add -p flag to fix permissions

This is useful if you run modderbaas as root but want the resulting
directories to be owned by the right uid/gid.

7 files changed, 113 insertions, 3 deletions

diff --git a/Cargo.lock b/Cargo.lock
index fe6497f..f100a34 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -450,6 +450,15 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "308cc39be01b73d0d18f82a0e7b2a3df85245f84af96fdddc5d202d27e47b86a"
 
 [[package]]
+name = "memoffset"
+version = "0.6.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "59accc507f1338036a0477ef61afdae33cde60840f4dfe481319ce3ad116ddf9"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
 name = "miniz_oxide"
 version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -468,6 +477,7 @@ dependencies = [
  "dirs",
  "itertools",
  "log",
+ "nix",
  "once_cell",
  "regex",
  "scraper",
@@ -490,6 +500,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e4a24736216ec316047a1fc4252e27dabb04218aa4a3f37c6e7ddbf1f9782b54"
 
 [[package]]
+name = "nix"
+version = "0.23.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f305c2c2e4c39a82f7bf0bf65fb557f9070ce06781d4f2454295cc34b1c43188"
+dependencies = [
+ "bitflags",
+ "cc",
+ "cfg-if",
+ "libc",
+ "memoffset",
+]
+
+[[package]]
 name = "nodrop"
 version = "0.1.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
diff --git a/Cargo.toml b/Cargo.toml
index 02650e4..158273a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,3 +25,6 @@ ureq = { version = "2.3.0", features = ["json"] }
 url = { version = "2.2.2", features = ["serde"] }
 uuid = { version = "0.8.2", features = ["v4"] }
 zip = "0.5.13"
+
+[target.'cfg(unix)'.dependencies]
+nix = "0.23.0"
diff --git a/src/error.rs b/src/error.rs
index 08539c0..86d758f 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -32,6 +32,9 @@ pub enum Error {
     UrlError(#[from] url::ParseError),
     #[error("the mod ID '{0}' does not point to a single mod")]
     AmbiguousModId(String),
+    #[cfg(unix)]
+    #[error("underlying Unix error")]
+    NixError(#[from] nix::errno::Errno),
 }
 
 pub type Result<T, E = Error> = std::result::Result<T, E>;
diff --git a/src/lib.rs b/src/lib.rs
index 9a3598f..bf9e3c9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,7 +16,7 @@ pub mod error;
 pub mod game;
 pub mod kvstore;
 pub mod minemod;
-mod util;
+pub mod util;
 pub mod world;
 
 pub use baas::{Baas, Snapshot};
diff --git a/src/main.rs b/src/main.rs
index da04f9c..f42647a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -12,7 +12,7 @@ use log::debug;
 use termcolor::{Color, ColorChoice, ColorSpec, StandardStream, WriteColor};
 
 use modderbaas::{
-    minemod::ModContainer, Baas, ContentDb, Downloader, MineMod, Snapshot, Source, World,
+    minemod::ModContainer, util, Baas, ContentDb, Downloader, MineMod, Snapshot, Source, World,
 };
 
 fn main() -> Result<()> {
@@ -52,6 +52,12 @@ fn main() -> Result<()> {
                         .short("n")
                         .long("dry-run")
                         .required(false),
+                )
+                .arg(
+                    Arg::with_name("fix-permissions")
+                        .short("p")
+                        .long("fix-permissions")
+                        .required(false),
                 ),
         )
         .get_matches();
@@ -192,8 +198,9 @@ fn install_mods(
     mods: &[&str],
     matches: &ArgMatches,
 ) -> Result<()> {
-    let target_dir = &Path::new(matches.value_of("target").unwrap());
+    let target_dir = Path::new(matches.value_of("target").unwrap());
     let dry_run = matches.is_present("dry-run");
+    let fix_permissions = matches.is_present("fix-permissions");
 
     let content_db = ContentDb::new();
     let downloader = Downloader::new()?;
@@ -301,6 +308,19 @@ fn install_mods(
             .install_to(target_dir)
             .context(format!("Error installing '{}'", mod_id))?;
         to_enable.extend(installed.mods()?);
+
+        #[cfg(unix)]
+        {
+            use nix::{
+                sys::stat,
+                unistd::{Gid, Uid},
+            };
+            if fix_permissions {
+                let perms = stat::stat(target_dir)?;
+                let (uid, gid) = (Uid::from_raw(perms.st_uid), Gid::from_raw(perms.st_gid));
+                util::chown_recursive(installed.path(), Some(uid), Some(gid))?;
+            }
+        }
     }
 
     for m in to_enable {
diff --git a/src/minemod.rs b/src/minemod.rs
index 9162907..f45b897 100644
--- a/src/minemod.rs
+++ b/src/minemod.rs
@@ -33,6 +33,11 @@ impl MineMod {
         Ok(MineMod { path: path.into() })
     }
 
+    /// Returns the path of this mod.
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
     fn read_conf(&self) -> Result<HashMap<String, String>> {
         let conf = self.path.join("mod.conf");
         kvstore::read(&conf)
@@ -101,6 +106,11 @@ impl Modpack {
         Ok(Modpack { path: path.into() })
     }
 
+    /// Returns the path of this modpack.
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
     fn conf(&self) -> Result<HashMap<String, String>> {
         let conf = self.path.join("modpack.conf");
         kvstore::read(&conf)
@@ -148,6 +158,9 @@ pub trait ModContainer: Any + fmt::Display {
     /// Returns the name of the mod container.
     fn name(&self) -> Result<String>;
 
+    /// Returns the on-disk path of this mod container.
+    fn path(&self) -> &Path;
+
     /// Return all contained mods.
     fn mods(&self) -> Result<Vec<MineMod>>;
 
@@ -160,6 +173,10 @@ impl ModContainer for MineMod {
         self.mod_id()
     }
 
+    fn path(&self) -> &Path {
+        self.path()
+    }
+
     fn mods(&self) -> Result<Vec<MineMod>> {
         Ok(vec![self.clone()])
     }
@@ -175,6 +192,10 @@ impl ModContainer for Modpack {
         self.name()
     }
 
+    fn path(&self) -> &Path {
+        self.path()
+    }
+
     fn mods(&self) -> Result<Vec<MineMod>> {
         self.mods()
     }
diff --git a/src/util.rs b/src/util.rs
index 24b8701..d5f9ec2 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -1,5 +1,19 @@
 use std::{fs, io, path::Path};
 
+#[cfg(unix)]
+use nix::unistd::{self, Gid, Uid};
+
+use super::error::Result;
+
+#[cfg(not(unix))]
+pub mod nix {
+    //! Stub mod on non-unix systems.
+    pub mod unistd {
+        pub enum Uid {}
+        pub enum Gid {}
+    }
+}
+
 /// Recursively copy the *contents* of the given directory to the given path.
 pub fn copy_recursive<S: AsRef<Path>, D: AsRef<Path>>(source: S, destination: D) -> io::Result<()> {
     copy_inner(source.as_ref(), destination.as_ref())
@@ -19,3 +33,29 @@ fn copy_inner(source: &Path, destination: &Path) -> io::Result<()> {
     }
     Ok(())
 }
+
+/// Recursively change the owner of the given path to the given ones.
+///
+/// Note that this function only works on Unix systems. **It will panic on other systems!**
+pub fn chown_recursive<P: AsRef<Path>>(path: P, uid: Option<Uid>, gid: Option<Gid>) -> Result<()> {
+    chown_inner(path.as_ref(), uid, gid)
+}
+
+#[cfg(unix)]
+fn chown_inner(path: &Path, uid: Option<Uid>, gid: Option<Gid>) -> Result<()> {
+    unistd::chown(path, uid, gid)?;
+
+    let metadata = fs::metadata(path)?;
+    if metadata.is_dir() {
+        for item in fs::read_dir(path)? {
+            let item = item?;
+            chown_inner(&item.path(), uid, gid)?;
+        }
+    }
+    Ok(())
+}
+
+#[cfg(not(unix))]
+fn chown_inner(_: &Path, _: Option<Uid>, _: Option<Gid>) -> Result<()> {
+    panic!("chown() is not available on non-Unix systems!");
+}