VERSION: Raise version number up to 3.4.6.

[Samba/gbeck.git] / source3 / modules / onefs_system.c

/*
 * Unix SMB/CIFS implementation.
 * Support for OneFS system interfaces.
 *
 * Copyright (C) Tim Prouty, 2008
 *
 * 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/>.
 */

#include "includes.h"
#include "onefs.h"
#include "onefs_config.h"
#include "oplock_onefs.h"

#include <ifs/ifs_syscalls.h>
#include <isi_acl/isi_acl_util.h>
#include <sys/isi_acl.h>

/*
 * Initialize the sm_lock struct before passing it to ifs_createfile.
 */
static void smlock_init(connection_struct *conn, struct sm_lock *sml,
    bool isexe, uint32_t access_mask, uint32_t share_access,
    uint32_t create_options)
{
        sml->sm_type.doc = false;
        sml->sm_type.isexe = isexe;
        sml->sm_type.statonly = is_stat_open(access_mask);
        sml->sm_type.access_mask = access_mask;
        sml->sm_type.share_access = share_access;

        /*
         * private_options was previously used for DENY_DOS/DENY_FCB checks in
         * the kernel, but are now properly handled by fcb_or_dos_open. In
         * these cases, ifs_createfile will return a sharing violation, which
         * gives fcb_or_dos_open the chance to open a duplicate file handle.
         */
        sml->sm_type.private_options = 0;

        /* 1 second delay is handled in onefs_open.c by deferring the open */
        sml->sm_timeout = timeval_set(0, 0);
}

static void smlock_dump(int debuglevel, const struct sm_lock *sml)
{
        if (sml == NULL) {
                DEBUG(debuglevel, ("sml == NULL\n"));
                return;
        }

        DEBUG(debuglevel,
              ("smlock: doc=%s, isexec=%s, statonly=%s, access_mask=0x%x, "
               "share_access=0x%x, private_options=0x%x timeout=%d/%d\n",
               sml->sm_type.doc ? "True" : "False",
               sml->sm_type.isexe ? "True" : "False",
               sml->sm_type.statonly ? "True" : "False",
               sml->sm_type.access_mask,
               sml->sm_type.share_access,
               sml->sm_type.private_options,
               (int)sml->sm_timeout.tv_sec,
               (int)sml->sm_timeout.tv_usec));
}

/**
 * External interface to ifs_createfile
 */
int onefs_sys_create_file(connection_struct *conn,
                          int base_fd,
                          const char *path,
                          uint32_t access_mask,
                          uint32_t open_access_mask,
                          uint32_t share_access,
                          uint32_t create_options,
                          int flags,
                          mode_t mode,
                          int oplock_request,
                          uint64_t id,
                          struct security_descriptor *sd,
                          uint32_t dos_flags,
                          int *granted_oplock)
{
        struct sm_lock sml, *psml = NULL;
        enum oplock_type onefs_oplock;
        enum oplock_type onefs_granted_oplock = OPLOCK_NONE;
        struct ifs_security_descriptor ifs_sd = {}, *pifs_sd = NULL;
        uint32_t sec_info_effective = 0;
        int ret_fd = -1;
        uint32_t onefs_dos_attributes;
        struct ifs_createfile_flags cf_flags = CF_FLAGS_NONE;

        START_PROFILE(syscall_createfile);

        /* Setup security descriptor and get secinfo. */
        if (sd != NULL) {
                NTSTATUS status;
                uint32_t sec_info_sent = 0;

                sec_info_sent = (get_sec_info(sd) & IFS_SEC_INFO_KNOWN_MASK);

                status = onefs_samba_sd_to_sd(sec_info_sent, sd, &ifs_sd,
                                              SNUM(conn), &sec_info_effective);

                if (!NT_STATUS_IS_OK(status)) {
                        DEBUG(1, ("SD initialization failure: %s\n",
                                  nt_errstr(status)));
                        errno = EINVAL;
                        goto out;
                }

                pifs_sd = &ifs_sd;
        }

        /* Stripping off private bits will be done for us. */
        onefs_oplock = onefs_samba_oplock_to_oplock(oplock_request);

        if (!lp_oplocks(SNUM(conn))) {
                SMB_ASSERT(onefs_oplock == OPLOCK_NONE);
        }

        /* Convert samba dos flags to UF_DOS_* attributes. */
        onefs_dos_attributes = dos_attributes_to_stat_dos_flags(dos_flags);

        /**
         * Deal with kernel creating Default ACLs. (Isilon bug 47447.)
         *
         * 1) "nt acl support = no", default_acl = no
         * 2) "inherit permissions = yes", default_acl = no
         */
        if (lp_nt_acl_support(SNUM(conn)) && !lp_inherit_perms(SNUM(conn)))
                cf_flags = cf_flags_or(cf_flags, CF_FLAGS_DEFAULT_ACL);

        /*
         * Some customer workflows require the execute bit to be ignored.
         */
        if (lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
                         PARM_ALLOW_EXECUTE_ALWAYS,
                         PARM_ALLOW_EXECUTE_ALWAYS_DEFAULT) &&
            (open_access_mask & FILE_EXECUTE)) {

                DEBUG(3, ("Stripping execute bit from %s: (0x%x)\n", path,
                          open_access_mask));

                /* Strip execute. */
                open_access_mask &= ~FILE_EXECUTE;

                /*
                 * Add READ_DATA, so we're not left with desired_access=0. An
                 * execute call should imply the client will read the data.
                 */
                open_access_mask |= FILE_READ_DATA;

                DEBUGADD(3, ("New stripped access mask: 0x%x\n",
                             open_access_mask));
        }

        DEBUG(10,("onefs_sys_create_file: base_fd = %d, fname = %s"
                  "open_access_mask = 0x%x, flags = 0x%x, mode = 0%o, "
                  "desired_oplock = %s, id = 0x%x, secinfo = 0x%x, sd = %p, "
                  "dos_attributes = 0x%x, path = %s, "
                  "default_acl=%s\n", base_fd, path,
                  (unsigned int)open_access_mask,
                  (unsigned int)flags,
                  (unsigned int)mode,
                  onefs_oplock_str(onefs_oplock),
                  (unsigned int)id,
                  sec_info_effective, sd,
                  (unsigned int)onefs_dos_attributes, path,
                  cf_flags_and_bool(cf_flags, CF_FLAGS_DEFAULT_ACL) ?
                      "true" : "false"));

        /* Initialize smlock struct for files/dirs but not internal opens */
        if (!(oplock_request & INTERNAL_OPEN_ONLY)) {
                smlock_init(conn, &sml, is_executable(path), access_mask,
                    share_access, create_options);
                psml = &sml;
        }

        smlock_dump(10, psml);

        ret_fd = ifs_createfile(base_fd, path,
            (enum ifs_ace_rights)open_access_mask, flags & ~O_ACCMODE, mode,
            onefs_oplock, id, psml, sec_info_effective, pifs_sd,
            onefs_dos_attributes, cf_flags, &onefs_granted_oplock);

        DEBUG(10,("onefs_sys_create_file(%s): ret_fd = %d, "
                  "onefs_granted_oplock = %s\n",
                  ret_fd < 0 ? strerror(errno) : "success", ret_fd,
                  onefs_oplock_str(onefs_granted_oplock)));

        if (granted_oplock) {
                *granted_oplock =
                    onefs_oplock_to_samba_oplock(onefs_granted_oplock);
        }

 out:
        END_PROFILE(syscall_createfile);
        aclu_free_sd(pifs_sd, false);

        return ret_fd;
}

/**
 * FreeBSD based sendfile implementation that allows for atomic semantics.
 */
static ssize_t onefs_sys_do_sendfile(int tofd, int fromfd,
    const DATA_BLOB *header, SMB_OFF_T offset, size_t count, bool atomic)
{
        size_t total=0;
        struct sf_hdtr hdr;
        struct iovec hdtrl;
        size_t hdr_len = 0;
        int flags = 0;

        if (atomic) {
                flags = SF_ATOMIC;
        }

        hdr.headers = &hdtrl;
        hdr.hdr_cnt = 1;
        hdr.trailers = NULL;
        hdr.trl_cnt = 0;

        /* Set up the header iovec. */
        if (header) {
                hdtrl.iov_base = header->data;
                hdtrl.iov_len = hdr_len = header->length;
        } else {
                hdtrl.iov_base = NULL;
                hdtrl.iov_len = 0;
        }

        total = count;
        while (total + hdtrl.iov_len) {
                SMB_OFF_T nwritten;
                int ret;

                /*
                 * FreeBSD sendfile returns 0 on success, -1 on error.
                 * Remember, the tofd and fromfd are reversed..... :-).
                 * nwritten includes the header data sent.
                 */

                do {
                        ret = sendfile(fromfd, tofd, offset, total, &hdr,
                                       &nwritten, flags);
                } while (ret == -1 && errno == EINTR);

                /* On error we're done. */
                if (ret == -1) {
                        return -1;
                }

                /*
                 * If this was an ATOMIC sendfile, nwritten doesn't
                 * necessarily indicate an error.  It could mean count > than
                 * what sendfile can handle atomically (usually 64K) or that
                 * there was a short read due to the file being truncated.
                 */
                if (nwritten == 0) {
                        return atomic ? 0 : -1;
                }

                /*
                 * An atomic sendfile should never send partial data!
                 */
                if (atomic && nwritten != total + hdtrl.iov_len) {
                        DEBUG(0,("Atomic sendfile() sent partial data: "
                                 "%llu of %d\n", nwritten,
                                 total + hdtrl.iov_len));
                        return -1;
                }

                /*
                 * If this was a short (signal interrupted) write we may need
                 * to subtract it from the header data, or null out the header
                 * data altogether if we wrote more than hdtrl.iov_len bytes.
                 * We change nwritten to be the number of file bytes written.
                 */

                if (hdtrl.iov_base && hdtrl.iov_len) {
                        if (nwritten >= hdtrl.iov_len) {
                                nwritten -= hdtrl.iov_len;
                                hdtrl.iov_base = NULL;
                                hdtrl.iov_len = 0;
                        } else {
                                hdtrl.iov_base =
                                    (caddr_t)hdtrl.iov_base + nwritten;
                                hdtrl.iov_len -= nwritten;
                                nwritten = 0;
                        }
                }
                total -= nwritten;
                offset += nwritten;
        }
        return count + hdr_len;
}

/**
 * Handles the subtleties of using sendfile with CIFS.
 */
ssize_t onefs_sys_sendfile(connection_struct *conn, int tofd, int fromfd,
                           const DATA_BLOB *header, SMB_OFF_T offset,
                           size_t count)
{
        bool atomic = false;
        ssize_t ret = 0;

        START_PROFILE_BYTES(syscall_sendfile, count);

        if (lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
                         PARM_ATOMIC_SENDFILE,
                         PARM_ATOMIC_SENDFILE_DEFAULT)) {
                atomic = true;
        }

        /* Try the sendfile */
        ret = onefs_sys_do_sendfile(tofd, fromfd, header, offset, count,
                                    atomic);

        /* If the sendfile wasn't atomic, we're done. */
        if (!atomic) {
                DEBUG(10, ("non-atomic sendfile read %ul bytes\n", ret));
                END_PROFILE(syscall_sendfile);
                return ret;
        }

        /*
         * Atomic sendfile takes care to not write anything to the socket
         * until all of the requested bytes have been read from the file.
         * There are two atomic cases that need to be handled.
         *
         *  1. The file was truncated causing less data to be read than was
         *     requested.  In this case, we return back to the caller to
         *     indicate 0 bytes were written to the socket.  This should
         *     prompt the caller to fallback to the standard read path: read
         *     the data, create a header that indicates how many bytes were
         *     actually read, and send the header/data back to the client.
         *
         *     This saves us from standard sendfile behavior of sending a
         *     header promising more data then will actually be sent.  The
         *     only two options are to close the socket and kill the client
         *     connection, or write a bunch of 0s.  Closing the client
         *     connection is bad because there could actually be multiple
         *     sessions multiplexed from the same client that are all dropped
         *     because of a truncate.  Writing the remaining data as 0s also
         *     isn't good, because the client will have an incorrect version
         *     of the file.  If the file is written back to the server, the 0s
         *     will be written back.  Fortunately, atomic sendfile allows us
         *     to avoid making this choice in most cases.
         *
         *  2. One downside of atomic sendfile, is that there is a limit on
         *     the number of bytes that can be sent atomically.  The kernel
         *     has a limited amount of mbuf space that it can read file data
         *     into without exhausting the system's mbufs, so a buffer of
         *     length xfsize is used.  The xfsize at the time of writing this
         *     is 64K.  xfsize bytes are read from the file, and subsequently
         *     written to the socket.  This makes it impossible to do the
         *     sendfile atomically for a byte count > xfsize.
         *
         *     To cope with large requests, atomic sendfile returns -1 with
         *     errno set to E2BIG.  Since windows maxes out at 64K writes,
         *     this is currently only a concern with non-windows clients.
         *     Posix extensions allow the full 24bit bytecount field to be
         *     used in ReadAndX, and clients such as smbclient and the linux
         *     cifs client can request up to 16MB reads!  There are a few
         *     options for handling large sendfile requests.
         *
         *      a. Fall back to the standard read path.  This is unacceptable
         *         because it would require prohibitively large mallocs.
         *
         *      b. Fall back to using samba's fake_send_file which emulates
         *         the kernel sendfile in userspace.  This still has the same
         *         problem of sending the header before all of the data has
         *         been read, so it doesn't buy us anything, and has worse
         *         performance than the kernel's zero-copy sendfile.
         *
         *      c. Use non-atomic sendfile syscall to attempt a zero copy
         *         read, and hope that there isn't a short read due to
         *         truncation.  In the case of a short read, there are two
         *         options:
         *
         *          1. Kill the client connection
         *
         *          2. Write zeros to the socket for the remaining bytes
         *             promised in the header.
         *
         *         It is safer from a data corruption perspective to kill the
         *         client connection, so this is our default behavior, but if
         *         this causes problems this can be configured to write zeros
         *         via smb.conf.
         */

        /* Handle case 1: short read -> truncated file. */
        if (ret == 0) {
                END_PROFILE(syscall_sendfile);
                return ret;
        }

        /* Handle case 2: large read. */
        if (ret == -1 && errno == E2BIG) {

                if (!lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
                                 PARM_SENDFILE_LARGE_READS,
                                 PARM_SENDFILE_LARGE_READS_DEFAULT)) {
                        DEBUG(3, ("Not attempting non-atomic large sendfile: "
                                  "%lu bytes\n", count));
                        END_PROFILE(syscall_sendfile);
                        return 0;
                }

                if (count < 0x10000) {
                        DEBUG(0, ("Count < 2^16 and E2BIG was returned! %lu\n",
                                  count));
                }

                DEBUG(10, ("attempting non-atomic large sendfile: %lu bytes\n",
                           count));

                /* Try a non-atomic sendfile. */
                ret = onefs_sys_do_sendfile(tofd, fromfd, header, offset,
                                            count, false);
                /* Real error: kill the client connection. */
                if (ret == -1) {
                        DEBUG(1, ("error on non-atomic large sendfile "
                                  "(%lu bytes): %s\n", count,
                                  strerror(errno)));
                        END_PROFILE(syscall_sendfile);
                        return ret;
                }

                /* Short read: kill the client connection. */
                if (ret != count + header->length) {
                        DEBUG(1, ("short read on non-atomic large sendfile "
                                  "(%lu of %lu bytes): %s\n", ret, count,
                                  strerror(errno)));

                        /*
                         * Returning ret here would cause us to drop into the
                         * codepath that calls sendfile_short_send, which
                         * sends the client a bunch of zeros instead.
                         * Returning -1 kills the connection.
                         */
                        if (lp_parm_bool(SNUM(conn), PARM_ONEFS_TYPE,
                                PARM_SENDFILE_SAFE,
                                PARM_SENDFILE_SAFE_DEFAULT)) {
                                END_PROFILE(syscall_sendfile);
                                return -1;
                        }

                        END_PROFILE(syscall_sendfile);
                        return ret;
                }

                DEBUG(10, ("non-atomic large sendfile successful\n"));
        }

        /* There was error in the atomic sendfile. */
        if (ret == -1) {
                DEBUG(1, ("error on %s sendfile (%lu bytes): %s\n",
                          atomic ? "atomic" : "non-atomic",
                          count, strerror(errno)));
        }

        END_PROFILE(syscall_sendfile);
        return ret;
}

/**
 * Only talloc the spill buffer once (reallocing when necessary).
 */
static char *get_spill_buffer(size_t new_count)
{
        static int cur_count = 0;
        static char *spill_buffer = NULL;

        /* If a sufficiently sized buffer exists, just return. */
        if (new_count <= cur_count) {
                SMB_ASSERT(spill_buffer);
                return spill_buffer;
        }

        /* Allocate the first time. */
        if (cur_count == 0) {
                SMB_ASSERT(!spill_buffer);
                spill_buffer = talloc_array(NULL, char, new_count);
                if (spill_buffer) {
                        cur_count = new_count;
                }
                return spill_buffer;
        }

        /* A buffer exists, but it's not big enough, so realloc. */
        SMB_ASSERT(spill_buffer);
        spill_buffer = talloc_realloc(NULL, spill_buffer, char, new_count);
        if (spill_buffer) {
                cur_count = new_count;
        }
        return spill_buffer;
}

/**
 * recvfile does zero-copy writes given an fd to write to, and a socket with
 * some data to write.  If recvfile read more than it was able to write, it
 * spills the data into a buffer.  After first reading any additional data
 * from the socket into the buffer, the spill buffer is then written with a
 * standard pwrite.
 */
ssize_t onefs_sys_recvfile(int fromfd, int tofd, SMB_OFF_T offset,
                           size_t count)
{
        char *spill_buffer = NULL;
        bool socket_drained = false;
        int ret;
        off_t total_rbytes = 0;
        off_t total_wbytes = 0;
        off_t rbytes;
        off_t wbytes;

        START_PROFILE_BYTES(syscall_recvfile, count);

        DEBUG(10,("onefs_recvfile: from = %d, to = %d, offset=%llu, count = "
                  "%lu\n", fromfd, tofd, offset, count));

        if (count == 0) {
                END_PROFILE(syscall_recvfile);
                return 0;
        }

        /*
         * Setup up a buffer for recvfile to spill data that has been read
         * from the socket but not written.
         */
        spill_buffer = get_spill_buffer(count);
        if (spill_buffer == NULL) {
                ret = -1;
                goto out;
        }

        /*
         * Keep trying recvfile until:
         *  - There is no data left to read on the socket, or
         *  - bytes read != bytes written, or
         *  - An error is returned that isn't EINTR/EAGAIN
         */
        do {
                /* Keep track of bytes read/written for recvfile */
                rbytes = 0;
                wbytes = 0;

                DEBUG(10, ("calling recvfile loop, offset + total_wbytes = "
                           "%llu, count - total_rbytes = %llu\n",
                           offset + total_wbytes, count - total_rbytes));

                ret = recvfile(tofd, fromfd, offset + total_wbytes,
                               count - total_wbytes, &rbytes, &wbytes, 0,
                               spill_buffer);

                DEBUG(10, ("recvfile ret = %d, errno = %d, rbytes = %llu, "
                           "wbytes = %llu\n", ret, ret >= 0 ? 0 : errno,
                           rbytes, wbytes));

                /* Update our progress so far */
                total_rbytes += rbytes;
                total_wbytes += wbytes;

        } while ((count - total_rbytes) && (rbytes == wbytes) &&
                 (ret == -1 && (errno == EINTR || errno == EAGAIN)));

        DEBUG(10, ("total_rbytes = %llu, total_wbytes = %llu\n",
                   total_rbytes, total_wbytes));

        /* Log if recvfile didn't write everything it read. */
        if (total_rbytes != total_wbytes) {
                DEBUG(3, ("partial recvfile: total_rbytes=%llu but "
                          "total_wbytes=%llu, diff = %llu\n", total_rbytes,
                          total_wbytes, total_rbytes - total_wbytes));
                SMB_ASSERT(total_rbytes > total_wbytes);
        }

        /*
         * If there is still data on the socket, read it off.
         */
        while (total_rbytes < count) {

                DEBUG(3, ("shallow recvfile (%s), reading %llu\n",
                          strerror(errno), count - total_rbytes));

                /*
                 * Read the remaining data into the spill buffer.  recvfile
                 * may already have some data in the spill buffer, so start
                 * filling the buffer at total_rbytes - total_wbytes.
                 */
                ret = sys_read(fromfd,
                               spill_buffer + (total_rbytes - total_wbytes),
                               count - total_rbytes);

                if (ret <= 0) {
                        if (ret == 0) {
                                DEBUG(0, ("shallow recvfile read: EOF\n"));
                        } else {
                                DEBUG(0, ("shallow recvfile read failed: %s\n",
                                          strerror(errno)));
                        }
                        /* Socket is dead, so treat as if it were drained. */
                        socket_drained = true;
                        goto out;
                }

                /* Data was read so update the rbytes */
                total_rbytes += ret;
        }

        if (total_rbytes != count) {
                smb_panic("Unread recvfile data still on the socket!");
        }

        /*
         * Now write any spilled data + the extra data read off the socket.
         */
        while (total_wbytes < count) {

                DEBUG(3, ("partial recvfile, writing %llu\n", count - total_wbytes));

                ret = sys_pwrite(tofd, spill_buffer, count - total_wbytes,
                                 offset + total_wbytes);

                if (ret == -1) {
                        DEBUG(0, ("partial recvfile write failed: %s\n",
                                  strerror(errno)));
                        goto out;
                }

                /* Data was written so update the wbytes */
                total_wbytes += ret;
        }

        /* Success! */
        ret = total_wbytes;

out:

        END_PROFILE(syscall_recvfile);

        /* Make sure we always try to drain the socket. */
        if (!socket_drained && count - total_rbytes) {
                int saved_errno = errno;

                if (drain_socket(fromfd, count - total_rbytes) !=
                    count - total_rbytes) {
                        /* Socket is dead! */
                        DEBUG(0, ("drain socket failed: %d\n", errno));
                }
                errno = saved_errno;
        }

        return ret;
}