| Message ID | 20230528172013.73111-2-bugaevc@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | fcntl fortification | expand |
On 28/05/23 14:20, Sergey Bugaev via Libc-alpha wrote: > Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> LGTM, thanks. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> > --- > > support_xxx_support_yyy () seems to be the naming pattern for this > kind of functions? That's the pattern I use to follow. > > support/Makefile | 1 + > support/support.h | 3 ++ > support/support_fcntl_support_ofd_locks.c | 44 +++++++++++++++++++++++ > 3 files changed, 48 insertions(+) > create mode 100644 support/support_fcntl_support_ofd_locks.c > > diff --git a/support/Makefile b/support/Makefile > index 92f1a246..e9a00b2d 100644 > --- a/support/Makefile > +++ b/support/Makefile > @@ -58,6 +58,7 @@ libsupport-routines = \ > support_descriptors \ > support_enter_mount_namespace \ > support_enter_network_namespace \ > + support_fcntl_support_ofd_locks \ > support_format_address_family \ > support_format_addrinfo \ > support_format_dns_packet \ > diff --git a/support/support.h b/support/support.h > index b7f76bf0..e20d2ce7 100644 > --- a/support/support.h > +++ b/support/support.h > @@ -178,6 +178,9 @@ static __inline bool support_itimer_support_time64 (void) > #endif > } > > +/* Return true if the kernel/file supports open file description locks. */ > +extern bool support_fcntl_support_ofd_locks (int fd); > + > /* Return true if stat supports nanoseconds resolution. PATH is used > for tests and its ctime may change. */ > extern bool support_stat_nanoseconds (const char *path); > diff --git a/support/support_fcntl_support_ofd_locks.c b/support/support_fcntl_support_ofd_locks.c > new file mode 100644 > index 00000000..fb197a70 > --- /dev/null > +++ b/support/support_fcntl_support_ofd_locks.c > @@ -0,0 +1,44 @@ > +/* Return whether the kernel/file supports OFD locks. > + Copyright (C) 2023 Free Software Foundation, Inc. > + This file is part of the GNU C Library. > + > + The GNU C Library is free software; you can redistribute it and/or > + modify it under the terms of the GNU Lesser General Public > + License as published by the Free Software Foundation; either > + version 2.1 of the License, or (at your option) any later version. > + > + The GNU C Library is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + Lesser General Public License for more details. > + > + You should have received a copy of the GNU Lesser General Public > + License along with the GNU C Library; if not, see > + <https://www.gnu.org/licenses/>. */ > + > +#include <support/support.h> > +#include <errno.h> > +#include <fcntl.h> > +#include <string.h> > + > +bool > +support_fcntl_support_ofd_locks (int fd) > +{ > +#ifdef F_OFD_GETLK > + int res; > + struct flock flock; > + memset (&flock, 0, sizeof (flock)); > + > + flock.l_type = F_WRLCK; > + flock.l_whence = SEEK_SET; > + flock.l_start = 0; > + flock.l_len = INT32_MAX; > + flock.l_pid = 0; > + > + res = fcntl (fd, F_OFD_GETLK, &flock); > + return res != -1 || errno != EINVAL; I think returning an unexpected error here as supported should be ok here. > +#else > + (void) fd; > + return false; > +#endif > +}
diff --git a/support/Makefile b/support/Makefile index 92f1a246..e9a00b2d 100644 --- a/support/Makefile +++ b/support/Makefile @@ -58,6 +58,7 @@ libsupport-routines = \ support_descriptors \ support_enter_mount_namespace \ support_enter_network_namespace \ + support_fcntl_support_ofd_locks \ support_format_address_family \ support_format_addrinfo \ support_format_dns_packet \ diff --git a/support/support.h b/support/support.h index b7f76bf0..e20d2ce7 100644 --- a/support/support.h +++ b/support/support.h @@ -178,6 +178,9 @@ static __inline bool support_itimer_support_time64 (void) #endif } +/* Return true if the kernel/file supports open file description locks. */ +extern bool support_fcntl_support_ofd_locks (int fd); + /* Return true if stat supports nanoseconds resolution. PATH is used for tests and its ctime may change. */ extern bool support_stat_nanoseconds (const char *path); diff --git a/support/support_fcntl_support_ofd_locks.c b/support/support_fcntl_support_ofd_locks.c new file mode 100644 index 00000000..fb197a70 --- /dev/null +++ b/support/support_fcntl_support_ofd_locks.c @@ -0,0 +1,44 @@ +/* Return whether the kernel/file supports OFD locks. + Copyright (C) 2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <support/support.h> +#include <errno.h> +#include <fcntl.h> +#include <string.h> + +bool +support_fcntl_support_ofd_locks (int fd) +{ +#ifdef F_OFD_GETLK + int res; + struct flock flock; + memset (&flock, 0, sizeof (flock)); + + flock.l_type = F_WRLCK; + flock.l_whence = SEEK_SET; + flock.l_start = 0; + flock.l_len = INT32_MAX; + flock.l_pid = 0; + + res = fcntl (fd, F_OFD_GETLK, &flock); + return res != -1 || errno != EINVAL; +#else + (void) fd; + return false; +#endif +}
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com> --- support_xxx_support_yyy () seems to be the naming pattern for this kind of functions? support/Makefile | 1 + support/support.h | 3 ++ support/support_fcntl_support_ofd_locks.c | 44 +++++++++++++++++++++++ 3 files changed, 48 insertions(+) create mode 100644 support/support_fcntl_support_ofd_locks.c