Modify pw_copy:
- if pw is NULL and oldpw is not NULL then the oldpw is deleted - if pw->pw_name != oldpw->pw_name but pw->pw_uid == oldpw->pw_uid then it renames the user add new gr_* functions so now gr_util API is similar to pw_util API, this allow to manipulate groups in a safe way. Reviewed by: des Approved by: des MFC after: 1 month
This commit is contained in:
Baptiste Daroussin
parent
f59936d642
commit
1926f2f6fa
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=228545
@ -28,22 +28,318 @@
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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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struct group_storage {
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struct group gr;
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char *members[];
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};
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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 const char group_line_format[] = "%s:%s:%ju:";
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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 = open(group_file, O_RDONLY, 0);
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if (lockfd < 0 || fcntl(lockfd, F_SETFD, 1) == -1)
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err(1, "%s", group_file);
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if (flock(lockfd, LOCK_EX|LOCK_NB) == -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 = mkstemp(tempname)) == -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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sgr = gr;
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if (gr == NULL) {
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line = NULL;
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if (old_gr == NULL)
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return (-1);
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sgr = old_gr;
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} else if ((line = gr_make(gr)) == NULL)
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return (-1);
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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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return (rename(tempname, group_file));
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}
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/*
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* Clean up. Preserver 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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@ -152,9 +152,15 @@ int pw_tmp(int _mfd);
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#endif
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#ifdef _GRP_H_
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int gr_equal(const struct group *gr1, const struct group *gr2);
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char *gr_make(const struct group *gr);
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int gr_copy(int __ffd, int _tfd, const struct group *_gr, struct group *_old_gr);
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struct group *gr_dup(const struct group *gr);
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int gr_equal(const struct group *gr1, const struct group *gr2);
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void gr_fini(void);
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int gr_init(const char *_dir, const char *_master);
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int gr_lock(void);
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char *gr_make(const struct group *gr);
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int gr_mkdb(void);
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int gr_tmp(int _mdf);
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struct group *gr_scan(const char *line);
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#endif
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@ -410,18 +410,25 @@ pw_make(const struct passwd *pw)
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}
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/*
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* Copy password file from one descriptor to another, replacing or adding
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* a single record on the way.
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* Copy password 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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pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
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{
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char buf[8192], *end, *line, *p, *q, *r, t;
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struct passwd *fpw;
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const struct passwd *spw;
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size_t len;
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int eof, readlen;
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if ((line = pw_make(pw)) == NULL)
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spw = pw;
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if (pw == NULL) {
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line = NULL;
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if (old_pw == NULL)
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return (-1);
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spw = old_pw;
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} else if ((line = pw_make(pw)) == NULL)
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return (-1);
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eof = 0;
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@ -489,7 +496,7 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
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*/
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*q = t;
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if (fpw == NULL || strcmp(fpw->pw_name, pw->pw_name) != 0) {
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if (fpw == NULL || fpw->pw_uid != spw->pw_uid) {
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/* nope */
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if (fpw != NULL)
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free(fpw);
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@ -506,11 +513,15 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
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}
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free(fpw);
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/* it is, replace it */
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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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/* 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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@ -528,16 +539,22 @@ pw_copy(int ffd, int tfd, const struct passwd *pw, struct passwd *old_pw)
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goto done;
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}
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/* if we got here, we have a new entry */
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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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free(line);
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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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free(line);
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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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