From: John Hodge <tpg@mutabah.net>
Date: Sat, 7 May 2011 13:17:03 +0000 (+0800)
Subject: Debugging a segfault in ELF loader (when loading CLIShell)
X-Git-Tag: rel0.10~125
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=a2b49f92646ef666e17172faf72a9dcc0d18942a;p=tpg%2Facess2.git

Debugging a segfault in ELF loader (when loading CLIShell)
---

diff --git a/AcessNative/ld-acess_src/elf.c b/AcessNative/ld-acess_src/elf.c
index b99f1901..c01d24d4 100644
--- a/AcessNative/ld-acess_src/elf.c
+++ b/AcessNative/ld-acess_src/elf.c
@@ -2,7 +2,7 @@
  * Acess v0.1
  * ELF Executable Loader Code
  */
-#define DEBUG	0
+#define DEBUG	1
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
@@ -248,6 +248,9 @@ uintptr_t Elf_Relocate(void *Base)
 
 	hdr->entrypoint += iBaseDiff;
 	
+	hdr->misc.SymTable = 0;
+	hdr->misc.HashTable = 0;
+	
 	// === Get Symbol table and String Table ===
 	for( j = 0; dynamicTab[j].d_tag != DT_NULL; j++)
 	{
@@ -274,6 +277,9 @@ uintptr_t Elf_Relocate(void *Base)
 			break;
 		}
 	}
+	
+	LOG("hdr->misc.SymTable = %x, hdr->misc.HashTable = %x",
+		hdr->misc.SymTable, hdr->misc.HashTable);
 
 
 	// Alter Symbols to true base
@@ -486,6 +492,9 @@ int Elf_GetSymbol(void *Base, char *Name, uintptr_t *ret)
 	pBuckets = PTR(hdr->misc.HashTable);
 	symtab = PTR(hdr->misc.SymTable);
 	
+	if(!pBuckets || !symtab)
+		return 0;
+	
 	nbuckets = pBuckets[0];
 	iSymCount = pBuckets[1];
 	pBuckets = &pBuckets[2];
diff --git a/AcessNative/ld-acess_src/request.c b/AcessNative/ld-acess_src/request.c
index 75565f15..8655377e 100644
--- a/AcessNative/ld-acess_src/request.c
+++ b/AcessNative/ld-acess_src/request.c
@@ -1,5 +1,15 @@
 /*
  */
+#define DEBUG	0
+
+
+#if DEBUG
+# define DEBUG_S	printf
+#else
+# define DEBUG_S(...)
+# define DONT_INCLUDE_SYSCALL_NAMES
+#endif
+
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
@@ -154,31 +164,31 @@ int SendRequest(tRequestHeader *Request, int RequestSize, int ResponseSize)
 	{
 		 int	i;
 		char	*data = (char*)&Request->Params[Request->NParams];
-		printf("Request #%i (%s) -", Request->CallID, casSYSCALL_NAMES[Request->CallID]);
+		DEBUG_S("Request #%i (%s) -", Request->CallID, casSYSCALL_NAMES[Request->CallID]);
 		for( i = 0; i < Request->NParams; i ++ )
 		{
 			switch(Request->Params[i].Type)
 			{
 			case ARG_TYPE_INT32:
-				printf(" 0x%08x", *(uint32_t*)data);
+				DEBUG_S(" 0x%08x", *(uint32_t*)data);
 				data += sizeof(uint32_t);
 				break;
 			case ARG_TYPE_INT64:
-				printf(" 0x%016llx", *(uint64_t*)data);
+				DEBUG_S(" 0x%016llx", *(uint64_t*)data);
 				data += sizeof(uint64_t);
 				break;
 			case ARG_TYPE_STRING:
-				printf(" '%s'", (char*)data);
+				DEBUG_S(" '%s'", (char*)data);
 				data += Request->Params[i].Length;
 				break;
 			case ARG_TYPE_DATA:
-				printf(" %p:0x%x", (char*)data, Request->Params[i].Length);
+				DEBUG_S(" %p:0x%x", (char*)data, Request->Params[i].Length);
 				if( !(Request->Params[i].Flags & ARG_FLAG_ZEROED) )
 					data += Request->Params[i].Length;
 				break;
 			}
 		}
-		printf("\n");
+		DEBUG_S("\n");
 	}
 	
 	// Send it off
@@ -246,7 +256,7 @@ int ReadData(void *Dest, int MaxLength, int Timeout)
 		exit(-1);
 	}
 	
-	printf("%i bytes read from socket\n", ret);
+	DEBUG_S("%i bytes read from socket\n", ret);
 	
 	return ret;
 }
diff --git a/AcessNative/ld-acess_src/syscalls.c b/AcessNative/ld-acess_src/syscalls.c
index 2a63622a..58824351 100644
--- a/AcessNative/ld-acess_src/syscalls.c
+++ b/AcessNative/ld-acess_src/syscalls.c
@@ -271,7 +271,7 @@ uint64_t _Syscall(int SyscallID, const char *ArgTypes, ...)
 	free( req );
 	free( retPtrs );
 	
-	printf("Return %llx\n", retValue);
+	DEBUG(": %llx\n", retValue);
 	
 	return retValue;
 }
@@ -289,7 +289,7 @@ int acess_open(const char *Path, int Flags)
 		if(!gaSyscall_LocalFPs[ret])	return -1;
 		return ret|NATIVE_FILE_MASK;
 	}
-	DEBUG("open(\"%s\", 0x%x)\n", Path, Flags);
+	DEBUG("open(\"%s\", 0x%x)", Path, Flags);
 	return _Syscall(SYS_OPEN, ">s >i", Path, Flags);
 }
 
@@ -299,26 +299,26 @@ void acess_close(int FD) {
 		gaSyscall_LocalFPs[FD & (NATIVE_FILE_MASK-1)] = NULL;
 		return ;
 	}
-	DEBUG("close(%i)\n", FD);
+	DEBUG("close(%i)", FD);
 	_Syscall(SYS_CLOSE, ">i", FD);
 }
 
 int acess_reopen(int FD, const char *Path, int Flags) {
-	DEBUG("reopen(0x%x, \"%s\", 0x%x)\n", FD, Path, Flags);
+	DEBUG("reopen(0x%x, \"%s\", 0x%x)", FD, Path, Flags);
 	return _Syscall(SYS_REOPEN, ">i >s >i", FD, Path, Flags);
 }
 
 size_t acess_read(int FD, size_t Bytes, void *Dest) {
 	if(FD & NATIVE_FILE_MASK)
 		return fread( Dest, Bytes, 1, gaSyscall_LocalFPs[FD & (NATIVE_FILE_MASK-1)] );
-	DEBUG("read(0x%x, 0x%x, *%p)\n", FD, Bytes, Dest);
+	DEBUG("read(0x%x, 0x%x, *%p)", FD, Bytes, Dest);
 	return _Syscall(SYS_READ, ">i >i <d", FD, Bytes, Bytes, Dest);
 }
 
 size_t acess_write(int FD, size_t Bytes, void *Src) {
 	if(FD & NATIVE_FILE_MASK)
 		return fwrite( Src, Bytes, 1, gaSyscall_LocalFPs[FD & (NATIVE_FILE_MASK-1)] );
-	DEBUG("write(0x%x, 0x%x, %p(\"%.*s\"))\n", FD, Bytes, Src, Bytes, (char*)Src);
+	DEBUG("write(0x%x, 0x%x, %p(\"%.*s\"))", FD, Bytes, Src, Bytes, (char*)Src);
 	return _Syscall(SYS_WRITE, ">i >i >d", FD, Bytes, Bytes, Src);
 }
 
@@ -332,7 +332,7 @@ int acess_seek(int FD, int64_t Ofs, int Dir) {
 		}
 		return fseek( gaSyscall_LocalFPs[FD & (NATIVE_FILE_MASK-1)], Ofs, Dir );
 	}
-	DEBUG("seek(0x%x, 0x%llx, %i)\n", FD, Ofs, Dir);
+	DEBUG("seek(0x%x, 0x%llx, %i)", FD, Ofs, Dir);
 	return _Syscall(SYS_SEEK, ">i >I >i", FD, Ofs, Dir);
 }
 
@@ -390,9 +390,9 @@ int acess_clone(int flags, void *stack)
 	extern int fork(void);
 	if(flags & CLONE_VM) {
 		 int	ret, newID, kernel_tid=0;
-		printf("fork()\n");
+		printf("fork()");
 		
-		newID = _Syscall(SYS_FORK, "<i", &kernel_tid);
+		newID = _Syscall(SYS_FORK, "<d", sizeof(int), &kernel_tid);
 		ret = fork();
 		if(ret < 0)	return ret;
 		
@@ -451,7 +451,7 @@ void acess_sleep(void)
 
 int acess_waittid(int TID, int *ExitStatus)
 {
-	return _Syscall(SYS_WAITTID, ">i <i", TID, ExitStatus);
+	return _Syscall(SYS_WAITTID, ">i <d", TID, sizeof(int), &ExitStatus);
 }
 
 int acess_setuid(int ID)