From 5d89217f6b90627d3ca9736c9e41390996a343c6 Mon Sep 17 00:00:00 2001
From: Ozkan Sezer <sezeroz@gmail.com>
Date: Wed, 14 Oct 2020 23:01:03 +0300
Subject: [PATCH] os2/SDL_sysfilesystem.c: fix crash if one of the parameters
 is NULL

Has been happening with testfilesystem from 2.0.6 and newer because
of commit 572a721879ef.

Also set error strings in certain error conditions.

Also applied coding style / whitespace fixes, while I was there.
---
 src/filesystem/os2/SDL_sysfilesystem.c | 84 ++++++++++++++------------
 1 file changed, 46 insertions(+), 38 deletions(-)

diff --git a/src/filesystem/os2/SDL_sysfilesystem.c b/src/filesystem/os2/SDL_sysfilesystem.c
index dce3f2897..a440b0933 100644
--- a/src/filesystem/os2/SDL_sysfilesystem.c
+++ b/src/filesystem/os2/SDL_sysfilesystem.c
@@ -40,80 +40,88 @@ SDL_GetBasePath(void)
 {
   PTIB       tib;
   PPIB       pib;
-  ULONG      ulRC = DosGetInfoBlocks( &tib, &pib );
+  ULONG      ulRC = DosGetInfoBlocks(&tib, &pib);
   PCHAR      pcEnd;
   ULONG      cbResult;
   CHAR       acBuf[_MAX_PATH];
-  
-  if ( ulRC != NO_ERROR )
-  {
-    debug( "DosGetInfoBlocks() failed, rc = %u", ulRC );
+
+  if (ulRC != NO_ERROR) {
+    debug("DosGetInfoBlocks() failed, rc = %u", ulRC);
     return NULL;
   }
 
-  pcEnd = SDL_strrchr( pib->pib_pchcmd, '\\' );
-  if ( pcEnd != NULL )
+  pcEnd = SDL_strrchr(pib->pib_pchcmd, '\\');
+  if (pcEnd != NULL)
     pcEnd++;
-  else
-  {
-    if ( pib->pib_pchcmd[1] == ':' )
+  else {
+    if (pib->pib_pchcmd[1] == ':')
       pcEnd = &pib->pib_pchcmd[2];
-    else
+    else {
+      SDL_SetError("No path in pib->pib_pchcmd");
       return NULL;
+    }
   }
 
   cbResult = pcEnd - pib->pib_pchcmd;
-  SDL_memcpy( acBuf, pib->pib_pchcmd, cbResult );
+  SDL_memcpy(acBuf, pib->pib_pchcmd, cbResult);
   acBuf[cbResult] = '\0';
 
-  return OS2_SysToUTF8( acBuf );
+  return OS2_SysToUTF8(acBuf);
 }
 
 char *
 SDL_GetPrefPath(const char *org, const char *app)
 {
-  PSZ        pszPath = SDL_getenv( "HOME" );
+  PSZ        pszPath;
   CHAR       acBuf[_MAX_PATH];
   int        lPosApp, lPosOrg;
-  PSZ        pszApp, pszOrg = OS2_UTF8ToSys( org );
+  PSZ        pszApp, pszOrg;
 
-  if ( pszOrg == NULL )
-  {
-    SDL_OutOfMemory();
-    return NULL;
-  }
-
-  if ( pszPath == NULL )
-  {
-    pszPath = SDL_getenv( "ETC" );
-    if ( pszPath == NULL )
+  if (!app) {
+      SDL_InvalidParamError("app");
       return NULL;
   }
 
-  lPosApp = SDL_snprintf( acBuf, sizeof(acBuf) - 1, "%s\\%s", pszPath, pszOrg );
-  SDL_free( pszOrg );
-  if ( lPosApp < 0 )
+  pszPath = SDL_getenv( "HOME" );
+  if (!pszPath) {
+    pszPath = SDL_getenv( "ETC" );
+    if (!pszPath) {
+      SDL_SetError("HOME or ETC environment not set");
+      return NULL;
+    }
+  }
+
+  if (!org) {
+    lPosApp = SDL_snprintf(acBuf, sizeof(acBuf) - 1, "%s", pszPath);
+  } else {
+    pszOrg = OS2_UTF8ToSys(org);
+    if (!pszOrg) {
+      SDL_OutOfMemory();
+      return NULL;
+    }
+    lPosApp = SDL_snprintf(acBuf, sizeof(acBuf) - 1, "%s\\%s", pszPath, pszOrg);
+    SDL_free(pszOrg);
+  }
+  if (lPosApp < 0)
     return NULL;
 
-  DosCreateDir( acBuf, NULL );
+  DosCreateDir(acBuf, NULL);
 
-  pszApp = OS2_UTF8ToSys( app );
-  if ( pszApp == NULL )
-  {
+  pszApp = OS2_UTF8ToSys(app);
+  if (!pszApp) {
     SDL_OutOfMemory();
     return NULL;
   }
 
-  lPosOrg = SDL_snprintf( &acBuf[lPosApp], sizeof(acBuf) - lPosApp - 1, "\\%s",
-                          pszApp );
-  SDL_free( pszApp );
-  if ( lPosOrg < 0 )
+  lPosOrg = SDL_snprintf(&acBuf[lPosApp], sizeof(acBuf) - lPosApp - 1, "\\%s", pszApp);
+  SDL_free(pszApp);
+  if (lPosOrg < 0)
     return NULL;
 
-  DosCreateDir( acBuf, NULL );
+  DosCreateDir(acBuf, NULL);
   *((PUSHORT)&acBuf[lPosApp + lPosOrg]) = (USHORT)'\0\\';
 
-  return OS2_SysToUTF8( acBuf );
+  return OS2_SysToUTF8(acBuf);
 }
 
 #endif /* SDL_FILESYSTEM_OS2 */