transmission/libtransmission/fdlimit.c

593 lines
14 KiB
C

/*
* This file Copyright (C) 2005-2014 Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
* $Id$
*/
#include <assert.h>
#include <errno.h>
#include <inttypes.h>
#include <string.h>
#include <sys/time.h> /* getrlimit */
#include <sys/resource.h> /* getrlimit */
#include "transmission.h"
#include "error.h"
#include "error-types.h"
#include "fdlimit.h"
#include "file.h"
#include "log.h"
#include "session.h"
#include "torrent.h" /* tr_isTorrent () */
#define dbgmsg(...) \
do \
{ \
if (tr_logGetDeepEnabled ()) \
tr_logAddDeep (__FILE__, __LINE__, NULL, __VA_ARGS__); \
} \
while (0)
/***
****
**** Local Files
****
***/
static bool
preallocate_file_sparse (tr_sys_file_t fd, uint64_t length, tr_error ** error)
{
tr_error * my_error = NULL;
if (length == 0)
return true;
if (tr_sys_file_preallocate (fd, length, TR_SYS_FILE_PREALLOC_SPARSE, &my_error))
return true;
dbgmsg ("Preallocating (sparse, normal) failed (%d): %s", my_error->code, my_error->message);
if (!TR_ERROR_IS_ENOSPC (my_error->code))
{
const char zero = '\0';
tr_error_clear (&my_error);
/* fallback: the old-style seek-and-write */
if (tr_sys_file_write_at (fd, &zero, 1, length - 1, NULL, &my_error) &&
tr_sys_file_truncate (fd, length, &my_error))
return true;
dbgmsg ("Preallocating (sparse, fallback) failed (%d): %s", my_error->code, my_error->message);
}
tr_error_propagate (error, &my_error);
return false;
}
static bool
preallocate_file_full (tr_sys_file_t fd, uint64_t length, tr_error ** error)
{
tr_error * my_error = NULL;
if (length == 0)
return true;
if (tr_sys_file_preallocate (fd, length, 0, &my_error))
return true;
dbgmsg ("Preallocating (full, normal) failed (%d): %s", my_error->code, my_error->message);
if (!TR_ERROR_IS_ENOSPC (my_error->code))
{
uint8_t buf[4096];
bool success = true;
memset (buf, 0, sizeof (buf));
tr_error_clear (&my_error);
/* fallback: the old-fashioned way */
while (success && length > 0)
{
const uint64_t thisPass = MIN (length, sizeof (buf));
uint64_t bytes_written;
success = tr_sys_file_write (fd, buf, thisPass, &bytes_written, &my_error);
length -= bytes_written;
}
if (success)
return true;
dbgmsg ("Preallocating (full, fallback) failed (%d): %s", my_error->code, my_error->message);
}
tr_error_propagate (error, &my_error);
return false;
}
/*****
******
******
******
*****/
struct tr_cached_file
{
bool is_writable;
tr_sys_file_t fd;
int torrent_id;
tr_file_index_t file_index;
time_t used_at;
};
static inline bool
cached_file_is_open (const struct tr_cached_file * o)
{
assert (o != NULL);
return o->fd != TR_BAD_SYS_FILE;
}
static void
cached_file_close (struct tr_cached_file * o)
{
assert (cached_file_is_open (o));
tr_sys_file_close (o->fd, NULL);
o->fd = TR_BAD_SYS_FILE;
}
/**
* returns 0 on success, or an errno value on failure.
* errno values include ENOENT if the parent folder doesn't exist,
* plus the errno values set by tr_sys_dir_create () and tr_sys_file_open ().
*/
static int
cached_file_open (struct tr_cached_file * o,
const char * filename,
bool writable,
tr_preallocation_mode allocation,
uint64_t file_size)
{
int flags;
tr_sys_path_info info;
bool already_existed;
bool resize_needed;
tr_sys_file_t fd = TR_BAD_SYS_FILE;
tr_error * error = NULL;
/* create subfolders, if any */
if (writable)
{
char * dir = tr_sys_path_dirname (filename, NULL);
if (!tr_sys_dir_create (dir, TR_SYS_DIR_CREATE_PARENTS, 0777, &error))
{
tr_logAddError (_("Couldn't create \"%1$s\": %2$s"), dir, error->message);
tr_free (dir);
goto fail;
}
tr_free (dir);
}
already_existed = tr_sys_path_get_info (filename, 0, &info, NULL) && info.type == TR_SYS_PATH_IS_FILE;
/* we can't resize the file w/o write permissions */
resize_needed = already_existed && (file_size < info.size);
writable |= resize_needed;
/* open the file */
flags = writable ? (TR_SYS_FILE_WRITE | TR_SYS_FILE_CREATE) : 0;
flags |= TR_SYS_FILE_READ | TR_SYS_FILE_SEQUENTIAL;
fd = tr_sys_file_open (filename, flags, 0666, &error);
if (fd == TR_BAD_SYS_FILE)
{
tr_logAddError (_("Couldn't open \"%1$s\": %2$s"), filename, error->message);
goto fail;
}
if (writable && !already_existed && allocation != TR_PREALLOCATE_NONE)
{
bool success = false;
const char * type = NULL;
if (allocation == TR_PREALLOCATE_FULL)
{
success = preallocate_file_full (fd, file_size, &error);
type = _("full");
}
else if (allocation == TR_PREALLOCATE_SPARSE)
{
success = preallocate_file_sparse (fd, file_size, &error);
type = _("sparse");
}
assert (type != NULL);
if (!success)
{
tr_logAddError (_("Couldn't preallocate file \"%1$s\" (%2$s, size: %3$"PRIu64"): %4$s"),
filename, type, file_size, error->message);
goto fail;
}
tr_logAddDebug (_("Preallocated file \"%1$s\" (%2$s, size: %3$"PRIu64")"), filename, type, file_size);
}
/* If the file already exists and it's too large, truncate it.
* This is a fringe case that happens if a torrent's been updated
* and one of the updated torrent's files is smaller.
* http://trac.transmissionbt.com/ticket/2228
* https://bugs.launchpad.net/ubuntu/+source/transmission/+bug/318249
*/
if (resize_needed && !tr_sys_file_truncate (fd, file_size, &error))
{
tr_logAddError (_("Couldn't truncate \"%1$s\": %2$s"), filename, error->message);
goto fail;
}
o->fd = fd;
return 0;
fail:
{
const int err = error->code;
tr_error_free (error);
if (fd != TR_BAD_SYS_FILE)
tr_sys_file_close (fd, NULL);
return err;
}
}
/***
****
***/
struct tr_fileset
{
struct tr_cached_file * begin;
const struct tr_cached_file * end;
};
static void
fileset_construct (struct tr_fileset * set, int n)
{
struct tr_cached_file * o;
const struct tr_cached_file TR_CACHED_FILE_INIT = { false, TR_BAD_SYS_FILE, 0, 0, 0 };
set->begin = tr_new (struct tr_cached_file, n);
set->end = set->begin + n;
for (o=set->begin; o!=set->end; ++o)
*o = TR_CACHED_FILE_INIT;
}
static void
fileset_close_all (struct tr_fileset * set)
{
struct tr_cached_file * o;
if (set != NULL)
for (o=set->begin; o!=set->end; ++o)
if (cached_file_is_open (o))
cached_file_close (o);
}
static void
fileset_destruct (struct tr_fileset * set)
{
fileset_close_all (set);
tr_free (set->begin);
set->end = set->begin = NULL;
}
static void
fileset_close_torrent (struct tr_fileset * set, int torrent_id)
{
struct tr_cached_file * o;
if (set != NULL)
for (o=set->begin; o!=set->end; ++o)
if ((o->torrent_id == torrent_id) && cached_file_is_open (o))
cached_file_close (o);
}
static struct tr_cached_file *
fileset_lookup (struct tr_fileset * set, int torrent_id, tr_file_index_t i)
{
struct tr_cached_file * o;
if (set != NULL)
for (o=set->begin; o!=set->end; ++o)
if ((torrent_id == o->torrent_id) && (i == o->file_index) && cached_file_is_open (o))
return o;
return NULL;
}
static struct tr_cached_file *
fileset_get_empty_slot (struct tr_fileset * set)
{
struct tr_cached_file * cull = NULL;
if (set->begin != NULL)
{
struct tr_cached_file * o;
/* try to find an unused slot */
for (o=set->begin; o!=set->end; ++o)
if (!cached_file_is_open (o))
return o;
/* all slots are full... recycle the least recently used */
for (cull=NULL, o=set->begin; o!=set->end; ++o)
if (!cull || o->used_at < cull->used_at)
cull = o;
cached_file_close (cull);
}
return cull;
}
/***
****
**** Startup / Shutdown
****
***/
struct tr_fdInfo
{
int peerCount;
struct tr_fileset fileset;
};
static void
ensureSessionFdInfoExists (tr_session * session)
{
assert (tr_isSession (session));
if (session->fdInfo == NULL)
{
struct rlimit limit;
struct tr_fdInfo * i;
const int FILE_CACHE_SIZE = 32;
/* Create the local file cache */
i = tr_new0 (struct tr_fdInfo, 1);
fileset_construct (&i->fileset, FILE_CACHE_SIZE);
session->fdInfo = i;
/* set the open-file limit to the largest safe size wrt FD_SETSIZE */
if (!getrlimit (RLIMIT_NOFILE, &limit))
{
const int old_limit = (int) limit.rlim_cur;
const int new_limit = MIN (limit.rlim_max, FD_SETSIZE);
if (new_limit != old_limit)
{
limit.rlim_cur = new_limit;
setrlimit (RLIMIT_NOFILE, &limit);
getrlimit (RLIMIT_NOFILE, &limit);
tr_logAddInfo ("Changed open file limit from %d to %d", old_limit, (int)limit.rlim_cur);
}
}
}
}
void
tr_fdClose (tr_session * session)
{
if (session && session->fdInfo)
{
struct tr_fdInfo * i = session->fdInfo;
fileset_destruct (&i->fileset);
tr_free (i);
session->fdInfo = NULL;
}
}
/***
****
***/
static struct tr_fileset*
get_fileset (tr_session * session)
{
if (!session)
return NULL;
ensureSessionFdInfoExists (session);
return &session->fdInfo->fileset;
}
void
tr_fdFileClose (tr_session * s, const tr_torrent * tor, tr_file_index_t i)
{
struct tr_cached_file * o;
if ((o = fileset_lookup (get_fileset (s), tr_torrentId (tor), i)))
{
/* flush writable files so that their mtimes will be
* up-to-date when this function returns to the caller... */
if (o->is_writable)
tr_sys_file_flush (o->fd, NULL);
cached_file_close (o);
}
}
tr_sys_file_t
tr_fdFileGetCached (tr_session * s, int torrent_id, tr_file_index_t i, bool writable)
{
struct tr_cached_file * o = fileset_lookup (get_fileset (s), torrent_id, i);
if (!o || (writable && !o->is_writable))
return TR_BAD_SYS_FILE;
o->used_at = tr_time ();
return o->fd;
}
bool
tr_fdFileGetCachedMTime (tr_session * s, int torrent_id, tr_file_index_t i, time_t * mtime)
{
bool success;
tr_sys_path_info info;
struct tr_cached_file * o = fileset_lookup (get_fileset (s), torrent_id, i);
if ((success = (o != NULL) && tr_sys_file_get_info (o->fd, &info, NULL)))
*mtime = info.last_modified_at;
return success;
}
void
tr_fdTorrentClose (tr_session * session, int torrent_id)
{
assert (tr_sessionIsLocked (session));
fileset_close_torrent (get_fileset (session), torrent_id);
}
/* returns an fd on success, or a TR_BAD_SYS_FILE on failure and sets errno */
tr_sys_file_t
tr_fdFileCheckout (tr_session * session,
int torrent_id,
tr_file_index_t i,
const char * filename,
bool writable,
tr_preallocation_mode allocation,
uint64_t file_size)
{
struct tr_fileset * set = get_fileset (session);
struct tr_cached_file * o = fileset_lookup (set, torrent_id, i);
if (o && writable && !o->is_writable)
cached_file_close (o); /* close it so we can reopen in rw mode */
else if (!o)
o = fileset_get_empty_slot (set);
if (!cached_file_is_open (o))
{
const int err = cached_file_open (o, filename, writable, allocation, file_size);
if (err)
{
errno = err;
return TR_BAD_SYS_FILE;
}
dbgmsg ("opened '%s' writable %c", filename, writable?'y':'n');
o->is_writable = writable;
}
dbgmsg ("checking out '%s'", filename);
o->torrent_id = torrent_id;
o->file_index = i;
o->used_at = tr_time ();
return o->fd;
}
/***
****
**** Sockets
****
***/
int
tr_fdSocketCreate (tr_session * session, int domain, int type)
{
int s = -1;
struct tr_fdInfo * gFd;
assert (tr_isSession (session));
ensureSessionFdInfoExists (session);
gFd = session->fdInfo;
if (gFd->peerCount < session->peerLimit)
if ((s = socket (domain, type, 0)) < 0)
if (sockerrno != EAFNOSUPPORT)
tr_logAddError (_("Couldn't create socket: %s"), tr_strerror (sockerrno));
if (s > -1)
++gFd->peerCount;
assert (gFd->peerCount >= 0);
if (s >= 0)
{
static bool buf_logged = false;
if (!buf_logged)
{
int i;
socklen_t size = sizeof (int);
buf_logged = true;
getsockopt (s, SOL_SOCKET, SO_SNDBUF, &i, &size);
tr_logAddDebug ("SO_SNDBUF size is %d", i);
getsockopt (s, SOL_SOCKET, SO_RCVBUF, &i, &size);
tr_logAddDebug ("SO_RCVBUF size is %d", i);
}
}
return s;
}
int
tr_fdSocketAccept (tr_session * s, int sockfd, tr_address * addr, tr_port * port)
{
int fd;
unsigned int len;
struct tr_fdInfo * gFd;
struct sockaddr_storage sock;
assert (tr_isSession (s));
assert (addr);
assert (port);
ensureSessionFdInfoExists (s);
gFd = s->fdInfo;
len = sizeof (struct sockaddr_storage);
fd = accept (sockfd, (struct sockaddr *) &sock, &len);
if (fd >= 0)
{
if ((gFd->peerCount < s->peerLimit)
&& tr_address_from_sockaddr_storage (addr, port, &sock))
{
++gFd->peerCount;
}
else
{
tr_netCloseSocket (fd);
fd = -1;
}
}
return fd;
}
void
tr_fdSocketClose (tr_session * session, int fd)
{
assert (tr_isSession (session));
if (session->fdInfo != NULL)
{
struct tr_fdInfo * gFd = session->fdInfo;
if (fd >= 0)
{
tr_netCloseSocket (fd);
--gFd->peerCount;
}
assert (gFd->peerCount >= 0);
}
}