntpq.c b/ntpq/ntpq.c
index fe3fbac8b..5b3c9cb80 100644
--- a/ntpq/ntpq.c
+++ b/ntpq/ntpq.c
@@ -175,7 +175,7 @@ static	char *	tstflags	(u_long);
 #ifndef BUILD_AS_LIB
 static	void	getcmds		(void);
 #ifndef SYS_WINNT
-static	RETSIGTYPE abortcmd	(int);
+static	int	abortcmd	(void);
 #endif	/* SYS_WINNT */
 static	void	docmd		(const char *);
 static	void	tokenize	(const char *, char **, int *);
@@ -216,6 +216,7 @@ static	void	output		(FILE *, const char *, const char *);
 static	void	endoutput	(FILE *);
 static	void	outputarr	(FILE *, char *, int, l_fp *);
 static	int	assoccmp	(const void *, const void *);
+static	void	on_ctrlc	(void);
 	u_short	varfmt		(const char *);
 
 void	ntpq_custom_opt_handler	(tOptions *, tOptDesc *);
@@ -559,9 +560,10 @@ ntpqmain(
 		interactive = 1;
 	}
 
+	set_ctrl_c_hook(on_ctrlc);
 #ifndef SYS_WINNT /* Under NT cannot handle SIGINT, WIN32 spawns a handler */
 	if (interactive)
-	    (void) signal_no_reset(SIGINT, abortcmd);
+		push_ctrl_c_handler(abortcmd);
 #endif /* SYS_WINNT */
 
 	if (numcmds == 0) {
@@ -1460,16 +1462,18 @@ getcmds(void)
 /*
  * abortcmd - catch interrupts and abort the current command
  */
-static RETSIGTYPE
-abortcmd(
-	int sig
-	)
+static int
+abortcmd(void)
 {
 	if (current_output == stdout)
-	    (void) fflush(stdout);
+		(void) fflush(stdout);
 	putc('\n', stderr);
 	(void) fflush(stderr);
-	if (jump) longjmp(interrupt_buf, 1);
+	if (jump) {
+		jump = 0;
+		longjmp(interrupt_buf, 1);
+	}
+	return TRUE;
 }
 #endif	/* !SYS_WINNT && !BUILD_AS_LIB */
 
@@ -3566,3 +3570,48 @@ static char *list_digest_names(void)
 
     return list;
 }
+
+#define CTRLC_STACK_MAX 4
+static volatile size_t		ctrlc_stack_len = 0;
+static volatile Ctrl_C_Handler	ctrlc_stack[CTRLC_STACK_MAX];
+
+
+
+int/*BOOL*/
+push_ctrl_c_handler(
+	Ctrl_C_Handler func
+	)
+{
+	size_t size = ctrlc_stack_len;
+	if (func && (size < CTRLC_STACK_MAX)) {
+		ctrlc_stack[size] = func;
+		ctrlc_stack_len = size + 1;
+		return TRUE;
+	}
+	return FALSE;	
+}
+
+int/*BOOL*/
+pop_ctrl_c_handler(
+	Ctrl_C_Handler func
+	)
+{
+	size_t size = ctrlc_stack_len;
+	if (size) {
+		--size;
+		if (func == NULL || func == ctrlc_stack[size]) {
+			ctrlc_stack_len = size;
+			return TRUE;
+		}
+	}
+	return FALSE;
+}
+
+static void
+on_ctrlc(void)
+{
+	size_t size = ctrlc_stack_len;
+	while (size)
+		if ((*ctrlc_stack[--size])())
+			break;
+}
diff --git a/ntpq/ntpq.h b/ntpq/ntpq.h
index 171b80768..55ea0fb5c 100644
--- a/ntpq/ntpq.h
+++ b/ntpq/ntpq.h
@@ -152,3 +152,7 @@ extern	int	decodeint	(char *, long *);
 extern	void	makeascii	(size_t, const char *, FILE *);
 extern	const char * trunc_left	(const char *, size_t);
 extern	const char * trunc_right(const char *, size_t);
+
+typedef	int/*BOOL*/ (*Ctrl_C_Handler)(void);
+extern	int/*BOOL*/ 	push_ctrl_c_handler(Ctrl_C_Handler);
+extern	int/*BOOL*/ 	pop_ctrl_c_handler(Ctrl_C_Handler);