newlib/winsup/cygwin/cygserver.cc

775 lines
18 KiB
C++
Executable File

/* cygserver.cc
Copyright 2001, 2002 Red Hat Inc.
Written by Egor Duda <deo@logos-m.ru>
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 "woutsup.h"
#include <sys/types.h>
#include <assert.h>
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "cygerrno.h"
#include "cygwin_version.h"
#include "cygwin/cygserver.h"
#include "cygwin/cygserver_process.h"
#include "cygwin/cygserver_transport.h"
// Version string.
static const char version[] = "$Revision$";
/*
* Support function for the XXX_printf () macros in "woutsup.h".
* Copied verbatim from "strace.cc".
*/
static int
getfunc (char *in_dst, const char *func)
{
const char *p;
const char *pe;
char *dst = in_dst;
for (p = func; (pe = strchr (p, '(')); p = pe + 1)
if (isalnum ((int)pe[-1]) || pe[-1] == '_')
break;
else if (isspace ((int)pe[-1]))
{
pe--;
break;
}
if (!pe)
pe = strchr (func, '\0');
for (p = pe; p > func; p--)
if (p != pe && *p == ' ')
{
p++;
break;
}
if (*p == '*')
p++;
while (p < pe)
*dst++ = *p++;
*dst++ = ':';
*dst++ = ' ';
*dst = '\0';
return dst - in_dst;
}
/*
* Support function for the XXX_printf () macros in "woutsup.h".
*/
extern "C" void
__cygserver__printf (const char *const function, const char *const fmt, ...)
{
const DWORD lasterror = GetLastError ();
const int lasterrno = errno;
va_list ap;
char *const buf = (char *) alloca (BUFSIZ);
assert (buf);
int len = 0;
if (function)
len += getfunc (buf, function);
va_start (ap, fmt);
len += vsnprintf (buf + len, BUFSIZ - len, fmt, ap);
va_end (ap);
len += snprintf (buf + len, BUFSIZ - len, "\n");
const int actual = (len > BUFSIZ ? BUFSIZ : len);
write (2, buf, actual);
errno = lasterrno;
SetLastError (lasterror);
return;
}
#ifdef DEBUGGING
int __stdcall
__set_errno (const char *func, int ln, int val)
{
debug_printf ("%s:%d val %d", func, ln, val);
return _impure_ptr->_errno = val;
}
#endif /* DEBUGGING */
GENERIC_MAPPING access_mapping;
static BOOL
setup_privileges ()
{
BOOL rc, ret_val;
HANDLE hToken = NULL;
TOKEN_PRIVILEGES sPrivileges;
rc = OpenProcessToken (GetCurrentProcess () , TOKEN_ALL_ACCESS , &hToken) ;
if (!rc)
{
system_printf ("error opening process token (%lu)", GetLastError ());
ret_val = FALSE;
goto out;
}
rc = LookupPrivilegeValue (NULL, SE_DEBUG_NAME, &sPrivileges.Privileges[0].Luid);
if (!rc)
{
system_printf ("error getting privilege luid (%lu)", GetLastError ());
ret_val = FALSE;
goto out;
}
sPrivileges.PrivilegeCount = 1 ;
sPrivileges.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED ;
rc = AdjustTokenPrivileges (hToken, FALSE, &sPrivileges, 0, NULL, NULL) ;
if (!rc)
{
system_printf ("error adjusting privilege level. (%lu)",
GetLastError ());
ret_val = FALSE;
goto out;
}
access_mapping.GenericRead = FILE_READ_DATA;
access_mapping.GenericWrite = FILE_WRITE_DATA;
access_mapping.GenericExecute = 0;
access_mapping.GenericAll = FILE_READ_DATA | FILE_WRITE_DATA;
ret_val = TRUE;
out:
CloseHandle (hToken);
return ret_val;
}
int
check_and_dup_handle (HANDLE from_process, HANDLE to_process,
HANDLE from_process_token,
DWORD access,
HANDLE from_handle,
HANDLE *to_handle_ptr, BOOL bInheritHandle = FALSE)
{
HANDLE local_handle = NULL;
int ret_val = EACCES;
if (from_process != GetCurrentProcess ())
{
if (!DuplicateHandle (from_process, from_handle,
GetCurrentProcess (), &local_handle,
0, bInheritHandle,
DUPLICATE_SAME_ACCESS))
{
system_printf ("error getting handle(%u) to server (%lu)",
(unsigned int)from_handle, GetLastError ());
goto out;
}
} else
local_handle = from_handle;
if (!wincap.has_security ())
assert (!from_process_token);
else
{
char sd_buf [1024];
PSECURITY_DESCRIPTOR sd = (PSECURITY_DESCRIPTOR) &sd_buf;
DWORD bytes_needed;
PRIVILEGE_SET ps;
DWORD ps_len = sizeof (ps);
BOOL status;
if (!GetKernelObjectSecurity (local_handle,
(OWNER_SECURITY_INFORMATION
| GROUP_SECURITY_INFORMATION
| DACL_SECURITY_INFORMATION),
sd, sizeof (sd_buf), &bytes_needed))
{
system_printf ("error getting handle SD (%lu)", GetLastError ());
goto out;
}
MapGenericMask (&access, &access_mapping);
if (!AccessCheck (sd, from_process_token, access, &access_mapping,
&ps, &ps_len, &access, &status))
{
system_printf ("error checking access rights (%lu)",
GetLastError ());
goto out;
}
if (!status)
{
system_printf ("access to object denied");
goto out;
}
}
if (!DuplicateHandle (from_process, from_handle,
to_process, to_handle_ptr,
access, bInheritHandle, 0))
{
system_printf ("error getting handle to client (%lu)", GetLastError ());
goto out;
}
// verbose: debug_printf ("Duplicated %p to %p", from_handle, *to_handle_ptr);
ret_val = 0;
out:
if (local_handle && from_process != GetCurrentProcess ())
CloseHandle (local_handle);
return (ret_val);
}
/*
* client_request_attach_tty::serve ()
*/
void
client_request_attach_tty::serve (transport_layer_base *const conn,
process_cache *)
{
assert (conn);
assert (!error_code ());
if (!wincap.has_security ())
{
syscall_printf ("operation only supported on systems with security");
error_code (EINVAL);
msglen (0);
return;
}
if (msglen () != sizeof (req))
{
syscall_printf ("bad request body length: expecting %lu bytes, got %lu",
sizeof (req), msglen ());
error_code (EINVAL);
msglen (0);
return;
}
msglen (0); // Until we fill in some fields.
// verbose: debug_printf ("pid %ld:(%p,%p) -> pid %ld",
// req.master_pid, req.from_master, req.to_master,
// req.pid);
// verbose: debug_printf ("opening process %ld", req.master_pid);
const HANDLE from_process_handle =
OpenProcess (PROCESS_DUP_HANDLE, FALSE, req.master_pid);
if (!from_process_handle)
{
system_printf ("error opening `from' process, error = %lu",
GetLastError ());
error_code (EACCES);
return;
}
// verbose: debug_printf ("opening process %ld", req.pid);
const HANDLE to_process_handle =
OpenProcess (PROCESS_DUP_HANDLE, FALSE, req.pid);
if (!to_process_handle)
{
system_printf ("error opening `to' process, error = %lu",
GetLastError ());
CloseHandle (from_process_handle);
error_code (EACCES);
return;
}
// verbose: debug_printf ("Impersonating client");
conn->impersonate_client ();
HANDLE token_handle = NULL;
// verbose: debug_printf ("about to open thread token");
const DWORD rc = OpenThreadToken (GetCurrentThread (),
TOKEN_QUERY,
TRUE,
&token_handle);
// verbose: debug_printf ("opened thread token, rc=%lu", rc);
conn->revert_to_self ();
if (!rc)
{
system_printf ("error opening thread token, error = %lu",
GetLastError ());
CloseHandle (from_process_handle);
CloseHandle (to_process_handle);
error_code (EACCES);
return;
}
// From this point on, a reply body is returned to the client.
const HANDLE from_master = req.from_master;
const HANDLE to_master = req.to_master;
req.from_master = NULL;
req.to_master = NULL;
msglen (sizeof (req));
if (from_master)
if (check_and_dup_handle (from_process_handle, to_process_handle,
token_handle,
GENERIC_READ,
from_master,
&req.from_master, TRUE) != 0)
{
system_printf ("error duplicating from_master handle, error = %lu",
GetLastError ());
error_code (EACCES);
}
if (to_master)
if (check_and_dup_handle (from_process_handle, to_process_handle,
token_handle,
GENERIC_WRITE,
to_master,
&req.to_master, TRUE) != 0)
{
system_printf ("error duplicating to_master handle, error = %lu",
GetLastError ());
error_code (EACCES);
}
CloseHandle (from_process_handle);
CloseHandle (to_process_handle);
CloseHandle (token_handle);
debug_printf ("%lu(%lu, %lu) -> %lu(%lu,%lu)",
req.master_pid, from_master, to_master,
req.pid, req.from_master, req.to_master);
return;
}
void
client_request_get_version::serve (transport_layer_base *, process_cache *)
{
assert (!error_code ());
if (msglen ())
syscall_printf ("unexpected request body ignored: %lu bytes", msglen ());
msglen (sizeof (version));
version.major = CYGWIN_SERVER_VERSION_MAJOR;
version.api = CYGWIN_SERVER_VERSION_API;
version.minor = CYGWIN_SERVER_VERSION_MINOR;
version.patch = CYGWIN_SERVER_VERSION_PATCH;
}
class server_request : public queue_request
{
public:
server_request (transport_layer_base *const conn, process_cache *const cache)
: _conn (conn), _cache (cache)
{}
virtual ~server_request ()
{
safe_delete (_conn);
}
virtual void process ()
{
client_request::handle_request (_conn, _cache);
}
private:
transport_layer_base *const _conn;
process_cache *const _cache;
};
class server_submission_loop : public queue_submission_loop
{
public:
server_submission_loop (threaded_queue *const queue,
transport_layer_base *const transport,
process_cache *const cache)
: queue_submission_loop (queue, false),
_transport (transport),
_cache (cache)
{
assert (_transport);
assert (_cache);
}
private:
transport_layer_base *const _transport;
process_cache *const _cache;
virtual void request_loop ();
};
/* FIXME: this is a little ugly. What we really want is to wait on
* two objects: one for the pipe/socket, and one for being told to
* shutdown. Otherwise this will stay a problem (we won't actually
* shutdown until the request _AFTER_ the shutdown request. And
* sending ourselves a request is ugly
*/
void
server_submission_loop::request_loop ()
{
/* I'd like the accepting thread's priority to be above any "normal"
* thread in the system to avoid overflowing the listen queue (for
* sockets; similar issues exist for named pipes); but, for example,
* a normal priority thread in a foregrounded process is boosted to
* THREAD_PRIORITY_HIGHEST (AFAICT). Thus try to set the current
* thread's priority to a level one above that. This fails on
* win9x/ME so assume any failure in that call is due to that and
* simply call again at one priority level lower.
*/
if (!SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_HIGHEST + 1))
if (!SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_HIGHEST))
debug_printf ("failed to raise accept thread priority, error = %lu",
GetLastError ());
while (_running)
{
bool recoverable = false;
transport_layer_base *const conn = _transport->accept (&recoverable);
if (!conn && !recoverable)
{
system_printf ("fatal error on IPC transport: closing down");
return;
}
// EINTR probably implies a shutdown request; so back off for a
// moment to let the main thread take control, otherwise the
// server spins here receiving EINTR repeatedly since the signal
// handler in the main thread doesn't get a chance to be called.
if (!conn && errno == EINTR)
{
if (!SetThreadPriority (GetCurrentThread (), THREAD_PRIORITY_NORMAL))
debug_printf ("failed to reset thread priority, error = %lu",
GetLastError ());
Sleep (0);
if (!SetThreadPriority (GetCurrentThread (),
THREAD_PRIORITY_HIGHEST + 1))
if (!SetThreadPriority (GetCurrentThread (),
THREAD_PRIORITY_HIGHEST))
debug_printf ("failed to raise thread priority, error = %lu",
GetLastError ());
}
if (conn)
_queue->add (safe_new (server_request, conn, _cache));
}
}
client_request_shutdown::client_request_shutdown ()
: client_request (CYGSERVER_REQUEST_SHUTDOWN)
{
// verbose: syscall_printf ("created");
}
void
client_request_shutdown::serve (transport_layer_base *, process_cache *)
{
assert (!error_code ());
if (msglen ())
syscall_printf ("unexpected request body ignored: %lu bytes", msglen ());
/* FIXME: link upwards, and then this becomes a trivial method call to
* only shutdown _this queue_
*/
kill (getpid (), SIGINT);
msglen (0);
}
static sig_atomic_t shutdown_server = false;
static void
handle_signal (const int signum)
{
/* any signal makes us die :} */
shutdown_server = true;
}
/*
* print_usage ()
*/
static void
print_usage (const char *const pgm)
{
printf ("Usage: %s [OPTIONS]\n", pgm);
printf (" -c, --cleanup-threads number of cleanup threads to use\n");
printf (" -h, --help output usage information and exit\n");
printf (" -r, --request-threads number of request threads to use\n");
printf (" -s, --shutdown shutdown the daemon\n");
printf (" -v, --version output version information and exit\n");
}
/*
* print_version ()
*/
static void
print_version (const char *const pgm)
{
char *vn = NULL;
const char *const colon = strchr (version, ':');
if (!colon)
{
vn = strdup ("?");
}
else
{
vn = strdup (colon + 2); // Skip ": "
char *const spc = strchr (vn, ' ');
if (spc)
*spc = '\0';
}
char buf[200];
snprintf (buf, sizeof (buf), "%d.%d.%d(%d.%d/%d/%d)-(%d.%d.%d.%d) %s",
cygwin_version.dll_major / 1000,
cygwin_version.dll_major % 1000,
cygwin_version.dll_minor,
cygwin_version.api_major,
cygwin_version.api_minor,
cygwin_version.shared_data,
CYGWIN_SERVER_VERSION_MAJOR,
CYGWIN_SERVER_VERSION_API,
CYGWIN_SERVER_VERSION_MINOR,
CYGWIN_SERVER_VERSION_PATCH,
cygwin_version.mount_registry,
cygwin_version.dll_build_date);
printf ("%s (cygwin) %s\n", pgm, vn);
printf ("API version %s\n", buf);
printf ("Copyright 2001, 2002 Red Hat, Inc.\n");
printf ("Compiled on %s\n", __DATE__);
free (vn);
}
/*
* main ()
*/
int
main (const int argc, char *argv[])
{
const struct option longopts[] = {
{"cleanup-threads", required_argument, NULL, 'c'},
{"help", no_argument, NULL, 'h'},
{"request-threads", required_argument, NULL, 'r'},
{"shutdown", no_argument, NULL, 's'},
{"version", no_argument, NULL, 'v'},
{0, no_argument, NULL, 0}
};
const char opts[] = "c:hr:sv";
int cleanup_threads = 2;
int request_threads = 10;
bool shutdown = false;
const char *pgm = NULL;
if (!(pgm = strrchr (*argv, '\\')) && !(pgm = strrchr (*argv, '/')))
pgm = *argv;
else
pgm++;
wincap.init ();
if (wincap.has_security ())
setup_privileges ();
int opt;
while ((opt = getopt_long (argc, argv, opts, longopts, NULL)) != EOF)
switch (opt)
{
case 'c':
cleanup_threads = atoi (optarg);
if (cleanup_threads <= 0)
{
fprintf (stderr,
"%s: number of cleanup threads must be positive\n",
pgm);
exit (1);
}
break;
case 'h':
print_usage (pgm);
return 0;
case 'r':
request_threads = atoi (optarg);
if (request_threads <= 0)
{
fprintf (stderr,
"%s: number of request threads must be positive\n",
pgm);
exit (1);
}
break;
case 's':
shutdown = true;
break;
case 'v':
print_version (pgm);
return 0;
case '?':
fprintf (stderr, "Try `%s --help' for more information.\n", pgm);
exit (1);
}
if (optind != argc)
{
fprintf (stderr, "%s: too many arguments\n", pgm);
exit (1);
}
if (shutdown)
{
/* Setting `cygserver_running' stops the request code making a
* version request, which is not much to the point.
*/
cygserver_running = CYGSERVER_OK;
client_request_shutdown req;
if (req.make_request () == -1 || req.error_code ())
{
fprintf (stderr, "%s: shutdown request failed: %s\n",
pgm, strerror (req.error_code ()));
exit (1);
}
// FIXME: It would be nice to wait here for the daemon to exit.
return 0;
}
#define SIGHANDLE(SIG) \
do \
{ \
struct sigaction act; \
\
act.sa_handler = &handle_signal; \
act.sa_mask = 0; \
act.sa_flags = 0; \
\
if (sigaction (SIG, &act, NULL) == -1) \
{ \
system_printf ("failed to install handler for " #SIG ": %s", \
strerror (errno)); \
exit (1); \
} \
} while (false)
SIGHANDLE (SIGHUP);
SIGHANDLE (SIGINT);
SIGHANDLE (SIGTERM);
print_version (pgm);
setbuf (stdout, NULL);
printf ("daemon starting up");
threaded_queue request_queue (request_threads);
printf (".");
transport_layer_base *const transport = create_server_transport ();
assert (transport);
printf (".");
process_cache cache (cleanup_threads);
printf (".");
server_submission_loop submission_loop (&request_queue, transport, &cache);
printf (".");
request_queue.add_submission_loop (&submission_loop);
printf (".");
if (transport->listen () == -1)
{
exit (1);
}
printf (".");
cache.start ();
printf (".");
request_queue.start ();
printf (".");
printf ("complete\n");
/* TODO: wait on multiple objects - the thread handle for each
* request loop + all the process handles. This should be done by
* querying the request_queue and the process cache for all their
* handles, and then waiting for (say) 30 seconds. after that we
* recreate the list of handles to wait on, and wait again. the
* point of all this abstraction is that we can trivially server
* both sockets and pipes simply by making a new transport, and then
* calling request_queue.process_requests (transport2);
*/
/* WaitForMultipleObjects abort && request_queue && process_queue && signal
-- if signal event then retrigger it
*/
while (!shutdown_server && request_queue.running () && cache.running ())
pause ();
printf ("\nShutdown request received - new requests will be denied\n");
request_queue.stop ();
printf ("All pending requests processed\n");
safe_delete (transport);
printf ("No longer accepting requests - cygwin will operate in daemonless mode\n");
cache.stop ();
printf ("All outstanding process-cache activities completed\n");
printf ("daemon shutdown\n");
return 0;
}