X-Git-Url: https://git.cameronkatri.com/pw-darwin.git/blobdiff_plain/83c1d785dfb8bceaad5d4f1b9ce2f7cd4cb802a0..fb90d29ec2763027a93943b3f30250bd05afd62c:/libutil/gr_util.c

diff --git a/libutil/gr_util.c b/libutil/gr_util.c
index fc5e442..465efd9 100644
--- a/libutil/gr_util.c
+++ b/libutil/gr_util.c
@@ -28,55 +28,372 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/errno.h>
+#include <sys/stat.h>
 
+#include <ctype.h>
+#include <err.h>
+#include <fcntl.h>
 #include <grp.h>
 #include <inttypes.h>
 #include <libutil.h>
+#include <paths.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
-static const char GroupLineFormat[] = "%s:%s:%ju:";
+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);
 
 /*
- * Compares two struct group's.
+ * Initialize statics
  */
 int
-gr_equal(const struct group *gr1, const struct group *gr2)
+gr_init(const char *dir, const char *group)
 {
-	int gr1Ndx;
-	int gr2Ndx;
-	bool equal;
-	bool found;
 
-	/* Check that the non-member information is the same. */
-	equal = strcmp(gr1->gr_name, gr2->gr_name) == 0 &&
-	    strcmp(gr1->gr_passwd, gr2->gr_passwd) == 0 &&
-	    gr1->gr_gid == gr2->gr_gid;
-
-	/* Check all members in both groups. */
-	if (equal) {
-		for (found = false, gr1Ndx = 0; gr1->gr_mem[gr1Ndx] != NULL;
-		    gr1Ndx++) {
-			for (gr2Ndx = 0; gr2->gr_mem[gr2Ndx] != NULL; gr2Ndx++)
-				if (strcmp(gr1->gr_mem[gr1Ndx],
-				    gr2->gr_mem[gr2Ndx]) == 0) {
-					found = true;
-					break;
-				}
-			if (! found) {
-				equal = false;
+	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 = mkstemp(tempname)) == -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[8192], *end, *line, *p, *q, *r, t;
+	struct group *fgr;
+	const struct group *sgr;
+	size_t len;
+	int eof, readlen;
+
+	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;
+
+	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;
+			if ((size_t)(q - p) >= sizeof(buf)) {
+				warnx("group line too long");
+				errno = EINVAL; /* hack */
+				goto err;
+			}
+			if (p < end) {
+				q = memmove(buf, p, end -p);
+				end -= p - buf;
+			} else {
+				p = q = end = buf;
 			}
+			readlen = read(ffd, end, sizeof(buf) - (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 < (ssize_t)sizeof(buf)) {
+				eof = 1;
+				if (len > 0 && buf[len -1] != '\n')
+					++len, *end++ = '\n';
+			}
+			continue;
 		}
 
-		/* Check that group2 does not have more members than group1. */
-		if (gr2->gr_mem[gr1Ndx] != NULL)
-			equal = false;
+		/* 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, sizeof(buf));
+			if (readlen == 0)
+				break;
+			else
+				len = (size_t)readlen;
+			if (readlen == -1)
+				goto err;
+			end = buf + len;
+		}
+		goto done;
 	}
 
-	return (equal);
+	/* 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:
+	if (line != NULL)
+		free(line);
+	return (0);
+ err:
+	if (line != NULL)
+		free(line);
+	return (-1);
+}
+
+/*
+ * Regenerate the group file
+ */
+int
+gr_mkdb(void)
+{
+	if (chmod(tempname, 0644) != 0)
+		return (-1);
+
+	return (rename(tempname, group_file));
+}
+
+/*
+ * Clean up. Preserves errno for the caller's convenience.
+ */
+void
+gr_fini(void)
+{
+	int serrno;
+
+	if (!initialized)
+		return;
+	initialized = 0;
+	serrno = errno;
+	if (*tempname != '\0') {
+		unlink(tempname);
+		*tempname = '\0';
+	}
+	if (lockfd != -1)
+		close(lockfd);
+	errno = serrno;
+}
+
+/*
+ * Compares two struct group's.
+ */
+int
+gr_equal(const struct group *gr1, const struct group *gr2)
+{
+	int gr1_ndx;
+	int gr2_ndx;
+
+	/* Check that the non-member information is the same. */
+	if (gr1->gr_name == NULL || gr2->gr_name == NULL) {
+		if (gr1->gr_name != gr2->gr_name)
+			return (false);
+	} else if (strcmp(gr1->gr_name, gr2->gr_name) != 0)
+		return (false);
+	if (gr1->gr_passwd == NULL || gr2->gr_passwd == NULL) {
+		if (gr1->gr_passwd != gr2->gr_passwd)
+			return (false);
+	} else if (strcmp(gr1->gr_passwd, gr2->gr_passwd) != 0)
+		return (false);
+	if (gr1->gr_gid != gr2->gr_gid)
+		return (false);
+
+	/* Check all members in both groups.
+	 * getgrnam can return gr_mem with a pointer to NULL.
+	 * gr_dup and gr_add strip out this superfluous NULL, setting
+	 * gr_mem to NULL for no members.
+	*/
+	if (gr1->gr_mem != NULL && gr2->gr_mem != NULL) {
+		int i;
+
+		for (i = 0; gr1->gr_mem[i] != NULL; i++) {
+			if (strcmp(gr1->gr_mem[i], gr2->gr_mem[i]) != 0)
+				return (false);
+		}
+	}
+	/* Count number of members in both structs */
+	gr2_ndx = 0;
+	if (gr2->gr_mem != NULL)
+		for(; gr2->gr_mem[gr2_ndx] != NULL; gr2_ndx++)
+			/* empty */;
+	gr1_ndx = 0;
+	if (gr1->gr_mem != NULL)
+		for(; gr1->gr_mem[gr1_ndx] != NULL; gr1_ndx++)
+			/* empty */;
+	if (gr1_ndx != gr2_ndx)
+		return (false);
+
+	return (true);
 }
 
 /*
@@ -85,27 +402,35 @@ gr_equal(const struct group *gr1, const struct group *gr2)
 char *
 gr_make(const struct group *gr)
 {
+	const char *group_line_format = "%s:%s:%ju:";
+	const char *sep;
 	char *line;
-	size_t lineSize;
+	char *p;
+	size_t line_size;
 	int ndx;
 
 	/* Calculate the length of the group line. */
-	lineSize = snprintf(NULL, 0, GroupLineFormat, gr->gr_name,
+	line_size = snprintf(NULL, 0, group_line_format, gr->gr_name,
 	    gr->gr_passwd, (uintmax_t)gr->gr_gid) + 1;
-	for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++)
-		lineSize += strlen(gr->gr_mem[ndx]) + 1;
-	if (ndx > 0)
-		lineSize--;
+	if (gr->gr_mem != NULL) {
+		for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++)
+			line_size += strlen(gr->gr_mem[ndx]) + 1;
+		if (ndx > 0)
+			line_size--;
+	}
 
 	/* Create the group line and fill it. */
-	if ((line = malloc(lineSize)) == NULL)
+	if ((line = p = malloc(line_size)) == NULL)
 		return (NULL);
-	lineSize = snprintf(line, lineSize, GroupLineFormat, gr->gr_name,
-	    gr->gr_passwd, (uintmax_t)gr->gr_gid);
-	for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
-		strcat(line, gr->gr_mem[ndx]);
-		if (gr->gr_mem[ndx + 1] != NULL)
-			strcat(line, ",");
+	p += sprintf(p, group_line_format, gr->gr_name, gr->gr_passwd,
+	    (uintmax_t)gr->gr_gid);
+	if (gr->gr_mem != NULL) {
+		sep = "";
+		for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
+			p = stpcpy(p, sep);
+			p = stpcpy(p, gr->gr_mem[ndx]);
+			sep = ",";
+		}
 	}
 
 	return (line);
@@ -117,47 +442,129 @@ gr_make(const struct group *gr)
 struct group *
 gr_dup(const struct group *gr)
 {
+	return (gr_add(gr, NULL));
+}
+/*
+ * Add a new member name to a struct group.
+ */
+struct group *
+gr_add(const struct group *gr, const char *newmember)
+{
+	char *mem;
 	size_t len;
-	struct group *ngr;
-	int ndx;
-	int numMem;
-
-	/* Calculate size of group. */
-	len = sizeof(*gr) +
-	    (gr->gr_name != NULL ? strlen(gr->gr_name) + 1 : 0) +
-	    (gr->gr_passwd != NULL ? strlen(gr->gr_passwd) + 1 : 0);
-	numMem = 0;
-	if (gr->gr_mem != NULL) {
-		for (; gr->gr_mem[numMem] != NULL; numMem++)
-			len += strlen(gr->gr_mem[numMem]) + 1;
-		len += (numMem + 1) * sizeof(*gr->gr_mem);
-	}
+	int num_mem;
 
+	num_mem = 0;
+	len = grmemlen(gr, newmember, &num_mem);
 	/* Create new group and copy old group into it. */
-	if ((ngr = calloc(1, len)) == NULL)
+	if ((mem = malloc(len)) == NULL)
 		return (NULL);
-	len = sizeof(*ngr);
-	ngr->gr_gid = gr->gr_gid;
+	return (grcopy(gr, mem, newmember, num_mem));
+}
+
+/* It is safer to walk the pointers given at gr_mem since there is no
+ * guarantee the gr_mem + strings are contiguous in the given struct group
+ * but compactify the new group into the following form.
+ *
+ * The new struct is laid out like this in memory. The example given is
+ * for a group with two members only.
+ *
+ * {
+ * (char *name)
+ * (char *passwd)
+ * (int gid)
+ * (gr_mem * newgrp + sizeof(struct group) + sizeof(**)) points to gr_mem area
+ * gr_mem area
+ * (member1 *) 
+ * (member2 *)
+ * (NULL)
+ * (name string)
+ * (passwd string)
+ * (member1 string)
+ * (member2 string)
+ * }
+ */
+/*
+ * Copy the contents of a group plus given name to a preallocated group struct
+ */
+static struct group *
+grcopy(const struct group *gr, char *dst, const char *name, int ndx)
+{
+	int i;
+	struct group *newgr;
+
+	newgr = (struct group *)(void *)dst;	/* avoid alignment warning */
+	dst += sizeof(*newgr);
+	if (ndx != 0) {
+		newgr->gr_mem = (char **)(void *)(dst);	/* avoid alignment warning */
+		dst += (ndx + 1) * sizeof(*newgr->gr_mem);
+	} else
+		newgr->gr_mem = NULL;
 	if (gr->gr_name != NULL) {
-		ngr->gr_name = (char *)ngr + len;
-		len += sprintf(ngr->gr_name, "%s", gr->gr_name) + 1;
-	}
+		newgr->gr_name = dst;
+		dst = stpcpy(dst, gr->gr_name) + 1;
+	} else
+		newgr->gr_name = NULL;
 	if (gr->gr_passwd != NULL) {
-		ngr->gr_passwd = (char *)ngr + len;
-		len += sprintf(ngr->gr_passwd, "%s", gr->gr_passwd) + 1;
-	}
+		newgr->gr_passwd = dst;
+		dst = stpcpy(dst, gr->gr_passwd) + 1;
+	} else
+		newgr->gr_passwd = NULL;
+	newgr->gr_gid = gr->gr_gid;
+	i = 0;
+	/* Original group struct might have a NULL gr_mem */
 	if (gr->gr_mem != NULL) {
-		ngr->gr_mem = (char **)((char *)ngr + len);
-		len += (numMem + 1) * sizeof(*ngr->gr_mem);
-		for (ndx = 0; gr->gr_mem[ndx] != NULL; ndx++) {
-			ngr->gr_mem[ndx] = (char *)ngr + len;
-			len += sprintf(ngr->gr_mem[ndx], "%s",
-			    gr->gr_mem[ndx]) + 1;
+		for (; gr->gr_mem[i] != NULL; i++) {
+			newgr->gr_mem[i] = dst;
+			dst = stpcpy(dst, gr->gr_mem[i]) + 1;
 		}
-		ngr->gr_mem[ndx] = NULL;
 	}
+	/* If name is not NULL, newgr->gr_mem is known to be not NULL */
+	if (name != NULL) {
+		newgr->gr_mem[i++] = dst;
+		dst = stpcpy(dst, name) + 1;
+	}
+	/* if newgr->gr_mem is not NULL add NULL marker */
+	if (newgr->gr_mem != NULL)
+		newgr->gr_mem[i] = NULL;
 
-	return (ngr);
+	return (newgr);
+}
+
+/*
+ *  Calculate length of a struct group + given name
+ */
+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);
 }
 
 /*
@@ -190,15 +597,18 @@ __gr_scan(char *line, struct group *gr)
 		return (false);
 	line = loc + 1;
 	gr->gr_mem = NULL;
-	if (*line != '\0') {
-		ndx = 0;
+	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 {
-			if ((gr->gr_mem = reallocf(gr->gr_mem,
-			    sizeof(*gr->gr_mem) * (ndx + 1))) == NULL)
-				return (false);
 			gr->gr_mem[ndx] = strsep(&line, ",");
-		} while (gr->gr_mem[ndx++] != NULL);
-	}
+		} while (gr->gr_mem[ndx] != NULL && *gr->gr_mem[ndx] == '\0');
+	} while (gr->gr_mem[ndx++] != NULL);
 
 	return (true);
 }
@@ -210,19 +620,19 @@ struct group *
 gr_scan(const char *line)
 {
 	struct group gr;
-	char *lineCopy;
-	struct group *newGr;
+	char *line_copy;
+	struct group *new_gr;
 
-	if ((lineCopy = strdup(line)) == NULL)
+	if ((line_copy = strdup(line)) == NULL)
 		return (NULL);
-	if (!__gr_scan(lineCopy, &gr)) {
-		free(lineCopy);
+	if (!__gr_scan(line_copy, &gr)) {
+		free(line_copy);
 		return (NULL);
 	}
-	newGr = gr_dup(&gr);
-	free(lineCopy);
+	new_gr = gr_dup(&gr);
+	free(line_copy);
 	if (gr.gr_mem != NULL)
 		free(gr.gr_mem);
 
-	return (newGr);
+	return (new_gr);
 }