From 2d77b89476a34bff605f4b1ca578e7361d748ed3 Mon Sep 17 00:00:00 2001
From: Jiajie Chen <noc@jiegec.ac.cn>
Date: Thu, 7 Mar 2019 22:06:26 +0800
Subject: [PATCH] Infer phdr from elf loading address, skip the first page in
 sys_mmap and update user to musl-enabled biscuit programs

---
 kernel/src/process/structs.rs | 6 ++++++
 kernel/src/syscall/mem.rs     | 7 +++++++
 user                          | 2 +-
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/kernel/src/process/structs.rs b/kernel/src/process/structs.rs
index 78d3aa4..59ccc9e 100644
--- a/kernel/src/process/structs.rs
+++ b/kernel/src/process/structs.rs
@@ -141,7 +141,13 @@ impl Thread {
                 let mut map = BTreeMap::new();
                 if let Some(phdr) = elf.program_iter()
                     .find(|ph| ph.get_type() == Ok(Type::Phdr)) {
+                    // if phdr exists in program header, use it
                     map.insert(abi::AT_PHDR, phdr.virtual_addr() as usize);
+                } else if let Some(elf_addr) = elf.program_iter().find(|ph| ph.get_type() == Ok(Type::Load) && ph.offset() == 0) {
+                    // otherwise, check if elf is loaded from the beginning, then phdr can be inferred.
+                    map.insert(abi::AT_PHDR, elf_addr.virtual_addr() as usize + elf.header.pt2.ph_offset() as usize);
+                } else {
+                    debug!("new_user: no phdr found, tls might not work");
                 }
                 map.insert(abi::AT_PHENT, elf.header.pt2.ph_entry_size() as usize);
                 map.insert(abi::AT_PHNUM, elf.header.pt2.ph_count() as usize);
diff --git a/kernel/src/syscall/mem.rs b/kernel/src/syscall/mem.rs
index 2f05578..6a3bb59 100644
--- a/kernel/src/syscall/mem.rs
+++ b/kernel/src/syscall/mem.rs
@@ -1,5 +1,6 @@
 use rcore_memory::memory_set::handler::Delay;
 use rcore_memory::memory_set::MemoryAttr;
+use rcore_memory::PAGE_SIZE;
 
 use crate::memory::GlobalFrameAlloc;
 
@@ -11,6 +12,12 @@ pub fn sys_mmap(mut addr: usize, len: usize, prot: usize, flags: usize, fd: i32,
     info!("mmap addr={:#x}, size={:#x}, prot={:?}, flags={:?}, fd={}, offset={:#x}", addr, len, prot, flags, fd, offset);
 
     let mut proc = process();
+    if addr == 0 {
+        // although NULL can be a valid address
+        // but in C, NULL is regarded as allocation failure
+        // so just skip it
+        addr = PAGE_SIZE;
+    }
     addr = proc.memory_set.find_free_area(addr, len);
 
     if flags.contains(MmapFlags::ANONYMOUS) {
diff --git a/user b/user
index fb9a1d5..93bac1c 160000
--- a/user
+++ b/user
@@ -1 +1 @@
-Subproject commit fb9a1d5f7014b3be4f4a234bcaecd069335a216c
+Subproject commit 93bac1ce10eae9aa541b64e955316b325f8dc9cb