Added os_file_modtime, and changed everything that looks at mtime to use it

rather than os_stat_file.

4 files changed, 29 insertions, 13 deletions

diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c
index 79a2cdb..fa36c6e 100644
--- a/arch/um/drivers/cow_user.c
+++ b/arch/um/drivers/cow_user.c
@@ -162,7 +162,7 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
 		     int sectorsize, int alignment, long long *size)
 {
         struct cow_header_v3 *header;
-	struct uml_stat buf;
+	unsigned long modtime;
 	int err;
 
 	err = cow_seek_file(fd, 0);
@@ -192,10 +192,10 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
 		      backing_file))
 		goto out_free;
 
-	err = os_stat_file(header->backing_file, &buf);
+	err = os_file_modtime(header->backing_file, &modtime);
 	if(err < 0){
-		cow_printf("Stat of backing file '%s' failed, err = %d\n",
-			   header->backing_file, -err);
+		cow_printf("Backing file '%s' mtime request failed, "
+			   "err = %d\n", header->backing_file, -err);
 		goto out_free;
 	}
 
@@ -206,7 +206,7 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
 		goto out_free;
 	}
 
-	header->mtime = htonl(buf.ust_mtime);
+	header->mtime = htonl(modtime);
 	header->size = htonll(*size);
 	header->sectorsize = htonl(sectorsize);
 	header->alignment = htonl(alignment);
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index f745d2c..2c549e7 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -56,14 +56,14 @@ static int same_backing_files(char *from_cmdline, char *from_cow, char *cow)
 
 static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
 {
-	struct uml_stat buf;
+	unsigned long modtime;
 	long long actual;
 	int err;
 
-  	err = os_stat_file(file, &buf);
+	err = os_file_modtime(file, &modtime);
   	if(err < 0){
-		printk("Failed to stat backing file \"%s\", err = %d\n",
-		       file, -err);
+		printk("Failed to get modification time of backing file "
+		       "\"%s\", err = %d\n", file, -err);
 		return(err);
 	}
 
@@ -79,9 +79,9 @@ static int backing_file_mismatch(char *file, __u64 size, time_t mtime)
 		       "file\n", size, actual);
 		return(-EINVAL);
 	}
-	if(buf.ust_mtime != mtime){
+	if(modtime != mtime){
 		printk("mtime mismatch (%ld vs %ld) of COW header vs backing "
-		       "file\n", mtime, buf.ust_mtime);
+		       "file\n", mtime, modtime);
 		return(-EINVAL);
 	}
 	return(0);
@@ -243,7 +243,7 @@ void do_io(struct io_thread_req *req)
 		/* Touch the page to force the host to do any necessary IO to 
 		 * get it into memory 
 		 */
-		n = *((int *) req->buffer);   
+		n = *((volatile int *) req->buffer);
 		req->error = update_bitmap(req);
 		return;
 	}
diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 65af4d9..5d5a5ad 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -137,6 +137,7 @@ extern int os_open_file(char *file, struct openflags flags, int mode);
 extern int os_read_file(int fd, void *buf, int len);
 extern int os_write_file(int fd, const void *buf, int count);
 extern int os_file_size(char *file, long long *size_out);
+extern int os_file_modtime(char *file, unsigned long *modtime);
 extern int os_pipe(int *fd, int stream, int close_on_exec);
 extern int os_set_fd_async(int fd, int owner);
 extern int os_set_fd_block(int fd, int blocking);
diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c
index e48b997..eabdf9a 100644
--- a/arch/um/os-Linux/file.c
+++ b/arch/um/os-Linux/file.c
@@ -293,7 +293,7 @@ int os_connect_socket(char *name)
 
 	err = connect(fd, (struct sockaddr *) &sock, sizeof(sock));
 	if(err)
-		return(err);
+		return(-errno);
 
 	return(fd);
 }
@@ -388,6 +388,21 @@ int os_file_size(char *file, long long *size_out)
 	return(0);
 }
 
+int os_file_modtime(char *file, unsigned long *modtime)
+{
+	struct uml_stat buf;
+	int err;
+
+	err = os_stat_file(file, &buf);
+	if(err < 0){
+		printk("Couldn't stat \"%s\" : err = %d\n", file, -err);
+		return(err);
+	}
+
+	*modtime = buf.ust_mtime;
+	return(0);
+}
+ 
 int os_get_exec_close(int fd, int* close_on_exec)
 {
 	int ret;