init: Read and launch service files in order using sort()

apps/init.cpp

@@ -1,6 +1,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <luna/PathParser.h>
+#include <luna/Sort.h>
 #include <luna/String.h>
 #include <luna/Vector.h>
 #include <os/Directory.h>
@@ -239,6 +240,7 @@ static Result<void> load_services()
     auto dir = TRY(os::Directory::open("/etc/init"));
 
     auto services = TRY(dir->list(os::Directory::Filter::ParentAndBase));
+    sort(services.begin(), services.end(), String::compare);
 
     for (const auto& entry : services)
     {

initrd/etc/init/00-motd

@@ -0,0 +1,3 @@
+Name=motd
+Command=/bin/cat /etc/motd
+Wait=true

initrd/etc/motd

@@ -1 +1,2 @@
-Hello, world!
+Welcome to the Luna system!
+Have a look around, you can run 'ls /bin' to list available commands.

libc/include/stdlib.h

@@ -35,16 +35,16 @@ extern "C"
 #endif
 
     /* Return the absolute value of an integer. */
-    int abs(int v);
+    int abs(int);
 
     /* Return the absolute value of a long integer. */
-    long labs(long v);
+    long labs(long);
 
     /* Return the absolute value of a long long integer. */
-    long long llabs(long long v);
+    long long llabs(long long);
 
     /* Return the result of dividing two integers, including the remainder. */
-    div_t div(int num, int den);
+    div_t div(int, int);
 
     /* Return the result of dividing two long integers, including the remainder. */
     ldiv_t ldiv(long, long);
@@ -62,7 +62,7 @@ extern "C"
     void* realloc(void* ptr, size_t size);
 
     /* Free heap memory. */
-    void free(void*);
+    void free(void* ptr);
 
     /* Abort the program without performing any normal cleanup. */
     __noreturn void abort();
@@ -115,7 +115,9 @@ extern "C"
     /* Clear all environment variables. */
     int clearenv(void);
 
-    void qsort(void*, size_t, size_t, int (*)(const void*, const void*));
+    /* Sort an array of arbitrary elements using a comparison function. */
+    void qsort(void* base, size_t nmemb, size_t size, int (*compar)(const void*, const void*));
+
     void* bsearch(const void*, const void*, size_t, size_t, int (*)(const void*, const void*));
 
     /* Convert a multibyte character string to a wide character string. */

libc/src/stdlib.cpp

@@ -2,6 +2,7 @@
 #include <limits.h>
 #include <luna/Heap.h>
 #include <luna/NumberParsing.h>
+#include <luna/Sort.h>
 #include <luna/Utf8.h>
 #include <stdlib.h>
 #include <sys/syscall.h>
@@ -199,4 +200,9 @@ extern "C"
 
         return status;
     }
+
+    void qsort(void* base, size_t nmemb, size_t size, int (*compar)(const void*, const void*))
+    {
+        c_quicksort(base, nmemb, size, compar);
+    }
 }

libluna/CMakeLists.txt

@@ -5,6 +5,7 @@ file(GLOB HEADERS include/luna/*.h)
 set(FREESTANDING_SOURCES
     ${HEADERS}
     src/Format.cpp
+    src/Sort.cpp
     src/NumberParsing.cpp
     src/CString.cpp
     src/CPath.cpp

libluna/include/luna/Sort.h

@@ -0,0 +1,26 @@
+#pragma once
+#include <luna/Types.h>
+
+typedef int (*compar_t)(const void*, const void*);
+
+void c_quicksort(void* base, usize nmemb, usize size, compar_t compar);
+
+template <typename T> void sort(T* base, usize nmemb, int (*compar)(const T*, const T*))
+{
+    return c_quicksort(base, nmemb, sizeof(T), (compar_t)compar);
+}
+
+template <typename T> void sort(T* base, usize nmemb, compar_t compar)
+{
+    return c_quicksort(base, nmemb, sizeof(T), compar);
+}
+
+template <typename T> void sort(T* begin, T* end, int (*compar)(const T*, const T*))
+{
+    return c_quicksort(begin, end - begin, sizeof(T), (compar_t)compar);
+}
+
+template <typename T> void sort(T* begin, T* end, compar_t compar)
+{
+    return c_quicksort(begin, end - begin, sizeof(T), compar);
+}

libluna/include/luna/String.h

@@ -65,6 +65,8 @@ class String
     static Result<String> from_cstring(const char* str);
     static Result<String> from_string_view(StringView str);
 
+    static int compare(const String* a, const String* b);
+
     const char* chars() const
     {
         return m_inline ? m_inline_storage : m_string;

libluna/src/Sort.cpp

@@ -0,0 +1,53 @@
+#include <luna/Alignment.h>
+#include <luna/Sort.h>
+
+static void swap_sized(void* ptr1, void* ptr2, usize size)
+{
+    char* x = (char*)ptr1;
+    char* y = (char*)ptr2;
+
+    while (size--)
+    {
+        char t = *x;
+        *x = *y;
+        *y = t;
+        x += 1;
+        y += 1;
+    }
+}
+
+static usize partition(void* base, usize start, usize end, usize size, compar_t compar)
+{
+    auto atindex = [&base, &size](usize index) { return offset_ptr(base, index * size); };
+
+    void* pivot = atindex(end);
+    usize i = (start - 1);
+
+    for (usize j = start; j <= end - 1; j++)
+    {
+        if (compar(atindex(j), pivot) < 0)
+        {
+            i++;
+            swap_sized(atindex(i), atindex(j), size);
+        }
+    }
+
+    swap_sized(atindex(i + 1), pivot, size);
+    return i + 1;
+}
+
+static void quicksort_impl(void* base, usize start, usize end, usize size, compar_t compar)
+{
+    if (start < end)
+    {
+        usize pivot = partition(base, start, end, size, compar);
+        if ((end - start) < 2) return;
+        quicksort_impl(base, start, pivot - 1, size, compar);
+        quicksort_impl(base, pivot + 1, end, size, compar);
+    }
+}
+
+void c_quicksort(void* base, usize nmemb, usize size, compar_t compar)
+{
+    quicksort_impl(base, 0, nmemb - 1, size, compar);
+}

libluna/src/String.cpp

@@ -180,3 +180,8 @@ Result<String> String::join(const Vector<String>& vec, StringView delim)
 
     return sb.string();
 }
+
+int String::compare(const String* a, const String* b)
+{
+    return strcmp(a->chars(), b->chars());
+}