product-config: factor out methods to create different file creation options

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>

proxmox-product-config/src/filesystem_helpers.rs

@@ -7,14 +7,73 @@ use nix::fcntl::OFlag;
 use nix::sys::stat::Mode;
 use nix::unistd::{Gid, Uid};
 
+use proxmox_sys::fs::CreateOptions;
+
 use super::product_config;
 
-// Check file/directory permissions
+/// Return [CreateOptions] for files owned by `api_user.uid/api_user.gid` with mode `0640`.
-//
+pub fn default_create_options() -> CreateOptions {
-// For security reasons, we want to make sure they are set correctly:
+    let api_user = &product_config().api_user;
-// * owned by uid/gid
+    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0640);
-// * nobody else can read (mode 0700)
+    proxmox_sys::fs::CreateOptions::new()
-pub fn check_permissions<P: AsRef<Path>>(dir: P, uid: Uid, gid: Gid, mode: u32) -> Result<(), Error> {
+        .perm(mode)
+        .owner(api_user.uid)
+        .group(api_user.gid)
+}
+
+/// Return [CreateOptions] for files owned by `root:api-user.gid` with permission `0640`.
+///
+/// Only the superuser can write those files, but group `api-user.gid` can read them.
+pub fn privileged_create_options() -> CreateOptions {
+    let api_user = &product_config().api_user;
+    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0640);
+    proxmox_sys::fs::CreateOptions::new()
+        .perm(mode)
+        .owner(nix::unistd::ROOT)
+        .group(api_user.gid)
+}
+
+/// Return [CreateOptions] for files owned by `root:root` with permission `0600`.
+///
+/// Only the superuser can read and write those files.
+pub fn secret_create_options() -> CreateOptions {
+    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0600);
+    proxmox_sys::fs::CreateOptions::new()
+        .perm(mode)
+        .owner(nix::unistd::ROOT)
+        .group(nix::unistd::Gid::from_raw(0))
+}
+
+/// Return [CreateOptions] for files owned by `root:root` with permission `0644`.
+///
+/// Everyone can read, but only the superuser can write those files. This is usually used
+/// for system configuration files inside "/etc/" (i.e. "/etc/resolv.conf").
+pub fn system_config_create_options() -> CreateOptions {
+    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0644);
+    proxmox_sys::fs::CreateOptions::new()
+        .perm(mode)
+        .owner(nix::unistd::ROOT)
+        .group(nix::unistd::Gid::from_raw(0))
+}
+
+/// Return [CreateOptions] for lock files, owner `api_user.uid/api_user.gid` and mode `0660`.
+pub fn lockfile_create_options() -> CreateOptions {
+    let api_user = &product_config().api_user;
+    proxmox_sys::fs::CreateOptions::new()
+        .perm(nix::sys::stat::Mode::from_bits_truncate(0o660))
+        .owner(api_user.uid)
+        .group(api_user.gid)
+}
+
+/// Check file/directory permissions.
+///
+/// Make sure that the file or dir is owned by uid/gid and has the correct mode.
+pub fn check_permissions<P: AsRef<Path>>(
+    dir: P,
+    uid: Uid,
+    gid: Gid,
+    mode: u32,
+) -> Result<(), Error> {
     let uid = uid.as_raw();
     let gid = gid.as_raw();
     let dir = dir.as_ref();
@@ -43,7 +102,12 @@ pub fn check_permissions<P: AsRef<Path>>(dir: P, uid: Uid, gid: Gid, mode: u32)
 /// Create a new directory with uid/gid and mode.
 ///
 /// Returns Ok if the directory already exists with correct access permissions.
-pub fn mkdir_permissions<P: AsRef<Path>>(dir: P, uid: Uid, gid: Gid, mode: u32) -> Result<(), Error> {
+pub fn mkdir_permissions<P: AsRef<Path>>(
+    dir: P,
+    uid: Uid,
+    gid: Gid,
+    mode: u32,
+) -> Result<(), Error> {
     let nix_mode = Mode::from_bits(mode).expect("bad mode bits for nix crate");
     let dir = dir.as_ref();
 
@@ -69,78 +133,47 @@ pub fn mkdir_permissions<P: AsRef<Path>>(dir: P, uid: Uid, gid: Gid, mode: u32)
     Ok(())
 }
 
-/// Atomically write data to file owned by `root:api-user` with permission `0640`
+/// Atomically write data to file owned by `root:api-user.gid` with permission `0640`
 ///
 /// Only the superuser can write those files, but group 'api-user' can read them.
 pub fn replace_privileged_config<P: AsRef<std::path::Path>>(
     path: P,
     data: &[u8],
 ) -> Result<(), Error> {
-    let api_user = &product_config().api_user;
+    let options = privileged_create_options();
-    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0640);
-    // set the correct owner/group/permissions while saving file
-    // owner(rw) = root, group(r)= api-user
-    let options = proxmox_sys::fs::CreateOptions::new()
-        .perm(mode)
-        .owner(nix::unistd::ROOT)
-        .group(api_user.gid);
-
     proxmox_sys::fs::replace_file(path, data, options, true)?;
-
     Ok(())
 }
 
-/// Atomically write data to file owned by `api-user:api-user` with permission `0660`.
+/// Atomically write data to file owned by `api-user.uid:api-user.gid` with permission `0660`.
 pub fn replace_config<P: AsRef<std::path::Path>>(path: P, data: &[u8]) -> Result<(), Error> {
-    let api_user = &product_config().api_user;
+    let options = default_create_options();
-    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0640);
-    // set the correct owner/group/permissions while saving file
-    // owner(rw) = root, group(r)= api-user
-    let options = proxmox_sys::fs::CreateOptions::new()
-        .perm(mode)
-        .owner(api_user.uid)
-        .group(api_user.gid);
-
     proxmox_sys::fs::replace_file(path, data, options, true)?;
-
     Ok(())
 }
 
-/// Atomically write data to file owned by "root:root" with permission "0600"
+/// Atomically write data to file owned by `root:root` with permission `0600`.
 ///
 /// Only the superuser can read and write those files.
 pub fn replace_secret_config<P: AsRef<std::path::Path>>(path: P, data: &[u8]) -> Result<(), Error> {
-    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0600);
+    let options = secret_create_options();
-    // set the correct owner/group/permissions while saving file
-    // owner(rw) = root, group(r)= root
-    let options = proxmox_sys::fs::CreateOptions::new()
-        .perm(mode)
-        .owner(nix::unistd::ROOT)
-        .group(nix::unistd::Gid::from_raw(0));
-
     proxmox_sys::fs::replace_file(path, data, options, true)?;
-
     Ok(())
 }
 
-/// Atomically write data to file owned by "root:root" with permission "0644"
+/// Atomically write data to file owned by `root:root` with permission `0644`.
 ///
 /// Everyone can read, but only the superuser can write those files. This is usually used
 /// for system configuration files inside "/etc/" (i.e. "/etc/resolv.conf").
 pub fn replace_system_config<P: AsRef<std::path::Path>>(path: P, data: &[u8]) -> Result<(), Error> {
-    let mode = nix::sys::stat::Mode::from_bits_truncate(0o0644);
+    let options = system_config_create_options();
-    // set the correct owner/group/permissions while saving file
-    // owner(rw) = root, group(r)= root
-    let options = proxmox_sys::fs::CreateOptions::new()
-        .perm(mode)
-        .owner(nix::unistd::ROOT)
-        .group(nix::unistd::Gid::from_raw(0));
-
     proxmox_sys::fs::replace_file(path, data, options, true)?;
-
     Ok(())
 }
 
+/// Lock guard used by [open_api_lockfile]
+///
+/// The lock is released if you drop this guard.
 #[allow(dead_code)]
 pub struct ApiLockGuard(Option<std::fs::File>);
 
@@ -150,26 +183,22 @@ pub unsafe fn create_mocked_lock() -> ApiLockGuard {
     ApiLockGuard(None)
 }
 
-/// Open or create a lock file owned by user "api-user" and lock it.
+/// Open or create a lock file owned by user `api-user` and lock it.
 ///
-/// Owner/Group of the file is set to api-user/api-group.
+/// Owner/Group of the file is set to `api-user.uid/api-user.gid`.
-/// File mode is 0660.
+/// File mode is `0660`.
 /// Default timeout is 10 seconds.
 ///
-/// Note: This method needs to be called by user "root" or "api-user".
+/// The lock is released as soon as you drop the returned lock guard.
+///
+/// Note: This method needs to be called by user `root` or `api-user`.
 pub fn open_api_lockfile<P: AsRef<std::path::Path>>(
     path: P,
     timeout: Option<std::time::Duration>,
     exclusive: bool,
 ) -> Result<ApiLockGuard, Error> {
-    let api_user = &product_config().api_user;
+    let options = lockfile_create_options();
-    let options = proxmox_sys::fs::CreateOptions::new()
-        .perm(nix::sys::stat::Mode::from_bits_truncate(0o660))
-        .owner(api_user.uid)
-        .group(api_user.gid);
-
     let timeout = timeout.unwrap_or(std::time::Duration::new(10, 0));
-
     let file = proxmox_sys::fs::open_file_locked(&path, timeout, exclusive, options)?;
     Ok(ApiLockGuard(Some(file)))
 }