From: misomosi <misomosispi@gmail.com>
Date: Tue, 7 May 2024 01:54:50 +0000 (-0400)
Subject: Add POSIX implementation
X-Git-Url: http://git.misomosispi.com/?a=commitdiff_plain;h=c2dd6d300469bdcdf975ac80926189aeaf4dc53c;p=pldh.git

Add POSIX implementation
---

diff --git a/README.md b/README.md
index 9a52158..f11cef5 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,4 @@
 # pld.h
 Functions and logging generally useful for preloads
+
+
diff --git a/examples/printf.c b/examples/printf.c
new file mode 100644
index 0000000..7cdb93d
--- /dev/null
+++ b/examples/printf.c
@@ -0,0 +1,8 @@
+#include "../pld.h"
+#include <stdio.h>
+PLD("libc.so.6");
+int main(void)
+{
+	PFN(printf)("Hello World! %d\n", 2);
+	return 0;
+}
diff --git a/examples/writefile.c b/examples/writefile.c
index 3528609..5f6e4b3 100644
--- a/examples/writefile.c
+++ b/examples/writefile.c
@@ -1,6 +1,6 @@
 #include "../pld.h"
 
-PLD(KERNEL32.DLL)
+PLD("KERNEL32.DLL")
 int main(void) {
 	DWORD dummy;
 	PFN(WriteFile)(GetStdHandle(STD_OUTPUT_HANDLE), "Hello World!\n", 13, &dummy, NULL);
diff --git a/pld.h b/pld.h
index dd67f04..7c50c95 100644
--- a/pld.h
+++ b/pld.h
@@ -15,11 +15,12 @@ static int PLD_Private_strlen(const char *s)
 	return len - 1;
 }
 
-static void PLD_Private_Log(const char *, const char *, int);
 
 #ifdef _WIN32
 
 #include <windows.h>
+typedef DWORD PLD_ErrCode;
+static void PLD_Private_Log(const char *, const char *, PLD_ErrCode);
 
 static void PLD_Private_WriteString(const char *s)
 {
@@ -27,7 +28,7 @@ static void PLD_Private_WriteString(const char *s)
 	WriteFile(GetStdHandle(STD_ERROR_HANDLE), s, PLD_Private_strlen(s), &dummy, NULL);
 }
 
-static void PLD_Private_FormatError(int code, char *s, int len)
+static void PLD_Private_FormatError(DWORD code, char *s, int len)
 {
 	DWORD_PTR arg = (DWORD_PTR)s;
 	FormatMessageA(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ARGUMENT_ARRAY,
@@ -42,12 +43,13 @@ static void PLD_Private_FormatError(int code, char *s, int len)
 static HMODULE PLD_Private_LoadLibrary_wrapper(LPCSTR lpLibFileName)
 {
 	HMODULE hModule = GetModuleHandleA(lpLibFileName);
-	if (hModule != NULL)
+	if (hModule == NULL)
 		hModule = LoadLibraryA(lpLibFileName);
 	if (hModule == NULL)
 		PLD_Private_Log("Failed to load library!", lpLibFileName, GetLastError());
 	return hModule;
 }
+
 static FARPROC PLD_Private_GetProcAddress_wrapper(HMODULE hModule, LPCSTR lpProcName)
 {
 	FARPROC lpProc = GetProcAddress(hModule, lpProcName);
@@ -59,17 +61,66 @@ static FARPROC PLD_Private_GetProcAddress_wrapper(HMODULE hModule, LPCSTR lpProc
 #define PLD(name) \
 	static HMODULE PLDH(void) { \
 		static HMODULE hModule = NULL; \
-		if (hModule == NULL) hModule =  PLD_Private_LoadLibrary_wrapper(#name); \
+		if (hModule == NULL) hModule =  PLD_Private_LoadLibrary_wrapper(name); \
 		return hModule; \
 	} \
 
-#define PFN(name) ((PLDTYPEOF(name))PLD_Private_GetProcAddress_wrapper(PLDH(), #name))
+#define PFN(name) ((PLDTYPEOF(&name))PLD_Private_GetProcAddress_wrapper(PLDH(), #name))
 
 #else
-#error POSIX Unimplemented!
+
+#define _GNU_SOURCE
+#include <unistd.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+#include <dlfcn.h>
+typedef intptr_t PLD_ErrCode;
+static void PLD_Private_Log(const char *, const char *, PLD_ErrCode);
+
+static void PLD_Private_WriteString(const char *s)
+{
+	write(2, s, PLD_Private_strlen(s));
+}
+
+static void PLD_Private_FormatError(intptr_t code, char *s, int len)
+{
+	*s = 0;
+	strncat(s, (const char *)code, len);
+}
+
+static void *PLD_Private_dlopen_wrapper(const char *name)
+{
+	if (name == NULL)
+		return (void *)RTLD_NEXT;
+	void *handle = dlopen(name, RTLD_NOLOAD);
+	if (handle == NULL)
+		handle = dlopen(name, RTLD_LAZY);
+	if (handle == NULL)
+		PLD_Private_Log("Failed to load library!", name, (intptr_t)dlerror());
+	return handle;
+}
+
+static void *PLD_Private_dlsym_wrapper(void *handle, const char *name)
+{
+	void *sym = dlsym(handle, name);
+	if (sym == NULL)
+		PLD_Private_Log("Failed to load procedure!", name, (intptr_t)dlerror());
+	return sym;
+}
+
+#define PLD(name) \
+	static void *PLDH(void) { \
+		static void *handle = NULL; \
+		if (handle == NULL) handle = PLD_Private_dlopen_wrapper(name); \
+		return handle; \
+	} \
+
+#define PFN(name) ((PLDTYPEOF(&name))PLD_Private_dlsym_wrapper(PLDH(), #name))
+
 #endif
 
-static void PLD_Private_Log(const char *message, const char *name, int err)
+static void PLD_Private_Log(const char *message, const char *name, PLD_ErrCode err)
 {
 	PLD_Private_WriteString(message);
 	PLD_Private_WriteString(" ");
@@ -82,6 +133,11 @@ static void PLD_Private_Log(const char *message, const char *name, int err)
 	char errtext[256];
 	PLD_Private_FormatError(err, errtext, sizeof(errtext));
 	PLD_Private_WriteString(errtext);
+
+	// An extra newline because dlerror doesn't append one
+#ifndef _WIN32
+	PLD_Private_WriteString("\n");
+#endif
 }
 
 #ifndef PLDLOG