1 files changed, 17 insertions, 4 deletions

diff --git a/arch/um/os-Linux/mem.c b/arch/um/os-Linux/mem.c
index c6432e729241..560c8063c77c 100644
--- a/arch/um/os-Linux/mem.c
+++ b/arch/um/os-Linux/mem.c
@@ -55,7 +55,7 @@ static void __init find_tempdir(void)
  */
 static int next(int fd, char *buf, int size, char c)
 {
-	int n;
+	int n, len;
 	char *ptr;
 
 	while((ptr = strchr(buf, c)) == NULL){
@@ -69,7 +69,17 @@ static int next(int fd, char *buf, int size, char c)
 	}
 
 	ptr++;
-	memmove(buf, ptr, strlen(ptr) + 1);
+	len = strlen(ptr);
+	memmove(buf, ptr, len + 1);
+
+	/* Refill the buffer so that if there's a partial string that we care
+	 * about, it will be completed, and we can recognize it.
+	 */
+	n = read(fd, &buf[len], size - len - 1);
+	if(n < 0)
+		return -errno;
+
+	buf[len + n] = '\0';
 	return 1;
 }
 
@@ -200,8 +210,11 @@ int create_tmp_file(unsigned long long len)
 		exit(1);
 	}
 
-        if (lseek64(fd, len, SEEK_SET) < 0) {
- 		perror("os_seek_file");
+	/* Seek to len - 1 because writing a character there will
+	 * increase the file size by one byte, to the desired length.
+	 */
+	if (lseek64(fd, len - 1, SEEK_SET) < 0) {
+		perror("os_seek_file");
 		exit(1);
 	}