| Message ID | 1475237406-26917-5-git-send-email-famz@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 30.09.2016 14:09, Fam Zheng wrote: > They are wrappers of POSIX fcntl "file private locking". > > Signed-off-by: Fam Zheng <famz@redhat.com> > --- > 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); Can EINTR happen? My fcntl() man page claims it's only possible with F(_OFD)_SETLKW. Max > + 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 > > /* >
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 /*
They are wrappers of POSIX fcntl "file private locking". Signed-off-by: Fam Zheng <famz@redhat.com> --- include/qemu/osdep.h | 2 ++ util/osdep.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 31 insertions(+)