helper/bwrap: ordered filesystem args

The argument builder was written based on the incorrect assumption that bwrap arguments are unordered. The argument builder is replaced in this commit to correct that mistake.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

helper/bwrap/config.set.go

@@ -0,0 +1,138 @@
+package bwrap
+
+import "os"
+
+/*
+Bind binds mount src on host to dest in sandbox.
+
+Bind(src, dest) bind mount host path readonly on sandbox
+(--ro-bind SRC DEST).
+Bind(src, dest, true) equal to ROBind but ignores non-existent host path
+(--ro-bind-try SRC DEST).
+
+Bind(src, dest, false, true) bind mount host path on sandbox.
+(--bind SRC DEST).
+Bind(src, dest, true, true) equal to Bind but ignores non-existent host path
+(--bind-try SRC DEST).
+
+Bind(src, dest, false, true, true) bind mount host path on sandbox, allowing device access
+(--dev-bind SRC DEST).
+Bind(src, dest, true, true, true) equal to DevBind but ignores non-existent host path
+(--dev-bind-try SRC DEST).
+*/
+func (c *Config) Bind(src, dest string, opts ...bool) *Config {
+	var (
+		try   bool
+		write bool
+		dev   bool
+	)
+
+	if len(opts) > 0 {
+		try = opts[0]
+	}
+	if len(opts) > 1 {
+		write = opts[1]
+	}
+	if len(opts) > 2 {
+		dev = opts[2]
+	}
+
+	if dev {
+		if try {
+			c.Filesystem = append(c.Filesystem, &pairF{pairArgs[DevBindTry], src, dest})
+		} else {
+			c.Filesystem = append(c.Filesystem, &pairF{pairArgs[DevBind], src, dest})
+		}
+		return c
+	} else if write {
+		if try {
+			c.Filesystem = append(c.Filesystem, &pairF{pairArgs[BindTry], src, dest})
+		} else {
+			c.Filesystem = append(c.Filesystem, &pairF{pairArgs[Bind], src, dest})
+		}
+		return c
+	} else {
+		if try {
+			c.Filesystem = append(c.Filesystem, &pairF{pairArgs[ROBindTry], src, dest})
+		} else {
+			c.Filesystem = append(c.Filesystem, &pairF{pairArgs[ROBind], src, dest})
+		}
+		return c
+	}
+}
+
+// RemountRO remount path as readonly; does not recursively remount
+// (--remount-ro DEST)
+func (c *Config) RemountRO(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{stringArgs[RemountRO], dest})
+	return c
+}
+
+// Procfs mount new procfs in sandbox
+// (--proc DEST)
+func (c *Config) Procfs(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{stringArgs[Procfs], dest})
+	return c
+}
+
+// DevTmpfs mount new dev in sandbox
+// (--dev DEST)
+func (c *Config) DevTmpfs(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{stringArgs[DevTmpfs], dest})
+	return c
+}
+
+// Tmpfs mount new tmpfs in sandbox
+// (--tmpfs DEST)
+func (c *Config) Tmpfs(dest string, size int, perm ...os.FileMode) *Config {
+	tmpfs := &PermConfig[*TmpfsConfig]{Inner: &TmpfsConfig{Dir: dest}}
+	if size >= 0 {
+		tmpfs.Inner.Size = size
+	}
+	if len(perm) == 1 {
+		tmpfs.Mode = &perm[0]
+	}
+	c.Filesystem = append(c.Filesystem, tmpfs)
+	return c
+}
+
+// Mqueue mount new mqueue in sandbox
+// (--mqueue DEST)
+func (c *Config) Mqueue(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{stringArgs[Mqueue], dest})
+	return c
+}
+
+// Dir create dir in sandbox
+// (--dir DEST)
+func (c *Config) Dir(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{stringArgs[Dir], dest})
+	return c
+}
+
+// Symlink create symlink within sandbox
+// (--symlink SRC DEST)
+func (c *Config) Symlink(src, dest string, perm ...os.FileMode) *Config {
+	symlink := &PermConfig[SymlinkConfig]{Inner: SymlinkConfig{src, dest}}
+	if len(perm) == 1 {
+		symlink.Mode = &perm[0]
+	}
+	c.Filesystem = append(c.Filesystem, symlink)
+	return c
+}
+
+// SetUID sets custom uid in the sandbox, requires new user namespace (--uid UID).
+func (c *Config) SetUID(uid int) *Config {
+	if uid >= 0 {
+		c.UID = &uid
+	}
+	return c
+}
+
+// SetGID sets custom gid in the sandbox, requires new user namespace (--gid GID).
+func (c *Config) SetGID(gid int) *Config {
+	if gid >= 0 {
+		c.GID = &gid
+	}
+	return c
+}