From fad8194f15d32bc683ae20337c11b8ae655d5db1 Mon Sep 17 00:00:00 2001
From: Anicka Bernathova <anicka@anicka.net>
Date: Fri, 29 Aug 2008 22:41:34 +0200
Subject: [PATCH] and clean up it

---
 lock.c | 112 +++++++++++++++++++++++++++++++++++----------------------
 1 file changed, 69 insertions(+), 43 deletions(-)

diff --git a/lock.c b/lock.c
index 219f199..0b04ef2 100644
--- a/lock.c
+++ b/lock.c
@@ -12,6 +12,26 @@
 
 #define LOCK_MAX_TRIES 30
 
+gid_t rgid, egid, sgid;
+
+void
+save_gids(void)
+{
+	getresgid(&rgid, &egid, &sgid);	
+}
+
+static void
+drop_gid(void)
+{
+	setresgid(rgid, rgid, egid);
+}
+
+static void
+raise_gid(void)
+{
+	setresgid(rgid, sgid, sgid);
+}
+
 static void
 random_sleep(unsigned int about, unsigned int offset)
 {
@@ -43,7 +63,7 @@ dot_lock(char* path)
 	int fd;
 	int res = -1;
 	char* lockfile = cat(path, ".lock");
-	
+
 	for (i = 0; i < LOCK_MAX_TRIES; i++){
 		if ((fd = open(lockfile, O_WRONLY | O_EXCL | O_CREAT, 0)) 
 			>= 0) {
@@ -69,13 +89,14 @@ dot_unlock(char* path)
 {
 	char* lockfile = cat(path, ".lock");
 
+	raise_gid();
 	unlink(lockfile);
-
+	drop_gid();
 	free(lockfile);
 }
 
-int
-open_mailbox(char* path, int use_default_mailbox)
+static int
+do_open_mailbox(char* path, int is_default_mailbox)
 {
 	int fd;
 
@@ -86,36 +107,17 @@ open_mailbox(char* path, int use_default_mailbox)
 	/* if OK, try to open the file:
 		either we are saving to default mailbox (no problem here)
 		or we are saving somewhere else (no need to be privileged)
-	*/	
-	if (use_default_mailbox){
-		/* get our preciousss out of pocket */
-		gid_t ruid, euid, suid;
-		getresgid(&ruid, &euid, &suid);
-		setresgid(ruid, suid, suid);
-
-		/* we are not going to create default mailbox */
-		fd = open(path, O_RDWR);
-		if (fd < 0){
-			dot_unlock(path);
-			return -1;
-		}
-
-		/* hide it again */
-		setresgid(ruid, ruid, suid);
-	} else {
-		fd = open(path, O_RDWR);
-		if (fd < 0 && errno == ENOENT){
-			fd = open(path, O_RDWR | O_CREAT | O_EXCL,
-				S_IRUSR | S_IWUSR);
-			if (fd < 0){
-				dot_unlock(path);
-				return -1;	
-			}
-
-		} else if (fd < 0){
-			dot_unlock(path);
-			return -1;
-		}	
+	*/
+	int perms = S_IRUSR | S_IWUSR;
+	if (is_default_mailbox)
+		perms |=  (S_IRGRP | S_IWGRP);
+
+	mode_t oldmask = umask(0);
+	fd = open(path, O_RDWR | O_CREAT, perms);
+	umask(oldmask);
+	if (fd < 0){
+		dot_unlock(path);
+		return -1;
 	}	
 
 	/* fcntl then */
@@ -133,8 +135,8 @@ open_mailbox(char* path, int use_default_mailbox)
 	return fd; 
 }
 
-void
-close_mailbox(int fd, char* path)
+static void
+do_close_mailbox(int fd, char* path)
 {
 	struct flock mb_lock;
 	memset(&mb_lock, 0, sizeof(struct flock));
@@ -144,23 +146,47 @@ close_mailbox(int fd, char* path)
 	dot_unlock(path);
 }
 
+void
+close_mailbox(int fd, char* path, int is_default_mailbox)
+{
+	if (is_default_mailbox)
+		raise_gid();
+	do_close_mailbox(fd, path);
+	if (is_default_mailbox)
+		drop_gid();
+}
+
+int
+open_mailbox(char* path, int is_default_mailbox)
+{
+	int fd;
+
+	if (is_default_mailbox)
+		raise_gid();
+	fd = do_open_mailbox(path, is_default_mailbox);
+	if (is_default_mailbox)
+		drop_gid();
+
+	return fd;
+}
+
 int
 main(int argc, char** argv)
 {
 	/* FIXME: move somewhere */
 	int fd;
-	gid_t ruid, euid, suid;
-	if (argc < 2)
+	if (argc < 3)
 		return 1;
-	char* mb = argv[1]; 
-	getresgid(&ruid, &euid, &suid);
-	setresgid(ruid, ruid, euid);
-	fd = open_mailbox(mb, 0);
+	char* mb = argv[1];
+	int is_default_mailbox = atoi(argv[2]);
+	save_gids();
+	drop_gid(); 
+	fd = open_mailbox(mb, is_default_mailbox);
 	printf("%d\n", fd); 
 	if (fd < 0)
 		return 1;	
 
-	close_mailbox(fd, mb);
+	close_mailbox(fd, mb, is_default_mailbox);
 
 	return 0;
 }
-- 
2.39.2