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.
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
31 #include <sys/errno.h>
47 static int lockfd = -1;
48 static char group_dir[PATH_MAX];
49 static char group_file[PATH_MAX];
50 static char tempname[PATH_MAX];
51 static int initialized;
52 static size_t grmemlen(const struct group *, const char *, int *);
53 static struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx);
59 gr_init(const char *dir, const char *group)
63 strcpy(group_dir, _PATH_ETC);
65 if (strlen(dir) >= sizeof(group_dir)) {
69 strcpy(group_dir, dir);
74 strcpy(group_file, _PATH_GROUP);
75 } else if (snprintf(group_file, sizeof(group_file), "%s/group",
76 group_dir) > (int)sizeof(group_file)) {
81 if (strlen(group) >= sizeof(group_file)) {
85 strcpy(group_file, group);
98 if (*group_file == '\0')
104 lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0);
106 if (errno == EWOULDBLOCK) {
107 errx(1, "the group file is busy");
109 err(1, "could not lock the group file: ");
112 if (fstat(lockfd, &st) == -1)
113 err(1, "fstat() failed: ");
114 if (st.st_nlink != 0)
123 * Create and open a presmuably safe temp file for editing group data
133 if (*group_file == '\0')
135 if ((p = strrchr(group_file, '/')))
139 if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX",
140 (int)(p - group_file), group_file) >= (int)sizeof(tempname)) {
141 errno = ENAMETOOLONG;
144 if ((tfd = mkostemp(tempname, O_SYNC)) == -1)
147 while ((nr = read(mfd, buf, sizeof(buf))) > 0)
148 if (write(tfd, buf, (size_t)nr) != nr)
161 * Copy the group file from one descriptor to another, replacing, deleting
162 * or adding a single record on the way.
165 gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
167 char buf[8192], *end, *line, *p, *q, *r, t;
169 const struct group *sgr;
173 if (old_gr == NULL && gr == NULL)
177 /* deleting a group */
181 if ((line = gr_make(gr)) == NULL)
193 /* find the end of the current line */
194 for (p = q; q < end && *q != '\0'; ++q)
198 /* if we don't have a complete line, fill up the buffer */
202 if ((size_t)(q - p) >= sizeof(buf)) {
203 warnx("group line too long");
204 errno = EINVAL; /* hack */
208 q = memmove(buf, p, end -p);
213 readlen = read(ffd, end, sizeof(buf) - (end -buf));
217 len = (size_t)readlen;
218 if (len == 0 && p == buf)
222 if (len < (ssize_t)sizeof(buf)) {
224 if (len > 0 && buf[len -1] != '\n')
225 ++len, *end++ = '\n';
230 /* is it a blank line or a comment? */
231 for (r = p; r < q && isspace(*r); ++r)
233 if (r == q || *r == '#') {
235 if (write(tfd, p, q -p + 1) != q - p + 1)
241 /* is it the one we're looking for? */
248 /* fgr is either a struct group for the current line,
249 * or NULL if the line is malformed.
253 if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) {
257 if (write(tfd, p, q - p + 1) != q - p + 1)
262 if (old_gr && !gr_equal(fgr, old_gr)) {
263 warnx("entry inconsistent");
265 errno = EINVAL; /* hack */
270 /* it is, replace or remove it */
273 if (write(tfd, line, len) != (int) len)
276 /* when removed, avoid the \n */
279 /* we're done, just copy the rest over */
281 if (write(tfd, q, end - q) != end - q)
284 readlen = read(ffd, buf, sizeof(buf));
288 len = (size_t)readlen;
296 /* if we got here, we didn't find the old entry */
302 if ((size_t)write(tfd, line, len) != len ||
303 write(tfd, "\n", 1) != 1)
316 * Regenerate the group file
323 if (chmod(tempname, 0644) != 0)
326 if (rename(tempname, group_file) != 0)
330 * Make sure new group file is safe on disk. To improve performance we
331 * will call fsync() to the directory where file lies
333 if ((fd = open(group_dir, O_RDONLY|O_DIRECTORY)) == -1)
336 if (fsync(fd) != 0) {
346 * Clean up. Preserves errno for the caller's convenience.
357 if (*tempname != '\0') {
367 * Compares two struct group's.
370 gr_equal(const struct group *gr1, const struct group *gr2)
375 /* Check that the non-member information is the same. */
376 if (gr1->gr_name == NULL || gr2->gr_name == NULL) {
377 if (gr1->gr_name != gr2->gr_name)
379 } else if (strcmp(gr1->gr_name, gr2->gr_name) != 0)
381 if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) {
382 if (gr1->gr_passwd != gr2->gr_passwd)
384 } else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0)
386 if (gr1->gr_gid != gr2->gr_gid)
389 /* Check all members in both groups.
390 * getgrnam can return gr_mem with a pointer to NULL.
391 * gr_dup and gr_add strip out this superfluous NULL, setting
392 * gr_mem to NULL for no members.
394 if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) {
397 for (i = 0; gr1->gr_mem[i] != NULL; i++) {
398 if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0)
402 /* Count number of members in both structs */
404 if (gr2->gr_mem != NULL)
405 for(; gr2->gr_mem[gr2_ndx] != NULL; gr2_ndx++)
408 if (gr1->gr_mem != NULL)
409 for(; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++)
411 if (gr1_ndx != gr2_ndx)
418 * Make a group line out of a struct group.
421 gr_make(const struct group *gr)
423 const char *group_line_format = "%s:%s:%ju:";
430 /* Calculate the length of the group line. */
431 line_size = snprintf(NULL, 0, group_line_format, gr->gr_name,
432 gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1;
433 if (gr->gr_mem != NULL) {
434 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++)
435 line_size += strlen(gr->gr_mem[ndx]) + 1;
440 /* Create the group line and fill it. */
441 if ((line = p = malloc(line_size)) == NULL)
443 p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd,
444 (uintmax_t)gr->gr_gid);
445 if (gr->gr_mem != NULL) {
447 for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
449 p = stpcpy(p, gr->gr_mem[ndx]);
458 * Duplicate a struct group.
461 gr_dup(const struct group *gr)
463 return (gr_add(gr, NULL));
466 * Add a new member name to a struct group.
469 gr_add(const struct group *gr, const char *newmember)
476 len = grmemlen(gr, newmember, &num_mem);
477 /* Create new group and copy old group into it. */
478 if ((mem = malloc(len)) == NULL)
480 return (grcopy(gr, mem, newmember, num_mem));
483 /* It is safer to walk the pointers given at gr_mem since there is no
484 * guarantee the gr_mem + strings are contiguous in the given struct group
485 * but compactify the new group into the following form.
487 * The new struct is laid out like this in memory. The example given is
488 * for a group with two members only.
494 * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
506 * Copy the contents of a group plus given name to a preallocated group struct
508 static struct group *
509 grcopy(const struct group *gr, char *dst, const char *name, int ndx)
514 newgr = (struct group *)(void *)dst; /* avoid alignment warning */
515 dst += sizeof(*newgr);
517 newgr->gr_mem = (char **)(void *)(dst); /* avoid alignment warning */
518 dst += (ndx + 1) * sizeof(*newgr->gr_mem);
520 newgr->gr_mem = NULL;
521 if (gr->gr_name != NULL) {
522 newgr->gr_name = dst;
523 dst = stpcpy(dst, gr->gr_name) + 1;
525 newgr->gr_name = NULL;
526 if (gr->gr_passwd != NULL) {
527 newgr->gr_passwd = dst;
528 dst = stpcpy(dst, gr->gr_passwd) + 1;
530 newgr->gr_passwd = NULL;
531 newgr->gr_gid = gr->gr_gid;
533 /* Original group struct might have a NULL gr_mem */
534 if (gr->gr_mem != NULL) {
535 for (; gr->gr_mem[i] != NULL; i++) {
536 newgr->gr_mem[i] = dst;
537 dst = stpcpy(dst, gr->gr_mem[i]) + 1;
540 /* If name is not NULL, newgr->gr_mem is known to be not NULL */
542 newgr->gr_mem[i++] = dst;
543 dst = stpcpy(dst, name) + 1;
545 /* if newgr->gr_mem is not NULL add NULL marker */
546 if (newgr->gr_mem != NULL)
547 newgr->gr_mem[i] = NULL;
553 * Calculate length of a struct group + given name
556 grmemlen(const struct group *gr, const char *name, int *num_mem)
563 /* Calculate size of the group. */
565 if (gr->gr_name != NULL)
566 len += strlen(gr->gr_name) + 1;
567 if (gr->gr_passwd != NULL)
568 len += strlen(gr->gr_passwd) + 1;
570 if (gr->gr_mem != NULL) {
571 for (; gr->gr_mem[i] != NULL; i++) {
572 len += strlen(gr->gr_mem[i]) + 1;
573 len += sizeof(*gr->gr_mem);
578 len += strlen(name) + 1;
579 len += sizeof(*gr->gr_mem);
581 /* Allow for NULL pointer */
583 len += sizeof(*gr->gr_mem);
589 * Scan a line and place it into a group structure.
592 __gr_scan(char *line, struct group *gr)
597 /* Assign non-member information to structure. */
599 if ((loc = strchr(line, ':')) == NULL)
602 gr->gr_passwd = loc + 1;
603 if (*gr->gr_passwd == ':')
604 *gr->gr_passwd = '\0';
606 if ((loc = strchr(loc + 1, ':')) == NULL)
610 if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1)
613 /* Assign member information to structure. */
614 if ((loc = strchr(loc + 1, ':')) == NULL)
620 gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) *
622 if (gr->gr_mem == NULL)
625 /* Skip locations without members (i.e., empty string). */
627 gr->gr_mem[ndx] = strsep(&line, ",");
628 } while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0');
629 } while (gr->gr_mem[ndx++] != NULL);
635 * Create a struct group from a line.
638 gr_scan(const char *line)
642 struct group *new_gr;
644 if ((line_copy = strdup(line)) == NULL)
646 if (!__gr_scan(line_copy, &gr)) {
650 new_gr = gr_dup(&gr);
652 if (gr.gr_mem != NULL)