1 /* vi: set sw=4 ts=4: */
2 /* Copyright (C) 2014 Tito Ragusa <farmatito@tiscali.it>
4 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
6 /* This program is distributed in the hope that it will be useful,
7 * but WITHOUT ANY WARRANTY!!
9 * Rewrite of some parts. Main differences are:
11 * 1) the buffer for getpwuid, getgrgid, getpwnam, getgrnam is dynamically
13 * If ENABLE_FEATURE_CLEAN_UP is set the buffers are freed at program
14 * exit using the atexit function to make valgrind happy.
15 * 2) the passwd/group files:
16 * a) must contain the expected number of fields (as per count of field
17 * delimeters ":") or we will complain with a error message.
18 * b) leading and trailing whitespace in fields is stripped.
19 * c) some fields are not allowed to be empty (e.g. username, uid/gid,
20 * homedir, shell) and in this case NULL is returned and errno is
21 * set to EINVAL. This behaviour could be easily changed by
22 * modifying PW_DEF, GR_DEF, SP_DEF strings (uppercase
23 * makes a field mandatory).
24 * d) the string representing uid/gid must be convertible by strtoXX
25 * functions, or errno is set to EINVAL.
26 * e) leading and trailing whitespace in group member names is stripped.
27 * 3) the internal function for getgrouplist uses dynamically allocated buffer.
28 * 4) at the moment only the functions really used by busybox code are
29 * implemented, if you need a particular missing function it should be
30 * easy to write it by using the internal common code.
37 char def[7 + 2*ENABLE_USE_BB_SHADOW];
38 uint8_t off[7 + 2*ENABLE_USE_BB_SHADOW];
44 char def[7 + 2*ENABLE_USE_BB_SHADOW];
45 uint8_t off[7 + 2*ENABLE_USE_BB_SHADOW];
51 /* Note: for shadow db, def[] will not contain terminating NUL,
52 * but convert_to_struct() logic detects def[] end by "less than SP?",
53 * not by "is it NUL?" condition; and off[0] happens to be zero
54 * for every db anyway, so there _is_ in fact a terminating NUL there.
57 /* S = string not empty, s = string maybe empty,
58 * I = uid,gid, l = long maybe empty, m = members,
61 #define PW_DEF "SsIIsSS"
63 #define SP_DEF "Ssllllllr"
65 static const struct const_passdb const_pw_db = {
68 offsetof(struct passwd, pw_name), /* 0 S */
69 offsetof(struct passwd, pw_passwd), /* 1 s */
70 offsetof(struct passwd, pw_uid), /* 2 I */
71 offsetof(struct passwd, pw_gid), /* 3 I */
72 offsetof(struct passwd, pw_gecos), /* 4 s */
73 offsetof(struct passwd, pw_dir), /* 5 S */
74 offsetof(struct passwd, pw_shell) /* 6 S */
76 sizeof(PW_DEF)-1, sizeof(struct passwd)
78 static const struct const_passdb const_gr_db = {
81 offsetof(struct group, gr_name), /* 0 S */
82 offsetof(struct group, gr_passwd), /* 1 s */
83 offsetof(struct group, gr_gid), /* 2 I */
84 offsetof(struct group, gr_mem) /* 3 m (char **) */
86 sizeof(GR_DEF)-1, sizeof(struct group)
88 #if ENABLE_USE_BB_SHADOW
89 static const struct const_passdb const_sp_db = {
92 offsetof(struct spwd, sp_namp), /* 0 S Login name */
93 offsetof(struct spwd, sp_pwdp), /* 1 s Encrypted password */
94 offsetof(struct spwd, sp_lstchg), /* 2 l */
95 offsetof(struct spwd, sp_min), /* 3 l */
96 offsetof(struct spwd, sp_max), /* 4 l */
97 offsetof(struct spwd, sp_warn), /* 5 l */
98 offsetof(struct spwd, sp_inact), /* 6 l */
99 offsetof(struct spwd, sp_expire), /* 7 l */
100 offsetof(struct spwd, sp_flag) /* 8 r Reserved */
102 sizeof(SP_DEF)-1, sizeof(struct spwd)
106 /* We avoid having big global data. */
108 /* We use same buffer (db[0].malloced) for getpwuid and getpwnam.
110 * "The return value may point to a static area, and may be overwritten
111 * by subsequent calls to getpwent(), getpwnam(), or getpwuid()."
113 struct passdb db[2 + ENABLE_USE_BB_SHADOW];
115 unsigned string_size;
118 static struct statics *ptr_to_statics;
119 #define S (*ptr_to_statics)
120 #define has_S (ptr_to_statics)
122 #if ENABLE_FEATURE_CLEAN_UP
123 static void free_static(void)
125 free(S.db[0].malloced);
126 free(S.db[1].malloced);
127 # if ENABLE_USE_BB_SHADOW
128 free(S.db[2].malloced);
130 free(ptr_to_statics);
134 static struct statics *get_S(void)
136 if (!ptr_to_statics) {
137 ptr_to_statics = xzalloc(sizeof(S));
138 memcpy(&S.db[0], &const_pw_db, sizeof(const_pw_db));
139 memcpy(&S.db[1], &const_gr_db, sizeof(const_gr_db));
140 #if ENABLE_USE_BB_SHADOW
141 memcpy(&S.db[2], &const_sp_db, sizeof(const_sp_db));
143 #if ENABLE_FEATURE_CLEAN_UP
147 return ptr_to_statics;
150 /* Internal functions */
152 /* Divide the passwd/group/shadow record in fields
153 * by substituting the given delimeter
154 * e.g. ':' or ',' with '\0'.
155 * Returns the number of fields found.
156 * Strips leading and trailing whitespace in fields.
158 static int tokenize(char *buffer, int ch)
166 overlapping_strcpy(s, skip_whitespace(s));
168 if (*p == ch || *p == '\0') {
170 while (p != s && isblank(p[-1]))
173 overlapping_strcpy(p, end);
176 S.tokenize_end = p + 1;
186 /* Returns !NULL on success and matching line broken up in fields by '\0' in buf.
187 * We require the expected number of fields to be found.
189 static char *parse_common(FILE *fp, struct passdb *db,
190 const char *key, int field_pos)
194 while ((buf = xmalloc_fgetline(fp)) != NULL) {
195 /* Skip empty lines, comment lines */
196 if (buf[0] == '\0' || buf[0] == '#')
198 if (tokenize(buf, ':') != db->numfields) {
199 /* number of fields is wrong */
200 bb_error_msg("%s: bad record", db->filename);
204 if (field_pos == -1) {
205 /* no key specified: sequential read, return a record */
208 if (strcmp(key, nth_string(buf, field_pos)) == 0) {
216 S.string_size = S.tokenize_end - buf;
218 * Ugly hack: group db requires additional buffer space
219 * for members[] array. If there is only one group, we need space
220 * for 3 pointers: alignment padding, group name, NULL.
221 * +1 for every additional group.
223 if (buf && db->numfields == sizeof(GR_DEF)-1) { /* if we read group file... */
226 while (p < S.tokenize_end)
229 S.string_size += cnt * sizeof(char*);
230 //bb_error_msg("+%d words = %u key:%s buf:'%s'", cnt, S.string_size, key, buf);
231 buf = xrealloc(buf, S.string_size);
237 static char *parse_file(struct passdb *db,
238 const char *key, int field_pos)
241 FILE *fp = fopen_for_read(db->filename);
244 buf = parse_common(fp, db, key, field_pos);
250 /* Convert passwd/group/shadow file record in buffer to a struct */
251 static void *convert_to_struct(struct passdb *db,
252 char *buffer, void *result)
254 const char *def = db->def;
255 const uint8_t *off = db->off;
257 /* For consistency, zero out all fields */
258 memset(result, 0, db->size_of);
261 void *member = (char*)result + (*off++);
263 if ((*def | 0x20) == 's') { /* s or S */
264 *(char **)member = (char*)buffer;
265 if (!buffer[0] && (*def == 'S')) {
270 *(int *)member = bb_strtou(buffer, NULL, 10);
272 #if ENABLE_USE_BB_SHADOW
276 n = bb_strtol(buffer, NULL, 10);
282 int i = tokenize(buffer, ',');
284 /* Store members[] after buffer's end.
285 * This is safe ONLY because there is a hack
286 * in parse_common() which allocates additional space
287 * at the end of malloced buffer!
290 ( ((intptr_t)S.tokenize_end + sizeof(members[0]))
291 & -(intptr_t)sizeof(members[0])
293 ((struct group *)result)->gr_mem = members;
297 // bb_error_msg("member[]='%s'", buffer);
299 buffer += strlen(buffer) + 1;
303 /* def "r" does nothing */
306 if ((unsigned char)*def <= (unsigned char)' ')
308 buffer += strlen(buffer) + 1;
316 static int massage_data_for_r_func(struct passdb *db,
317 char *buffer, size_t buflen,
321 void *result_buf = *result;
324 if (S.string_size > buflen) {
327 memcpy(buffer, buf, S.string_size);
328 *result = convert_to_struct(db, buffer, result_buf);
332 /* "The reentrant functions return zero on success.
333 * In case of error, an error number is returned."
334 * NB: not finding the record is also a "success" here:
339 /****** getXXnam/id_r */
341 static int FAST_FUNC getXXnam_r(const char *name, uintptr_t db_and_field_pos,
342 char *buffer, size_t buflen,
346 struct passdb *db = &get_S()->db[db_and_field_pos >> 2];
348 buf = parse_file(db, name, 0 /*db_and_field_pos & 3*/);
349 /* "db_and_field_pos & 3" is commented out since so far we don't implement
350 * getXXXid_r() functions which would use that to pass 2 here */
352 return massage_data_for_r_func(db, buffer, buflen, result, buf);
355 int FAST_FUNC getpwnam_r(const char *name, struct passwd *struct_buf,
356 char *buffer, size_t buflen,
357 struct passwd **result)
359 /* Why the "store buffer address in result" trick?
360 * This way, getXXnam_r has the same ABI signature as getpwnam_r,
361 * hopefully compiler can optimize tail call better in this case.
363 *result = struct_buf;
364 return getXXnam_r(name, (0 << 2) + 0, buffer, buflen, result);
366 #if ENABLE_USE_BB_SHADOW
367 int FAST_FUNC getspnam_r(const char *name, struct spwd *struct_buf, char *buffer, size_t buflen,
368 struct spwd **result)
370 *result = struct_buf;
371 return getXXnam_r(name, (2 << 2) + 0, buffer, buflen, result);
375 /****** getXXent_r */
377 static int FAST_FUNC getXXent_r(uintptr_t db_idx, char *buffer, size_t buflen,
381 struct passdb *db = &get_S()->db[db_idx];
384 db->fp = fopen_for_read(db->filename);
388 close_on_exec_on(fileno(db->fp));
391 buf = parse_common(db->fp, db, /*no search key:*/ NULL, -1);
394 return massage_data_for_r_func(db, buffer, buflen, result, buf);
397 int FAST_FUNC getpwent_r(struct passwd *struct_buf, char *buffer, size_t buflen,
398 struct passwd **result)
400 *result = struct_buf;
401 return getXXent_r(0, buffer, buflen, result);
404 /****** getXXnam/id */
406 static void* FAST_FUNC getXXnam(const char *name, unsigned db_and_field_pos)
410 struct passdb *db = &get_S()->db[db_and_field_pos >> 2];
415 db->fp = fopen_for_read(db->filename);
419 close_on_exec_on(fileno(db->fp));
422 buf = parse_common(db->fp, db, name, db_and_field_pos & 3);
425 /* We enlarge buf and move string data up, freeing space
426 * for struct passwd/group/spwd at the beginning. This way,
427 * entire result of getXXnam is in a single malloced block.
428 * This enables easy creation of xmalloc_getpwnam() API.
430 db->malloced = buf = xrealloc(buf, db->size_of + S.string_size);
431 memmove(buf + db->size_of, buf, S.string_size);
432 result = convert_to_struct(db, buf + db->size_of, buf);
437 struct passwd* FAST_FUNC getpwnam(const char *name)
439 return getXXnam(name, (0 << 2) + 0);
441 struct group* FAST_FUNC getgrnam(const char *name)
443 return getXXnam(name, (1 << 2) + 0);
445 struct passwd* FAST_FUNC getpwuid(uid_t id)
447 return getXXnam(utoa(id), (0 << 2) + 2);
449 struct group* FAST_FUNC getgrgid(gid_t id)
451 return getXXnam(utoa(id), (1 << 2) + 2);
454 /****** end/setXXend */
456 void FAST_FUNC endpwent(void)
458 if (has_S && S.db[0].fp) {
463 void FAST_FUNC setpwent(void)
465 if (has_S && S.db[0].fp) {
469 void FAST_FUNC endgrent(void)
471 if (has_S && S.db[1].fp) {
477 /****** initgroups and getgrouplist */
479 static gid_t* FAST_FUNC getgrouplist_internal(int *ngroups_ptr,
480 const char *user, gid_t gid)
486 /* We alloc space for 8 gids at a time. */
487 group_list = xzalloc(8 * sizeof(group_list[0]));
491 fp = fopen_for_read(_PATH_GROUP);
493 struct passdb *db = &get_S()->db[1];
495 while ((buf = parse_common(fp, db, NULL, -1)) != NULL) {
498 if (!convert_to_struct(db, buf, &group))
500 if (group.gr_gid == gid)
502 for (m = group.gr_mem; *m; m++) {
503 if (strcmp(*m, user) != 0)
505 group_list = xrealloc_vector(group_list, /*8=2^3:*/ 3, ngroups);
506 group_list[ngroups++] = group.gr_gid;
514 *ngroups_ptr = ngroups;
518 int FAST_FUNC initgroups(const char *user, gid_t gid)
521 gid_t *group_list = getgrouplist_internal(&ngroups, user, gid);
523 ngroups = setgroups(ngroups, group_list);
528 int FAST_FUNC getgrouplist(const char *user, gid_t gid, gid_t *groups, int *ngroups)
530 int ngroups_old = *ngroups;
531 gid_t *group_list = getgrouplist_internal(ngroups, user, gid);
533 if (*ngroups <= ngroups_old) {
534 ngroups_old = *ngroups;
535 memcpy(groups, group_list, ngroups_old * sizeof(groups[0]));