402 lines
10 KiB
C++
402 lines
10 KiB
C++
/* dll_init.cc
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Copyright 1998, 1999, 2000 Cygnus Solutions.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#include <stdlib.h>
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#include "winsup.h"
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#include "exceptions.h"
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#include "dll_init.h"
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extern void __stdcall check_sanity_and_sync (per_process *);
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dll_list NO_COPY dlls;
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static NO_COPY int in_forkee = 0;
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static int dll_global_dtors_recorded = 0;
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/* Run destructors for all DLLs on exit. */
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static void
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dll_global_dtors()
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{
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for (dll *d = dlls.istart (DLL_ANY); d; d = dlls.inext ())
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d->p.run_dtors ();
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}
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/* Run all constructors associated with a dll */
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void
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per_module::run_ctors ()
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{
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void (**pfunc)() = ctors;
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/* Run ctors backwards, so skip the first entry and find how many
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there are, then run them. */
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if (pfunc)
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{
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int i;
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for (i = 1; pfunc[i]; i++);
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for (int j = i - 1; j > 0; j-- )
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(pfunc[j]) ();
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}
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}
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/* Run all destructors associated with a dll */
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void
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per_module::run_dtors ()
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{
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void (**pfunc)() = dtors;
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for (int i = 1; pfunc[i]; i++)
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(pfunc[i]) ();
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}
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/* Initialize an individual DLL */
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int
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dll::init ()
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{
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int ret = 1;
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/* Why didn't we just import this variable? */
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*(p.envptr) = __cygwin_environ;
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/* Don't run constructors or the "main" if we've forked. */
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if (!in_forkee)
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{
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/* global contructors */
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p.run_ctors ();
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/* entry point of dll (use main of per_process with null args...) */
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if (p.main)
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ret = (*(p.main)) (0, 0, 0);
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}
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return ret;
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}
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/* Look for a dll based on name */
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dll *
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dll_list::operator[] (const char *name)
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{
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dll *d = &start;
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while ((d = d->next) != NULL)
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if (strcasematch (name, d->name))
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return d;
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return NULL;
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}
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#define RETRIES 100
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/* Allocate space for a dll struct contiguous with the just-loaded dll. */
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dll *
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dll_list::alloc (HINSTANCE h, per_process *p, dll_type type)
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{
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char name[MAX_PATH + 1];
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DWORD namelen = GetModuleFileName (h, name, sizeof (name));
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/* Already loaded? */
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dll *d = dlls[name];
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if (d)
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{
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d->count++; /* Yes. Bump the usage count. */
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return d; /* Return previously allocated pointer. */
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}
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SYSTEM_INFO s1;
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GetSystemInfo (&s1);
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int i;
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void *s = p->bss_end;
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DWORD n;
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MEMORY_BASIC_INFORMATION m;
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/* Search for space after the DLL */
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for (i = 0; i <= RETRIES; i++, s = (char *) m.BaseAddress + m.RegionSize)
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{
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if (!VirtualQuery (s, &m, sizeof (m)))
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return NULL; /* Can't do it. */
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if (m.State == MEM_FREE)
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{
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/* Couldn't find any. Uh oh. FIXME: Issue an error? */
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if (i == RETRIES)
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return NULL; /* Oh well. Couldn't locate free space. */
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/* Ensure that this is rounded to the nearest page boundary.
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FIXME: Should this be ensured by VirtualQuery? */
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n = (DWORD) m.BaseAddress;
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DWORD r = n % s1.dwAllocationGranularity;
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if (r)
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n = ((n - r) + s1.dwAllocationGranularity);
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/* First reserve the area of memory, then commit it. */
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if (VirtualAlloc ((void *) n, sizeof (dll), MEM_RESERVE, PAGE_READWRITE))
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d = (dll *) VirtualAlloc ((void *) n, sizeof (dll), MEM_COMMIT,
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PAGE_READWRITE);
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if (d)
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break;
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}
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}
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/* Did we succeed? */
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if (d == NULL)
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{ /* Nope. */
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#ifdef DEBUGGING
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system_printf ("VirtualAlloc failed, %E");
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#endif
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__seterrno ();
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return NULL;
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}
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/* Now we've allocated a block of information. Fill it in with the supplied
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info about this DLL. */
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d->count = 1;
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d->namelen = namelen;
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strcpy (d->name, name);
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d->handle = h;
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d->p = p;
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d->type = type;
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if (end == NULL)
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end = &start; /* Point to "end" of dll chain. */
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end->next = d; /* Standard linked list stuff. */
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d->next = NULL;
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d->prev = end;
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end = d;
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tot++;
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if (type == DLL_LOAD)
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loaded_dlls++;
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return d;
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}
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/* Detach a DLL from the chain. */
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void
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dll_list::detach (dll *d)
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{
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if (d->count <= 0)
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system_printf ("WARNING: try to detach an already detached dll ...\n");
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else if (--d->count == 0)
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{
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d->p.run_dtors ();
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d->prev->next = d->next;
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if (d->next)
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d->next->prev = d->prev;
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if (d->type == DLL_LOAD)
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loaded_dlls--;
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if (end == d)
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end = d->prev;
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VirtualFree (d, 0, MEM_RELEASE);
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}
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}
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/* Initialization for all linked DLLs, called by dll_crt0_1. */
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void
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dll_list::init ()
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{
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debug_printf ("here");
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/* Make sure that destructors are called on exit. */
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if (!dll_global_dtors_recorded)
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{
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atexit (dll_global_dtors);
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dll_global_dtors_recorded = 1;
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}
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/* Walk the dll chain, initializing each dll */
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dll *d = &start;
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while ((d = d->next))
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d->init ();
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}
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#define A64K (64 * 1024)
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/* Mark every memory address up to "here" as reserved. This may force
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Windows NT to load a DLL in the next available, lowest slot. */
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static void
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reserve_upto (const char *name, DWORD here)
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{
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DWORD size;
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MEMORY_BASIC_INFORMATION mb;
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for (DWORD start = 0x10000; start < here; start += size)
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if (!VirtualQuery ((void *) start, &mb, sizeof (mb)))
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size = 64 * 1024;
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else
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{
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size = A64K * ((mb.RegionSize + A64K - 1) / A64K);
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start = A64K * (((DWORD) mb.BaseAddress + A64K - 1) / A64K);
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if (start + size > here)
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size = here - start;
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if (mb.State == MEM_FREE &&
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!VirtualAlloc ((void *) start, size, MEM_RESERVE, PAGE_NOACCESS))
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api_fatal ("couldn't allocate memory %p(%d) for '%s' alignment, %E\n",
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start, size, name);
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}
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}
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/* Release all of the memory previously allocated by "upto" above.
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Note that this may also free otherwise reserved memory. If that becomes
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a problem, we'll have to keep track of the memory that we reserve above. */
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static void
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release_upto (const char *name, DWORD here)
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{
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DWORD size;
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MEMORY_BASIC_INFORMATION mb;
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for (DWORD start = 0x10000; start < here; start += size)
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if (!VirtualQuery ((void *) start, &mb, sizeof (mb)))
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size = 64 * 1024;
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else
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{
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size = mb.RegionSize;
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if (!(mb.State == MEM_RESERVE && mb.AllocationProtect == PAGE_NOACCESS &&
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((void *) start < user_data->heapbase || (void *) start > user_data->heaptop)))
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continue;
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if (!VirtualFree ((void *) start, 0, MEM_RELEASE))
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api_fatal ("couldn't release memory %p(%d) for '%s' alignment, %E\n",
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start, size, name);
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}
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}
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/* Reload DLLs after a fork. Iterates over the list of dynamically loaded DLLs
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and attempts to load them in the same place as they were loaded in the parent. */
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void
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dll_list::load_after_fork (HANDLE parent, dll *first)
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{
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in_forkee = 1;
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int try2 = 0;
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dll d;
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void *next = first;
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while (next)
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{
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DWORD nb;
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/* Read the dll structure from the parent. */
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if (!ReadProcessMemory (parent, next, &d, sizeof (dll), &nb) ||
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nb != sizeof (dll))
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return;
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/* We're only interested in dynamically loaded dlls.
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Hopefully, this function wouldn't even have been called unless
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the parent had some of those. */
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if (d.type == DLL_LOAD)
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{
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HMODULE h = LoadLibraryEx (d.name, NULL, DONT_RESOLVE_DLL_REFERENCES);
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/* See if DLL will load in proper place. If so, free it and reload
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it the right way.
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It sort of stinks that we can't invert the order of the FreeLibrary
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and LoadLibrary since Microsoft documentation seems to imply that that
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should do what we want. However, since the library was loaded above,
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the second LoadLibrary does not execute it's startup code unless it
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is first unloaded. */
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if (h == d.handle)
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{
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FreeLibrary (h);
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LoadLibrary (d.name);
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}
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else if (try2)
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api_fatal ("unable to remap %s to same address as parent -- %p", d.name, h);
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else
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{
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/* It loaded in the wrong place. Dunno why this happens but it always
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seems to happen when there are multiple DLLs attempting to load into
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the same address space. In the "forked" process, the second DLL always
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loads into a different location. */
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FreeLibrary (h);
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/* Block all of the memory up to the new load address. */
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reserve_upto (d.name, (DWORD) d.handle);
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try2 = 1; /* And try */
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continue; /* again. */
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}
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/* If we reached here, and try2 is set, then there is a lot of memory to
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release. */
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if (try2)
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{
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release_upto (d.name, (DWORD) d.handle);
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try2 = 0;
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}
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}
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next = d.next; /* Get the address of the next DLL. */
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}
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in_forkee = 0;
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}
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extern "C" int
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dll_dllcrt0 (HMODULE h, per_process *p)
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{
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if (p == NULL)
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p = &__cygwin_user_data;
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else
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*(p->impure_ptr_ptr) = __cygwin_user_data.impure_ptr;
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/* Partially initialize Cygwin guts for non-cygwin apps. */
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if (dynamically_loaded && user_data->magic_biscuit == 0)
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dll_crt0 (p);
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else
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check_sanity_and_sync (p);
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dll_type type;
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/* If this function is called before cygwin has finished
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initializing, then the DLL must be a cygwin-aware DLL
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that was explicitly linked into the program rather than
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a dlopened DLL. */
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if (!cygwin_finished_initializing)
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type = DLL_LINK;
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else
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{
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type = DLL_LOAD;
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dlls.reload_on_fork = 1;
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}
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/* Allocate and initialize space for the DLL. */
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dll *d = dlls.alloc (h, p, type);
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/* If d == NULL, then something is broken.
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Otherwise, if we've finished initializing, it's ok to
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initialize the DLL. If we haven't finished initializing,
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it may not be safe to call the dll's "main" since not
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all of cygwin's internal structures may have been set up. */
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if (!d || (cygwin_finished_initializing && !d->init ()))
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return -1;
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return (DWORD) d;
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}
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/* OBSOLETE: This function is obsolescent and will go away in the
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future. Cygwin can now handle being loaded from a noncygwin app
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using the same entry point. */
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extern "C" int
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dll_noncygwin_dllcrt0 (HMODULE h, per_process *p)
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{
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return dll_dllcrt0 (h, p);
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}
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extern "C" void
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cygwin_detach_dll (dll *d)
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{
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dlls.detach (d);
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}
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extern "C" void
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dlfork (int val)
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{
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dlls.reload_on_fork = val;
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}
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/* Called from various places to update all of the individual
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ideas of the environ block. Explain to me again why we didn't
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just import __cygwin_environ? */
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void __stdcall
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update_envptrs ()
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{
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extern char ***main_environ;
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for (dll *d = dlls.istart (DLL_ANY); d; d = dlls.inext ())
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{
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*(d->p.envptr) = __cygwin_environ;
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}
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*main_environ = __cygwin_environ;
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}
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