652 lines
14 KiB
C
652 lines
14 KiB
C
/*-
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* Copyright (c) 2008 Sean C. Farley <scf@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer,
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* without modification, immediately at the beginning of the file.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/errno.h>
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#include <sys/stat.h>
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#include <ctype.h>
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#include <err.h>
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#include <fcntl.h>
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#include <grp.h>
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#include <inttypes.h>
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#include <libutil.h>
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#include <paths.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static int lockfd = -1;
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static char group_dir[PATH_MAX];
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static char group_file[PATH_MAX];
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static char tempname[PATH_MAX];
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static int initialized;
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static size_t grmemlen(const struct group *, const char *, int *);
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static struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx);
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/*
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* Initialize statics
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*/
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int
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gr_init(const char *dir, const char *group)
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{
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if (dir == NULL) {
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strcpy(group_dir, _PATH_ETC);
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} else {
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if (strlen(dir) >= sizeof(group_dir)) {
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errno = ENAMETOOLONG;
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return (-1);
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}
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strcpy(group_dir, dir);
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}
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if (group == NULL) {
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if (dir == NULL) {
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strcpy(group_file, _PATH_GROUP);
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} else if (snprintf(group_file, sizeof(group_file), "%s/group",
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group_dir) > (int)sizeof(group_file)) {
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errno = ENAMETOOLONG;
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return (-1);
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}
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} else {
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if (strlen(group) >= sizeof(group_file)) {
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errno = ENAMETOOLONG;
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return (-1);
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}
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strcpy(group_file, group);
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}
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initialized = 1;
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return (0);
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}
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/*
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* Lock the group file
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*/
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int
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gr_lock(void)
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{
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if (*group_file == '\0')
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return (-1);
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for (;;) {
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struct stat st;
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lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0);
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if (lockfd == -1) {
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if (errno == EWOULDBLOCK) {
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errx(1, "the group file is busy");
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} else {
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err(1, "could not lock the group file: ");
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}
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}
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if (fstat(lockfd, &st) == -1)
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err(1, "fstat() failed: ");
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if (st.st_nlink != 0)
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break;
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close(lockfd);
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lockfd = -1;
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}
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return (lockfd);
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}
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/*
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* Create and open a presmuably safe temp file for editing group data
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*/
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int
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gr_tmp(int mfd)
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{
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char buf[8192];
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ssize_t nr;
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const char *p;
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int tfd;
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if (*group_file == '\0')
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return (-1);
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if ((p = strrchr(group_file, '/')))
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++p;
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else
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p = group_file;
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if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX",
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(int)(p - group_file), group_file) >= (int)sizeof(tempname)) {
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errno = ENAMETOOLONG;
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return (-1);
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}
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if ((tfd = mkostemp(tempname, O_SYNC)) == -1)
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return (-1);
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if (mfd != -1) {
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while ((nr = read(mfd, buf, sizeof(buf))) > 0)
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if (write(tfd, buf, (size_t)nr) != nr)
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break;
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if (nr != 0) {
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unlink(tempname);
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*tempname = '\0';
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close(tfd);
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return (-1);
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}
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}
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return (tfd);
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}
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/*
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* Copy the group file from one descriptor to another, replacing, deleting
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* or adding a single record on the way.
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*/
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int
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gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
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{
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char buf[8192], *end, *line, *p, *q, *r, t;
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struct group *fgr;
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const struct group *sgr;
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size_t len;
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int eof, readlen;
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if (old_gr == NULL && gr == NULL)
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return(-1);
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sgr = old_gr;
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/* deleting a group */
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if (gr == NULL) {
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line = NULL;
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} else {
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if ((line = gr_make(gr)) == NULL)
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return (-1);
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}
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/* adding a group */
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if (sgr == NULL)
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sgr = gr;
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eof = 0;
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len = 0;
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p = q = end = buf;
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for (;;) {
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/* find the end of the current line */
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for (p = q; q < end && *q != '\0'; ++q)
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if (*q == '\n')
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break;
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/* if we don't have a complete line, fill up the buffer */
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if (q >= end) {
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if (eof)
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break;
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if ((size_t)(q - p) >= sizeof(buf)) {
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warnx("group line too long");
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errno = EINVAL; /* hack */
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goto err;
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}
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if (p < end) {
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q = memmove(buf, p, end -p);
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end -= p - buf;
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} else {
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p = q = end = buf;
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}
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readlen = read(ffd, end, sizeof(buf) - (end -buf));
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if (readlen == -1)
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goto err;
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else
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len = (size_t)readlen;
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if (len == 0 && p == buf)
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break;
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end += len;
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len = end - buf;
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if (len < (ssize_t)sizeof(buf)) {
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eof = 1;
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if (len > 0 && buf[len -1] != '\n')
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++len, *end++ = '\n';
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}
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continue;
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}
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/* is it a blank line or a comment? */
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for (r = p; r < q && isspace(*r); ++r)
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/* nothing */;
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if (r == q || *r == '#') {
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/* yep */
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if (write(tfd, p, q -p + 1) != q - p + 1)
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goto err;
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++q;
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continue;
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}
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/* is it the one we're looking for? */
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t = *q;
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*q = '\0';
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fgr = gr_scan(r);
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/* fgr is either a struct group for the current line,
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* or NULL if the line is malformed.
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*/
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*q = t;
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if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) {
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/* nope */
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if (fgr != NULL)
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free(fgr);
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if (write(tfd, p, q - p + 1) != q - p + 1)
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goto err;
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++q;
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continue;
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}
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if (old_gr && !gr_equal(fgr, old_gr)) {
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warnx("entry inconsistent");
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free(fgr);
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errno = EINVAL; /* hack */
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goto err;
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}
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free(fgr);
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/* it is, replace or remove it */
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if (line != NULL) {
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len = strlen(line);
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if (write(tfd, line, len) != (int) len)
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goto err;
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} else {
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/* when removed, avoid the \n */
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q++;
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}
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/* we're done, just copy the rest over */
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for (;;) {
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if (write(tfd, q, end - q) != end - q)
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goto err;
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q = buf;
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readlen = read(ffd, buf, sizeof(buf));
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if (readlen == 0)
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break;
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else
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len = (size_t)readlen;
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if (readlen == -1)
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goto err;
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end = buf + len;
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}
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goto done;
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}
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/* if we got here, we didn't find the old entry */
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if (line == NULL) {
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errno = ENOENT;
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goto err;
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}
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len = strlen(line);
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if ((size_t)write(tfd, line, len) != len ||
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write(tfd, "\n", 1) != 1)
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goto err;
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done:
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if (line != NULL)
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free(line);
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return (0);
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err:
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if (line != NULL)
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free(line);
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return (-1);
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}
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/*
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* Regenerate the group file
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*/
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int
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gr_mkdb(void)
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{
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int fd;
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if (chmod(tempname, 0644) != 0)
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return (-1);
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if (rename(tempname, group_file) != 0)
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return (-1);
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/*
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* Make sure new group file is safe on disk. To improve performance we
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* will call fsync() to the directory where file lies
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*/
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if ((fd = open(group_dir, O_RDONLY|O_DIRECTORY)) == -1)
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return (-1);
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if (fsync(fd) != 0) {
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close(fd);
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return (-1);
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}
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close(fd);
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return(0);
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}
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/*
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* Clean up. Preserves errno for the caller's convenience.
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*/
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void
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gr_fini(void)
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{
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int serrno;
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if (!initialized)
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return;
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initialized = 0;
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serrno = errno;
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if (*tempname != '\0') {
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unlink(tempname);
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*tempname = '\0';
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}
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if (lockfd != -1)
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close(lockfd);
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errno = serrno;
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}
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/*
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* Compares two struct group's.
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*/
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int
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gr_equal(const struct group *gr1, const struct group *gr2)
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{
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/* Check that the non-member information is the same. */
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if (gr1->gr_name == NULL || gr2->gr_name == NULL) {
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if (gr1->gr_name != gr2->gr_name)
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return (false);
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} else if (strcmp(gr1->gr_name, gr2->gr_name) != 0)
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return (false);
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if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) {
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if (gr1->gr_passwd != gr2->gr_passwd)
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return (false);
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} else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0)
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return (false);
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if (gr1->gr_gid != gr2->gr_gid)
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return (false);
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/*
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* Check all members in both groups.
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* getgrnam can return gr_mem with a pointer to NULL.
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* gr_dup and gr_add strip out this superfluous NULL, setting
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* gr_mem to NULL for no members.
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*/
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if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) {
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int i;
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for (i = 0;
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gr1->gr_mem[i] != NULL && gr2->gr_mem[i] != NULL; i++) {
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if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0)
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return (false);
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}
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if (gr1->gr_mem[i] != NULL || gr2->gr_mem[i] != NULL)
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return (false);
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} else if (gr1->gr_mem != NULL && gr1->gr_mem[0] != NULL) {
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return (false);
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} else if (gr2->gr_mem != NULL && gr2->gr_mem[0] != NULL) {
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return (false);
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}
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return (true);
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}
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/*
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* Make a group line out of a struct group.
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*/
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char *
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gr_make(const struct group *gr)
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{
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const char *group_line_format = "%s:%s:%ju:";
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const char *sep;
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char *line;
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char *p;
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size_t line_size;
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int ndx;
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/* Calculate the length of the group line. */
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line_size = snprintf(NULL, 0, group_line_format, gr->gr_name,
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gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1;
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if (gr->gr_mem != NULL) {
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for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++)
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line_size += strlen(gr->gr_mem[ndx]) + 1;
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if (ndx > 0)
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line_size--;
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}
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/* Create the group line and fill it. */
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if ((line = p = malloc(line_size)) == NULL)
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return (NULL);
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p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd,
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(uintmax_t)gr->gr_gid);
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if (gr->gr_mem != NULL) {
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sep = "";
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for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
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p = stpcpy(p, sep);
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p = stpcpy(p, gr->gr_mem[ndx]);
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sep = ",";
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}
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}
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return (line);
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}
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/*
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* Duplicate a struct group.
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*/
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struct group *
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gr_dup(const struct group *gr)
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{
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return (gr_add(gr, NULL));
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}
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/*
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* Add a new member name to a struct group.
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*/
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struct group *
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gr_add(const struct group *gr, const char *newmember)
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{
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char *mem;
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size_t len;
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int num_mem;
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num_mem = 0;
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len = grmemlen(gr, newmember, &num_mem);
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/* Create new group and copy old group into it. */
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if ((mem = malloc(len)) == NULL)
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return (NULL);
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return (grcopy(gr, mem, newmember, num_mem));
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}
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/* It is safer to walk the pointers given at gr_mem since there is no
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* guarantee the gr_mem + strings are contiguous in the given struct group
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* but compactify the new group into the following form.
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*
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* The new struct is laid out like this in memory. The example given is
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* for a group with two members only.
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*
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* {
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* (char *name)
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* (char *passwd)
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* (int gid)
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* (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
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* gr_mem area
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* (member1 *)
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* (member2 *)
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* (NULL)
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* (name string)
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* (passwd string)
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* (member1 string)
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* (member2 string)
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* }
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*/
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/*
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* Copy the contents of a group plus given name to a preallocated group struct
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*/
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static struct group *
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grcopy(const struct group *gr, char *dst, const char *name, int ndx)
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{
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int i;
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struct group *newgr;
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newgr = (struct group *)(void *)dst; /* avoid alignment warning */
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dst += sizeof(*newgr);
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if (ndx != 0) {
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newgr->gr_mem = (char **)(void *)(dst); /* avoid alignment warning */
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dst += (ndx + 1) * sizeof(*newgr->gr_mem);
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} else
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newgr->gr_mem = NULL;
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if (gr->gr_name != NULL) {
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newgr->gr_name = dst;
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dst = stpcpy(dst, gr->gr_name) + 1;
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} else
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newgr->gr_name = NULL;
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if (gr->gr_passwd != NULL) {
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newgr->gr_passwd = dst;
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dst = stpcpy(dst, gr->gr_passwd) + 1;
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} else
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newgr->gr_passwd = NULL;
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newgr->gr_gid = gr->gr_gid;
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i = 0;
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/* Original group struct might have a NULL gr_mem */
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if (gr->gr_mem != NULL) {
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for (; gr->gr_mem[i] != NULL; i++) {
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newgr->gr_mem[i] = dst;
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dst = stpcpy(dst, gr->gr_mem[i]) + 1;
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}
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}
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/* If name is not NULL, newgr->gr_mem is known to be not NULL */
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if (name != NULL) {
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newgr->gr_mem[i++] = dst;
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dst = stpcpy(dst, name) + 1;
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}
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/* if newgr->gr_mem is not NULL add NULL marker */
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if (newgr->gr_mem != NULL)
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newgr->gr_mem[i] = NULL;
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return (newgr);
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}
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/*
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* Calculate length of a struct group + given name
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*/
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static size_t
|
|
grmemlen(const struct group *gr, const char *name, int *num_mem)
|
|
{
|
|
size_t len;
|
|
int i;
|
|
|
|
if (gr == NULL)
|
|
return (0);
|
|
/* Calculate size of the group. */
|
|
len = sizeof(*gr);
|
|
if (gr->gr_name != NULL)
|
|
len += strlen(gr->gr_name) + 1;
|
|
if (gr->gr_passwd != NULL)
|
|
len += strlen(gr->gr_passwd) + 1;
|
|
i = 0;
|
|
if (gr->gr_mem != NULL) {
|
|
for (; gr->gr_mem[i] != NULL; i++) {
|
|
len += strlen(gr->gr_mem[i]) + 1;
|
|
len += sizeof(*gr->gr_mem);
|
|
}
|
|
}
|
|
if (name != NULL) {
|
|
i++;
|
|
len += strlen(name) + 1;
|
|
len += sizeof(*gr->gr_mem);
|
|
}
|
|
/* Allow for NULL pointer */
|
|
if (i != 0)
|
|
len += sizeof(*gr->gr_mem);
|
|
*num_mem = i;
|
|
return(len);
|
|
}
|
|
|
|
/*
|
|
* Scan a line and place it into a group structure.
|
|
*/
|
|
static bool
|
|
__gr_scan(char *line, struct group *gr)
|
|
{
|
|
char *loc;
|
|
int ndx;
|
|
|
|
/* Assign non-member information to structure. */
|
|
gr->gr_name = line;
|
|
if ((loc = strchr(line, ':')) == NULL)
|
|
return (false);
|
|
*loc = '\0';
|
|
gr->gr_passwd = loc + 1;
|
|
if (*gr->gr_passwd == ':')
|
|
*gr->gr_passwd = '\0';
|
|
else {
|
|
if ((loc = strchr(loc + 1, ':')) == NULL)
|
|
return (false);
|
|
*loc = '\0';
|
|
}
|
|
if (sscanf(loc + 1, "%u", &gr->gr_gid) != 1)
|
|
return (false);
|
|
|
|
/* Assign member information to structure. */
|
|
if ((loc = strchr(loc + 1, ':')) == NULL)
|
|
return (false);
|
|
line = loc + 1;
|
|
gr->gr_mem = NULL;
|
|
ndx = 0;
|
|
do {
|
|
gr->gr_mem = reallocf(gr->gr_mem, sizeof(*gr->gr_mem) *
|
|
(ndx + 1));
|
|
if (gr->gr_mem == NULL)
|
|
return (false);
|
|
|
|
/* Skip locations without members (i.e., empty string). */
|
|
do {
|
|
gr->gr_mem[ndx] = strsep(&line, ",");
|
|
} while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0');
|
|
} while (gr->gr_mem[ndx++] != NULL);
|
|
|
|
return (true);
|
|
}
|
|
|
|
/*
|
|
* Create a struct group from a line.
|
|
*/
|
|
struct group *
|
|
gr_scan(const char *line)
|
|
{
|
|
struct group gr;
|
|
char *line_copy;
|
|
struct group *new_gr;
|
|
|
|
if ((line_copy = strdup(line)) == NULL)
|
|
return (NULL);
|
|
if (!__gr_scan(line_copy, &gr)) {
|
|
free(line_copy);
|
|
return (NULL);
|
|
}
|
|
new_gr = gr_dup(&gr);
|
|
free(line_copy);
|
|
if (gr.gr_mem != NULL)
|
|
free(gr.gr_mem);
|
|
|
|
return (new_gr);
|
|
}
|