diff options
Diffstat (limited to 'winsup/cygwin/hookapi.cc')
| -rw-r--r-- | winsup/cygwin/hookapi.cc | 237 |
1 files changed, 0 insertions, 237 deletions
diff --git a/winsup/cygwin/hookapi.cc b/winsup/cygwin/hookapi.cc deleted file mode 100644 index 39ba6de88..000000000 --- a/winsup/cygwin/hookapi.cc +++ /dev/null @@ -1,237 +0,0 @@ -/* hookapi.cc - - Copyright 2005, 2006 Red Hat, Inc. - -This file is part of Cygwin. - -This software is a copyrighted work licensed under the terms of the -Cygwin license. Please consult the file "CYGWIN_LICENSE" for -details. */ - -#include "winsup.h" -#include "cygerrno.h" -#include "security.h" -#include "path.h" -#include "fhandler.h" -#include "dtable.h" -#include "cygheap.h" -#include <stdlib.h> -#include <imagehlp.h> -#include <alloca.h> - -#define rva(coerce, base, addr) (coerce) ((char *) (base) + (addr)) -#define rvacyg(coerce, addr) rva (coerce, cygwin_hmodule, addr) - -struct function_hook -{ - const char *name; // Function name, e.g. "DirectDrawCreateEx". - const void *hookfn; // Address of your function. - void *origfn; // Stored by HookAPICalls, the address of the original function. -}; - -/* Given an HMODULE, returns a pointer to the PE header */ -static PIMAGE_NT_HEADERS -PEHeaderFromHModule (HMODULE hModule) -{ - PIMAGE_NT_HEADERS pNTHeader; - - if (PIMAGE_DOS_HEADER(hModule) ->e_magic != IMAGE_DOS_SIGNATURE) - pNTHeader = NULL; - else - { - pNTHeader = PIMAGE_NT_HEADERS (PBYTE (hModule) - + PIMAGE_DOS_HEADER (hModule) ->e_lfanew); - if (pNTHeader->Signature != IMAGE_NT_SIGNATURE) - pNTHeader = NULL; - } - - return pNTHeader; -} - -static long -rvadelta (PIMAGE_NT_HEADERS pnt, DWORD import_rva) -{ - PIMAGE_SECTION_HEADER section = (PIMAGE_SECTION_HEADER) (pnt + 1); - for (int i = 0; i < pnt->FileHeader.NumberOfSections; i++) - if (section[i].VirtualAddress <= import_rva - && (section[i].VirtualAddress + section[i].Misc.VirtualSize) > import_rva) - // if (strncasematch ((char *) section[i].Name, ".idata", IMAGE_SIZEOF_SHORT_NAME)) - return section[i].VirtualAddress - section[i].PointerToRawData; - return -1; -} - -static void * -putmem (PIMAGE_THUNK_DATA pi, const void *hookfn) -{ - DWORD ofl; - if (!VirtualProtect (pi, sizeof (PVOID), PAGE_READWRITE, &ofl) ) - return NULL; - - void *origfn = (void *) pi->u1.Function; - pi->u1.Function = (DWORD) hookfn; - - VirtualProtect (pi, sizeof (PVOID), ofl, &ofl); - return origfn; -} - -/* Builds stubs for and redirects the IAT for one DLL (pImportDesc) */ - -static bool -RedirectIAT (function_hook& fh, PIMAGE_IMPORT_DESCRIPTOR pImportDesc, - HMODULE hm) -{ - // If no import names table, we can't redirect this, so bail - if (pImportDesc->OriginalFirstThunk == 0) - return false; - - /* import address table */ - PIMAGE_THUNK_DATA pt = rva (PIMAGE_THUNK_DATA, hm, pImportDesc->FirstThunk); - /* import names table */ - PIMAGE_THUNK_DATA pn = rva (PIMAGE_THUNK_DATA, hm, pImportDesc->OriginalFirstThunk); - - /* Scan through the IAT, completing the stubs and redirecting the IAT - entries to point to the stubs. */ - for (PIMAGE_THUNK_DATA pi = pt; pn->u1.Ordinal; pi++, pn++) - { - if (IMAGE_SNAP_BY_ORDINAL (pn->u1.Ordinal) ) - continue; - - /* import by name */ - PIMAGE_IMPORT_BY_NAME pimp = rva (PIMAGE_IMPORT_BY_NAME, hm, pn->u1.AddressOfData); - - if (strcmp (fh.name, (char *) pimp->Name) == 0) - { - fh.origfn = putmem (pi, fh.hookfn); - if (!fh.origfn) - return false; - hook_chain *hc; - for (hc = &cygheap->hooks; hc->next; hc = hc->next) - continue; - hc->next = (hook_chain *) cmalloc (HEAP_1_HOOK, sizeof (hook_chain)); - hc->next->loc = (void **) pi; - hc->next->func = fh.hookfn; - hc->next->next = NULL; - break; - } - } - - return true; -} - -static void -get_export (function_hook& fh) -{ - PIMAGE_DOS_HEADER pdh = (PIMAGE_DOS_HEADER) cygwin_hmodule; - if (pdh->e_magic != IMAGE_DOS_SIGNATURE) - return; - PIMAGE_NT_HEADERS pnt = (PIMAGE_NT_HEADERS) ((char *) pdh + pdh->e_lfanew); - if (pnt->Signature != IMAGE_NT_SIGNATURE || pnt->FileHeader.SizeOfOptionalHeader == 0) - return; - PIMAGE_EXPORT_DIRECTORY pexp = - rvacyg (PIMAGE_EXPORT_DIRECTORY, - pnt->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress); - if (!pexp) - return; - - PDWORD pfuncs = rvacyg (PDWORD, pexp->AddressOfFunctions); - PDWORD pnames = rvacyg (PDWORD, pexp->AddressOfNames); - for (DWORD i = 0; i < pexp->NumberOfNames; i++) - if (strcmp (fh.name, rvacyg (char *, pnames[i])) == 0) - { - fh.origfn = rvacyg (void *, pfuncs[i]); - break; - } -} - -static const char * -makename (const char *name, char *&buf, int& i, int inc) -{ - i += inc; - static const char *testers[] = {"NOTUSED", "64", "32"}; - if (i < 0 || i >= (int) (sizeof (testers) / sizeof (testers[0]))) - return NULL; - if (i) - { - __small_sprintf (buf, "_%s%s", name, testers[i]); - name = buf; - } - return name; -} - -// Top level routine to find the EXE's imports, and redirect them -void * -hook_or_detect_cygwin (const char *name, const void *fn, WORD& subsys) -{ - HMODULE hm = fn ? GetModuleHandle (NULL) : (HMODULE) name; - PIMAGE_NT_HEADERS pExeNTHdr = PEHeaderFromHModule (hm); - - if (!pExeNTHdr) - return false; - - subsys = pExeNTHdr->OptionalHeader.Subsystem; - - DWORD importRVA = pExeNTHdr->OptionalHeader.DataDirectory - [IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress; - if (!importRVA) - return false; - - long delta = fn ? 0 : rvadelta (pExeNTHdr, importRVA); - if (delta < 0) - return false; - - // Convert imports RVA to a usable pointer - PIMAGE_IMPORT_DESCRIPTOR pdfirst = rva (PIMAGE_IMPORT_DESCRIPTOR, hm, importRVA - delta); - - function_hook fh; - fh.origfn = NULL; - fh.hookfn = fn; - char *buf = (char *) alloca (strlen (name) + sizeof ("_64")); - int i; - // Iterate through each import descriptor, and redirect if appropriate - for (PIMAGE_IMPORT_DESCRIPTOR pd = pdfirst; pd->FirstThunk; pd++) - { - if (!strcasematch (rva (PSTR, hm, pd->Name - delta), "cygwin1.dll")) - continue; - if (!fn) - return (void *) "found it"; // just checking if executable used cygwin1.dll - i = -1; - while (!fh.origfn && (fh.name = makename (name, buf, i, 1))) - RedirectIAT (fh, pd, hm); - if (fh.origfn) - break; - } - - while (!fh.origfn && (fh.name = makename (name, buf, i, -1))) - get_export (fh); - - return fh.origfn; -} - -void -ld_preload () -{ - char *p = getenv ("LD_PRELOAD"); - if (!p) - return; - char *s = (char *) alloca (strlen (p) + 1); - strcpy (s, p); - char *here = NULL; - for (p = strtok_r (s, ":\t\n", &here); p; p = strtok_r (NULL, ":\t\n", &here)) - { - path_conv lib (p); - if (!LoadLibrary (lib)) - { - __seterrno (); - api_fatal ("error while loading shared libraries: %s: " - "cannot open shared object file: %s", p, - strerror (get_errno ())); - } - } -} - -void -fixup_hooks_after_fork () -{ - for (hook_chain *hc = &cygheap->hooks; (hc = hc->next); ) - putmem ((PIMAGE_THUNK_DATA) hc->loc, hc->func); -} |