From 41abe2c0e76ede64a043f710f217caaca16763b6 Mon Sep 17 00:00:00 2001
From: Jeff Hatch <jhatch@multitech.com>
Date: Thu, 23 Jun 2016 12:31:51 -0500
Subject: Add retry code for getting the lock on the modem tty, tries every
 100ms for one second before giving up.

---
 src/utils.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/utils.c b/src/utils.c
index 8e7bed7..b93634c 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -246,6 +246,8 @@ char *shell_path_expand(const char *path)
 	return strdup(line);
 }
 
+#define MAX_TRY 10
+
 char *device_lock(const char *path)
 {
 	int tmp;
@@ -253,6 +255,7 @@ char *device_lock(const char *path)
 	int fd;
 	char str[32];
 	char *lock;
+	unsigned char num_try=0;
 
 	tmp = asprintf(&lock, "/var/lock/LCK..%s", name);
 	if (tmp < 0) {
@@ -260,12 +263,21 @@ char *device_lock(const char *path)
 		return NULL;
 	}
 
-	fd = open(lock, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
-	if (fd < 0) {
-		log_error("failed to create %s: %m", lock);
-		free(lock);
-		return NULL;
-	}
+	do{
+	  fd = open(lock, O_CREAT | O_WRONLY | O_TRUNC | O_EXCL, 0644);
+	  if (fd > 0) {
+	    break;
+	  }else{
+	    log_error("%i number of trying to create %s: %m",num_try+1,lock);
+	  };
+	  if(num_try++>=MAX_TRY){
+		  //something locks device too long
+		  log_error("failed to create %s: %m", lock);
+		  free(lock);
+		  return NULL;
+	  }
+	  usleep(100000ul);//100ms
+	}while(1);
 
 	snprintf(str, sizeof(str), "%10d\n", getpid());
 
-- 
cgit v1.2.3