From f1ca70d3e1d320fe687348e8a8394b1ea571f279 Mon Sep 17 00:00:00 2001
From: Kyle Evans <kevans@FreeBSD.org>
Date: Tue, 7 Aug 2018 03:25:28 +0000
Subject: [PATCH] libbe(3): Return some more proper error codes

---
 lib/libbe/be.h        |  3 +++
 lib/libbe/be_access.c | 50 ++++++++++++++++++++++++++++++++-----------
 lib/libbe/libbe.3     |  5 ++++-
 3 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/lib/libbe/be.h b/lib/libbe/be.h
index a4d0f3954406..dea934af1dad 100644
--- a/lib/libbe/be.h
+++ b/lib/libbe/be.h
@@ -44,6 +44,8 @@ typedef enum be_error {
 	BE_ERR_PERMS,           /* insufficient permissions */
 	BE_ERR_DESTROYACT,      /* cannot destroy active boot env */
 	BE_ERR_DESTROYMNT,      /* destroying a mounted be requires force */
+	BE_ERR_BADPATH,		/* path not suitable for operation */
+	BE_ERR_PATHBUSY,	/* requested path is busy */
 	BE_ERR_PATHLEN,         /* provided name exceeds maximum length limit */
 	BE_ERR_INVORIGIN,       /* snapshot origin's mountpoint is not '/' */
 	BE_ERR_NOORIGIN,        /* could not open snapshot's origin */
@@ -51,6 +53,7 @@ typedef enum be_error {
 	BE_ERR_NOMOUNT,         /* boot environment is not mounted */
 	BE_ERR_ZFSOPEN,         /* calling zfs_open() failed */
 	BE_ERR_ZFSCLONE,        /* error when calling zfs_clone to create be */
+	BE_ERR_IO,		/* error when doing some I/O operation */
 	BE_ERR_UNKNOWN,         /* unknown error */
 } be_error_t;
 
diff --git a/lib/libbe/be_access.c b/lib/libbe/be_access.c
index 55481e04e14b..c0acac215eb7 100644
--- a/lib/libbe/be_access.c
+++ b/lib/libbe/be_access.c
@@ -121,18 +121,27 @@ be_mount(libbe_handle_t *lbh, char *bootenv, char *mountpoint, int flags,
 	if (mountpoint == NULL) {
 		strcpy(mnt_temp, "/tmp/be_mount.XXXX");
 		if (mkdtemp(mnt_temp) == NULL)
-			/* XXX TODO: create error for this */
-			return (set_error(lbh, BE_ERR_UNKNOWN));
+			return (set_error(lbh, BE_ERR_IO));
 	}
 
 	char opt = '\0';
 	if ((err = zmount(be, (mountpoint == NULL) ? mnt_temp : mountpoint,
-	    mntflags, __DECONST(char *, MNTTYPE_ZFS), NULL, 0, &opt, 1)) != 0)
-		/*
-		 * XXX TODO: zmount returns the nmount error, look into what
-		 * kind of errors we can report from that
-		 */
-		return (set_error(lbh, BE_ERR_UNKNOWN));
+	    mntflags, __DECONST(char *, MNTTYPE_ZFS), NULL, 0, &opt, 1)) != 0) {
+		switch (errno) {
+		case ENAMETOOLONG:
+			return (set_error(lbh, BE_ERR_PATHLEN));
+		case ELOOP:
+		case ENOENT:
+		case ENOTDIR:
+			return (set_error(lbh, BE_ERR_BADPATH));
+		case EPERM:
+			return (set_error(lbh, BE_ERR_PERMS));
+		case EBUSY:
+			return (set_error(lbh, BE_ERR_PATHBUSY));
+		default:
+			return (set_error(lbh, BE_ERR_UNKNOWN));
+		}
+	}
 
 	if (result_loc != NULL)
 		strcpy(result_loc, mountpoint == NULL ? mnt_temp : mountpoint);
@@ -156,9 +165,11 @@ be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
 	if ((err = be_root_concat(lbh, bootenv, be)) != 0)
 		return (set_error(lbh, err));
 
-	if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0)
-		/* XXX TODO correct error */
+	if ((mntsize = getmntinfo(&mntbuf, MNT_NOWAIT)) == 0) {
+		if (errno == EIO)
+			return (set_error(lbh, BE_ERR_IO));
 		return (set_error(lbh, BE_ERR_NOMOUNT));
+	}
 
 	mntpath = NULL;
 	for (int i = 0; i < mntsize; ++i) {
@@ -177,9 +188,22 @@ be_unmount(libbe_handle_t *lbh, char *bootenv, int flags)
 
 	mntflags = (flags & BE_MNT_FORCE) ? MNT_FORCE : 0;
 
-	if ((err = unmount(mntpath, mntflags)) != 0)
-		/* XXX TODO correct error */
-		return (set_error(lbh, BE_ERR_NOMOUNT));
+	if ((err = unmount(mntpath, mntflags)) != 0) {
+		switch (errno) {
+		case ENAMETOOLONG:
+			return (set_error(lbh, BE_ERR_PATHLEN));
+		case ELOOP:
+		case ENOENT:
+		case ENOTDIR:
+			return (set_error(lbh, BE_ERR_BADPATH));
+		case EPERM:
+			return (set_error(lbh, BE_ERR_PERMS));
+		case EBUSY:
+			return (set_error(lbh, BE_ERR_PATHBUSY));
+		default:
+			return (set_error(lbh, BE_ERR_UNKNOWN));
+		}
+	}
 
 	return (set_error(lbh, BE_ERR_SUCCESS));
 }
diff --git a/lib/libbe/libbe.3 b/lib/libbe/libbe.3
index b6cf5a460112..be026a30e754 100644
--- a/lib/libbe/libbe.3
+++ b/lib/libbe/libbe.3
@@ -30,7 +30,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd July 25, 2018
+.Dd August 6, 2018
 .Dt LIBBE 3
 .Os
 .Sh NAME
@@ -190,6 +190,8 @@ BE_ERR_NOENT,
 BE_ERR_PERMS,
 BE_ERR_DESTROYACT,
 BE_ERR_DESTROYMNT,
+BE_ERR_BADPATH,
+BE_ERR_PATHBUSY,
 BE_ERR_PATHLEN,
 BE_ERR_INVORIGIN,
 BE_ERR_NOORIGIN,
@@ -197,6 +199,7 @@ BE_ERR_MOUNTED,
 BE_ERR_NOMOUNT,
 BE_ERR_ZFSOPEN,
 BE_ERR_ZFSCLONE,
+BE_ERR_IO,
 BE_ERR_UNKNOWN
 .Ed
 .Sh SEE ALSO