Add four utility functions related to struct grp processing modeled in-part

after similar calls related to struct pwd in libutil/pw_util.c:
  - gr_equal()
    Perform a deep comparison of two struct grp's.  It does a thorough, yet
    unoptimized comparison of all the members regardless of order.

  - gr_make()
    Create a string (see group(5)) from a struct grp.

  - gr_dup()
    Duplicate a struct grp.  Returns a value that is a single contiguous
    block of memory.

  - gr_scan()
    Create a struct grp from a string (as produced by gr_make()).

MFC after:	3 weeks

2 files changed, 241 insertions, 0 deletions

diff --git a/libutil/gr_util.c b/libutil/gr_util.c
new file mode 100644
index 0000000..89f5fa3
--- /dev/null
+++ b/libutil/gr_util.c
@@ -0,0 +1,234 @@
+/*-
+ * Copyright (c) 2008 Sean C. Farley <scf@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer,
+ *    without modification, immediately at the beginning of the file.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <grp.h>
+#include <inttypes.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <libutil.h>
+
+
+static const char GroupLineFormat[] = "%s:%s:%ju:";
+
+
+/*
+ * Compares two struct group's.
+ */
+int
+gr_equal(const struct group *gr1, const struct group *gr2)
+{
+	bool found;
+	bool equal;
+	int gr1Ndx;
+	int gr2Ndx;
+
+	/* 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;
+				break;
+			}
+		}
+
+		/* Check that group2 does not have more members than group1. */
+		if (gr2->gr_mem[gr1Ndx] != NULL)
+			equal = false;
+	}
+
+	return (equal);
+}
+
+
+/*
+ * Make a group line out of a struct group.
+ */
+char *
+gr_make(const struct group *gr)
+{
+	char *line;
+	int ndx;
+	size_t lineSize;
+
+	/* Calculate the length of the group line. */
+	lineSize = snprintf(NULL, 0, GroupLineFormat, 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--;
+
+	/* Create the group line and fill it. */
+	if ((line = malloc(lineSize)) == 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, ",");
+	}
+
+	return (line);
+}
+
+
+/*
+ * Duplicate a struct group.
+ */
+struct group *
+gr_dup(const struct group *gr)
+{
+	int ndx;
+	int numMem;
+	size_t len;
+	struct group *ngr;
+
+	/* 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));
+	}
+
+	/* Create new group and copy old group into it. */
+	if ((ngr = calloc(1, len)) == NULL)
+		return (NULL);
+	len = sizeof(*ngr);
+	ngr->gr_gid = gr->gr_gid;
+	if (gr->gr_name != NULL) {
+		ngr->gr_name = (char *)ngr + len;
+		len += sprintf(ngr->gr_name, "%s", gr->gr_name) + 1;
+	}
+	if (gr->gr_passwd != NULL) {
+		ngr->gr_passwd = (char *)ngr + len;
+		len += sprintf(ngr->gr_passwd, "%s", gr->gr_passwd) + 1;
+	}
+	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;
+		}
+		ngr->gr_mem[ndx] = NULL;
+	}
+
+	return (ngr);
+}
+
+
+/*
+ * 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;
+	if (*line != '\0') {
+		ndx = 0;
+		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);
+	}
+
+	return (true);
+}
+
+
+/*
+ * Create a struct group from a line.
+ */
+struct group *
+gr_scan(const char *line)
+{
+	char *lineCopy;
+	struct group *newGr;
+	struct group gr;
+
+	if ((lineCopy = strdup(line)) == NULL)
+		return (NULL);
+	if (!__gr_scan(lineCopy, &gr)) {
+		free(lineCopy);
+		return (NULL);
+	}
+	newGr = gr_dup(&gr);
+	free(lineCopy);
+	if (gr.gr_mem != NULL)
+		free(gr.gr_mem);
+
+	return (newGr);
+}
diff --git a/libutil/libutil.h b/libutil/libutil.h
index aa663a7..8fafe9b 100644
--- a/libutil/libutil.h
+++ b/libutil/libutil.h
@@ -119,6 +119,13 @@ const char *pw_tempname(void);
 int	pw_tmp(int _mfd);
 #endif
 
+#ifdef _GRP_H_
+int	gr_equal(const struct group *gr1, const struct group *gr2);
+char	*gr_make(const struct group *gr);
+struct group *gr_dup(const struct group *gr);
+struct group *gr_scan(const char *line);
+#endif
+
 #ifdef _SYS_PARAM_H_
 struct pidfh *pidfile_open(const char *path, mode_t mode, pid_t *pidptr);
 int pidfile_write(struct pidfh *pfh);