From d14b5843a3f42afa2d7f9e4a5e65ab51545231d0 Mon Sep 17 00:00:00 2001
From: Tyler <tyler.steele@protonmail.com>
Date: Thu, 17 Jun 2021 14:33:30 -0700
Subject: [PATCH] Implements libc file open flags (unix only)

---
 Cargo.lock           |   1 +
 src/uu/dd/Cargo.toml |   1 +
 src/uu/dd/src/dd.rs  | 136 +++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 132 insertions(+), 6 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 779d4b99e..0e9bd8847 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1760,6 +1760,7 @@ dependencies = [
  "gcd",
  "getopts",
  "hex-literal",
+ "libc",
  "md-5",
  "signal-hook",
  "uucore",
diff --git a/src/uu/dd/Cargo.toml b/src/uu/dd/Cargo.toml
index ce53439b2..e10fd7f07 100644
--- a/src/uu/dd/Cargo.toml
+++ b/src/uu/dd/Cargo.toml
@@ -20,6 +20,7 @@ debug_print = "1.0"
 # Probably best to keep this identical to the version of getopts in the uucore crate
 getopts = "<= 0.2.21"
 gcd = "2.0"
+libc = "0.2"
 signal-hook = "0.3.9"
 uucore = { version=">=0.0.7", package="uucore", path="../../uucore" }
 uucore_procs = { version=">=0.0.5", package="uucore_procs", path="../../uucore_procs" }
diff --git a/src/uu/dd/src/dd.rs b/src/uu/dd/src/dd.rs
index 564e8804d..5eccf032a 100644
--- a/src/uu/dd/src/dd.rs
+++ b/src/uu/dd/src/dd.rs
@@ -35,6 +35,10 @@ use std::io::{
     self, Read, Write,
     Seek,
 };
+#[cfg(unix)]
+use libc;
+#[cfg(unix)]
+use std::os::unix::fs::OpenOptionsExt;
 use std::sync::{
     Arc, atomic::AtomicUsize, mpsc, atomic::Ordering,
 };
@@ -250,6 +254,53 @@ impl Input<io::Stdin>
     }
 }
 
+fn make_unix_iflags(oflags: &IFlags) -> Option<libc::c_int>
+{
+    let mut flag = 0;
+
+    if oflags.direct
+    {
+        flag |= libc::O_DIRECT;
+    }
+    if oflags.directory
+    {
+        flag |= libc::O_DIRECTORY;
+    }
+    if oflags.dsync
+    {
+        flag |= libc::O_DSYNC;
+    }
+    if oflags.noatime
+    {
+        flag |= libc::O_NOATIME;
+    }
+    if oflags.noctty
+    {
+        flag |= libc::O_NOCTTY;
+    }
+    if oflags.nofollow
+    {
+        flag |= libc::O_NOFOLLOW;
+    }
+    if oflags.nonblock
+    {
+        flag |= libc::O_NONBLOCK;
+    }
+    if oflags.sync
+    {
+        flag |= libc::O_SYNC;
+    }
+
+    if flag != 0
+    {
+        Some(flag)
+    }
+    else
+    {
+        None
+    }
+}
+
 impl Input<File>
 {
     fn new(matches: &getopts::Matches) -> Result<Self, Box<dyn Error>>
@@ -264,7 +315,21 @@ impl Input<File>
 
         if let Some(fname) = matches.opt_str("if")
         {
-            let mut src = File::open(fname)?;
+            let mut src =
+            {
+                let mut opts = OpenOptions::new();
+                opts.read(true);
+
+                if cfg!(unix)
+                {
+                    if let Some(libc_flags) = make_unix_iflags(&iflags)
+                    {
+                        opts.custom_flags(libc_flags);
+                    }
+                }
+
+                opts.open(fname)?
+            };
 
             if let Some(amt) = skip
             {
@@ -461,6 +526,53 @@ impl Output<io::Stdout> {
     }
 }
 
+fn make_unix_oflags(oflags: &OFlags) -> Option<libc::c_int>
+{
+    let mut flag = 0;
+
+    if oflags.direct
+    {
+        flag |= libc::O_DIRECT;
+    }
+    if oflags.directory
+    {
+        flag |= libc::O_DIRECTORY;
+    }
+    if oflags.dsync
+    {
+        flag |= libc::O_DSYNC;
+    }
+    if oflags.noatime
+    {
+        flag |= libc::O_NOATIME;
+    }
+    if oflags.noctty
+    {
+        flag |= libc::O_NOCTTY;
+    }
+    if oflags.nofollow
+    {
+        flag |= libc::O_NOFOLLOW;
+    }
+    if oflags.nonblock
+    {
+        flag |= libc::O_NONBLOCK;
+    }
+    if oflags.sync
+    {
+        flag |= libc::O_SYNC;
+    }
+
+    if flag != 0
+    {
+        Some(flag)
+    }
+    else
+    {
+        None
+    }
+}
+
 impl Output<File> {
     fn new(matches: &getopts::Matches) -> Result<Self, Box<dyn Error>>
     {
@@ -471,11 +583,23 @@ impl Output<File> {
 
         if let Some(fname) = matches.opt_str("of")
         {
-            let mut dst = OpenOptions::new()
-                .write(true)
-                .create(!cflags.nocreat)
-                .truncate(!cflags.notrunc)
-                .open(fname)?;
+            let mut dst = {
+                let mut opts = OpenOptions::new();
+                opts.write(true)
+                    .append(oflags.append)
+                    .create_new(cflags.excl || !cflags.nocreat)
+                    .truncate(!cflags.notrunc);
+
+                if cfg!(unix)
+                {
+                    if let Some(libc_flags) = make_unix_oflags(&oflags)
+                    {
+                        opts.custom_flags(libc_flags);
+                    }
+                }
+
+                opts.open(fname)?
+            };
 
             if let Some(amt) = seek
             {