This patch is only for shadow-native to fix the locking failure
issue when running groupadd/useradd in parallel:

groupadd: cannot lock /etc/group; try again later.
WARNING: groupadd command did not succeed. Retrying...
ERROR: tried running groupadd command 10 times without success, giving up

The tools useradd and groupadd in shadow-native use a trylock with
a default timeout of 15 seconds. Sometimes this fails. A change to
useradd.bbclass was made to retry the command 10 times. This still
fails some times. While we don't yet understand the root cause of
the extended delay, it is presumably due to pseudo's relatively
low IO performance. The locking for the native tools was changed
to block indefinitely rather than arbitrarily increasing the
retry count or extending the timeout.

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
---
 lib/groupio.c  |    8 ++++++++
 lib/pwio.c     |    8 ++++++++
 lib/sgroupio.c |    8 ++++++++
 lib/shadowio.c |    8 ++++++++
 src/groupadd.c |   12 ++++++------
 src/useradd.c  |   24 ++++++++++++------------
 6 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/lib/groupio.c b/lib/groupio.c
index 5aa5f74..2d21423 100644
--- a/lib/groupio.c
+++ b/lib/groupio.c
@@ -137,6 +137,14 @@ int gr_lock (void)
 	return commonio_lock (&group_db);
 }
 
+int gr_block (void)
+{
+	while(gr_lock() == 0) {
+		sleep(1);
+	}
+	return 1;
+}
+
 int gr_open (int mode)
 {
 	return commonio_open (&group_db, mode);
diff --git a/lib/pwio.c b/lib/pwio.c
index 112dc61..13eb80d 100644
--- a/lib/pwio.c
+++ b/lib/pwio.c
@@ -118,6 +118,14 @@ int pw_lock (void)
 	return commonio_lock (&passwd_db);
 }
 
+int pw_block (void)
+{
+	while(pw_lock() == 0) {
+		sleep(1);
+	}
+	return 1;
+}
+
 int pw_open (int mode)
 {
 	return commonio_open (&passwd_db, mode);
diff --git a/lib/sgroupio.c b/lib/sgroupio.c
index 64a9875..f65597f 100644
--- a/lib/sgroupio.c
+++ b/lib/sgroupio.c
@@ -218,6 +218,14 @@ int sgr_lock (void)
 	return commonio_lock (&gshadow_db);
 }
 
+int sgr_block (void)
+{
+	while(sgr_lock() == 0) {
+		sleep(1);
+	}
+	return 1;
+}
+
 int sgr_open (int mode)
 {
 	return commonio_open (&gshadow_db, mode);
diff --git a/lib/shadowio.c b/lib/shadowio.c
index d80f938..739cd24 100644
--- a/lib/shadowio.c
+++ b/lib/shadowio.c
@@ -123,6 +123,14 @@ int spw_lock (void)
 	return commonio_lock (&shadow_db);
 }
 
+int spw_block (void)
+{
+	while(spw_lock() == 0) {
+		sleep(1);
+	}
+	return 1;
+}
+
 int spw_open (int mode)
 {
 	return commonio_open (&shadow_db, mode);
diff --git a/src/groupadd.c b/src/groupadd.c
index 66b38de..67ce645 100644
--- a/src/groupadd.c
+++ b/src/groupadd.c
@@ -323,20 +323,20 @@ static void open_files (void)
 {
 	/* First, lock the databases */
 	if (gr_lock () == 0) {
-		fprintf (stderr,
-		         _("%s: cannot lock %s; try again later.\n"),
+		fprintf (stdout,
+		         _("%s: cannot lock %s; waiting.\n"),
 		         Prog, gr_dbname ());
-		exit (E_GRP_UPDATE);
+		gr_block();
 	}
 	add_cleanup (cleanup_unlock_group, NULL);
 
 #ifdef	SHADOWGRP
 	if (is_shadow_grp) {
 		if (sgr_lock () == 0) {
-			fprintf (stderr,
-			         _("%s: cannot lock %s; try again later.\n"),
+			fprintf (stdout,
+			         _("%s: cannot lock %s; waiting.\n"),
 			         Prog, sgr_dbname ());
-			exit (E_GRP_UPDATE);
+			sgr_block();
 		}
 		add_cleanup (cleanup_unlock_gshadow, NULL);
 	}
diff --git a/src/useradd.c b/src/useradd.c
index 2102630..6be3abf 100644
--- a/src/useradd.c
+++ b/src/useradd.c
@@ -1479,10 +1479,10 @@ static void close_files (void)
 static void open_files (void)
 {
 	if (pw_lock () == 0) {
-		fprintf (stderr,
-		         _("%s: cannot lock %s; try again later.\n"),
+		fprintf (stdout,
+		         _("%s: cannot lock %s; waiting.\n"),
 		         Prog, pw_dbname ());
-		exit (E_PW_UPDATE);
+		pw_block();
 	}
 	pw_locked = true;
 	if (pw_open (O_RDWR) == 0) {
@@ -1491,10 +1491,10 @@ static void open_files (void)
 	}
 	if (is_shadow_pwd) {
 		if (spw_lock () == 0) {
-			fprintf (stderr,
-			         _("%s: cannot lock %s; try again later.\n"),
+			fprintf (stdout,
+			         _("%s: cannot lock %s; waiting.\n"),
 			         Prog, spw_dbname ());
-			fail_exit (E_PW_UPDATE);
+			spw_block();
 		}
 		spw_locked = true;
 		if (spw_open (O_RDWR) == 0) {
@@ -1509,10 +1509,10 @@ static void open_files (void)
 	 * Lock and open the group file.
 	 */
 	if (gr_lock () == 0) {
-		fprintf (stderr,
-		         _("%s: cannot lock %s; try again later.\n"),
+		fprintf (stdout,
+		         _("%s: cannot lock %s; waiting.\n"),
 		         Prog, gr_dbname ());
-		fail_exit (E_GRP_UPDATE);
+		gr_block();
 	}
 	gr_locked = true;
 	if (gr_open (O_RDWR) == 0) {
@@ -1522,10 +1522,10 @@ static void open_files (void)
 #ifdef  SHADOWGRP
 	if (is_shadow_grp) {
 		if (sgr_lock () == 0) {
-			fprintf (stderr,
-			         _("%s: cannot lock %s; try again later.\n"),
+			fprintf (stdout,
+			         _("%s: cannot lock %s; waiting.\n"),
 			         Prog, sgr_dbname ());
-			fail_exit (E_GRP_UPDATE);
+			sgr_block();
 		}
 		sgr_locked = true;
 		if (sgr_open (O_RDWR) == 0) {
-- 
1.7.4