feature: better login program

Makefile

@@ -92,7 +92,9 @@ initrd:
 		--target=../etc/$(ARCH)-osdev5.json \
 		-Z build-std=core,alloc,compiler_builtins \
 		$(CARGO_COMMON_OPTS)
-	mkdir -p $(O)/rootfs/bin $(O)/rootfs/sbin $(O)/rootfs/dev
+	mkdir -p $(O)/rootfs/bin $(O)/rootfs/sbin $(O)/rootfs/dev $(O)/rootfs/etc
+	cp etc/initrd/passwd $(O)/rootfs/etc
+	cp etc/initrd/shadow $(O)/rootfs/etc
 	touch $(O)/rootfs/dev/.do_no_remove
 	cp target/$(ARCH)-osdev5/$(PROFILE)/init $(O)/rootfs/init
 	cp target/$(ARCH)-osdev5/$(PROFILE)/shell $(O)/rootfs/bin

etc/initrd/passwd

@@ -0,0 +1,2 @@
+root:0:0:root:/:/bin/shell
+alnyan:1000:1000:alnyan:/:/bin/shell

etc/initrd/shadow

@@ -0,0 +1,2 @@
+root:toor
+alnyan:

libsys/src/lib.rs

@@ -24,6 +24,55 @@ pub struct ProgramArgs {
     pub size: usize
 }
 
+// TODO utils
+use core::fmt;
+
+#[derive(Clone, Copy)]
+pub struct FixedStr<const N: usize> {
+    len: usize,
+    data: [u8; N],
+}
+
+impl<const N: usize> FixedStr<N> {
+    pub const fn empty() -> Self {
+        Self {
+            len: 0,
+            data: [0; N]
+        }
+    }
+
+    pub fn copy_from_str(&mut self, src: &str) {
+        if src.len() > self.data.len() {
+            panic!("copy_from_str: src len > data len");
+        }
+        self.len = src.len();
+        self.data[..self.len].copy_from_slice(src.as_bytes());
+    }
+
+    pub fn as_str(&self) -> &str {
+        unsafe {
+            core::str::from_utf8_unchecked(&self.data[..self.len])
+        }
+    }
+}
+
+impl<const N: usize> fmt::Debug for FixedStr<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "\"")?;
+        fmt::Display::fmt(self, f)?;
+        write!(f, "\"")
+    }
+}
+
+impl<const N: usize> fmt::Display for FixedStr<N> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        for &byte in &self.data[..self.len] {
+            write!(f, "{}", byte as char)?;
+        }
+        Ok(())
+    }
+}
+
 #[cfg(feature = "user")]
 pub mod calls;
 #[cfg(feature = "user")]

libusr/src/env/mod.rs

@@ -1,6 +1,14 @@
-use libsys::{debug::TraceLevel, ProgramArgs};
-use alloc::vec::Vec;
 use crate::trace;
+use alloc::vec::Vec;
+use libsys::{
+    debug::TraceLevel,
+    ProgramArgs,
+};
+
+mod passwd;
+pub use passwd::UserInfo;
+mod shadow;
+pub use shadow::UserShadow;
 
 static mut PROGRAM_ARGS: Vec<&'static str> = Vec::new();
 

libusr/src/env/passwd.rs

@@ -0,0 +1,99 @@
+use crate::io::{Read, read_line};
+use core::str::FromStr;
+use core::fmt;
+use crate::trace_debug;
+use crate::file::File;
+use libsys::{FixedStr, stat::{UserId, GroupId}};
+
+#[derive(Debug, Clone, Copy)]
+pub struct UserInfo {
+    name: FixedStr<32>,
+    uid: UserId,
+    gid: GroupId,
+    home: FixedStr<64>,
+    shell: FixedStr<64>,
+}
+
+impl UserInfo {
+    pub fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    pub fn home(&self) -> &str {
+        self.home.as_str()
+    }
+
+    pub fn shell(&self) -> &str {
+        self.shell.as_str()
+    }
+
+    pub fn uid(&self) -> UserId {
+        self.uid
+    }
+
+    pub fn gid(&self) -> GroupId {
+        self.gid
+    }
+
+    pub fn find<F: Fn(&Self) -> bool>(pred: F) -> Result<Self, ()> {
+        let mut file = File::open("/etc/passwd").map_err(|_| ())?;
+        let mut buf = [0; 128];
+        loop {
+            let line = read_line(&mut file, &mut buf).map_err(|_| ())?;
+            if let Some(line) = line {
+                let ent = UserInfo::from_str(line)?;
+                if pred(&ent) {
+                    return Ok(ent);
+                }
+            } else {
+                break;
+            }
+        }
+        Err(())
+    }
+
+    pub fn by_name(name: &str) -> Result<Self, ()> {
+        Self::find(|ent| ent.name() == name)
+    }
+}
+
+impl FromStr for UserInfo {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, ()> {
+        let mut iter = s.split(":");
+
+        let name = iter.next().ok_or(())?;
+        let uid = iter
+            .next()
+            .ok_or(())
+            .and_then(|e| u32::from_str(e).map_err(|_| ()))
+            .map(UserId::from)?;
+        let gid = iter
+            .next()
+            .ok_or(())
+            .and_then(|e| u32::from_str(e).map_err(|_| ()))
+            .map(GroupId::from)?;
+        let comment = iter.next().ok_or(())?;
+        let home = iter.next().ok_or(())?;
+        let shell = iter.next().ok_or(())?;
+
+        if iter.next().is_some() {
+            return Err(());
+        }
+
+        let mut res = Self {
+            uid,
+            gid,
+            name: FixedStr::empty(),
+            home: FixedStr::empty(),
+            shell: FixedStr::empty(),
+        };
+
+        res.name.copy_from_str(&name);
+        res.home.copy_from_str(&home);
+        res.shell.copy_from_str(&shell);
+
+        Ok(res)
+    }
+}

libusr/src/env/shadow.rs

@@ -0,0 +1,67 @@
+use crate::file::File;
+use crate::io::{Read, read_line};
+use core::str::FromStr;
+use libsys::FixedStr;
+
+#[derive(Debug, Clone, Copy)]
+pub struct UserShadow {
+    name: FixedStr<32>,
+    password: FixedStr<64>,
+}
+
+impl UserShadow {
+    pub fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    pub fn password(&self) -> &str {
+        self.password.as_str()
+    }
+
+
+    pub fn find<F: Fn(&Self) -> bool>(pred: F) -> Result<Self, ()> {
+        let mut file = File::open("/etc/shadow").map_err(|_| ())?;
+        let mut buf = [0; 128];
+        loop {
+            let line = read_line(&mut file, &mut buf).map_err(|_| ())?;
+            if let Some(line) = line {
+                let ent = UserShadow::from_str(line)?;
+                if pred(&ent) {
+                    return Ok(ent);
+                }
+            } else {
+                break;
+            }
+        }
+        Err(())
+    }
+
+    pub fn by_name(name: &str) -> Result<Self, ()> {
+        Self::find(|ent| ent.name() == name)
+    }
+}
+
+impl FromStr for UserShadow {
+    type Err = ();
+
+    fn from_str(s: &str) -> Result<Self, ()> {
+        let mut iter = s.split(':');
+
+        let name = iter.next().ok_or(())?;
+        let password = iter.next().ok_or(())?;
+
+        if iter.next().is_some() {
+            return Err(());
+        }
+
+        let mut res = Self {
+            name: FixedStr::empty(),
+            password: FixedStr::empty(),
+        };
+
+        res.name.copy_from_str(name);
+        res.password.copy_from_str(password);
+
+        Ok(res)
+    }
+}

libusr/src/io/mod.rs

@@ -42,3 +42,27 @@ pub fn stat(pathname: &str) -> Result<Stat, Error> {
     sys_fstatat(None, pathname, &mut buf, 0).unwrap();
     Ok(buf)
 }
+
+// TODO use BufRead instead once it's implemented
+pub(crate) fn read_line<'a, F: Read>(f: &mut F, buf: &'a mut [u8]) -> Result<Option<&'a str>, ()> {
+    let mut pos = 0;
+    loop {
+        if pos == buf.len() {
+            return Err(());
+        }
+
+        let count = f.read(&mut buf[pos..=pos]).map_err(|_| ())?;
+        if count == 0 {
+            if pos == 0 {
+                return Ok(None);
+            }
+            break;
+        }
+        if buf[pos] == b'\n' {
+            break;
+        }
+
+        pos += 1;
+    }
+    core::str::from_utf8(&buf[..pos]).map_err(|_| ()).map(Some)
+}

user/src/sbin/login.rs

@@ -14,7 +14,8 @@ use libsys::{
     stat::{FileDescriptor, FileMode, GroupId, OpenFlags, UserId},
     termios::{Termios, TermiosLflag},
 };
-use libusr::{env, io};
+use libusr::{env::{self, UserInfo, UserShadow}, io};
+use core::str::FromStr;
 
 struct HiddenInput {
     fd: FileDescriptor,
@@ -73,7 +74,7 @@ fn readline(fd: FileDescriptor, buf: &mut [u8]) -> Result<&str, Errno> {
     }
 }
 
-fn login_as(uid: UserId, gid: GroupId, shell: &str) -> Result<(), Errno> {
+fn login(uid: UserId, gid: GroupId, shell: &str) -> Result<(), Errno> {
     if let Some(pid) = unsafe { sys_fork() }? {
         let mut status = 0;
         sys_waitpid(pid, &mut status).ok();
@@ -90,6 +91,11 @@ fn login_as(uid: UserId, gid: GroupId, shell: &str) -> Result<(), Errno> {
     }
 }
 
+fn login_as(name: &str) -> Result<(), Errno> {
+    let ent = UserInfo::by_name(name).map_err(|_| Errno::DoesNotExist)?;
+    login(ent.uid(), ent.gid(), ent.shell())
+}
+
 // TODO baud rate and misc port settings
 #[no_mangle]
 fn main() -> i32 {
@@ -132,15 +138,26 @@ fn main() -> i32 {
     loop {
         print!("login: ");
         let username = readline(FileDescriptor::STDIN, &mut user_buf).expect("Login read failed");
-        print!("password: ");
-        let password = {
-            let mut input = HiddenInput::open(FileDescriptor::STDIN).unwrap();
-            input.readline(&mut password_buf)
-        }
-        .expect("Password read failed");
 
-        if username == "root" && password == "toor" {
-            login_as(UserId::from(0), GroupId::from(0), "/bin/shell").unwrap();
+        let shadow = match UserShadow::by_name(username) {
+            Ok(e) => e,
+            Err(_) => continue
+        };
+
+        if !shadow.password().is_empty() {
+            print!("password: ");
+            let password = {
+                let mut input = HiddenInput::open(FileDescriptor::STDIN).unwrap();
+                input.readline(&mut password_buf)
+            }
+            .expect("Password read failed");
+
+            if password != shadow.password() {
+                eprintln!("Incorrect password");
+                continue;
+            }
         }
+
+        login_as(username);
     }
 }