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