2 /*****************************************************************************
3 * libnss-afs (nss_afs.c)
5 * Copyright 2008, licensed under GNU Library General Public License (LGPL)
6 * see COPYING file for details
8 * by Adam Megacz <megacz@hcoop.net>
9 * derived from Frank Burkhardt's libnss_ptdb,
10 * which was derived from Todd M. Lewis' libnss_pts
11 *****************************************************************************/
14 * If you are reading this code for the first time, read the rest of
15 * this comment block, then start at the bottom of the file and work
18 * All functions which return an int use zero to signal success --
19 * except cpstr(), which returns zero on *failure*. This should be
22 * A note about memory allocation:
24 * NSS plugins generally ought to work without attempting to call
25 * malloc() (which may fail). Therefore, glibc allocates a buffer
26 * before calling NSS library functions, and passes that buffer to
27 * the NSS library; library functions store their results in the
28 * buffer and return pointers into that buffer.
30 * The convention used throughout this library is to pass around a
31 * char** which points to a pointer to the first unused byte in the
32 * provided buffer, and a size_t* which points to an int indicating
33 * how many bytes are left between the char** and the end of the
43 #include <netinet/in.h>
53 #include <sys/select.h>
54 #include <sys/socket.h>
57 #include <sys/types.h>
59 #include <afs/afsutil.h>
60 #include <afs/cellconfig.h>
61 #include <afs/com_err.h>
62 #include <afs/param.h>
63 #include <afs/ptclient.h>
64 #include <afs/pterror.h>
67 #define HOMEDIR_AUTO 0
68 #define HOMEDIR_ADMINLINK 1
69 #define HOMEDIR_PREFIX 2
71 #define SHELL_ADMINLINK 1
72 #define SHELL_USERLINK 2
74 #define AFS_MAGIC_ANONYMOUS_USERID 32766
75 #define MIN_PAG_GID 0x41000000L
76 #define MAX_PAG_GID 0x41FFFFFFL
77 #define MIN_OLDPAG_GID 0x3f00
78 #define MAX_OLDPAG_GID 0xff00
80 #define MAXCELLNAMELEN 256
81 #define MAXUSERNAMELEN 256
83 static pthread_mutex_t mutex
= PTHREAD_MUTEX_INITIALIZER
;
85 extern struct ubik_client
*pruclient
;
87 int afs_initialized
= 0;
88 char cellname
[MAXCELLNAMELEN
];
89 char homedir_prefix
[MAXPATHLEN
];
90 char cell_root
[MAXPATHLEN
];
91 int homedir_prefix_len
=0;
92 char homedirs_method
=0;
96 * The cpstr() function copies a null-terminated string from str*
97 * (the first argument) into buf and updates both buf and buflen. If
98 * the string would overflow the buffer, no action is taken. The
99 * number of bytes copied is returned (zero indicates failure).
101 int cpstr( char *str
, char **buf
, size_t *buflen
) {
102 int len
= strlen(str
);
103 if ( len
>= *buflen
-1 ) return 0;
111 * Look up the name corresponding to uid, store in buffer.
113 enum nss_status
ptsid2name(int uid
, char **buffer
, int *buflen
) {
118 if (init_afs()) return NSS_STATUS_UNAVAIL
;
120 if (uid
==AFS_MAGIC_ANONYMOUS_USERID
) {
121 if (!cpstr("anonymous", buffer
, buflen
)) return NSS_STATUS_UNAVAIL
;
122 return NSS_STATUS_SUCCESS
;
125 if (pthread_mutex_lock(&mutex
)) return NSS_STATUS_UNAVAIL
;
127 lid
.idlist_val
= (afs_int32
*)&uid
;
129 lnames
.namelist_val
= 0;
130 lnames
.namelist_len
= 0;
132 if (ubik_Call(PR_IDToName
,pruclient
,0,&lid
,&lnames
) != PRSUCCESS
) {
133 perror("ubik_Call() in ptsid2name() failed\n");
134 pthread_mutex_unlock(&mutex
);
135 return NSS_STATUS_UNAVAIL
;
138 ret
= NSS_STATUS_NOTFOUND
;
139 for (i
=0;i
<lnames
.namelist_len
;i
++) {
140 int delta
= strlen(lnames
.namelist_val
[i
]);
141 if ( (delta
< *buflen
) && islower(*(lnames
.namelist_val
[i
])) ) {
142 cpstr(lnames
.namelist_val
[i
], buffer
, buflen
);
143 ret
= NSS_STATUS_SUCCESS
;
146 free(lnames
.namelist_val
);
147 /* free(lid.idlist_val); */
151 pthread_mutex_unlock(&mutex
);
156 * Look up the uid corresponding to name in ptserver.
158 enum nss_status
ptsname2id(char *name
, uid_t
* uid
) {
162 char uname
[MAXUSERNAMELEN
];
164 if (init_afs()) return NSS_STATUS_UNAVAIL
;
166 if (!strcmp(name
,"anonymous")) {
167 *uid
= AFS_MAGIC_ANONYMOUS_USERID
;
168 return NSS_STATUS_SUCCESS
;
171 if (pthread_mutex_lock(&mutex
)) return NSS_STATUS_UNAVAIL
;
175 lnames
.namelist_val
= (prname
*)uname
;
176 // apparently ubik expects to be able to modify this?
177 strncpy(uname
, name
, MAXUSERNAMELEN
);
178 lnames
.namelist_len
= 1;
180 if (ubik_Call(PR_NameToID
,pruclient
,0,&lnames
,&lid
) != PRSUCCESS
) {
181 perror("ubik_Call() in ptsname2id() failed\n");
182 pthread_mutex_unlock(&mutex
);
183 return NSS_STATUS_UNAVAIL
;
185 pthread_mutex_unlock(&mutex
);
187 res
= (uid_t
)lid
.idlist_val
[0];
188 if (res
== AFS_MAGIC_ANONYMOUS_USERID
) return NSS_STATUS_NOTFOUND
;
190 return NSS_STATUS_SUCCESS
;
194 * Initialize the library; returns zero on success
205 if (afs_initialized
) {
206 /* wait until /afs/@cell/ appears as a proxy for "the network is up" */
207 if (stat(cell_root
, &statbuf
)) return -1;
211 // check to make sure that we are running inside nscd
213 fd
= open("/proc/self/cmdline", O_RDONLY
);
214 if (fd
==-1) return -1;
217 numread
= read(fd
, buf
+pos
, 1);
218 if (buf
[ (pos
+5)%6 ] == 'd' &&
219 buf
[ (pos
+4)%6 ] == 'c' &&
220 buf
[ (pos
+3)%6 ] == 's' &&
221 buf
[ (pos
+2)%6 ] == 'n' &&
222 (buf
[(pos
+1)%6 ] == '/' || pos
==4) &&
223 (buf
[(pos
+0)%6 ] == 0 || numread
==-1)
227 if (numread
==0) { close(fd
); return -1; }
231 if (pthread_mutex_lock(&mutex
)) return -1;
233 homedirs_method
=HOMEDIR_PREFIX
;
234 shells_method
=SHELL_USERLINK
;
236 len
= snprintf(cellname
, MAXCELLNAMELEN
,
237 "%s/ThisCell", AFSDIR_CLIENT_ETC_DIRPATH
);
238 if (len
< 0 || len
>= MAXCELLNAMELEN
) return -1;
240 thiscell
=fopen(cellname
,"r");
241 if (thiscell
== NULL
) break;
242 len
=fread(cellname
,1,MAXCELLNAMELEN
,thiscell
);
243 if (!feof(thiscell
)) {
246 strcpy(homedir_prefix
,"/tmp/\0");
247 homedir_prefix_len
=5;
252 if (cellname
[len
-1] == '\n') len
--;
255 /* wait until /afs/@cell/ appears as a proxy for "the network is up" */
256 sprintf(cell_root
,"/afs/%s/",cellname
);
257 if (stat(cell_root
, &statbuf
)) break;
259 sprintf(homedir_prefix
,"/afs/%s/user/",cellname
);
260 homedir_prefix_len
=strlen(homedir_prefix
);
262 /* time out requests after 5 seconds to avoid hanging things */
265 if (pr_Initialize(0L,AFSDIR_CLIENT_ETC_DIRPATH
, 0)) {
266 perror("pr_Initialize() failed\n");
271 pthread_mutex_unlock(&mutex
);
275 pthread_mutex_unlock(&mutex
);
281 * Retrieves the homedir for a given user; returns 0 on success.
283 int get_homedir(char *name
, char **buffer
, size_t *buflen
) {
288 switch (homedirs_method
) {
290 homedir_prefix
[homedir_prefix_len
+0]=name
[0];
291 homedir_prefix
[homedir_prefix_len
+1]='/';
292 homedir_prefix
[homedir_prefix_len
+2]=name
[0];
293 homedir_prefix
[homedir_prefix_len
+3]=name
[1];
294 homedir_prefix
[homedir_prefix_len
+4]='/';
295 homedir_prefix
[homedir_prefix_len
+5]=0;
296 strncpy(&homedir_prefix
[homedir_prefix_len
+5],name
,40);
297 if (! cpstr(homedir_prefix
,buffer
,buflen
) ) return -1;
300 homedir_prefix
[homedir_prefix_len
]=0;
301 strncpy(&homedir_prefix
[homedir_prefix_len
],name
,40);
302 if (! cpstr(homedir_prefix
,buffer
,buflen
) ) return -1;
304 case HOMEDIR_ADMINLINK
:
305 if ( snprintf(buf
,256,"/afs/%s/admin/homedirs/%s",cellname
,name
) > 0 ) {
306 temp
=readlink(buf
,*buffer
,*buflen
);
309 *buflen
= *buflen
- temp
- 1;
313 if (! cpstr("/tmp",buffer
,buflen
) ) return -1;
320 * Retrieves the shell for a given user; returns 0 on success.
322 int get_shell(char *name
, char **buffer
, size_t *buflen
) {
330 switch (shells_method
) {
334 case SHELL_ADMINLINK
:
335 if (snprintf(buf
,256,"/afs/%s/admin/shells/%s",cellname
,name
)<=0) break;
336 temp
= readlink(buf
,*buffer
,*buflen
);
339 *buflen
= *buflen
- temp
- 1;
343 if (get_homedir(name
, &bufx
, &bufxlen
)) break;
344 if (strncpy(buf
+strlen(buf
),"/.loginshell",bufxlen
)<=0) break;
345 temp
= readlink(buf
,*buffer
,*buflen
);
348 *buflen
= *buflen
- temp
- 1;
351 if (! cpstr("/bin/bash",buffer
,buflen
) )
358 * This function is exported; glibc will invoke it in order to find
359 * the name and list of members of a group specified by a numerical
362 enum nss_status
_nss_afs_getgrgid_r (gid_t gid
,
363 struct group
*result
,
369 if (gid
>= MIN_PAG_GID
&& gid
<= MAX_PAG_GID
) {
370 showgid
= gid
-MIN_PAG_GID
;
371 } else if (gid
>= MIN_OLDPAG_GID
&& gid
<= MAX_OLDPAG_GID
) {
372 showgid
= gid
-MIN_OLDPAG_GID
;
375 return NSS_STATUS_NOTFOUND
;
380 result
->gr_name
=buffer
;
381 length
=snprintf(buffer
,buflen
,"AfsPag-%x",showgid
);
383 if (length
< 0) break;
388 result
->gr_passwd
=buffer
;
390 if (!cpstr("z",&buffer
,&buflen
)) break;
392 if (buflen
< sizeof(char*)) break;
393 result
->gr_mem
=&buffer
;
394 result
->gr_mem
[0] = NULL
;
397 return NSS_STATUS_SUCCESS
;
401 return NSS_STATUS_UNAVAIL
;
405 * A helper function to fill in the fields of "struct passwd"; used by
406 * both _nss_afs_getpwuid_r() and _nss_afs_getpwnam_r().
408 enum nss_status
fill_result_buf(uid_t uid
,
410 struct passwd
*result_buf
,
414 result_buf
->pw_name
= name
;
416 /* set the password to "z"; we can't use "x" because of pam_unix.so */
417 result_buf
->pw_passwd
= buffer
;
418 if ( ! cpstr("z",&buffer
, &buflen
) ) break;
420 /* the uid and gid are both the uid passed in */
421 result_buf
->pw_uid
= uid
;
422 result_buf
->pw_gid
= 65534;
424 /* make the gecos the same as the PTS name */
425 result_buf
->pw_gecos
= buffer
;
426 if ( ! cpstr(result_buf
->pw_name
, &buffer
, &buflen
) ) break;
428 // Set the homedirectory
429 result_buf
->pw_dir
= buffer
;
430 if ( get_homedir(result_buf
->pw_name
,&buffer
,&buflen
) ) break;
432 // Set the login shell
433 result_buf
->pw_shell
= buffer
;
434 if ( get_shell(result_buf
->pw_name
,&buffer
,&buflen
) ) break;
436 #ifdef LIMIT_USERNAME_CHARS
437 if ( strlen(result_buf
->pw_name
) > LIMIT_USERNAME_CHARS
) {
438 result_buf
->pw_name
[LIMIT_USERNAME_CHARS
] = '\0';
439 buflen
= buflen
+ ( buffer
- &result_buf
->pw_name
[LIMIT_USERNAME_CHARS
+1] );
440 buffer
= &result_buf
->pw_name
[LIMIT_USERNAME_CHARS
+1];
445 return NSS_STATUS_SUCCESS
;
449 return NSS_STATUS_UNAVAIL
;
454 * This function is exported; glibc will invoke it in order to gather
455 * the user information (userid, homedir, shell) associated with a
458 enum nss_status
_nss_afs_getpwuid_r (uid_t uid
,
459 struct passwd
*result_buf
,
466 if (init_afs()) return NSS_STATUS_UNAVAIL
;
469 temp
= ptsid2name( uid
, &buffer
, &buflen
);
470 if (temp
!= NSS_STATUS_SUCCESS
) {
475 return fill_result_buf(uid
, name
, result_buf
, buffer
, buflen
, errnop
);
479 * This function is exported; glibc will invoke it in order to gather
480 * the user information (userid, homedir, shell) associated with a
483 enum nss_status
_nss_afs_getpwnam_r (char *name
,
484 struct passwd
*result_buf
,
491 if (init_afs()) return NSS_STATUS_UNAVAIL
;
493 temp
= ptsname2id(name
,&uid
);
494 if (temp
!= NSS_STATUS_SUCCESS
) {
499 return fill_result_buf(uid
, name
, result_buf
, buffer
, buflen
, errnop
);