add support for dumping motd on session creation

.github/workflows/nightly.yml

@@ -9,10 +9,11 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
-      - uses: moonrepo/setup-rust@v1
+      - uses: moonrepo/setup-rust@b8edcc56aab474d90c7cf0bb8beeaf8334c15e9f
         with:
           channel: '1.74.0'
           bins: cargo-deny
+      - run: sudo apt-get install libpam0g-dev
       - run: cargo deny --all-features check
 
   postsubmit:

.github/workflows/presubmit.yml

@@ -1,24 +1,27 @@
 name: presubmit
-on: [push, pull_request, workflow_call, workflow_dispatch]
+on: [pull_request, workflow_call, workflow_dispatch]
 
 jobs:
   test:
     name: cargo test --all-features
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
-      - uses: moonrepo/setup-rust@v1
+      - uses: moonrepo/setup-rust@b8edcc56aab474d90c7cf0bb8beeaf8334c15e9f
         with:
           channel: '1.74.0'
-      - run: sudo apt-get install zsh fish
-      - run: cargo test --all-features
-      - uses: actions/upload-artifact@v4
+      - run: sudo apt-get install zsh fish libpam0g-dev
+      - run: SHPOOL_LEAVE_TEST_LOGS=true cargo test --all-features
+      - name: Archive Logs
+        if: always()
+        uses: actions/upload-artifact@v4
+        id: artifact-upload-step
         with:
           name: test-logs
           path: /tmp/shpool-test*/*.log
 
   # miri does not handle all the IO we do, disabled for now.
-  # 
+  #
   # miri:
   #   name: cargo +nightly miri test
   #   runs-on: ubuntu-22.04
@@ -36,32 +39,34 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
-      - uses: moonrepo/setup-rust@v1
+      - uses: moonrepo/setup-rust@b8edcc56aab474d90c7cf0bb8beeaf8334c15e9f
         with:
           components: rustfmt
           channel: nightly
+      - run: sudo apt-get install libpam0g-dev
       - run: cargo +nightly fmt -- --check
 
   cranky:
     name: cargo +nightly cranky --all-targets -- -D warnings
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
-      - uses: moonrepo/setup-rust@v1
+      - uses: moonrepo/setup-rust@b8edcc56aab474d90c7cf0bb8beeaf8334c15e9f
         with:
           components: clippy
           bins: [email protected]
           channel: nightly
-      - run: sudo apt-get install zsh fish
+      - run: sudo apt-get install zsh fish libpam0g-dev
       - run: cargo +nightly cranky --all-targets -- -D warnings
 
   deny:
     name: cargo deny --all-features check licenses
     runs-on: ubuntu-22.04
     steps:
       - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
-      - uses: moonrepo/setup-rust@v1
+      - uses: moonrepo/setup-rust@b8edcc56aab474d90c7cf0bb8beeaf8334c15e9f
         with:
           channel: '1.74.0'
           bins: cargo-deny
+      - run: sudo apt-get install libpam0g-dev
       - run: cargo deny --all-features check licenses

deny.toml

@@ -1,20 +1,18 @@
+[graph]
+all-features = true
+
 [advisories]
+version = 2
 db-path = "~/.cargo/advisory-db"
 db-urls = ["https://github.com/rustsec/advisory-db"]
-vulnerability = "deny"
-unmaintained = "deny"
 yanked = "deny"
-notice = "deny"
 ignore = [
 ]
 
 [licenses]
-unlicensed = "deny"
 allow = [
     "Apache-2.0",
     "MIT",
     "Unicode-DFS-2016",
 ]
-copyleft = "deny"
-default = "deny"
 confidence-threshold = 1.0

libshpool/Cargo.toml

@@ -37,6 +37,8 @@ tracing = "0.1" # logging and performance monitoring facade
 bincode = "1" # serialization for the control protocol
 shpool_vt100 = "0.1.2" # terminal emulation for the scrollback buffer
 shell-words = "1" # parsing the -c/--cmd argument
+motd = "0.2.0" # getting the message-of-the-day
+termini = "1.0.0" # terminfo database
 
 [dependencies.tracing-subscriber]
 version = "0.3"

libshpool/README.md

@@ -8,3 +8,14 @@ to an internal google version of the tool, but don't believe
 that telemetry belongs in an open-source tool. Other potential
 use-cases such as incorporating a shpool daemon into an
 IDE that hosts remote terminals could be imagined though.
+
+## Integrating
+
+In order to call libshpool, you must keep a few things in mind.
+In spirit, you just need to call `libshpool::run(libshpoo::Args::parse())`,
+but you need to take care of a few things manually.
+
+1. Handle the `version` subcommand. Since libshpool is a library, the output
+   will not be very good if the library handles the versioning.
+2. Depend on the `motd` crate and call `motd::handle_reexec()` in your `main`
+   function.

libshpool/src/config.rs

@@ -110,6 +110,21 @@ pub struct Config {
     /// verbatim except that the string '$SHPOOL_SESSION_NAME' will
     /// get replaced with the actual name of the shpool session.
     pub prompt_prefix: Option<String>,
+
+    /// Control when and how shpool will display the message of the day.
+    pub motd: Option<MotdDisplayMode>,
+
+    /// Override arguments to pass to pam_motd.so when resolving the
+    /// message of the day. Normally, you want to leave this blank
+    /// so that shpool will scrape the default arguments used in
+    /// `/etc/pam.d/{ssh,login}` which typically produces the expected
+    /// result, but in some cases you may need to override the argument
+    /// list. You can also use this to make a custom message of the
+    /// day that is only displayed when using shpool.
+    ///
+    /// See https://man7.org/linux/man-pages/man8/pam_motd.8.html
+    /// for more info.
+    pub motd_args: Option<Vec<String>>,
 }
 
 #[derive(Deserialize, Debug, Clone)]
@@ -140,6 +155,31 @@ pub enum SessionRestoreMode {
     Lines(u16),
 }
 
+#[derive(Deserialize, Debug, Clone, Default)]
+#[serde(rename_all = "lowercase")]
+pub enum MotdDisplayMode {
+    /// Never display the message of the day.
+    #[default]
+    Never,
+
+    /// Display the message of the day using the given program
+    /// as the pager. The pager will be invoked like `pager /tmp/motd.txt`,
+    /// and normal connection will only proceed once the pager has
+    /// exited.
+    ///
+    /// Display the message of the day each time a user attaches
+    /// (wether to a new session or reattaching to an existing session).
+    ///
+    /// `less` by default.
+    // Pager(String),
+
+    /// Just dump the message of the day directly to the screen.
+    /// Dumps are only performed when a new session is created.
+    /// There is no safe way to dump directly when reattaching,
+    /// so we don't attempt it.
+    Dump,
+}
+
 #[cfg(test)]
 mod test {
     use super::*;