afssys.c revision 55682 
1/*
2 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * 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 *
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the Institute nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include "kafs_locl.h"
35
36RCSID("$Id: afssys.c,v 1.65 1999/12/02 16:58:40 joda Exp $");
37
38int _kafs_debug; /* this should be done in a better way */
39
40#define NO_ENTRY_POINT		0
41#define SINGLE_ENTRY_POINT	1
42#define MULTIPLE_ENTRY_POINT	2
43#define SINGLE_ENTRY_POINT2	3
44#define SINGLE_ENTRY_POINT3	4
45#define AIX_ENTRY_POINTS	5
46#define UNKNOWN_ENTRY_POINT	6
47static int afs_entry_point = UNKNOWN_ENTRY_POINT;
48static int afs_syscalls[2];
49
50/* Magic to get AIX syscalls to work */
51#ifdef _AIX
52
53static int (*Pioctl)(char*, int, struct ViceIoctl*, int);
54static int (*Setpag)(void);
55
56#include "dlfcn.h"
57
58/*
59 *
60 */
61
62static int
63try_aix(void)
64{
65#ifdef STATIC_AFS_SYSCALLS
66    Pioctl = aix_pioctl;
67    Setpag = aix_setpag;
68#else
69    void *ptr;
70    char path[MaxPathLen], *p;
71    /*
72     * If we are root or running setuid don't trust AFSLIBPATH!
73     */
74    if (getuid() != 0 && !issuid() && (p = getenv("AFSLIBPATH")) != NULL)
75	strlcpy(path, p, sizeof(path));
76    else
77	snprintf(path, sizeof(path), "%s/afslib.so", LIBDIR);
78
79    ptr = dlopen(path, RTLD_NOW);
80    if(ptr == NULL) {
81	if(_kafs_debug) {
82	    if(errno == ENOEXEC && (p = dlerror()) != NULL)
83		fprintf(stderr, "dlopen(%s): %s\n", path, p);
84	    else if (errno != ENOENT)
85		fprintf(stderr, "dlopen(%s): %s\n", path, strerror(errno));
86	}
87	return 1;
88    }
89    Setpag = (int (*)(void))dlsym(ptr, "aix_setpag");
90    Pioctl = (int (*)(char*, int,
91		      struct ViceIoctl*, int))dlsym(ptr, "aix_pioctl");
92#endif
93    afs_entry_point = AIX_ENTRY_POINTS;
94    return 0;
95}
96#endif /* _AIX */
97
98/*
99 * This probably only works under Solaris and could get confused if
100 * there's a /etc/name_to_sysnum file.
101 */
102
103#define _PATH_ETC_NAME_TO_SYSNUM "/etc/name_to_sysnum"
104
105static int
106map_syscall_name_to_number (const char *str, int *res)
107{
108    FILE *f;
109    char buf[256];
110    size_t str_len = strlen (str);
111
112    f = fopen (_PATH_ETC_NAME_TO_SYSNUM, "r");
113    if (f == NULL)
114	return -1;
115    while (fgets (buf, sizeof(buf), f) != NULL) {
116	if (strncmp (str, buf, str_len) == 0) {
117	    char *begptr = buf + str_len;
118	    char *endptr;
119	    long val = strtol (begptr, &endptr, 0);
120
121	    if (val != 0 && endptr != begptr) {
122		fclose (f);
123		*res = val;
124		return 0;
125	    }
126	}
127    }
128    fclose (f);
129    return -1;
130}
131
132int
133k_pioctl(char *a_path,
134	 int o_opcode,
135	 struct ViceIoctl *a_paramsP,
136	 int a_followSymlinks)
137{
138#ifndef NO_AFS
139    switch(afs_entry_point){
140#if defined(AFS_SYSCALL) || defined(AFS_SYSCALL2) || defined(AFS_SYSCALL3)
141    case SINGLE_ENTRY_POINT:
142    case SINGLE_ENTRY_POINT2:
143    case SINGLE_ENTRY_POINT3:
144	return syscall(afs_syscalls[0], AFSCALL_PIOCTL,
145		       a_path, o_opcode, a_paramsP, a_followSymlinks);
146#endif
147#if defined(AFS_PIOCTL)
148    case MULTIPLE_ENTRY_POINT:
149	return syscall(afs_syscalls[0],
150		       a_path, o_opcode, a_paramsP, a_followSymlinks);
151#endif
152#ifdef _AIX
153    case AIX_ENTRY_POINTS:
154	return Pioctl(a_path, o_opcode, a_paramsP, a_followSymlinks);
155#endif
156    }
157
158    errno = ENOSYS;
159#ifdef SIGSYS
160    kill(getpid(), SIGSYS);	/* You loose! */
161#endif
162#endif /* NO_AFS */
163    return -1;
164}
165
166int
167k_afs_cell_of_file(const char *path, char *cell, int len)
168{
169    struct ViceIoctl parms;
170    parms.in = NULL;
171    parms.in_size = 0;
172    parms.out = cell;
173    parms.out_size = len;
174    return k_pioctl((char*)path, VIOC_FILE_CELL_NAME, &parms, 1);
175}
176
177int
178k_unlog(void)
179{
180    struct ViceIoctl parms;
181    memset(&parms, 0, sizeof(parms));
182    return k_pioctl(0, VIOCUNLOG, &parms, 0);
183}
184
185int
186k_setpag(void)
187{
188#ifndef NO_AFS
189    switch(afs_entry_point){
190#if defined(AFS_SYSCALL) || defined(AFS_SYSCALL2) || defined(AFS_SYSCALL3)
191    case SINGLE_ENTRY_POINT:
192    case SINGLE_ENTRY_POINT2:
193    case SINGLE_ENTRY_POINT3:
194	return syscall(afs_syscalls[0], AFSCALL_SETPAG);
195#endif
196#if defined(AFS_PIOCTL)
197    case MULTIPLE_ENTRY_POINT:
198	return syscall(afs_syscalls[1]);
199#endif
200#ifdef _AIX
201    case AIX_ENTRY_POINTS:
202	return Setpag();
203#endif
204    }
205
206    errno = ENOSYS;
207#ifdef SIGSYS
208    kill(getpid(), SIGSYS);	/* You loose! */
209#endif
210#endif /* NO_AFS */
211    return -1;
212}
213
214static jmp_buf catch_SIGSYS;
215
216#ifdef SIGSYS
217
218static RETSIGTYPE
219SIGSYS_handler(int sig)
220{
221    errno = 0;
222    signal(SIGSYS, SIGSYS_handler); /* Need to reinstall handler on SYSV */
223    longjmp(catch_SIGSYS, 1);
224}
225
226#endif
227
228/*
229 * Try to see if `syscall' is a pioctl.  Return 0 iff succesful.
230 */
231
232#if defined(AFS_SYSCALL) || defined(AFS_SYSCALL2) || defined(AFS_SYSCALL3)
233static int
234try_one (int syscall_num)
235{
236    struct ViceIoctl parms;
237    memset(&parms, 0, sizeof(parms));
238
239    if (setjmp(catch_SIGSYS) == 0) {
240	syscall(syscall_num, AFSCALL_PIOCTL,
241		0, VIOCSETTOK, &parms, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
242	if (errno == EINVAL) {
243	    afs_entry_point = SINGLE_ENTRY_POINT;
244	    afs_syscalls[0] = syscall_num;
245	    return 0;
246	}
247    }
248    return 1;
249}
250#endif
251
252/*
253 * Try to see if `syscall_pioctl' is a pioctl syscall.  Return 0 iff
254 * succesful.
255 *
256 */
257
258#ifdef AFS_PIOCTL
259static int
260try_two (int syscall_pioctl, int syscall_setpag)
261{
262    struct ViceIoctl parms;
263    memset(&parms, 0, sizeof(parms));
264
265    if (setjmp(catch_SIGSYS) == 0) {
266	syscall(syscall_pioctl,
267		0, VIOCSETTOK, &parms, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
268	if (errno == EINVAL) {
269	    afs_entry_point = MULTIPLE_ENTRY_POINT;
270	    afs_syscalls[0] = syscall_pioctl;
271	    afs_syscalls[1] = syscall_setpag;
272	    return 0;
273	}
274    }
275    return 1;
276}
277#endif
278
279int
280k_hasafs(void)
281{
282#if !defined(NO_AFS) && defined(SIGSYS)
283    RETSIGTYPE (*saved_func)();
284#endif
285    int saved_errno;
286    char *env = getenv ("AFS_SYSCALL");
287
288    /*
289     * Already checked presence of AFS syscalls?
290     */
291    if (afs_entry_point != UNKNOWN_ENTRY_POINT)
292	return afs_entry_point != NO_ENTRY_POINT;
293
294    /*
295     * Probe kernel for AFS specific syscalls,
296     * they (currently) come in two flavors.
297     * If the syscall is absent we recive a SIGSYS.
298     */
299    afs_entry_point = NO_ENTRY_POINT;
300
301    saved_errno = errno;
302#ifndef NO_AFS
303#ifdef SIGSYS
304    saved_func = signal(SIGSYS, SIGSYS_handler);
305#endif
306
307#if defined(AFS_SYSCALL) || defined(AFS_SYSCALL2) || defined(AFS_SYSCALL3)
308    {
309	int tmp;
310
311	if (env != NULL) {
312	    if (sscanf (env, "%d", &tmp) == 1) {
313		if (try_one (tmp) == 0)
314		    goto done;
315	    } else {
316		char *end = NULL;
317		char *p;
318		char *s = strdup (env);
319
320		if (s != NULL) {
321		    for (p = strtok_r (s, ",", &end);
322			 p != NULL;
323			 p = strtok_r (NULL, ",", &end)) {
324			if (map_syscall_name_to_number (p, &tmp) == 0)
325			    if (try_one (tmp) == 0) {
326				free (s);
327				goto done;
328			    }
329		    }
330		    free (s);
331		}
332	    }
333	}
334    }
335#endif /* AFS_SYSCALL || AFS_SYSCALL2 || AFS_SYSCALL3 */
336
337#ifdef AFS_SYSCALL
338    if (try_one (AFS_SYSCALL) == 0)
339	goto done;
340#endif /* AFS_SYSCALL */
341
342#ifdef AFS_PIOCTL
343    {
344	int tmp[2];
345
346	if (env != NULL && sscanf (env, "%d%d", &tmp[0], &tmp[1]) == 2)
347	    if (try_two (tmp[0], tmp[1]) == 2)
348		goto done;
349    }
350#endif /* AFS_PIOCTL */
351
352#ifdef AFS_PIOCTL
353    if (try_two (AFS_PIOCTL, AFS_SETPAG) == 0)
354	goto done;
355#endif /* AFS_PIOCTL */
356
357#ifdef AFS_SYSCALL2
358    if (try_one (AFS_SYSCALL2) == 0)
359	goto done;
360#endif /* AFS_SYSCALL2 */
361
362#ifdef AFS_SYSCALL3
363    if (try_one (AFS_SYSCALL3) == 0)
364	goto done;
365#endif /* AFS_SYSCALL3 */
366
367#ifdef _AIX
368#if 0
369    if (env != NULL) {
370	char *pos = NULL;
371	char *pioctl_name;
372	char *setpag_name;
373
374	pioctl_name = strtok_r (env, ", \t", &pos);
375	if (pioctl_name != NULL) {
376	    setpag_name = strtok_r (NULL, ", \t", &pos);
377	    if (setpag_name != NULL)
378		if (try_aix (pioctl_name, setpag_name) == 0)
379		    goto done;
380	}
381    }
382#endif
383
384    if(try_aix() == 0)
385	goto done;
386#endif
387
388done:
389#ifdef SIGSYS
390    signal(SIGSYS, saved_func);
391#endif
392#endif /* NO_AFS */
393    errno = saved_errno;
394    return afs_entry_point != NO_ENTRY_POINT;
395}
396