From: Karel Zak <kzak@redhat.com>
Date: Thu, 14 Feb 2013 15:29:51 +0000 (+0100)
Subject: lslocks: detect blocked locks, fix /proc/locks parser
X-Git-Tag: v2.23-rc1~213
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=55c0d16bab8cc84b72bf11cb2fdd8aa6205ac608;p=thirdparty%2Futil-linux.git

lslocks: detect blocked locks, fix /proc/locks parser

$ flock foo -c "sleep 100" & flock foo -c "sleep 100"

old version:
  $ lslocks
  lslocks: failed to parse pid: 'WRITE'

new version:

COMMAND           PID  TYPE  SIZE MODE   M      START        END PATH
[...]
flock            1318 FLOCK    0B WRITE* 0          0          0 /home/projects/
flock            1319 FLOCK    0B WRITE  0          0          0 /home/projects/

 The asterisk (e.g. WRITE*) is used for blocked processes.

Reported-by: Mantas Mikulenas <grawity@gmail.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/misc-utils/lslocks.8 b/misc-utils/lslocks.8
index 24cda144e4..518ff0fbaa 100644
--- a/misc-utils/lslocks.8
+++ b/misc-utils/lslocks.8
@@ -44,8 +44,8 @@ Type of lock, can be FLOCK (created with flock(2)) or POSIX (created with fcntl(
 Size of the locked file.
 
 .IP "MODE"
-Lock access permissions (read, write).
-
+Lock access permissions (read, write). If the process is blocked and waiting for the lock
+than the '*' (asterisk) postfix is used for the mode.
 .IP "M"
 Mandatory state of the lock: 0 if none; 1 if set.  (See chmod(1)).
 
diff --git a/misc-utils/lslocks.c b/misc-utils/lslocks.c
index e837b014e4..fb40dcb73d 100644
--- a/misc-utils/lslocks.c
+++ b/misc-utils/lslocks.c
@@ -93,7 +93,8 @@ struct lock {
 	char *mode;
 	off_t start;
 	off_t end;
-	int mandatory;
+	unsigned int mandatory :1,
+		     blocked   :1;
 	char *size;
 };
 
@@ -250,11 +251,15 @@ static int get_local_locks(struct list_head *locks)
 			case 0: /* ignore */
 				break;
 			case 1: /* posix, flock, etc */
-				l->type = xstrdup(tok);
+				if (strcmp(tok, "->") == 0) {	/* optional field */
+					l->blocked = 1;
+					i--;
+				} else
+					l->type = xstrdup(tok);
 				break;
 
 			case 2: /* is this a mandatory lock? other values are advisory or noinode */
-				l->mandatory = *tok == 'M' ? TRUE : FALSE;
+				l->mandatory = *tok == 'M' ? 1 : 0;
 				break;
 			case 3: /* lock mode */
 				l->mode = xstrdup(tok);
@@ -406,10 +411,10 @@ static void add_tt_line(struct tt *tt, struct lock *l)
 			xasprintf(&str, "%s", l->size);
 			break;
 		case COL_MODE:
-			xasprintf(&str, "%s", l->mode);
+			xasprintf(&str, "%s%s", l->mode, l->blocked ? "*" : "");
 			break;
 		case COL_M:
-			xasprintf(&str, "%d", l->mandatory);
+			xasprintf(&str, "%d", l->mandatory ? 1 : 0);
 			break;
 		case COL_START:
 			xasprintf(&str, "%jd", l->start);