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3005c099ef
Allow capabilities to be added or removed from the allowed set for the daemon; e.g. default: CapPrm: 00000000880000df CapEff: 00000000880000df -o modcaps=+sys_admin CapPrm: 00000000882000df CapEff: 00000000882000df -o modcaps=+sys_admin:-chown CapPrm: 00000000882000de CapEff: 00000000882000de Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20200629115420.98443-4-dgilbert@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
399 lines
14 KiB
C
399 lines
14 KiB
C
/*
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* FUSE: Filesystem in Userspace
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* Copyright (C) 2001-2007 Miklos Szeredi <miklos@szeredi.hu>
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*
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* Helper functions to create (simple) standalone programs. With the
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* aid of these functions it should be possible to create full FUSE
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* file system by implementing nothing but the request handlers.
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* This program can be distributed under the terms of the GNU LGPLv2.
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* See the file COPYING.LIB.
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*/
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#include "qemu/osdep.h"
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#include "fuse_i.h"
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#include "fuse_lowlevel.h"
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#include "fuse_misc.h"
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#include "fuse_opt.h"
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#include <errno.h>
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#include <limits.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/param.h>
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#include <sys/time.h>
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#include <sys/resource.h>
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#include <unistd.h>
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#define FUSE_HELPER_OPT(t, p) \
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{ \
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t, offsetof(struct fuse_cmdline_opts, p), 1 \
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}
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#define FUSE_HELPER_OPT_VALUE(t, p, v) \
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{ \
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t, offsetof(struct fuse_cmdline_opts, p), v \
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}
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static const struct fuse_opt fuse_helper_opts[] = {
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FUSE_HELPER_OPT("-h", show_help),
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FUSE_HELPER_OPT("--help", show_help),
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FUSE_HELPER_OPT("-V", show_version),
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FUSE_HELPER_OPT("--version", show_version),
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FUSE_HELPER_OPT("--print-capabilities", print_capabilities),
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FUSE_HELPER_OPT("-d", debug),
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FUSE_HELPER_OPT("debug", debug),
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FUSE_HELPER_OPT("-d", foreground),
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FUSE_HELPER_OPT("debug", foreground),
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FUSE_OPT_KEY("-d", FUSE_OPT_KEY_KEEP),
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FUSE_OPT_KEY("debug", FUSE_OPT_KEY_KEEP),
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FUSE_HELPER_OPT("-f", foreground),
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FUSE_HELPER_OPT_VALUE("--daemonize", foreground, 0),
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FUSE_HELPER_OPT("fsname=", nodefault_subtype),
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FUSE_OPT_KEY("fsname=", FUSE_OPT_KEY_KEEP),
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FUSE_HELPER_OPT("subtype=", nodefault_subtype),
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FUSE_OPT_KEY("subtype=", FUSE_OPT_KEY_KEEP),
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FUSE_HELPER_OPT("max_idle_threads=%u", max_idle_threads),
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FUSE_HELPER_OPT("--rlimit-nofile=%lu", rlimit_nofile),
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FUSE_HELPER_OPT("--syslog", syslog),
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FUSE_HELPER_OPT_VALUE("log_level=debug", log_level, FUSE_LOG_DEBUG),
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FUSE_HELPER_OPT_VALUE("log_level=info", log_level, FUSE_LOG_INFO),
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FUSE_HELPER_OPT_VALUE("log_level=warn", log_level, FUSE_LOG_WARNING),
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FUSE_HELPER_OPT_VALUE("log_level=err", log_level, FUSE_LOG_ERR),
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FUSE_OPT_END
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};
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struct fuse_conn_info_opts {
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int atomic_o_trunc;
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int no_remote_posix_lock;
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int no_remote_flock;
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int splice_write;
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int splice_move;
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int splice_read;
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int no_splice_write;
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int no_splice_move;
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int no_splice_read;
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int auto_inval_data;
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int no_auto_inval_data;
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int no_readdirplus;
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int no_readdirplus_auto;
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int async_dio;
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int no_async_dio;
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int writeback_cache;
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int no_writeback_cache;
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int async_read;
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int sync_read;
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unsigned max_write;
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unsigned max_readahead;
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unsigned max_background;
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unsigned congestion_threshold;
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unsigned time_gran;
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int set_max_write;
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int set_max_readahead;
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int set_max_background;
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int set_congestion_threshold;
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int set_time_gran;
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};
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#define CONN_OPTION(t, p, v) \
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{ \
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t, offsetof(struct fuse_conn_info_opts, p), v \
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}
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static const struct fuse_opt conn_info_opt_spec[] = {
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CONN_OPTION("max_write=%u", max_write, 0),
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CONN_OPTION("max_write=", set_max_write, 1),
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CONN_OPTION("max_readahead=%u", max_readahead, 0),
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CONN_OPTION("max_readahead=", set_max_readahead, 1),
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CONN_OPTION("max_background=%u", max_background, 0),
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CONN_OPTION("max_background=", set_max_background, 1),
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CONN_OPTION("congestion_threshold=%u", congestion_threshold, 0),
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CONN_OPTION("congestion_threshold=", set_congestion_threshold, 1),
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CONN_OPTION("sync_read", sync_read, 1),
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CONN_OPTION("async_read", async_read, 1),
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CONN_OPTION("atomic_o_trunc", atomic_o_trunc, 1),
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CONN_OPTION("no_remote_lock", no_remote_posix_lock, 1),
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CONN_OPTION("no_remote_lock", no_remote_flock, 1),
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CONN_OPTION("no_remote_flock", no_remote_flock, 1),
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CONN_OPTION("no_remote_posix_lock", no_remote_posix_lock, 1),
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CONN_OPTION("splice_write", splice_write, 1),
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CONN_OPTION("no_splice_write", no_splice_write, 1),
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CONN_OPTION("splice_move", splice_move, 1),
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CONN_OPTION("no_splice_move", no_splice_move, 1),
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CONN_OPTION("splice_read", splice_read, 1),
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CONN_OPTION("no_splice_read", no_splice_read, 1),
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CONN_OPTION("auto_inval_data", auto_inval_data, 1),
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CONN_OPTION("no_auto_inval_data", no_auto_inval_data, 1),
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CONN_OPTION("readdirplus=no", no_readdirplus, 1),
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CONN_OPTION("readdirplus=yes", no_readdirplus, 0),
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CONN_OPTION("readdirplus=yes", no_readdirplus_auto, 1),
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CONN_OPTION("readdirplus=auto", no_readdirplus, 0),
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CONN_OPTION("readdirplus=auto", no_readdirplus_auto, 0),
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CONN_OPTION("async_dio", async_dio, 1),
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CONN_OPTION("no_async_dio", no_async_dio, 1),
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CONN_OPTION("writeback_cache", writeback_cache, 1),
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CONN_OPTION("no_writeback_cache", no_writeback_cache, 1),
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CONN_OPTION("time_gran=%u", time_gran, 0),
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CONN_OPTION("time_gran=", set_time_gran, 1),
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FUSE_OPT_END
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};
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void fuse_cmdline_help(void)
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{
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printf(" -h --help print help\n"
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" -V --version print version\n"
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" --print-capabilities print vhost-user.json\n"
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" -d -o debug enable debug output (implies -f)\n"
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" --syslog log to syslog (default stderr)\n"
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" -f foreground operation\n"
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" --daemonize run in background\n"
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" -o cache=<mode> cache mode. could be one of \"auto, "
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"always, none\"\n"
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" default: auto\n"
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" -o flock|no_flock enable/disable flock\n"
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" default: no_flock\n"
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" -o log_level=<level> log level, default to \"info\"\n"
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" level could be one of \"debug, "
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"info, warn, err\"\n"
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" -o max_idle_threads the maximum number of idle worker "
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"threads\n"
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" allowed (default: 10)\n"
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" -o norace disable racy fallback\n"
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" default: false\n"
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" -o posix_lock|no_posix_lock\n"
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" enable/disable remote posix lock\n"
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" default: posix_lock\n"
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" -o readdirplus|no_readdirplus\n"
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" enable/disable readirplus\n"
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" default: readdirplus except with "
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"cache=none\n"
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" -o timeout=<number> I/O timeout (seconds)\n"
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" default: depends on cache= option.\n"
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" -o writeback|no_writeback enable/disable writeback cache\n"
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" default: no_writeback\n"
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" -o xattr|no_xattr enable/disable xattr\n"
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" default: no_xattr\n"
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" -o modcaps=CAPLIST Modify the list of capabilities\n"
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" e.g. -o modcaps=+sys_admin:-chown\n"
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" --rlimit-nofile=<num> set maximum number of file descriptors\n"
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" (0 leaves rlimit unchanged)\n"
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" default: min(1000000, fs.file-max - 16384)\n"
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" if the current rlimit is lower\n"
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);
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}
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static int fuse_helper_opt_proc(void *data, const char *arg, int key,
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struct fuse_args *outargs)
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{
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(void)data;
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(void)outargs;
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switch (key) {
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case FUSE_OPT_KEY_NONOPT:
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fuse_log(FUSE_LOG_ERR, "fuse: invalid argument `%s'\n", arg);
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return -1;
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default:
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/* Pass through unknown options */
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return 1;
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}
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}
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static unsigned long get_default_rlimit_nofile(void)
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{
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g_autofree gchar *file_max_str = NULL;
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const rlim_t reserved_fds = 16384; /* leave at least this many fds free */
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rlim_t max_fds = 1000000; /* our default RLIMIT_NOFILE target */
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rlim_t file_max;
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struct rlimit rlim;
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/*
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* Reduce max_fds below the system-wide maximum, if necessary. This
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* ensures there are fds available for other processes so we don't
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* cause resource exhaustion.
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*/
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if (!g_file_get_contents("/proc/sys/fs/file-max", &file_max_str,
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NULL, NULL)) {
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fuse_log(FUSE_LOG_ERR, "can't read /proc/sys/fs/file-max\n");
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exit(1);
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}
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file_max = g_ascii_strtoull(file_max_str, NULL, 10);
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if (file_max < 2 * reserved_fds) {
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fuse_log(FUSE_LOG_ERR,
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"The fs.file-max sysctl is too low (%lu) to allow a "
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"reasonable number of open files.\n",
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(unsigned long)file_max);
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exit(1);
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}
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max_fds = MIN(file_max - reserved_fds, max_fds);
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if (getrlimit(RLIMIT_NOFILE, &rlim) < 0) {
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fuse_log(FUSE_LOG_ERR, "getrlimit(RLIMIT_NOFILE): %m\n");
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exit(1);
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}
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if (rlim.rlim_cur >= max_fds) {
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return 0; /* we have more fds available than required! */
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}
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return max_fds;
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}
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int fuse_parse_cmdline(struct fuse_args *args, struct fuse_cmdline_opts *opts)
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{
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memset(opts, 0, sizeof(struct fuse_cmdline_opts));
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opts->max_idle_threads = 10;
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opts->rlimit_nofile = get_default_rlimit_nofile();
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opts->foreground = 1;
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if (fuse_opt_parse(args, opts, fuse_helper_opts, fuse_helper_opt_proc) ==
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-1) {
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return -1;
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}
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return 0;
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}
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int fuse_daemonize(int foreground)
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{
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int ret = 0, rett;
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if (!foreground) {
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int nullfd;
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int waiter[2];
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char completed;
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if (pipe(waiter)) {
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fuse_log(FUSE_LOG_ERR, "fuse_daemonize: pipe: %s\n",
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strerror(errno));
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return -1;
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}
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/*
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* demonize current process by forking it and killing the
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* parent. This makes current process as a child of 'init'.
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*/
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switch (fork()) {
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case -1:
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fuse_log(FUSE_LOG_ERR, "fuse_daemonize: fork: %s\n",
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strerror(errno));
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return -1;
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case 0:
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break;
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default:
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_exit(read(waiter[0], &completed,
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sizeof(completed) != sizeof(completed)));
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}
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if (setsid() == -1) {
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fuse_log(FUSE_LOG_ERR, "fuse_daemonize: setsid: %s\n",
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strerror(errno));
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return -1;
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}
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ret = chdir("/");
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nullfd = open("/dev/null", O_RDWR, 0);
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if (nullfd != -1) {
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rett = dup2(nullfd, 0);
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if (!ret) {
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ret = rett;
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}
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rett = dup2(nullfd, 1);
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if (!ret) {
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ret = rett;
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}
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rett = dup2(nullfd, 2);
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if (!ret) {
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ret = rett;
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}
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if (nullfd > 2) {
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close(nullfd);
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}
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}
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/* Propagate completion of daemon initialization */
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completed = 1;
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rett = write(waiter[1], &completed, sizeof(completed));
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if (!ret) {
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ret = rett;
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}
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close(waiter[0]);
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close(waiter[1]);
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} else {
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ret = chdir("/");
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}
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return ret;
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}
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void fuse_apply_conn_info_opts(struct fuse_conn_info_opts *opts,
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struct fuse_conn_info *conn)
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{
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if (opts->set_max_write) {
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conn->max_write = opts->max_write;
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}
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if (opts->set_max_background) {
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conn->max_background = opts->max_background;
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}
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if (opts->set_congestion_threshold) {
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conn->congestion_threshold = opts->congestion_threshold;
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}
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if (opts->set_time_gran) {
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conn->time_gran = opts->time_gran;
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}
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if (opts->set_max_readahead) {
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conn->max_readahead = opts->max_readahead;
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}
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#define LL_ENABLE(cond, cap) \
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if (cond) \
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conn->want |= (cap)
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#define LL_DISABLE(cond, cap) \
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if (cond) \
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conn->want &= ~(cap)
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LL_ENABLE(opts->splice_read, FUSE_CAP_SPLICE_READ);
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LL_DISABLE(opts->no_splice_read, FUSE_CAP_SPLICE_READ);
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LL_ENABLE(opts->splice_write, FUSE_CAP_SPLICE_WRITE);
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LL_DISABLE(opts->no_splice_write, FUSE_CAP_SPLICE_WRITE);
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LL_ENABLE(opts->splice_move, FUSE_CAP_SPLICE_MOVE);
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LL_DISABLE(opts->no_splice_move, FUSE_CAP_SPLICE_MOVE);
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LL_ENABLE(opts->auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
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LL_DISABLE(opts->no_auto_inval_data, FUSE_CAP_AUTO_INVAL_DATA);
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LL_DISABLE(opts->no_readdirplus, FUSE_CAP_READDIRPLUS);
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LL_DISABLE(opts->no_readdirplus_auto, FUSE_CAP_READDIRPLUS_AUTO);
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LL_ENABLE(opts->async_dio, FUSE_CAP_ASYNC_DIO);
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LL_DISABLE(opts->no_async_dio, FUSE_CAP_ASYNC_DIO);
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LL_ENABLE(opts->writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
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LL_DISABLE(opts->no_writeback_cache, FUSE_CAP_WRITEBACK_CACHE);
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LL_ENABLE(opts->async_read, FUSE_CAP_ASYNC_READ);
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LL_DISABLE(opts->sync_read, FUSE_CAP_ASYNC_READ);
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LL_DISABLE(opts->no_remote_posix_lock, FUSE_CAP_POSIX_LOCKS);
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LL_DISABLE(opts->no_remote_flock, FUSE_CAP_FLOCK_LOCKS);
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}
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struct fuse_conn_info_opts *fuse_parse_conn_info_opts(struct fuse_args *args)
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{
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struct fuse_conn_info_opts *opts;
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opts = calloc(1, sizeof(struct fuse_conn_info_opts));
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if (opts == NULL) {
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fuse_log(FUSE_LOG_ERR, "calloc failed\n");
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return NULL;
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}
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if (fuse_opt_parse(args, opts, conn_info_opt_spec, NULL) == -1) {
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free(opts);
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return NULL;
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}
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return opts;
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}
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