diff --git a/sysinstall/devices.c b/sysinstall/devices.c
index 235b139f..bd12364d 100644
--- a/sysinstall/devices.c
+++ b/sysinstall/devices.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016 Jonas 'Sortie' Termansen.
+ * Copyright (c) 2015, 2016, 2021 Jonas 'Sortie' Termansen.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -69,7 +69,8 @@ void unscan_filesystem(struct blockdevice* bdev)
 
 void scan_filesystem(struct blockdevice* bdev)
 {
-	enum filesystem_error fserr = blockdevice_inspect_filesystem(&bdev->fs, bdev);
+	enum filesystem_error fserr =
+		blockdevice_inspect_filesystem(&bdev->fs, bdev);
 	if ( fserr == FILESYSTEM_ERROR_ABSENT ||
 	     fserr == FILESYSTEM_ERROR_UNRECOGNIZED )
 		return;
@@ -94,7 +95,8 @@ void scan_device(struct harddisk* hd)
 {
 	unscan_device(hd);
 	struct blockdevice* bdev = &hd->bdev;
-	enum partition_error parterr = blockdevice_get_partition_table(&bdev->pt, bdev);
+	enum partition_error parterr =
+		blockdevice_get_partition_table(&bdev->pt, bdev);
 	if ( parterr == PARTITION_ERROR_ABSENT ||
 	     parterr == PARTITION_ERROR_UNRECOGNIZED )
 	{
@@ -261,9 +263,14 @@ bool load_mountpoints(const char* fstab_path,
 	FILE* fp = fopen(fstab_path, "r");
 	if ( !fp )
 		return false;
-	struct mountpoint* mountpoints = NULL;
+	struct mountpoint* mountpoints = malloc(sizeof(struct mountpoint));
+	if ( !mountpoints )
+	{
+		fclose(fp);
+		return false;
+	}
 	size_t mountpoints_used = 0;
-	size_t mountpoints_length = 0;
+	size_t mountpoints_length = 1;
 	char* line = NULL;
 	size_t line_size;
 	ssize_t line_length;
@@ -276,11 +283,9 @@ bool load_mountpoints(const char* fstab_path,
 			continue;
 		if ( mountpoints_used == mountpoints_length )
 		{
-			size_t new_length = 2 * mountpoints_length;
-			if ( !new_length )
-				new_length = 16;
 			struct mountpoint* new_mountpoints = (struct mountpoint*)
-				reallocarray(mountpoints, new_length, sizeof(struct mountpoint));
+				reallocarray(mountpoints, mountpoints_length,
+				             2 * sizeof(struct mountpoint));
 			if ( !new_mountpoints )
 			{
 				free_mountpoints(mountpoints, mountpoints_used);
@@ -289,7 +294,7 @@ bool load_mountpoints(const char* fstab_path,
 				return false;
 			}
 			mountpoints = new_mountpoints;
-			mountpoints_length = new_length;
+			mountpoints_length *= 2;
 		}
 		struct mountpoint* mountpoint = &mountpoints[mountpoints_used++];
 		memset(mountpoint, 0, sizeof(*mountpoint));
@@ -326,7 +331,7 @@ bool mountpoint_mount(struct mountpoint* mountpoint)
 	// TODO: It would be ideal to get an exclusive lock so that no other
 	//       processes have currently mounted that filesystem.
 	struct blockdevice* bdev = fs->bdev;
-	const char* bdev_path = bdev->p ? bdev->p->path : bdev->hd->path;
+	const char* bdev_path = path_of_blockdevice(bdev);
 	assert(bdev_path);
 	if ( fs->flags & FILESYSTEM_FLAG_FSCK_MUST && !fsck(fs) )
 	{
diff --git a/sysinstall/fileops.c b/sysinstall/fileops.c
index 9e713ad8..718b057e 100644
--- a/sysinstall/fileops.c
+++ b/sysinstall/fileops.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016, 2017, 2020 Jonas 'Sortie' Termansen.
+ * Copyright (c) 2015, 2016, 2017, 2020, 2021 Jonas 'Sortie' Termansen.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -55,7 +55,7 @@ int mkdir_p(const char* path, mode_t mode)
 		char* prev = strdup(path);
 		if ( !prev )
 			return -1;
-		int status =  mkdir_p(dirname(prev), mode | 0500);
+		int status = mkdir_p(dirname(prev), mode | 0500);
 		free(prev);
 		if ( status < 0 )
 			return -1;
@@ -92,9 +92,11 @@ void mkdir_or_chmod_or_die(const char* path, mode_t mode)
 	{
 		if ( chmod(path, mode) == 0 )
 			return;
-		err(2, "chmod: %s", path);
+		warn("chmod: %s", path);
+		_exit(2);
 	}
-	err(2, "mkdir: %s", path);
+	warn("mkdir: %s", path);
+	_exit(2);
 }
 
 void write_random_seed(const char* path)
diff --git a/sysinstall/release.c b/sysinstall/release.c
index 0c476d9a..436b9861 100644
--- a/sysinstall/release.c
+++ b/sysinstall/release.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, 2016, 2017 Jonas 'Sortie' Termansen.
+ * Copyright (c) 2015, 2016, 2017, 2021 Jonas 'Sortie' Termansen.
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -91,7 +91,12 @@ static char* os_release_eval(const char* string)
 			doubly_quote = !doubly_quote;
 		else
 		{
-			fputc((unsigned char) c, fp);
+			if ( fputc((unsigned char) c, fp) == EOF )
+			{
+				fclose(fp);
+				free(result);
+				return NULL;
+			}
 			escaped = false;
 		}
 	}
diff --git a/sysinstall/sysinstall.c b/sysinstall/sysinstall.c
index 1097896f..b2c34179 100644
--- a/sysinstall/sysinstall.c
+++ b/sysinstall/sysinstall.c
@@ -135,6 +135,7 @@ static bool should_install_bootloader_path(const char* mnt,
 	}
 	free(release_path);
 	free(release_errpath);
+	release_free(&release);
 	char* conf_path;
 	if ( asprintf(&conf_path, "%s/etc/upgrade.conf", mnt) < 0 )
 	{
@@ -402,6 +403,8 @@ int main(void)
 	if ( !mkdtemp(etc) )
 		err(2, "mkdtemp: %s", "/tmp/etc.XXXXXX");
 	etc_made = true;
+	// Export for the convenience of users escaping to a shell.
+	setenv("SYSINSTALL_ETC", fs, 1);
 
 	if ( chdir(etc) < 0 )
 		err(2, "chdir: %s", etc);
@@ -859,6 +862,7 @@ int main(void)
 	if ( !mkdtemp(fs) )
 		err(2, "mkdtemp: %s", "/tmp/fs.XXXXXX");
 	fs_made = true;
+	// Export for the convenience of users escaping to a shell.
 	setenv("SYSINSTALL_TARGET", fs, 1);
 
 	for ( size_t i = 0; i < mountpoints_used; i++ )
diff --git a/sysinstall/sysupgrade.c b/sysinstall/sysupgrade.c
index e132b258..329a8e40 100644
--- a/sysinstall/sysupgrade.c
+++ b/sysinstall/sysupgrade.c
@@ -142,6 +142,7 @@ static void search_installation_path(const char* mnt, struct blockdevice* bdev)
 	if ( asprintf(&machine_path, "%s/etc/machine", mnt) < 0 )
 	{
 		warn("%s: malloc", path_of_blockdevice(bdev));
+		free_mountpoints(mountpoints, mountpoints_used);
 		release_free(&release);
 		return;
 	}
@@ -150,12 +151,14 @@ static void search_installation_path(const char* mnt, struct blockdevice* bdev)
 	if ( !machine )
 	{
 		warn("%s/etc/machine", path_of_blockdevice(bdev));
+		free_mountpoints(mountpoints, mountpoints_used);
 		release_free(&release);
 		return;
 	}
 	if ( !add_installation(bdev, &release, mountpoints, mountpoints_used,
 	                       machine) )
 	{
+		free(machine);
 		free_mountpoints(mountpoints, mountpoints_used);
 		release_free(&release);
 		return;
@@ -278,7 +281,7 @@ static void preserve_src(const char* where)
 		if ( mkdir("oldsrc", 0755) < 0 )
 		{
 			warn("oldsrc");
-			_exit(1);
+			_exit(2);
 		}
 	}
 	time_t now = time(NULL);
@@ -298,7 +301,7 @@ static void preserve_src(const char* where)
 			if ( !mkdtemp(buf) )
 			{
 				warnx("failed to find location to store old /%s", where);
-				_exit(1);
+				_exit(2);
 			}
 			rmdir(buf);
 		}
@@ -307,7 +310,7 @@ static void preserve_src(const char* where)
 	if ( rename(where, buf) < 0 )
 	{
 		warn("rename: %s -> %s", where, buf);
-		_exit(1);
+		_exit(2);
 	}
 }
 
@@ -502,6 +505,9 @@ int main(void)
 
 	if ( !mkdtemp(fs) )
 		err(2, "mkdtemp: %s", "/tmp/fs.XXXXXX");
+	fs_made = true;
+	// Export for the convenience of users escaping to a shell.
+	setenv("SYSINSTALL_TARGET", fs, 1);
 
 	struct installation* target = NULL;
 	while ( true )
@@ -817,7 +823,7 @@ int main(void)
 					if ( rename("src", "src.tmp") < 0 )
 					{
 						warn("rename: /src -> /src.tmp");
-						_exit(1);
+						_exit(2);
 					}
 				}
 				install_manifest("src", "", ".", (const char*[]){}, 0);
@@ -826,12 +832,12 @@ int main(void)
 					if ( rename("src", "newsrc") < 0 )
 					{
 						warn("rename: /src -> /newsrc");
-						_exit(1);
+						_exit(2);
 					}
 					if ( rename("src.tmp", "src") < 0 )
 					{
 						warn("rename: /src.tmp -> /src");
-						_exit(1);
+						_exit(2);
 					}
 				}
 			}