fix last commit. improve process code.

kernel/Makefile

@@ -1,3 +1,10 @@
+# Commands:
+#   make build                  Build
+#   make run                    Build and run in QEMU
+#   make justrun                Run the last build
+#   make doc                    Generate docs
+#   make asm                    Open the deassemble file of the last build
+#   make header                 Open 'objdump -h' of the last build
 #   make addr2line              Use addr2line to recover line info in backtrace
 #   make clean                  Clean
 #

kernel/src/process/structs.rs

@@ -3,7 +3,7 @@ use core::fmt;
 
 use log::*;
 use spin::{Mutex, RwLock};
-use xmas_elf::{ElfFile, header, program::{Flags, Type}};
+use xmas_elf::{ElfFile, header, program::{Flags, Type, SegmentData}};
 use rcore_memory::PAGE_SIZE;
 use rcore_thread::Tid;
 use core::str;
@@ -183,51 +183,41 @@ impl Thread {
     pub fn new_user<'a, Iter>(data: &[u8], args: Iter) -> Box<Thread>
         where Iter: Iterator<Item=&'a str>
     {
-        // Parse elf
+        // Parse ELF
         let elf = ElfFile::new(data).expect("failed to read elf");
         let is32 = match elf.header.pt2 {
             header::HeaderPt2::Header32(_) => true,
             header::HeaderPt2::Header64(_) => false,
         };
 
+        // Check ELF type
         match elf.header.pt2.type_().as_type() {
-            header::Type::Executable => {
-//                panic!("ELF is not shared object");
-            },
+            header::Type::Executable => {},
             header::Type::SharedObject => {},
             _ => panic!("ELF is not executable or shared object"),
         }
 
-        if let Some(interp) = elf.program_iter().filter(|ph| ph.get_type() == Ok(Type::Interp)).next() {
-            let offset = interp.offset() as usize;
-            let size = interp.file_size() as usize - 1; // skip last '\0'
-            if offset + size < data.len() {
-                if let Ok(loader_path) = str::from_utf8(&data[offset..(offset+size)]) {
-                    // assuming absolute path
-                    if let Ok(inode) = crate::fs::ROOT_INODE.lookup_follow(&loader_path[1..], FOLLOW_MAX_DEPTH) {
-                        if let Ok(buf) = inode.read_as_vec() {
-                            debug!("using loader {}", &loader_path);
-                            // Elf loader should not have INTERP
-                            // No infinite loop
-                            let mut new_args: Vec<&str> = args.collect();
-                            new_args.insert(0, loader_path);
-                            return Thread::new_user(buf.as_slice(), new_args.into_iter());
-                        } else {
-                            warn!("loader specified as {} but failed to read", &loader_path);
-                        }
-                    } else {
-                        warn!("loader specified as {} but not found", &loader_path);
-                    }
+        // Check interpreter
+        if let Ok(loader_path) = elf.get_interpreter() {
+            // assuming absolute path
+            if let Ok(inode) = crate::fs::ROOT_INODE.lookup_follow(&loader_path[1..], FOLLOW_MAX_DEPTH) {
+                if let Ok(buf) = inode.read_as_vec() {
+                    debug!("using loader {}", &loader_path);
+                    // Elf loader should not have INTERP
+                    // No infinite loop
+                    let mut new_args: Vec<&str> = args.collect();
+                    new_args.insert(0, loader_path);
+                    return Thread::new_user(buf.as_slice(), new_args.into_iter());
                 } else {
-                    warn!("loader specified but not found");
+                    warn!("loader specified as {} but failed to read", &loader_path);
                 }
             } else {
-                warn!("loader specified but invalid");
+                warn!("loader specified as {} but not found", &loader_path);
             }
         }
 
         // Make page table
-        let (mut vm, entry_addr) = memory_set_from(&elf);
+        let mut vm = elf.make_memory_set();
 
         // User stack
         use crate::consts::{USER_STACK_OFFSET, USER_STACK_SIZE, USER32_STACK_OFFSET};
@@ -240,20 +230,14 @@ impl Thread {
             ustack_top
         };
 
+        // Make init info
         let init_info = ProcInitInfo {
             args: args.map(|s| String::from(s)).collect(),
             envs: BTreeMap::new(),
             auxv: {
                 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 {
-                    warn!("new_user: no phdr found, tls might not work");
+                if let Some(phdr_vaddr) = elf.get_phdr_vaddr() {
+                    map.insert(abi::AT_PHDR, phdr_vaddr as usize);
                 }
                 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);
@@ -274,6 +258,8 @@ impl Thread {
         files.insert(1, FileLike::File(FileHandle::new(crate::fs::STDOUT.clone(), OpenOptions { read: false, write: true, append: false })));
         files.insert(2, FileLike::File(FileHandle::new(crate::fs::STDOUT.clone(), OpenOptions { read: false, write: true, append: false })));
 
+        let entry_addr = elf.header.pt2.entry_point() as usize;
+
         Box::new(Thread {
             context: unsafe {
                 Context::new_user_thread(
@@ -299,9 +285,11 @@ impl Thread {
     /// Fork a new process from current one
     pub fn fork(&self, tf: &TrapFrame) -> Box<Thread> {
         // Clone memory set, make a new page table
-        let vm = self.proc.lock().vm.clone();
-        let files = self.proc.lock().files.clone();
-        let cwd = self.proc.lock().cwd.clone();
+        let proc = self.proc.lock();
+        let vm = proc.vm.clone();
+        let files = proc.files.clone();
+        let cwd = proc.cwd.clone();
+        drop(proc);
         let parent = Some(self.proc.clone());
         debug!("fork: finish clone MemorySet");
 
@@ -324,7 +312,6 @@ impl Thread {
             }
         }
 
-
         Box::new(Thread {
             context: unsafe { Context::new_fork(tf, kstack.top(), vm.token()) },
             kstack,
@@ -376,50 +363,6 @@ impl Process {
     }
 }
 
-
-/// Generate a MemorySet according to the ELF file.
-/// Also return the real entry point address.
-fn memory_set_from(elf: &ElfFile<'_>) -> (MemorySet, usize) {
-    debug!("creating MemorySet from ELF");
-    let mut ms = MemorySet::new();
-    let entry = elf.header.pt2.entry_point() as usize;
-
-    // [NoMMU] Get total memory size and alloc space
-    let va_begin = elf.program_iter()
-        .filter(|ph| ph.get_type() == Ok(Type::Load))
-        .map(|ph| ph.virtual_addr()).min().unwrap() as usize;
-    let va_end = elf.program_iter()
-        .filter(|ph| ph.get_type() == Ok(Type::Load))
-        .map(|ph| ph.virtual_addr() + ph.mem_size()).max().unwrap() as usize;
-    let va_size = va_end - va_begin;
-
-    for ph in elf.program_iter() {
-        if ph.get_type() != Ok(Type::Load) {
-            continue;
-        }
-        let virt_addr = ph.virtual_addr() as usize;
-        let offset = ph.offset() as usize;
-        let file_size = ph.file_size() as usize;
-        let mem_size = ph.mem_size() as usize;
-
-        // Get target slice
-        let target = {
-            ms.push(virt_addr, virt_addr + mem_size, ph.flags().to_attr(), ByFrame::new(GlobalFrameAlloc), "");
-            unsafe { ::core::slice::from_raw_parts_mut(virt_addr as *mut u8, mem_size) }
-        };
-        // Copy data
-        unsafe {
-            ms.with(|| {
-                if file_size != 0 {
-                    target[..file_size].copy_from_slice(&elf.input[offset..offset + file_size]);
-                }
-                target[file_size..].iter_mut().for_each(|x| *x = 0);
-            });
-        }
-    }
-    (ms, entry)
-}
-
 trait ToMemoryAttr {
     fn to_attr(&self) -> MemoryAttr;
 }
@@ -432,3 +375,78 @@ impl ToMemoryAttr for Flags {
         flags
     }
 }
+
+/// Helper functions to process ELF file
+trait ElfExt {
+    /// Generate a MemorySet according to the ELF file.
+    fn make_memory_set(&self) -> MemorySet;
+
+    /// Get interpreter string if it has.
+    fn get_interpreter(&self) -> Result<&str, &str>;
+
+    /// Get virtual address of PHDR section if it has.
+    fn get_phdr_vaddr(&self) -> Option<u64>;
+}
+
+impl ElfExt for ElfFile<'_> {
+    fn make_memory_set(&self) -> MemorySet {
+        debug!("creating MemorySet from ELF");
+        let mut ms = MemorySet::new();
+
+        for ph in self.program_iter() {
+            if ph.get_type() != Ok(Type::Load) {
+                continue;
+            }
+            let virt_addr = ph.virtual_addr() as usize;
+            let mem_size = ph.mem_size() as usize;
+            let data = match ph.get_data(self).unwrap() {
+                SegmentData::Undefined(data) => data,
+                _ => unreachable!(),
+            };
+
+            // Get target slice
+            let target = {
+                ms.push(virt_addr, virt_addr + mem_size, ph.flags().to_attr(), ByFrame::new(GlobalFrameAlloc), "");
+                unsafe { ::core::slice::from_raw_parts_mut(virt_addr as *mut u8, mem_size) }
+            };
+            // Copy data
+            unsafe {
+                ms.with(|| {
+                    if data.len() != 0 {
+                        target[..data.len()].copy_from_slice(data);
+                    }
+                    target[data.len()..].iter_mut().for_each(|x| *x = 0);
+                });
+            }
+        }
+        ms
+    }
+
+    fn get_interpreter(&self) -> Result<&str, &str> {
+        let header = self.program_iter()
+            .filter(|ph| ph.get_type() == Ok(Type::Interp))
+            .next().ok_or("no interp header")?;
+        let data = match header.get_data(self)? {
+            SegmentData::Undefined(data) => data,
+            _ => unreachable!(),
+        };
+        let path = str::from_utf8(data)
+            .map_err(|_| "failed to convert to utf8")?;
+        Ok(path)
+    }
+
+    fn get_phdr_vaddr(&self) -> Option<u64> {
+        if let Some(phdr) = self.program_iter()
+            .find(|ph| ph.get_type() == Ok(Type::Phdr)) {
+            // if phdr exists in program header, use it
+            Some(phdr.virtual_addr())
+        } else if let Some(elf_addr) = self.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.
+            Some(elf_addr.virtual_addr() + self.header.pt2.ph_offset())
+        } else {
+            warn!("elf: no phdr found, tls might not work");
+            None
+        }
+    }
+}