2 * Copyright (c) 2008 Sean C. Farley <scf@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer,
10 * without modification, immediately at the beginning of the file.
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.
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 * $FreeBSD: head/lib/libutil/gr_util.c 248102 2013-03-09 13:30:06Z db $
29 #include <sys/param.h>
30 #include <sys/errno.h>
46 static int lockfd = -1;
47 static char group_dir[PATH_MAX];
48 static char group_file[PATH_MAX];
49 static char tempname[PATH_MAX];
50 static int initialized;
51 static size_t grmemlen(const struct group *, const char *, int *);
52 static struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx);
58 gr_init(const char *dir, const char *group)
62 strcpy(group_dir, _PATH_ETC);
64 if (strlen(dir) >= sizeof(group_dir)) {
68 strcpy(group_dir, dir);
73 strcpy(group_file, _PATH_GROUP);
74 } else if (snprintf(group_file, sizeof(group_file), "%s/group",
75 group_dir) > (int)sizeof(group_file)) {
80 if (strlen(group) >= sizeof(group_file)) {
84 strcpy(group_file, group);
97 if (*group_file == '\0')
103 lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0);
105 if (errno == EWOULDBLOCK) {
106 errx(1, "the group file is busy");
108 err(1, "could not lock the group file: ");
111 if (fstat(lockfd, &st) == -1)
112 err(1, "fstat() failed: ");
113 if (st.st_nlink != 0)
122 * Create and open a presmuably safe temp file for editing group data
132 if (*group_file == '\0')
134 if ((p = strrchr(group_file, '/')))
138 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX",
139 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) {
140 errno = ENAMETOOLONG;
143 if ((tfd = mkstemp(tempname)) == -1)
146 while ((nr = read(mfd, buf, sizeof(buf))) > 0)
147 if (write(tfd, buf, (size_t)nr) != nr)
160 * Copy the group file from one descriptor to another, replacing, deleting
161 * or adding a single record on the way.
164 gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
166 char buf[8192], *end, *line, *p, *q, *r, t;
168 const struct group *sgr;
178 } else if ((line = gr_make(gr)) == NULL)
185 /* find the end of the current line */
186 for (p = q; q < end && *q != '\0'; ++q)
190 /* if we don't have a complete line, fill up the buffer */
194 if ((size_t)(q - p) >= sizeof(buf)) {
195 warnx("group line too long");
196 errno = EINVAL; /* hack */
200 q = memmove(buf, p, end -p);
205 readlen = read(ffd, end, sizeof(buf) - (end -buf));
209 len = (size_t)readlen;
210 if (len == 0 && p == buf)
214 if (len < (ssize_t)sizeof(buf)) {
216 if (len > 0 && buf[len -1] != '\n')
217 ++len, *end++ = '\n';
222 /* is it a blank line or a comment? */
223 for (r = p; r < q && isspace(*r); ++r)
225 if (r == q || *r == '#') {
227 if (write(tfd, p, q -p + 1) != q - p + 1)
233 /* is it the one we're looking for? */
240 /* fgr is either a struct group for the current line,
241 * or NULL if the line is malformed.
245 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) {
249 if (write(tfd, p, q - p + 1) != q - p + 1)
254 if (old_gr && !gr_equal(fgr, old_gr)) {
255 warnx("entry inconsistent");
257 errno = EINVAL; /* hack */
262 /* it is, replace or remove it */
265 if (write(tfd, line, len) != (int) len)
268 /* when removed, avoid the \n */
271 /* we're done, just copy the rest over */
273 if (write(tfd, q, end - q) != end - q)
276 readlen = read(ffd, buf, sizeof(buf));
280 len = (size_t)readlen;
288 /* if we got here, we didn't find the old entry */
294 if ((size_t)write(tfd, line, len) != len ||
295 write(tfd, "\n", 1) != 1)
308 * Regenerate the group file
313 if (chmod(tempname, 0644) != 0)
316 return (rename(tempname, group_file));
320 * Clean up. Preserves errno for the caller's convenience.
331 if (*tempname != '\0') {
341 * Compares two struct group's.
344 gr_equal(const struct group *gr1, const struct group *gr2)
349 /* Check that the non-member information is the same. */
350 if (gr1->gr_name == NULL || gr2->gr_name == NULL) {
351 if (gr1->gr_name != gr2->gr_name)
353 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0)
355 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) {
356 if (gr1->gr_passwd != gr2->gr_passwd)
358 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0)
360 if (gr1->gr_gid != gr2->gr_gid)
363 /* Check all members in both groups.
364 * getgrnam can return gr_mem with a pointer to NULL.
365 * gr_dup and gr_add strip out this superfluous NULL, setting
366 * gr_mem to NULL for no members.
368 if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) {
371 for (i = 0; gr1->gr_mem[i] != NULL; i++) {
372 if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0)
376 /* Count number of members in both structs */
378 if (gr2->gr_mem != NULL)
379 for(; gr2->gr_mem[gr2_ndx] != NULL; gr2_ndx++)
382 if (gr1->gr_mem != NULL)
383 for(; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++)
385 if (gr1_ndx != gr2_ndx)
392 * Make a group line out of a struct group.
395 gr_make(const struct group *gr)
397 const char *group_line_format = "%s:%s:%ju:";
404 /* Calculate the length of the group line. */
405 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name,
406 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1;
407 if (gr->gr_mem != NULL) {
408 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++)
409 line_size += strlen(gr->gr_mem[ndx]) + 1;
414 /* Create the group line and fill it. */
415 if ((line = p = malloc(line_size)) == NULL)
417 p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd,
418 (uintmax_t)gr->gr_gid);
419 if (gr->gr_mem != NULL) {
421 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
423 p = stpcpy(p, gr->gr_mem[ndx]);
432 * Duplicate a struct group.
435 gr_dup(const struct group *gr)
437 return (gr_add(gr, NULL));
440 * Add a new member name to a struct group.
443 gr_add(const struct group *gr, const char *newmember)
450 len = grmemlen(gr, newmember, &num_mem);
451 /* Create new group and copy old group into it. */
452 if ((mem = malloc(len)) == NULL)
454 return (grcopy(gr, mem, newmember, num_mem));
457 /* It is safer to walk the pointers given at gr_mem since there is no
458 * guarantee the gr_mem + strings are contiguous in the given struct group
459 * but compactify the new group into the following form.
461 * The new struct is laid out like this in memory. The example given is
462 * for a group with two members only.
468 * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
480 * Copy the contents of a group plus given name to a preallocated group struct
482 static struct group *
483 grcopy(const struct group *gr, char *dst, const char *name, int ndx)
488 newgr = (struct group *)(void *)dst; /* avoid alignment warning */
489 dst += sizeof(*newgr);
491 newgr->gr_mem = (char **)(void *)(dst); /* avoid alignment warning */
492 dst += (ndx + 1) * sizeof(*newgr->gr_mem);
494 newgr->gr_mem = NULL;
495 if (gr->gr_name != NULL) {
496 newgr->gr_name = dst;
497 dst = stpcpy(dst, gr->gr_name) + 1;
499 newgr->gr_name = NULL;
500 if (gr->gr_passwd != NULL) {
501 newgr->gr_passwd = dst;
502 dst = stpcpy(dst, gr->gr_passwd) + 1;
504 newgr->gr_passwd = NULL;
505 newgr->gr_gid = gr->gr_gid;
507 /* Original group struct might have a NULL gr_mem */
508 if (gr->gr_mem != NULL) {
509 for (; gr->gr_mem[i] != NULL; i++) {
510 newgr->gr_mem[i] = dst;
511 dst = stpcpy(dst, gr->gr_mem[i]) + 1;
514 /* If name is not NULL, newgr->gr_mem is known to be not NULL */
516 newgr->gr_mem[i++] = dst;
517 dst = stpcpy(dst, name) + 1;
519 /* if newgr->gr_mem is not NULL add NULL marker */
520 if (newgr->gr_mem != NULL)
521 newgr->gr_mem[i] = NULL;
527 * Calculate length of a struct group + given name
530 grmemlen(const struct group *gr, const char *name, int *num_mem)
537 /* Calculate size of the group. */
539 if (gr->gr_name != NULL)
540 len += strlen(gr->gr_name) + 1;
541 if (gr->gr_passwd != NULL)
542 len += strlen(gr->gr_passwd) + 1;
544 if (gr->gr_mem != NULL) {
545 for (; gr->gr_mem[i] != NULL; i++) {
546 len += strlen(gr->gr_mem[i]) + 1;
547 len += sizeof(*gr->gr_mem);
552 len += strlen(name) + 1;
553 len += sizeof(*gr->gr_mem);
555 /* Allow for NULL pointer */
557 len += sizeof(*gr->gr_mem);
563 * Scan a line and place it into a group structure.
566 __gr_scan(char *line, struct group *gr)
571 /* Assign non-member information to structure. */
573 if ((loc = strchr(line, ':')) == NULL)
576 gr->gr_passwd = loc + 1;
577 if (*gr->gr_passwd == ':')
578 *gr->gr_passwd = '\0';
580 if ((loc = strchr(loc + 1, ':')) == NULL)
584 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1)
587 /* Assign member information to structure. */
588 if ((loc = strchr(loc + 1, ':')) == NULL)
594 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) *
596 if (gr->gr_mem == NULL)
599 /* Skip locations without members (i.e., empty string). */
601 gr->gr_mem[ndx] = strsep(&line, ",");
602 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0');
603 } while (gr->gr_mem[ndx++] != NULL);
609 * Create a struct group from a line.
612 gr_scan(const char *line)
616 struct group *new_gr;
618 if ((line_copy = strdup(line)) == NULL)
620 if (!__gr_scan(line_copy, &gr)) {
624 new_gr = gr_dup(&gr);
626 if (gr.gr_mem != NULL)