/*

 * Original authors: Albeu, probably Arpi

 *

 * This file is part of mpv.

 *

 * mpv 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.

 *

 * mpv 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 mpv.  If not, see <http://www.gnu.org/licenses/>.

 */

#include "config.h"

#include <stdio.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <errno.h>

#ifndef _WIN32

#include <poll.h>

#endif

#include "osdep/io.h"

#include "common/common.h"

#include "common/msg.h"

#include "misc/thread_tools.h"

#include "stream.h"

#include "options/m_option.h"

#include "options/path.h"

#if HAVE_BSD_FSTATFS

#include <sys/param.h>

#include <sys/mount.h>

#endif

#if HAVE_LINUX_FSTATFS

#include <sys/vfs.h>

#endif

#ifdef _WIN32

#include <windows.h>

#include <winioctl.h>

#include <winternl.h>

#include <io.h>

#ifdef _MSC_VER

// Those are defined only in Windows DDK

typedef struct _FILE_FS_DEVICE_INFORMATION {

    DEVICE_TYPE DeviceType;

    ULONG Characteristics;

} FILE_FS_DEVICE_INFORMATION, *PFILE_FS_DEVICE_INFORMATION;

typedef enum _FSINFOCLASS {

    FileFsVolumeInformation          = 1,

    FileFsLabelInformation,         // 2

    FileFsSizeInformation,          // 3

    FileFsDeviceInformation,        // 4

    FileFsAttributeInformation,     // 5

    FileFsControlInformation,       // 6

    FileFsFullSizeInformation,      // 7

    FileFsObjectIdInformation,      // 8

    FileFsDriverPathInformation,    // 9

    FileFsVolumeFlagsInformation,   // 10

    FileFsSectorSizeInformation,    // 11

    FileFsDataCopyInformation,      // 12

    FileFsMetadataSizeInformation,  // 13

    FileFsFullSizeInformationEx,    // 14

    FileFsGuidInformation,          // 15

    FileFsMaximumInformation

} FS_INFORMATION_CLASS, *PFS_INFORMATION_CLASS;

#endif

#ifndef FILE_REMOTE_DEVICE

#define FILE_REMOTE_DEVICE (0x10)

#endif

#endif

struct priv {

    int fd;

    bool close;

    bool use_poll;

    bool regular_file;

    bool appending;

    int64_t orig_size;

    struct mp_cancel *cancel;

};

// Total timeout = RETRY_TIMEOUT * MAX_RETRIES

#define RETRY_TIMEOUT 0.2

#define MAX_RETRIES 10

static int64_t get_size(stream_t *s)

{

    struct priv *p = s->priv;

    struct stat st;

    if (fstat(p->fd, &st) == 0) {

        if (st.st_size <= 0 && !s->seekable)

            st.st_size = -1;

        if (st.st_size >= 0)

            return st.st_size;

    }

    return -1;

}

static int fill_buffer(stream_t *s, void *buffer, int max_len)

{

    struct priv *p = s->priv;

#ifndef _WIN32

    if (p->use_poll) {

        int c = mp_cancel_get_fd(p->cancel);

        struct pollfd fds[2] = {

            {.fd = p->fd, .events = POLLIN},

            {.fd = c, .events = POLLIN},

        };

        poll(fds, c >= 0 ? 2 : 1, -1);

        if (fds[1].revents & POLLIN)

            return -1;

    }

#endif

    for (int retries = 0; retries < MAX_RETRIES; retries++) {

        int r = read(p->fd, buffer, max_len);

        if (r > 0)

            return r;

        // Try to detect and handle files being appended during playback.

        int64_t size = get_size(s);

        if (p->regular_file && size > p->orig_size && !p->appending) {

            MP_WARN(s, "File is apparently being appended to, will keep "

                    "retrying with timeouts.\n");

            p->appending = true;

        }

        if (!p->appending || p->use_poll)

            break;

        if (mp_cancel_wait(p->cancel, RETRY_TIMEOUT))

            break;

    }

    return 0;

}

static int write_buffer(stream_t *s, void *buffer, int len)

{

    struct priv *p = s->priv;

    return write(p->fd, buffer, len);

}

static int seek(stream_t *s, int64_t newpos)

{

    struct priv *p = s->priv;

    return lseek(p->fd, newpos, SEEK_SET) != (off_t)-1;

}

static void s_close(stream_t *s)

{

    struct priv *p = s->priv;

    if (p->close)

        close(p->fd);

}

// If url is a file:// URL, return the local filename, otherwise return NULL.

char *mp_file_url_to_filename(void *talloc_ctx, bstr url)

{

    bstr proto = mp_split_proto(url, &url);

    if (bstrcasecmp0(proto, "file") != 0)

        return NULL;

    char *filename = bstrto0(talloc_ctx, url);

    mp_url_unescape_inplace(filename);

#if HAVE_DOS_PATHS

    // extract '/' from '/x:/path'

    if (filename[0] == '/' && filename[1] && filename[2] == ':')

        memmove(filename, filename + 1, strlen(filename)); // including \0

#endif

    return filename;

}

// Return talloc_strdup's filesystem path if local, otherwise NULL.

// Unlike mp_file_url_to_filename(), doesn't return NULL if already local.

char *mp_file_get_path(void *talloc_ctx, bstr url)

{

    if (mp_split_proto(url, &(bstr){0}).len) {

        return mp_file_url_to_filename(talloc_ctx, url);

    } else {

        return bstrto0(talloc_ctx, url);

    }

}

#if HAVE_BSD_FSTATFS

static bool check_stream_network(int fd)

{

    struct statfs fs;

    const char *stypes[] = { "afpfs", "nfs", "smbfs", "webdav", "osxfusefs",

                             "fuse", "fusefs.sshfs", "macfuse", NULL };

    if (fstatfs(fd, &fs) == 0)

        for (int i=0; stypes[i]; i++)

            if (strcmp(stypes[i], fs.f_fstypename) == 0)

                return true;

    return false;

}

#elif HAVE_LINUX_FSTATFS

static bool check_stream_network(int fd)

{

    struct statfs fs;

    const uint32_t stypes[] = {

        0x5346414F  /*AFS*/,    0x61756673  /*AUFS*/,   0x00C36400  /*CEPH*/,

        0xFF534D42  /*CIFS*/,   0x73757245  /*CODA*/,   0x19830326  /*FHGFS*/,

        0x65735546  /*FUSEBLK*/,0x65735543  /*FUSECTL*/,0x1161970   /*GFS*/,

        0x47504653  /*GPFS*/,   0x6B414653  /*KAFS*/,   0x0BD00BD0  /*LUSTRE*/,

        0x564C      /*NCP*/,    0x6969      /*NFS*/,    0x6E667364  /*NFSD*/,

        0xAAD7AAEA  /*PANFS*/,  0x50495045  /*PIPEFS*/, 0x517B      /*SMB*/,

        0xBEEFDEAD  /*SNFS*/,   0xBACBACBC  /*VMHGFS*/, 0x7461636f  /*OCFS2*/,

        0xFE534D42  /*SMB2*/,   0x61636673  /*ACFS*/,   0x013111A8  /*IBRIX*/,

        0

    };

    if (fstatfs(fd, &fs) == 0) {

        for (int i=0; stypes[i]; i++) {

            if (stypes[i] == fs.f_type)

                return true;

        }

    }

    return false;

}

#elif defined(_WIN32)

static bool check_stream_network(int fd)

{

    NTSTATUS (NTAPI *pNtQueryVolumeInformationFile)(HANDLE,

        PIO_STATUS_BLOCK, PVOID, ULONG, FS_INFORMATION_CLASS) = NULL;

    // NtQueryVolumeInformationFile is an internal Windows function. It has

    // been present since Windows XP, however this code should fail gracefully

    // if it's removed from a future version of Windows.

    HMODULE ntdll = GetModuleHandleW(L"ntdll.dll");

    pNtQueryVolumeInformationFile = (NTSTATUS (NTAPI*)(HANDLE,

        PIO_STATUS_BLOCK, PVOID, ULONG, FS_INFORMATION_CLASS))

        GetProcAddress(ntdll, "NtQueryVolumeInformationFile");

    if (!pNtQueryVolumeInformationFile)

        return false;

    HANDLE h = (HANDLE)_get_osfhandle(fd);

    if (h == INVALID_HANDLE_VALUE)

        return false;

    FILE_FS_DEVICE_INFORMATION info = { 0 };

    IO_STATUS_BLOCK io;

    NTSTATUS status = pNtQueryVolumeInformationFile(h, &io, &info,

        sizeof(info), FileFsDeviceInformation);

    if (!NT_SUCCESS(status))

        return false;

    return info.DeviceType == FILE_DEVICE_NETWORK_FILE_SYSTEM ||

           (info.Characteristics & FILE_REMOTE_DEVICE);

}

#else

static bool check_stream_network(int fd)

{

    return false;

}

#endif

static int open_f(stream_t *stream, const struct stream_open_args *args)

{

    struct priv *p = talloc_ptrtype(stream, p);

    *p = (struct priv) {

        .fd = -1,

    };

    stream->priv = p;

    stream->is_local_fs = true;

    bool strict_fs = args->flags & STREAM_LOCAL_FS_ONLY;

    bool write = stream->mode == STREAM_WRITE;

    int m = O_CLOEXEC | (write ? O_RDWR | O_CREAT | O_TRUNC : O_RDONLY);

    char *filename = stream->path;

    char *url = "";

    if (!strict_fs) {

        char *fn = mp_file_url_to_filename(stream, bstr0(stream->url));

        if (fn)

            filename = stream->path = fn;

        url = stream->url;

    }

    bool is_fdclose = strncmp(url, "fdclose://", 10) == 0;

    if (strncmp(url, "fd://", 5) == 0 || is_fdclose) {

        stream->is_local_fs = false;

        char *begin = strstr(stream->url, "://") + 3, *end = NULL;

        p->fd = strtol(begin, &end, 0);

        if (!end || end == begin || end[0] || p->fd < 0) {

            MP_ERR(stream, "Invalid FD number: %s\n", stream->url);

            return STREAM_ERROR;

        }

#ifdef F_SETFD

        if (fcntl(p->fd, F_GETFD) == -1) {

            MP_ERR(stream, "Invalid FD: %d\n", p->fd);

            return STREAM_ERROR;

        }

#endif

        if (is_fdclose)

            p->close = true;

    } else if (!strict_fs && !strcmp(filename, "-")) {

        stream->is_local_fs = false;

        if (!write) {

            MP_INFO(stream, "Reading from stdin...\n");

            p->fd = 0;

        } else {

            MP_INFO(stream, "Writing to stdout...\n");

            p->fd = 1;

        }

    } else {

        if (bstr_startswith0(bstr0(stream->url), "appending://"))

            p->appending = true;

        mode_t openmode = S_IRUSR | S_IWUSR;

#ifndef __MINGW32__

        openmode |= S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;

        if (!write)

            m |= O_NONBLOCK;

#endif

        p->fd = open(filename, m | O_BINARY, openmode);

        if (p->fd < 0) {

            MP_ERR(stream, "Cannot open file '%s': %s\n",

                   filename, mp_strerror(errno));

            return STREAM_ERROR;

        }

        p->close = true;

    }

#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

    if (p->fd != 42) {

        s_close(stream);

        return STREAM_ERROR;

    }

#endif

    struct stat st;

    bool is_sock_or_fifo = false;

    if (fstat(p->fd, &st) == 0) {

        if (S_ISDIR(st.st_mode)) {

            stream->is_directory = true;

        } else if (S_ISREG(st.st_mode)) {

            p->regular_file = true;

#ifndef _WIN32

            // O_NONBLOCK has weird semantics on file locks; remove it.

            int val = fcntl(p->fd, F_GETFL) & ~(unsigned)O_NONBLOCK;

            fcntl(p->fd, F_SETFL, val);

#endif

        } else {

#ifndef __MINGW32__

            is_sock_or_fifo = S_ISSOCK(st.st_mode) || S_ISFIFO(st.st_mode);

#endif

            p->use_poll = true;

        }

    }

#ifdef _WIN32

    setmode(p->fd, O_BINARY);

#endif

    off_t len = lseek(p->fd, 0, SEEK_END);

    lseek(p->fd, 0, SEEK_SET);

    if (len != (off_t)-1) {

        stream->seek = seek;

        stream->seekable = true;

    }

    stream->fast_skip = true;

    stream->fill_buffer = fill_buffer;

    stream->write_buffer = write_buffer;

    stream->get_size = get_size;

    stream->close = s_close;

    if (is_sock_or_fifo || check_stream_network(p->fd)) {

        stream->streaming = true;

#if HAVE_COCOA

        if (fcntl(p->fd, F_RDAHEAD, 0) < 0) {

            MP_VERBOSE(stream, "Cannot disable read ahead on file '%s': %s\n",

                       filename, mp_strerror(errno));

        }

#endif

    }

    p->orig_size = get_size(stream);

    p->cancel = mp_cancel_new(p);

    if (stream->cancel)

        mp_cancel_set_parent(p->cancel, stream->cancel);

    return STREAM_OK;

}

const stream_info_t stream_info_file = {

    .name = "file",

    .open2 = open_f,

    .protocols = (const char*const[]){ "file", "", "appending", NULL },

    .can_write = true,

    .local_fs = true,

    .stream_origin = STREAM_ORIGIN_FS,

};

const stream_info_t stream_info_fd = {

    .name = "fd",

    .open2 = open_f,

    .protocols = (const char*const[]){ "fd", "fdclose", NULL },

    .can_write = true,

    .stream_origin = STREAM_ORIGIN_UNSAFE,

};