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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 17:20:00 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 17:20:00 +0000 |
commit | 8daa83a594a2e98f39d764422bfbdbc62c9efd44 (patch) | |
tree | 4099e8021376c7d8c05bdf8503093d80e9c7bad0 /source3/smbd/oplock_linux.c | |
parent | Initial commit. (diff) | |
download | samba-8daa83a594a2e98f39d764422bfbdbc62c9efd44.tar.xz samba-8daa83a594a2e98f39d764422bfbdbc62c9efd44.zip |
Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'source3/smbd/oplock_linux.c')
-rw-r--r-- | source3/smbd/oplock_linux.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/source3/smbd/oplock_linux.c b/source3/smbd/oplock_linux.c new file mode 100644 index 0000000..3ed2001 --- /dev/null +++ b/source3/smbd/oplock_linux.c @@ -0,0 +1,243 @@ +/* + Unix SMB/CIFS implementation. + kernel oplock processing for Linux + Copyright (C) Andrew Tridgell 2000 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +*/ + +#define DBGC_CLASS DBGC_LOCKING +#include "includes.h" +#include "system/filesys.h" +#include "smbd/smbd.h" +#include "smbd/globals.h" + +#ifdef HAVE_KERNEL_OPLOCKS_LINUX + +#ifndef RT_SIGNAL_LEASE +#define RT_SIGNAL_LEASE (SIGRTMIN+1) +#endif + +/* + * Call to set the kernel lease signal handler + */ +int linux_set_lease_sighandler(int fd) +{ + if (fcntl(fd, F_SETSIG, RT_SIGNAL_LEASE) == -1) { + DBG_NOTICE("Failed to set signal handler for kernel lease\n"); + return -1; + } + + return 0; +} + +/**************************************************************************** + Call SETLEASE. If we get EACCES then we try setting up the right capability and + try again. + Use the SMB_VFS_LINUX_SETLEASE instead of this call directly. +****************************************************************************/ + +int linux_setlease(int fd, int leasetype) +{ + int ret; + int saved_errno = 0; + + /* + * Ensure the lease owner is root to allow + * correct delivery of lease-break signals. + */ + + become_root(); + + /* First set the signal handler. */ + if (linux_set_lease_sighandler(fd) == -1) { + saved_errno = errno; + ret = -1; + goto out; + } + ret = fcntl(fd, F_SETLEASE, leasetype); + if (ret == -1) { + saved_errno = errno; + } + + out: + + unbecome_root(); + + if (ret == -1) { + errno = saved_errno; + } + return ret; +} + +/**************************************************************************** + * Deal with the Linux kernel <--> smbd + * oplock break protocol. +****************************************************************************/ + +static void linux_oplock_signal_handler(struct tevent_context *ev_ctx, + struct tevent_signal *se, + int signum, int count, + void *_info, void *private_data) +{ + struct kernel_oplocks *ctx = + talloc_get_type_abort(private_data, + struct kernel_oplocks); + struct smbd_server_connection *sconn = + talloc_get_type_abort(ctx->private_data, + struct smbd_server_connection); + siginfo_t *info = (siginfo_t *)_info; + int fd = info->si_fd; + files_struct *fsp; + + fsp = file_find_fd(sconn, fd); + if (fsp == NULL) { + DBG_ERR("linux_oplock_signal_handler: failed to find fsp for file fd=%d (file was closed ?)\n", fd ); + return; + } + break_kernel_oplock(sconn->msg_ctx, fsp); +} + +/**************************************************************************** + Attempt to set an kernel oplock on a file. +****************************************************************************/ + +static bool linux_set_kernel_oplock(struct kernel_oplocks *ctx, + files_struct *fsp, int oplock_type) +{ + struct file_id_buf idbuf; + + if ( SMB_VFS_LINUX_SETLEASE(fsp, F_WRLCK) == -1) { + DBG_NOTICE("Refused oplock on file %s, " + "fd = %d, file_id = %s. (%s)\n", + fsp_str_dbg(fsp), + fsp_get_io_fd(fsp), + file_id_str_buf(fsp->file_id, &idbuf), + strerror(errno)); + return False; + } + + DBG_NOTICE("got kernel oplock on file %s, " + "file_id = %s gen_id = %"PRIu64"\n", + fsp_str_dbg(fsp), + file_id_str_buf(fsp->file_id, &idbuf), + fh_get_gen_id(fsp->fh)); + + return True; +} + +/**************************************************************************** + Release a kernel oplock on a file. +****************************************************************************/ + +static void linux_release_kernel_oplock(struct kernel_oplocks *ctx, + files_struct *fsp, int oplock_type) +{ + struct file_id_buf idbuf; + + if (DEBUGLVL(DBGLVL_DEBUG)) { + /* + * Check and print out the current kernel + * oplock state of this file. + */ + int state = fcntl(fsp_get_io_fd(fsp), F_GETLEASE, 0); + dbgtext("linux_release_kernel_oplock: file %s, file_id = %s " + "gen_id = %"PRIu64" has kernel oplock state " + "of %x.\n", + fsp_str_dbg(fsp), + file_id_str_buf(fsp->file_id, &idbuf), + fh_get_gen_id(fsp->fh), + state); + } + + /* + * Remove the kernel oplock on this file. + */ + if ( SMB_VFS_LINUX_SETLEASE(fsp, F_UNLCK) == -1) { + if (DEBUGLVL(DBGLVL_ERR)) { + dbgtext("linux_release_kernel_oplock: Error when " + "removing kernel oplock on file " ); + dbgtext("%s, file_id = %s, gen_id = %"PRIu64". " + "Error was %s\n", + fsp_str_dbg(fsp), + file_id_str_buf(fsp->file_id, &idbuf), + fh_get_gen_id(fsp->fh), + strerror(errno)); + } + } +} + +/**************************************************************************** + See if the kernel supports oplocks. +****************************************************************************/ + +static bool linux_oplocks_available(void) +{ + int fd, ret; + fd = open("/dev/null", O_RDONLY); + if (fd == -1) + return False; /* uggh! */ + ret = fcntl(fd, F_GETLEASE, 0); + close(fd); + return ret == F_UNLCK; +} + +/**************************************************************************** + Setup kernel oplocks. +****************************************************************************/ + +static const struct kernel_oplocks_ops linux_koplocks = { + .set_oplock = linux_set_kernel_oplock, + .release_oplock = linux_release_kernel_oplock, +}; + +struct kernel_oplocks *linux_init_kernel_oplocks(struct smbd_server_connection *sconn) +{ + struct kernel_oplocks *ctx; + struct tevent_signal *se; + + if (!linux_oplocks_available()) { + DBG_NOTICE("Linux kernel oplocks not available\n"); + return NULL; + } + + ctx = talloc_zero(sconn, struct kernel_oplocks); + if (!ctx) { + DBG_ERR("Linux Kernel oplocks talloc_Zero failed\n"); + return NULL; + } + + ctx->ops = &linux_koplocks; + ctx->private_data = sconn; + + se = tevent_add_signal(sconn->ev_ctx, + ctx, + RT_SIGNAL_LEASE, SA_SIGINFO, + linux_oplock_signal_handler, + ctx); + if (!se) { + DBG_ERR("Failed to setup RT_SIGNAL_LEASE handler\n"); + TALLOC_FREE(ctx); + return NULL; + } + + DBG_NOTICE("Linux kernel oplocks enabled\n"); + + return ctx; +} +#else + void oplock_linux_dummy(void); + + void oplock_linux_dummy(void) {} +#endif /* HAVE_KERNEL_OPLOCKS_LINUX */ |