Implement posix_getdents

src/header/dirent/mod.rs

@@ -4,8 +4,12 @@
 
 #![deny(unsafe_op_in_unsafe_fn)]
 
+use crate::{
+    header::unistd::{SEEK_CUR, SEEK_SET},
+    platform::types::{c_int, c_void, off_t, size_t, ssize_t},
+};
 use alloc::{boxed::Box, vec::Vec};
-use core::{mem, ptr};
+use core::{mem, ptr, slice};
 
 use crate::{
     c_str::CStr,
@@ -219,14 +223,18 @@ pub extern "C" fn fdopendir(fd: c_int) -> *mut DIR {
 }
 
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/posix_getdents.html>.
-// #[no_mangle]
+#[no_mangle]
 pub extern "C" fn posix_getdents(
     fildes: c_int,
     buf: *mut c_void,
     nbyte: size_t,
-    flags: c_int,
+    _flags: c_int,
 ) -> ssize_t {
-    unimplemented!();
+    let slice = unsafe { slice::from_raw_parts_mut(buf as *mut u8, nbyte) };
+
+    Sys::posix_getdents(fildes, slice)
+        .map(|s| s as ssize_t)
+        .or_minus_one_errno()
 }
 
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/readdir.html>.

src/platform/linux/mod.rs

@@ -1,4 +1,3 @@
-use crate::{header::errno::EOPNOTSUPP, io::Write, out::Out};
 use core::{arch::asm, ptr};
 
 use super::{types::*, Pal, ERRNO};
@@ -6,15 +5,16 @@ use crate::{
     c_str::CStr,
     header::{
         dirent::dirent,
-        errno::EINVAL,
+        errno::{EINVAL, EIO, EOPNOTSUPP},
         fcntl::{AT_EMPTY_PATH, AT_FDCWD, AT_REMOVEDIR, AT_SYMLINK_NOFOLLOW},
         signal::SIGCHLD,
         sys_resource::{rlimit, rusage},
         sys_stat::{stat, S_IFIFO},
         sys_statvfs::statvfs,
         sys_time::{timeval, timezone},
-        unistd::SEEK_SET,
+        unistd::{SEEK_CUR, SEEK_SET},
     },
+    io::Write,
 };
 // use header::sys_times::tms;
 use crate::{
@@ -558,6 +558,32 @@ impl Pal for Sys {
         e_raw(unsafe { syscall!(PIPE2, fildes.as_mut_ptr(), flags) }).map(|_| ())
     }
 
+    fn posix_getdents(fildes: c_int, buf: &mut [u8]) -> Result<usize> {
+        let current_offset = Self::lseek(fildes, 0, SEEK_CUR)? as u64;
+        let bytes_read = Self::getdents(fildes, buf, current_offset)?;
+        if bytes_read == 0 {
+            return Ok(0);
+        }
+        let mut bytes_processed = 0;
+        let mut next_offset = current_offset;
+
+        while bytes_processed < bytes_read {
+            let remaining_slice = &buf[bytes_processed..];
+            let (reclen, opaque_next) =
+                unsafe { Self::dent_reclen_offset(remaining_slice, bytes_processed) }
+                    .ok_or(Errno(EIO))?;
+            if reclen == 0 {
+                return Err(Errno(EIO));
+            }
+
+            bytes_processed += reclen as usize;
+            next_offset = opaque_next;
+        }
+
+        Self::lseek(fildes, next_offset as off_t, SEEK_SET)?;
+        Ok(bytes_read)
+    }
+
     #[cfg(target_arch = "x86_64")]
     unsafe fn rlct_clone(stack: *mut usize) -> Result<crate::pthread::OsTid> {
         let flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD;

src/platform/pal/mod.rs

@@ -216,6 +216,8 @@ pub trait Pal {
 
     fn pipe2(fildes: Out<[c_int; 2]>, flags: c_int) -> Result<()>;
 
+    fn posix_getdents(fildes: c_int, buf: &mut [u8]) -> Result<usize>;
+
     unsafe fn rlct_clone(stack: *mut usize) -> Result<pthread::OsTid, Errno>;
     unsafe fn rlct_kill(os_tid: pthread::OsTid, signal: usize) -> Result<()>;
 

src/platform/redox/mod.rs

@@ -36,7 +36,7 @@ use crate::{
         sys_utsname::{utsname, UTSLENGTH},
         sys_wait,
         time::timespec,
-        unistd::{F_OK, R_OK, W_OK, X_OK},
+        unistd::{F_OK, R_OK, SEEK_CUR, SEEK_SET, W_OK, X_OK},
     },
     io::{self, prelude::*, BufReader},
     out::Out,
@@ -419,6 +419,7 @@ impl Pal for Sys {
 
         Ok(record_len.into())
     }
+
     fn dir_seek(_fd: c_int, _off: u64) -> Result<()> {
         // Redox getdents takes an explicit (opaque) offset, so this is a no-op.
         Ok(())
@@ -814,6 +815,32 @@ impl Pal for Sys {
         Ok(())
     }
 
+    fn posix_getdents(fildes: c_int, buf: &mut [u8]) -> Result<usize> {
+        let current_offset = Self::lseek(fildes, 0, SEEK_CUR)? as u64;
+        let bytes_read = Self::getdents(fildes, buf, current_offset)?;
+        if bytes_read == 0 {
+            return Ok(0);
+        }
+        let mut bytes_processed = 0;
+        let mut next_offset = current_offset;
+
+        while bytes_processed < bytes_read {
+            let remaining_slice = &buf[bytes_processed..];
+            let (reclen, opaque_next) =
+                unsafe { Self::dent_reclen_offset(remaining_slice, bytes_processed) }
+                    .ok_or(Errno(EIO))?;
+            if reclen == 0 {
+                return Err(Errno(EIO));
+            }
+
+            bytes_processed += reclen as usize;
+            next_offset = opaque_next;
+        }
+
+        Self::lseek(fildes, next_offset as off_t, SEEK_SET)?;
+        Ok(bytes_read)
+    }
+
     unsafe fn rlct_clone(stack: *mut usize) -> Result<crate::pthread::OsTid> {
         let _guard = CLONE_LOCK.read();
         let res = clone::rlct_clone_impl(stack);

tests/Makefile

@@ -189,6 +189,7 @@ DYNAMIC_ONLY_NAMES=\
 NAMES=\
 	$(EXPECT_NAMES) \
 	dirent/main \
+	dirent/posix_getdents \
 	kill-waitpid \
 	net/if \
 	pty/forkpty \

tests/dirent/posix_getdents.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include "test_helpers.h"
+
+#define BUFFER_SIZE 4096
+
+void read_and_print_directory(int fd) {
+    char buffer[BUFFER_SIZE];
+    long nread;
+    long bpos;
+    struct dirent *d;
+
+    for (;;) {
+        nread = posix_getdents(fd, buffer, BUFFER_SIZE, 0);
+        ERROR_IF(posix_getdents, nread, == -1);
+        UNEXP_IF(posix_getdents, nread, < 0);
+
+        if (nread == 0) {
+            break;
+        }
+
+        for (bpos = 0; bpos < nread;) {
+            d = (struct dirent *) (buffer + bpos);
+            printf("  ino = %-10lu  name = %s\n", (unsigned long)d->d_ino, d->d_name);
+            bpos += d->d_reclen;
+        }
+    }
+}
+
+int main(void) {
+    int fd = open("example_dir/", O_RDONLY | O_DIRECTORY);
+    ERROR_IF(open, fd, == -1);
+    read_and_print_directory(fd);
+
+    off_t seek_result = lseek(fd, 0, SEEK_SET);
+    ERROR_IF(lseek, seek_result, == -1);
+    read_and_print_directory(fd);
+
+    close(fd);
+}