helper/bwrap: separate sequential/static args

Signed-off-by: Ophestra <cat@gensokyo.uk>

helper/bwrap/builder.go

@@ -0,0 +1,170 @@
+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{DevBindTry.Unwrap(), src, dest})
+		} else {
+			c.Filesystem = append(c.Filesystem, &pairF{DevBind.Unwrap(), src, dest})
+		}
+		return c
+	} else if write {
+		if try {
+			c.Filesystem = append(c.Filesystem, &pairF{BindTry.Unwrap(), src, dest})
+		} else {
+			c.Filesystem = append(c.Filesystem, &pairF{Bind.Unwrap(), src, dest})
+		}
+		return c
+	} else {
+		if try {
+			c.Filesystem = append(c.Filesystem, &pairF{ROBindTry.Unwrap(), src, dest})
+		} else {
+			c.Filesystem = append(c.Filesystem, &pairF{ROBind.Unwrap(), src, dest})
+		}
+		return c
+	}
+}
+
+// Dir create dir in sandbox
+// (--dir DEST)
+func (c *Config) Dir(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{Dir.Unwrap(), 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{RemountRO.Unwrap(), dest})
+	return c
+}
+
+// Procfs mount new procfs in sandbox
+// (--proc DEST)
+func (c *Config) Procfs(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{Procfs.Unwrap(), dest})
+	return c
+}
+
+// DevTmpfs mount new dev in sandbox
+// (--dev DEST)
+func (c *Config) DevTmpfs(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{DevTmpfs.Unwrap(), dest})
+	return c
+}
+
+// Mqueue mount new mqueue in sandbox
+// (--mqueue DEST)
+func (c *Config) Mqueue(dest string) *Config {
+	c.Filesystem = append(c.Filesystem, &stringF{Mqueue.Unwrap(), 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
+}
+
+// Overlay mount overlayfs on DEST, with writes going to an invisible tmpfs
+// (--tmp-overlay DEST)
+func (c *Config) Overlay(dest string, src ...string) *Config {
+	c.Filesystem = append(c.Filesystem, &OverlayConfig{Src: src, Dest: dest})
+	return c
+}
+
+// Join mount overlayfs read-only on DEST
+// (--ro-overlay DEST)
+func (c *Config) Join(dest string, src ...string) *Config {
+	c.Filesystem = append(c.Filesystem, &OverlayConfig{Src: src, Dest: dest, Persist: new([2]string)})
+	return c
+}
+
+// Persist mount overlayfs on DEST, with RWSRC as the host path for writes and
+// WORKDIR an empty directory on the same filesystem as RWSRC
+// (--overlay RWSRC WORKDIR DEST)
+func (c *Config) Persist(dest, rwsrc, workdir string, src ...string) *Config {
+	if rwsrc == "" || workdir == "" {
+		panic("persist called without required paths")
+	}
+	c.Filesystem = append(c.Filesystem, &OverlayConfig{Src: src, Dest: dest, Persist: &[2]string{rwsrc, workdir}})
+	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
+}
+
+// SetSync sets the sync pipe kept open while sandbox is running
+// (--sync-fd FD)
+func (c *Config) SetSync(s *os.File) *Config {
+	c.sync = s
+	return c
+}