+#include <unistd.h>
+
+static int lockfd = -1;
+static char group_dir[PATH_MAX];
+static char group_file[PATH_MAX];
+static char tempname[PATH_MAX];
+static int initialized;
+static size_t grmemlen(const struct group *, const char *, int *);
+static struct group *grcopy(const struct group *gr, char *mem, const char *, int ndx);
+
+/*
+ * Initialize statics
+ */
+int
+gr_init(const char *dir, const char *group)
+{
+
+ if (dir == NULL) {
+ strcpy(group_dir, _PATH_ETC);
+ } else {
+ if (strlen(dir) >= sizeof(group_dir)) {
+ errno = ENAMETOOLONG;
+ return (-1);
+ }
+ strcpy(group_dir, dir);
+ }
+
+ if (group == NULL) {
+ if (dir == NULL) {
+ strcpy(group_file, _PATH_GROUP);
+ } else if (snprintf(group_file, sizeof(group_file), "%s/group",
+ group_dir) > (int)sizeof(group_file)) {
+ errno = ENAMETOOLONG;
+ return (-1);
+ }
+ } else {
+ if (strlen(group) >= sizeof(group_file)) {
+ errno = ENAMETOOLONG;
+ return (-1);
+ }
+ strcpy(group_file, group);
+ }
+
+ initialized = 1;
+ return (0);
+}
+
+/*
+ * Lock the group file
+ */
+int
+gr_lock(void)
+{
+ if (*group_file == '\0')
+ return (-1);
+
+ for (;;) {
+ struct stat st;
+
+ lockfd = flopen(group_file, O_RDONLY|O_NONBLOCK|O_CLOEXEC, 0);
+ if (lockfd == -1) {
+ if (errno == EWOULDBLOCK) {
+ errx(1, "the group file is busy");
+ } else {
+ err(1, "could not lock the group file: ");
+ }
+ }
+ if (fstat(lockfd, &st) == -1)
+ err(1, "fstat() failed: ");
+ if (st.st_nlink != 0)
+ break;
+ close(lockfd);
+ lockfd = -1;
+ }
+ return (lockfd);
+}
+
+/*
+ * Create and open a presmuably safe temp file for editing group data
+ */
+int
+gr_tmp(int mfd)
+{
+ char buf[8192];
+ ssize_t nr;
+ const char *p;
+ int tfd;
+
+ if (*group_file == '\0')
+ return (-1);
+ if ((p = strrchr(group_file, '/')))
+ ++p;
+ else
+ p = group_file;
+ if (snprintf(tempname, sizeof(tempname), "%.*sgroup.XXXXXX",
+ (int)(p - group_file), group_file) >= (int)sizeof(tempname)) {
+ errno = ENAMETOOLONG;
+ return (-1);
+ }
+ if ((tfd = mkostemp(tempname, 0)) == -1)
+ return (-1);
+ if (mfd != -1) {
+ while ((nr = read(mfd, buf, sizeof(buf))) > 0)
+ if (write(tfd, buf, (size_t)nr) != nr)
+ break;
+ if (nr != 0) {
+ unlink(tempname);
+ *tempname = '\0';
+ close(tfd);
+ return (-1);
+ }
+ }
+ return (tfd);
+}
+
+/*
+ * Copy the group file from one descriptor to another, replacing, deleting
+ * or adding a single record on the way.
+ */
+int
+gr_copy(int ffd, int tfd, const struct group *gr, struct group *old_gr)
+{
+ char *buf, *end, *line, *p, *q, *r, *tmp;
+ struct group *fgr;
+ const struct group *sgr;
+ size_t len, size;
+ int eof, readlen;
+ char t;
+
+ if (old_gr == NULL && gr == NULL)
+ return(-1);
+
+ sgr = old_gr;
+ /* deleting a group */
+ if (gr == NULL) {
+ line = NULL;
+ } else {
+ if ((line = gr_make(gr)) == NULL)
+ return (-1);
+ }
+
+ /* adding a group */
+ if (sgr == NULL)
+ sgr = gr;
+
+ /* initialize the buffer */
+ if ((buf = malloc(size = 1024)) == NULL)
+ goto err;
+
+ eof = 0;
+ len = 0;
+ p = q = end = buf;
+ for (;;) {
+ /* find the end of the current line */
+ for (p = q; q < end && *q != '\0'; ++q)
+ if (*q == '\n')
+ break;
+
+ /* if we don't have a complete line, fill up the buffer */
+ if (q >= end) {
+ if (eof)
+ break;
+ while ((size_t)(q - p) >= size) {
+ if ((tmp = reallocarray(buf, 2, size)) == NULL) {
+ warnx("group line too long");
+ goto err;
+ }
+ p = tmp + (p - buf);
+ q = tmp + (q - buf);
+ end = tmp + (end - buf);
+ buf = tmp;
+ size = size * 2;
+ }
+ if (p < end) {
+ q = memmove(buf, p, end -p);
+ end -= p - buf;
+ } else {
+ p = q = end = buf;
+ }
+ readlen = read(ffd, end, size - (end - buf));
+ if (readlen == -1)
+ goto err;
+ else
+ len = (size_t)readlen;
+ if (len == 0 && p == buf)
+ break;
+ end += len;
+ len = end - buf;
+ if (len < size) {
+ eof = 1;
+ if (len > 0 && buf[len -1] != '\n')
+ ++len, *end++ = '\n';
+ }
+ continue;
+ }
+
+ /* is it a blank line or a comment? */
+ for (r = p; r < q && isspace(*r); ++r)
+ /* nothing */;
+ if (r == q || *r == '#') {
+ /* yep */
+ if (write(tfd, p, q -p + 1) != q - p + 1)
+ goto err;
+ ++q;
+ continue;
+ }
+
+ /* is it the one we're looking for? */
+
+ t = *q;
+ *q = '\0';
+
+ fgr = gr_scan(r);
+
+ /* fgr is either a struct group for the current line,
+ * or NULL if the line is malformed.
+ */
+
+ *q = t;
+ if (fgr == NULL || fgr->gr_gid != sgr->gr_gid) {
+ /* nope */
+ if (fgr != NULL)
+ free(fgr);
+ if (write(tfd, p, q - p + 1) != q - p + 1)
+ goto err;
+ ++q;
+ continue;
+ }
+ if (old_gr && !gr_equal(fgr, old_gr)) {
+ warnx("entry inconsistent");
+ free(fgr);
+ errno = EINVAL; /* hack */
+ goto err;
+ }
+ free(fgr);
+
+ /* it is, replace or remove it */
+ if (line != NULL) {
+ len = strlen(line);
+ if (write(tfd, line, len) != (int) len)
+ goto err;
+ } else {
+ /* when removed, avoid the \n */
+ q++;
+ }
+ /* we're done, just copy the rest over */
+ for (;;) {
+ if (write(tfd, q, end - q) != end - q)
+ goto err;
+ q = buf;
+ readlen = read(ffd, buf, size);
+ if (readlen == 0)
+ break;
+ else
+ len = (size_t)readlen;
+ if (readlen == -1)
+ goto err;
+ end = buf + len;
+ }
+ goto done;
+ }
+
+ /* if we got here, we didn't find the old entry */
+ if (line == NULL) {
+ errno = ENOENT;
+ goto err;
+ }
+ len = strlen(line);
+ if ((size_t)write(tfd, line, len) != len ||
+ write(tfd, "\n", 1) != 1)
+ goto err;
+ done:
+ free(line);
+ free(buf);
+ return (0);
+ err:
+ free(line);
+ free(buf);
+ return (-1);
+}
+
+/*
+ * Regenerate the group file
+ */
+int
+gr_mkdb(void)
+{
+ int fd;
+
+ if (chmod(tempname, 0644) != 0)
+ return (-1);
+
+ if (rename(tempname, group_file) != 0)
+ return (-1);
+
+ /*
+ * Make sure new group file is safe on disk. To improve performance we
+ * will call fsync() to the directory where file lies
+ */
+ if ((fd = open(group_dir, O_RDONLY|O_DIRECTORY)) == -1)
+ return (-1);
+
+ if (fsync(fd) != 0) {
+ close(fd);
+ return (-1);
+ }
git.ckatri.com / pw-darwin.git / blobdiff