Shift file locking to source file instead of temp file. This fixes

data buffering issue that corrupts files if two pw(8)'s run at the
same time as well as changing pw(8) so it uses the same locking
mechanism as PAM, vipw(8), pwd_mkdb(8), etc.

PR:		bin/23501
Submitted by:	Alex Kapranoff <alex (at) kapran (dot) bitmcnit (dot) bryansk (dot) su>
Approved by:	rwatson (mentor)
MFC after:	5 days

2 files changed, 5 insertions, 8 deletions

diff --git a/usr.sbin/pw/edgroup.c b/usr.sbin/pw/edgroup.c
index 40313d2..1cc46b4 100644
--- a/usr.sbin/pw/edgroup.c
+++ b/usr.sbin/pw/edgroup.c
@@ -68,7 +68,7 @@ editgroups(char *name, char **groups)
 	strcpy(grouptmp, groupfile);
 	strcat(grouptmp, ".new");
 
-	if ((infd = open(groupfile, O_RDWR | O_CREAT, 0644)) != -1) {
+	if ((infd = open(groupfile, O_RDWR | O_CREAT | O_EXLOCK, 0644)) != -1) {
 		FILE           *infp;
 
 		if ((infp = fdopen(infd, "r+")) == NULL)
@@ -76,7 +76,7 @@ editgroups(char *name, char **groups)
 		else {
 			int             outfd;
 
-			if ((outfd = open(grouptmp, O_RDWR | O_CREAT | O_TRUNC | O_EXLOCK, 0644)) != -1) {
+			if ((outfd = open(grouptmp, O_RDWR | O_CREAT | O_TRUNC, 0644)) != -1) {
 				FILE           *outfp;
 
 				if ((outfp = fdopen(outfd, "w+")) == NULL)
@@ -207,8 +207,7 @@ editgroups(char *name, char **groups)
 
 							/*
 							 * This is a gross hack, but we may have corrupted the
-							 * original file. Unfortunately, it will lose preservation
-							 * of the inode.
+							 * original file.
 							 */
 							if (fflush(infp) == EOF || ferror(infp))
 								rc = rename(grouptmp, groupfile) == 0;
diff --git a/usr.sbin/pw/fileupd.c b/usr.sbin/pw/fileupd.c
index a846513..b88f4fa 100644
--- a/usr.sbin/pw/fileupd.c
+++ b/usr.sbin/pw/fileupd.c
@@ -76,7 +76,7 @@ fileupdate(char const * filename, mode_t fmode, char const * newline, char const
 	if (pfxlen <= 1)
 		rc = EINVAL;
 	else {
-		int    infd = open(filename, O_RDWR | O_CREAT, fmode);
+		int    infd = open(filename, O_RDWR | O_CREAT | O_EXLOCK, fmode);
 
 		if (infd == -1)
 			rc = errno;
@@ -92,7 +92,7 @@ fileupdate(char const * filename, mode_t fmode, char const * newline, char const
 
 				strcpy(file, filename);
 				strcat(file, ".new");
-				outfd = open(file, O_RDWR | O_CREAT | O_TRUNC | O_EXLOCK, fmode);
+				outfd = open(file, O_RDWR | O_CREAT | O_TRUNC, fmode);
 				if (outfd == -1)
 					rc = errno;
 				else {
@@ -183,8 +183,6 @@ fileupdate(char const * filename, mode_t fmode, char const * newline, char const
 								 * to 'file'.
 								 * This is a gross hack, but we may have
 								 * corrupted the original file
-								 * Unfortunately, it will lose the inode
-								 * and hence the lock.
 								 */
 								if (fflush(infp) == EOF || ferror(infp))
 									rename(file, filename);