winsup/cygwin/fhandler_mqueue.cc

   1 /* fhandler_mqueue.cc: fhandler for POSIX message queue
   2
   3 This file is part of Cygwin.
   4
   5 This software is a copyrighted work licensed under the terms of the
   6 Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
   7 details. */
   8
   9 #include "winsup.h"
  10 #include "shared_info.h"
  11 #include "path.h"
  12 #include "fhandler.h"
  13 #include "dtable.h"
  14
  15 fhandler_mqueue::fhandler_mqueue () :
  16   fhandler_base ()
  17 {
  18   nohandle (true);
  19   close_on_exec (true);
  20 }
  21
  22 struct mq_info *
  23 fhandler_mqueue::_mqinfo (HANDLE fh, SIZE_T filesize, mode_t mode, int flags,
  24                           bool just_open)
  25 {
  26   WCHAR buf[NAME_MAX + sizeof ("mqueue/XXX")];
  27   UNICODE_STRING uname;
  28   OBJECT_ATTRIBUTES attr;
  29   NTSTATUS status;
  30   LARGE_INTEGER fsiz = { QuadPart: (LONGLONG) filesize };
  31   PVOID mptr = NULL;
  32
  33   /* Set sectsize prior to using filesize in NtMapViewOfSection.  It will
  34      get pagesize aligned, which breaks the next NtMapViewOfSection in fork. */
  35   mqinfo ()->mqi_sectsize = filesize;
  36   mqinfo ()->mqi_mode = mode;
  37   mqinfo ()->mqi_flags = flags;
  38
  39   __small_swprintf (buf, L"mqueue/mtx%s", get_name ());
  40   RtlInitUnicodeString (&uname, buf);
  41   InitializeObjectAttributes (&attr, &uname, OBJ_OPENIF | OBJ_CASE_INSENSITIVE,
  42                               get_shared_parent_dir (),
  43                               everyone_sd (CYG_MUTANT_ACCESS));
  44   status = NtCreateMutant (&mqinfo ()->mqi_lock, CYG_MUTANT_ACCESS, &attr,
  45                            FALSE);
  46   if (!NT_SUCCESS (status))
  47     goto err;
  48
  49   wcsncpy (buf + 7, L"snd", 3);
  50   /* same length, no RtlInitUnicodeString required */
  51   InitializeObjectAttributes (&attr, &uname, OBJ_OPENIF | OBJ_CASE_INSENSITIVE,
  52                               get_shared_parent_dir (),
  53                               everyone_sd (CYG_EVENT_ACCESS));
  54   status = NtCreateEvent (&mqinfo ()->mqi_waitsend, CYG_EVENT_ACCESS, &attr,
  55                           NotificationEvent, FALSE);
  56   if (!NT_SUCCESS (status))
  57     goto err;
  58   wcsncpy (buf + 7, L"rcv", 3);
  59   /* same length, same attributes, no more init required */
  60   status = NtCreateEvent (&mqinfo ()->mqi_waitrecv, CYG_EVENT_ACCESS, &attr,
  61                           NotificationEvent, FALSE);
  62   if (!NT_SUCCESS (status))
  63     goto err;
  64
  65   InitializeObjectAttributes (&attr, NULL, 0, NULL, NULL);
  66   status = NtCreateSection (&mqinfo ()->mqi_sect, SECTION_ALL_ACCESS, &attr,
  67                             &fsiz, PAGE_READWRITE, SEC_COMMIT, fh);
  68   if (!NT_SUCCESS (status))
  69     goto err;
  70
  71   status = NtMapViewOfSection (mqinfo ()->mqi_sect, NtCurrentProcess (),
  72                                &mptr, 0, filesize, NULL, &filesize,
  73                                ViewShare, 0, PAGE_READWRITE);
  74   if (!NT_SUCCESS (status))
  75     goto err;
  76
  77   mqinfo ()->mqi_hdr = (struct mq_hdr *) mptr;
  78
  79   /* Special problem on Cygwin.  /dev/mqueue is just a simple dir,
  80      so there's a chance normal files are created in there. */
  81   if (just_open && mqinfo ()->mqi_hdr->mqh_magic != MQI_MAGIC)
  82     {
  83       status = STATUS_ACCESS_DENIED;
  84       goto err;
  85     }
  86
  87   mqinfo ()->mqi_magic = MQI_MAGIC;
  88   return mqinfo ();
  89
  90 err:
  91   if (mqinfo ()->mqi_sect)
  92     NtClose (mqinfo ()->mqi_sect);
  93   if (mqinfo ()->mqi_waitrecv)
  94     NtClose (mqinfo ()->mqi_waitrecv);
  95   if (mqinfo ()->mqi_waitsend)
  96     NtClose (mqinfo ()->mqi_waitsend);
  97   if (mqinfo ()->mqi_lock)
  98     NtClose (mqinfo ()->mqi_lock);
  99   __seterrno_from_nt_status (status);
 100   return NULL;
 101 }
 102
 103 char *
 104 fhandler_mqueue::get_proc_fd_name (char *buf)
 105 {
 106   return strcpy (buf, get_name ());
 107 }
 108
 109 int __reg2
 110 fhandler_mqueue::fstat (struct stat *buf)
 111 {
 112   int ret = fhandler_base::fstat (buf);
 113   if (!ret)
 114     {
 115       buf->st_mode = S_IFREG | mqinfo ()->mqi_mode;
 116       buf->st_dev = FH_MQUEUE;
 117       buf->st_ino = hash_path_name (0, get_name ());
 118     }
 119   return ret;
 120 }
 121
 122 int
 123 fhandler_mqueue::dup (fhandler_base *child, int flags)
 124 {
 125   /* FIXME */
 126   set_errno (EBADF);
 127   return -1;
 128 }
 129
 130 void
 131 fhandler_mqueue::fixup_after_fork (HANDLE parent)
 132 {
 133   __try
 134     {
 135       PVOID mptr = NULL;
 136       SIZE_T filesize = mqinfo ()->mqi_sectsize;
 137       NTSTATUS status;
 138
 139       if (!DuplicateHandle (parent, mqinfo ()->mqi_sect,
 140                             GetCurrentProcess (), &mqinfo ()->mqi_sect,
 141                             0, FALSE, DUPLICATE_SAME_ACCESS))
 142         __leave;
 143       status = NtMapViewOfSection (mqinfo ()->mqi_sect, NtCurrentProcess (),
 144                                    &mptr, 0, filesize, NULL, &filesize,
 145                                    ViewShare, 0, PAGE_READWRITE);
 146       if (!NT_SUCCESS (status))
 147         api_fatal ("Mapping message queue failed in fork, status 0x%x\n",
 148                    status);
 149
 150       mqinfo ()->mqi_hdr = (struct mq_hdr *) mptr;
 151       if (!DuplicateHandle (parent, mqinfo ()->mqi_waitsend,
 152                             GetCurrentProcess (), &mqinfo ()->mqi_waitsend,
 153                             0, FALSE, DUPLICATE_SAME_ACCESS))
 154         __leave;
 155       if (!DuplicateHandle (parent, mqinfo ()->mqi_waitrecv,
 156                             GetCurrentProcess (), &mqinfo ()->mqi_waitrecv,
 157                             0, FALSE, DUPLICATE_SAME_ACCESS))
 158         __leave;
 159       if (!DuplicateHandle (parent, mqinfo ()->mqi_lock,
 160                             GetCurrentProcess (), &mqinfo ()->mqi_lock,
 161                             0, FALSE, DUPLICATE_SAME_ACCESS))
 162         __leave;
 163       return;
 164     }
 165   __except (EFAULT) {}
 166   __endtry
 167   api_fatal ("Creating IPC object failed in fork, %E");
 168 }
 169
 170 int
 171 fhandler_mqueue::close ()
 172 {
 173   int ret = -1;
 174
 175   __try
 176     {
 177       mqinfo ()->mqi_magic = 0;          /* just in case */
 178       NtUnmapViewOfSection (NtCurrentProcess (), mqinfo ()->mqi_hdr);
 179       NtClose (mqinfo ()->mqi_sect);
 180       NtClose (mqinfo ()->mqi_waitsend);
 181       NtClose (mqinfo ()->mqi_waitrecv);
 182       NtClose (mqinfo ()->mqi_lock);
 183     }
 184   __except (0) {}
 185   __endtry
 186   return 0;
 187 }