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perfused.c revision 1.1
      1 /*  $NetBSD: perfused.c,v 1.1 2010/08/25 07:18:01 manu Exp $ */
      2 
      3 /*-
      4  *  Copyright (c) 2010 Emmanuel Dreyfus. All rights reserved.
      5  *
      6  *  Redistribution and use in source and binary forms, with or without
      7  *  modification, are permitted provided that the following conditions
      8  *  are met:
      9  *  1. Redistributions of source code must retain the above copyright
     10  *     notice, this list of conditions and the following disclaimer.
     11  *  2. Redistributions in binary form must reproduce the above copyright
     12  *     notice, this list of conditions and the following disclaimer in the
     13  *     documentation and/or other materials provided with the distribution.
     14  *
     15  *  THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     16  *  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     17  *  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     18  *  PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     19  *  BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     20  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     21  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     22  *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     23  *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     24  *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     25  *  POSSIBILITY OF SUCH DAMAGE.
     26  */
     27 
     28 #include <stdio.h>
     29 #include <unistd.h>
     30 #include <stdlib.h>
     31 #include <fcntl.h>
     32 #include <syslog.h>
     33 #include <ctype.h>
     34 #include <paths.h>
     35 #include <stdarg.h>
     36 #include <err.h>
     37 #include <errno.h>
     38 #include <string.h>
     39 #include <sysexits.h>
     40 #include <signal.h>
     41 #include <puffs.h>
     42 #include <sys/wait.h>
     43 #include <sys/param.h>
     44 #include <sys/queue.h>
     45 #include <sys/uio.h>
     46 #include <sys/socket.h>
     47 #include <sys/un.h>
     48 #include <machine/vmparam.h>
     49 
     50 #include "../../lib/libperfuse/perfuse_if.h"
     51 #include "perfused.h"
     52 
     53 static int getpeerid(int, pid_t *, uid_t *, gid_t *);
     54 static int access_mount(const char *, uid_t, int);
     55 static int accept_new_mount(int);
     56 static int parse_debug(char *);
     57 static void siginfo_handler(int);
     58 static void parse_options(int, char **);
     59 static void get_mount_info(int, struct perfuse_mount_info *);
     60 int main(int, char **);
     61 
     62 
     63 static int
     64 getpeerid(s, pidp, uidp, gidp)
     65 	int s;
     66 	pid_t *pidp;
     67 	uid_t *uidp;
     68 	gid_t *gidp;
     69 {
     70 	struct unpcbid unp;
     71 	socklen_t len;
     72 	int error;
     73 
     74 	len = sizeof(unp);
     75 	error = getsockopt(s, 0, LOCAL_PEEREID, &unp, &len);
     76 	if (error != 0)
     77 		return error;
     78 
     79 	if (pidp != NULL)
     80 		*pidp = unp.unp_pid;
     81 
     82 	if (uidp != NULL)
     83 		*uidp = unp.unp_euid;
     84 
     85 	if (gidp != NULL)
     86 		*gidp = unp.unp_egid;
     87 
     88 	return 0;
     89 }
     90 
     91 static int
     92 access_mount(mnt, uid, ro)
     93 	const char *mnt;
     94 	uid_t uid;
     95 	int ro;
     96 {
     97 	struct stat st;
     98 	mode_t mode;
     99 
    100 	if (uid == 0)
    101 		return 0;
    102 
    103 	if (stat(mnt, &st) == -1)
    104 		return -1;
    105 
    106 	if (st.st_uid != uid)
    107 		return -1;
    108 
    109 	mode = S_IRUSR;
    110 	if (!ro)
    111 		mode |= S_IWUSR;
    112 
    113 	if ((st.st_mode & mode) == mode)
    114 		return 0;
    115 
    116 	return -1;
    117 }
    118 
    119 static void
    120 get_mount_info(fd, pmi)
    121 	int fd;
    122 	struct perfuse_mount_info *pmi;
    123 {
    124 	struct perfuse_mount_out *pmo;
    125 	char *source = NULL;
    126 	char *target = NULL;
    127 	char *filesystemtype = NULL;
    128 	long mountflags = 0;
    129 	void *data;
    130 	size_t len;
    131 
    132 	pmo = (struct perfuse_mount_out *)perfuse_recv_early(fd, sizeof(*pmo));
    133 	if (pmo == NULL) {
    134 		if (shutdown(fd, SHUT_RDWR) != 0)
    135 			DERR(EX_OSERR, "shutdown failed");
    136 		exit(EX_PROTOCOL);
    137 	}
    138 
    139 #ifdef PERFUSE_DEBUG
    140 	DPRINTF("perfuse lengths: source = %d, target = %d, "
    141 	       "filesystemtype = %d, data = %d\n",
    142 		pmo->pmo_source_len,
    143 		pmo->pmo_target_len,
    144 		pmo->pmo_filesystemtype_len,
    145 		pmo->pmo_data_len);
    146 #endif
    147 	len = pmo->pmo_source_len;
    148 	source = perfuse_recv_early(fd, len);
    149 
    150 	len = pmo->pmo_target_len;
    151 	target = perfuse_recv_early(fd, len);
    152 
    153 	len = pmo->pmo_filesystemtype_len;
    154 	filesystemtype = perfuse_recv_early(fd, len);
    155 
    156 	mountflags = pmo->pmo_mountflags;
    157 
    158 	len = pmo->pmo_data_len;
    159 	data = perfuse_recv_early(fd, len);
    160 
    161 #ifdef PERFUSE_DEBUG
    162 	DPRINTF("%s(\"%s\", \"%s\", \"%s\", 0x%lx, \"%s\")\n", __func__,
    163 	       source, target, filesystemtype, mountflags, (const char *)data);
    164 #endif
    165 	pmi->pmi_source = source;
    166 	pmi->pmi_target = target;
    167 	pmi->pmi_filesystemtype = filesystemtype;
    168 	pmi->pmi_mountflags = mountflags;
    169 	pmi->pmi_data = data;
    170 
    171 	return;
    172 }
    173 
    174 static int
    175 accept_new_mount(s)
    176 	int s;
    177 {
    178 	struct puffs_usermount *pu;
    179 	struct sockaddr_storage ss;
    180 	socklen_t ss_len;
    181 	struct sockaddr *sa;
    182 	struct perfuse_mount_info pmi;
    183 	struct perfuse_callbacks pc;
    184 	int ro_flag;
    185 	pid_t pid;
    186 	int fd;
    187 	int flags;
    188 
    189 #ifdef PERFUSE_DEBUG
    190 	DPRINTF("waiting connexion\n");
    191 #endif
    192 	sa = (struct sockaddr *)(void *)&ss;
    193 	ss_len = sizeof(ss);
    194 	if ((fd = accept(s, sa, &ss_len)) == -1)
    195 		DERR(EX_OSERR,  "accept failed");
    196 
    197 #ifdef PERFUSE_DEBUG
    198 	DPRINTF("connexion accepted\n");
    199 #endif
    200 
    201 	pid = (perfuse_diagflags & PDF_FOREGROUND) ? 0 : fork();
    202 	switch(pid) {
    203 	case -1:
    204 		DERR(EX_OSERR, "cannot fork");
    205 		break;
    206 	case 0:
    207 		break;
    208 	default:
    209 		return fd;
    210 		/* NOTREACHED */
    211 		break;
    212 	}
    213 
    214 	/*
    215 	 * Mount information (source, target, mount flags...)
    216 	 */
    217 	get_mount_info(fd, &pmi);
    218 
    219 	/*
    220 	 * Get peer identity
    221 	 */
    222 	if (getpeerid(fd, NULL, &pmi.pmi_uid, NULL) != 0)
    223 		DWARNX("Unable to retreive peer identity");
    224 
    225 	/*
    226 	 * Check that peer owns mountpoint and read (and write) on it?
    227 	 */
    228 	ro_flag = pmi.pmi_mountflags & MNT_RDONLY;
    229 	if (access_mount(pmi.pmi_target, pmi.pmi_uid, ro_flag) != 0)
    230 		DERRX(EX_NOPERM, "insuficient privvileges to mount %s",
    231 		      pmi.pmi_target);
    232 
    233 
    234 	/*
    235 	 * Initialize libperfuse, which will initialize libpuffs
    236 	 */
    237 	pc.pc_new_msg = perfuse_new_pb;
    238 	pc.pc_xchg_msg = perfuse_xchg_pb;
    239 	pc.pc_destroy_msg = (perfuse_destroy_msg_fn)puffs_framebuf_destroy;
    240 	pc.pc_get_inhdr = perfuse_get_inhdr;
    241 	pc.pc_get_inpayload = perfuse_get_inpayload;
    242 	pc.pc_get_outhdr = perfuse_get_outhdr;
    243 	pc.pc_get_outpayload = perfuse_get_outpayload;
    244 
    245 	pu = perfuse_init(&pc, &pmi);
    246 
    247 	puffs_framev_init(pu, perfuse_readframe, perfuse_writeframe,
    248 			  perfuse_cmpframe, perfuse_gotframe, NULL);
    249 
    250 	if (puffs_framev_addfd(pu, fd, PUFFS_FBIO_READ|PUFFS_FBIO_WRITE) == -1)
    251 		DERR(EX_SOFTWARE, "puffs_framev_addfd failed");
    252 
    253 	perfuse_setspecific(pu, (void *)fd);
    254 
    255 	setproctitle("perfused %s", pmi.pmi_target);
    256 	(void)kill(getpid(), SIGINFO);		/* This is for -s option */
    257 
    258 	perfuse_fs_init(pu);
    259 
    260 	/*
    261 	 * Non blocking I/O on /dev/fuse
    262 	 * This must be done after perfuse_fs_init
    263 	 */
    264 	if ((flags = fcntl(fd, F_GETFL, 0)) == -1)
    265 		DERR(EX_OSERR, "fcntl failed");
    266 	if (fcntl(fd, F_SETFL, flags|O_NONBLOCK) != 0)
    267 		DERR(EX_OSERR, "fcntl failed");
    268 
    269 	/*
    270 	 * Hand over control to puffs main loop.
    271 	 */
    272 	return perfuse_mainloop(pu);
    273 }
    274 
    275 static int
    276 parse_debug(optstr)
    277 	char *optstr;
    278 {
    279 	int retval = PDF_SYSLOG;
    280 	char *opt;
    281 	char *lastp;
    282 
    283 	for (opt = strtok_r(optstr, ",", &lastp);
    284 	     opt;
    285 	     opt = strtok_r(NULL, ",", &lastp)) {
    286 		if (strcmp(opt, "fuse") == 0)
    287 			retval |= PDF_FUSE;
    288 		else if (strcmp(opt, "puffs") == 0)
    289 			retval |= PDF_PUFFS;
    290 		else if (strcmp(opt, "dump") == 0)
    291 			retval |= PDF_DUMP;
    292 		else if (strcmp(opt, "fh") == 0)
    293 			retval |= PDF_FH;
    294 		else if (strcmp(opt, "readdir") == 0)
    295 			retval |= PDF_READDIR;
    296 		else if (strcmp(opt, "reclaim") == 0)
    297 			retval |= PDF_RECLAIM;
    298 		else if (strcmp(opt, "requeue") == 0)
    299 			retval |= PDF_REQUEUE;
    300 		else if (strcmp(opt, "misc") == 0)
    301 			retval |= PDF_MISC;
    302 		else
    303 			DERRX(EX_USAGE, "unknown debug flag \"%s\"", opt);
    304 	}
    305 
    306 	return retval;
    307 }
    308 
    309 /* ARGSUSED0 */
    310 static void
    311 siginfo_handler(sig)
    312 	int sig;
    313 {
    314 	static int old_flags = 0;
    315 	int swap;
    316 
    317 	swap = perfuse_diagflags;
    318 	perfuse_diagflags = old_flags;
    319 	old_flags = swap;
    320 
    321 	DWARNX("debug %sabled", old_flags == 0 ? "en" : "dis");
    322 
    323 	return;
    324 }
    325 
    326 static void
    327 parse_options(argc, argv)
    328 	int argc;
    329 	char **argv;
    330 {
    331 	int ch;
    332 	int foreground = 0;
    333 
    334 	perfuse_diagflags = PDF_FOREGROUND | PDF_SYSLOG;
    335 
    336 	while ((ch = getopt(argc, argv, "d:fs")) != -1) {
    337 		switch (ch) {
    338 		case 'd':
    339 			perfuse_diagflags |= parse_debug(optarg);
    340 			break;
    341 		case 's':
    342 			if (signal(SIGINFO, siginfo_handler) != 0)
    343 				DERR(EX_OSERR, "signal failed");
    344 			break;
    345 		case 'f':
    346 			foreground = 1;
    347 			break;
    348 		default:
    349 			DERR(EX_USAGE, "%s [-d level] [-s] [-f]", argv[0]);
    350 			break;
    351 		}
    352 	}
    353 
    354 	if (!foreground)
    355 		perfuse_diagflags &= ~PDF_FOREGROUND;
    356 
    357 	return;
    358 }
    359 
    360 int
    361 main(argc, argv)
    362 	int argc;
    363 	char **argv;
    364 {
    365 	int s;
    366 
    367 	parse_options(argc, argv);
    368 
    369 	if (perfuse_diagflags & PDF_SYSLOG)
    370 		openlog("perfused", 0, LOG_DAEMON);
    371 
    372 	if (!(perfuse_diagflags & PDF_FOREGROUND))
    373 		if (daemon(0, 0) != 0)
    374 			DERR(EX_OSERR, "daemon failed");
    375 
    376 	s = perfuse_open_sock();
    377 
    378 	do {
    379 		(void)accept_new_mount(s);
    380 	} while (1 /* CONSTCOND */);
    381 
    382 	/* NOTREACHED */
    383 	return 0;
    384 }
    385