They are wrappers of POSIX fcntl "file private locking".
Signed-off-by: Fam Zheng <[email protected]>
---
include/qemu/osdep.h | 2 ++
util/osdep.c | 29 +++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index 9e9fa61..f773f49 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -286,6 +286,8 @@ int qemu_close(int fd);
#ifndef _WIN32
int qemu_dup(int fd);
#endif
+int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive);
+int qemu_unlock_fd(int fd, int64_t start, int64_t len);
#if defined(__HAIKU__) && defined(__i386__)
#define FMT_pid "%ld"
diff --git a/util/osdep.c b/util/osdep.c
index 06fb1cf..b85a490 100644
--- a/util/osdep.c
+++ b/util/osdep.c
@@ -140,6 +140,35 @@ static int qemu_parse_fdset(const char *param)
{
return qemu_parse_fd(param);
}
+
+static int qemu_lock_fcntl(int fd, int64_t start, int64_t len, int fl_type)
+{
+#ifdef F_OFD_SETLK
+ int ret;
+ struct flock fl = {
+ .l_whence = SEEK_SET,
+ .l_start = start,
+ .l_len = len,
+ .l_type = fl_type,
+ };
+ do {
+ ret = fcntl(fd, F_OFD_SETLK, &fl);
+ } while (ret == -1 && errno == EINTR);
+ return ret == -1 ? -errno : 0;
+#else
+ return -ENOTSUP;
+#endif
+}
+
+int qemu_lock_fd(int fd, int64_t start, int64_t len, bool exclusive)
+{
+ return qemu_lock_fcntl(fd, start, len, exclusive ? F_WRLCK : F_RDLCK);
+}
+
+int qemu_unlock_fd(int fd, int64_t start, int64_t len)
+{
+ return qemu_lock_fcntl(fd, start, len, F_UNLCK);
+}
#endif
/*
--
2.7.4
