Canonicalize the path used by sh.

With a bunch of LibC work to support the feature. LibC now initializes
AK::StringImpl by default. It's now fine to use AK in LibC/Userland! :^)

LibC/Makefile

@@ -1,4 +1,11 @@
-OBJS = \
+AK_OBJS = \
+    ../AK/StringImpl.o \
+    ../AK/String.o \
+    ../AK/StringBuilder.o \
+    ../AK/FileSystemPath.o \
+    ../AK/kmalloc.o
+
+LIBC_OBJS = \
        stdio.o \
        unistd.o \
        string.o \
@@ -8,8 +15,11 @@ OBJS = \
        stdlib.o \
        time.o \
        utsname.o \
+       assert.o \
        entry.o
 
+OBJS = $(AK_OBJS) $(LIBC_OBJS)
+
 LIBRARY = LibC.a
 ARCH_FLAGS =
 STANDARD_FLAGS = -std=c++17 -nostdinc++ -nostdlib
@@ -19,7 +29,7 @@ FLAVOR_FLAGS = -fomit-frame-pointer -mregparm=3 -march=i386 -m32 -fno-exceptions
 OPTIMIZATION_FLAGS = -Os -fno-asynchronous-unwind-tables
 INCLUDE_FLAGS = -I.. -I.
 
-DEFINES = -DSERENITY -DSANITIZE_PTRS
+DEFINES = -DSERENITY -DUSERLAND -DSANITIZE_PTRS
 
 CXXFLAGS = $(WARNING_FLAGS) $(OPTIMIZATION_FLAGS) $(LIBC_FLAGS) $(FLAVOR_FLAGS) $(ARCH_FLAGS) $(STANDARD_FLAGS) $(INCLUDE_FLAGS) $(DEFINES)
 CXX = g++-8

LibC/assert.cpp

@@ -0,0 +1,14 @@
+#include "assert.h"
+#include "stdlib.h"
+#include "stdio.h"
+
+extern "C" {
+
+extern void __assertion_failed(const char* msg, const char* file, unsigned line, const char* func)
+{
+    printf("ASSERTION FAILED: %s\n%s:%u in %s\n", msg, file, line, func);
+    abort();
+}
+
+}
+

LibC/assert.h

@@ -0,0 +1,14 @@
+#pragma once
+
+extern "C" {
+
+void __assertion_failed(const char* msg, const char* file, unsigned line, const char* func);
+
+#define assert(expr) (static_cast<bool>(expr) ? (void)0 : __assertion_failed(#expr, __FILE__, __LINE__, __PRETTY_FUNCTION__))
+#define CRASH() do { asm volatile("ud2"); } while(0)
+#define ASSERT assert
+#define RELEASE_ASSERT assert
+#define ASSERT_NOT_REACHED() assert(false)
+
+}
+

LibC/entry.cpp

@@ -1,4 +1,5 @@
 #include <Kernel/Syscall.h>
+#include <AK/StringImpl.h>
 
 extern "C" int main(int, char**);
 
@@ -8,6 +9,8 @@ extern "C" int _start()
 {
     errno = 0;
 
+    StringImpl::initializeGlobals();
+
     int argc;
     char** argv;
     int rc = Syscall::invoke(Syscall::GetArguments, (dword)&argc, (dword)&argv);

LibC/stdlib.cpp

@@ -1,5 +1,7 @@
 #include "stdlib.h"
 #include "mman.h"
+#include <Kernel/Syscall.h>
+#include <AK/Assertions.h>
 
 extern "C" {
 
@@ -20,5 +22,28 @@ void free(void* ptr)
     munmap(ptr, 4096);
 }
 
+void* calloc(size_t nmemb, size_t)
+{
+    ASSERT_NOT_REACHED();
+    return nullptr;
+}
+
+void* realloc(void *ptr, size_t)
+{
+    ASSERT_NOT_REACHED();
+    return nullptr;
+}
+
+void exit(int status)
+{
+    Syscall::invoke(Syscall::PosixExit, (dword)status);
+}
+
+void abort()
+{
+    // FIXME: Implement proper abort().
+    exit(253);
+}
+
 }
 

LibC/stdlib.h

@@ -6,6 +6,11 @@ extern "C" {
 
 void* malloc(size_t);
 void free(void*);
+void* calloc(size_t nmemb, size_t);
+void* realloc(void *ptr, size_t);
+
+void exit(int status);
+void abort();
 
 }
 

LibC/string.cpp

@@ -21,6 +21,17 @@ int strcmp(const char* s1, const char* s2)
     return *(const unsigned char*)s1 < *(const unsigned char*)s2 ? -1 : 1;
 }
 
+int memcmp(const void* v1, const void* v2, size_t n)
+{
+    auto* s1 = (const byte*)v1;
+    auto* s2 = (const byte*)v2;
+    while (n-- > 0) {
+        if (*s1++ != *s2++)
+            return s1[-1] < s2[-1] ? -1 : 1;
+    }
+    return 0;
+}
+
 void memcpy(void* dest, const void* src, size_t n)
 {
     auto* bdest = (unsigned char*)dest;

LibC/string.h

@@ -6,6 +6,7 @@ extern "C" {
 
 size_t strlen(const char*);
 int strcmp(const char*, const char*);
+int memcmp(const void*, const void*, size_t);
 void memcpy(void*, const void*, size_t);
 const char* strerror(int errnum);