glibc/sysdeps/mach/hurd/dl-sysdep.c

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/* Operating system support for run-time dynamic linker. Hurd version.
Copyright (C) 1995-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* In the static library, this is all handled by dl-support.c
or by the vanilla definitions in the rest of the C library. */
#ifdef SHARED
#include <hurd.h>
#include <link.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <ldsodefs.h>
#include <sys/wait.h>
#include <assert.h>
#include <sysdep.h>
#include <argz.h>
#include <mach/mig_support.h>
#include <mach/machine/vm_param.h>
#include "hurdstartup.h"
#include <hurd/lookup.h>
#include <hurd/auth.h>
#include <hurd/term.h>
#include <stdarg.h>
#include <ctype.h>
#include <sys/stat.h>
#include <sys/uio.h>
#include <entry.h>
#include <dl-machine.h>
#include <dl-procinfo.h>
#include <dl-tunables.h>
#include <not-errno.h>
#include <not-cancel.h>
extern void __mach_init (void);
extern int _dl_argc;
extern char **_dl_argv;
extern char **_environ;
int __libc_enable_secure = 0;
rtld_hidden_data_def (__libc_enable_secure)
/* This variable contains the lowest stack address ever used. */
void *__libc_stack_end = NULL;
rtld_hidden_data_def(__libc_stack_end)
/* TODO: Initialize. */
void *_dl_random attribute_relro = NULL;
struct hurd_startup_data *_dl_hurd_data;
ElfW(Addr)
_dl_sysdep_start (void **start_argptr,
void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phent,
ElfW(Addr) *user_entry,
ElfW(auxv_t) *auxv))
{
void go (intptr_t *argdata)
{
char *orig_argv0;
char **p;
/* Cache the information in various global variables. */
_dl_argc = *argdata;
_dl_argv = 1 + (char **) argdata;
_environ = &_dl_argv[_dl_argc + 1];
for (p = _environ; *p++;); /* Skip environ pointers and terminator. */
orig_argv0 = _dl_argv[0];
if ((void *) p == _dl_argv[0])
{
static struct hurd_startup_data nodata;
_dl_hurd_data = &nodata;
nodata.user_entry = (vm_address_t) ENTRY_POINT;
}
else
_dl_hurd_data = (void *) p;
GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */
__libc_enable_secure = _dl_hurd_data->flags & EXEC_SECURE;
__tunables_init (_environ);
/* Initialize DSO sorting algorithm after tunables. */
_dl_sort_maps_init ();
#ifdef DL_SYSDEP_INIT
DL_SYSDEP_INIT;
#endif
#ifdef DL_PLATFORM_INIT
DL_PLATFORM_INIT;
#endif
/* Determine the length of the platform name. */
if (GLRO(dl_platform) != NULL)
GLRO(dl_platformlen) = strlen (GLRO(dl_platform));
if (_dl_hurd_data->flags & EXEC_STACK_ARGS
&& _dl_hurd_data->user_entry == 0)
_dl_hurd_data->user_entry = (vm_address_t) ENTRY_POINT;
#if 0 /* XXX make this work for real someday... */
if (_dl_hurd_data->user_entry == (vm_address_t) ENTRY_POINT)
/* We were invoked as a command, not as the program interpreter.
The generic ld.so code supports this: it will parse the args
as "ld.so PROGRAM [ARGS...]". For booting the Hurd, we
support an additional special syntax:
ld.so [-LIBS...] PROGRAM [ARGS...]
Each LIBS word consists of "FILENAME=MEMOBJ";
for example "-/lib/libc.so=123" says that the contents of
/lib/libc.so are found in a memory object whose port name
in our task is 123. */
while (_dl_argc > 2 && _dl_argv[1][0] == '-' && _dl_argv[1][1] != '-')
{
char *lastslash, *memobjname, *p;
struct link_map *l;
mach_port_t memobj;
error_t err;
--_dl_argc;
p = _dl_argv++[1] + 1;
memobjname = strchr (p, '=');
if (! memobjname)
_dl_sysdep_fatal ("Bogus library spec: ", p, "\n", NULL);
*memobjname++ = '\0';
memobj = 0;
while (*memobjname != '\0')
memobj = (memobj * 10) + (*memobjname++ - '0');
/* Add a user reference on the memory object port, so we will
still have one after _dl_map_object_from_fd calls our
`close'. */
err = __mach_port_mod_refs (__mach_task_self (), memobj,
MACH_PORT_RIGHT_SEND, +1);
assert_perror (err);
lastslash = strrchr (p, '/');
l = _dl_map_object_from_fd (lastslash ? lastslash + 1 : p, NULL,
memobj, strdup (p), 0);
/* Squirrel away the memory object port where it
can be retrieved by the program later. */
l->l_info[DT_NULL] = (void *) memobj;
}
#endif
/* Call elf/rtld.c's main program. It will set everything
up and leave us to transfer control to USER_ENTRY. */
(*dl_main) ((const ElfW(Phdr) *) _dl_hurd_data->phdr,
_dl_hurd_data->phdrsz / sizeof (ElfW(Phdr)),
(ElfW(Addr) *) &_dl_hurd_data->user_entry, NULL);
/* The call above might screw a few things up.
P is the location after the terminating NULL of the list of
environment variables. It has to point to the Hurd startup
data or if that's missing then P == ARGV[0] must hold. The
startup code in init-first.c will get confused if this is not
the case, so we must rearrange things to make it so. We'll
recompute P and move the Hurd data or the new ARGV[0] there.
Note: directly invoked ld.so can move arguments and env vars.
We use memmove, since the locations might overlap. */
char **newp;
for (newp = _environ; *newp++;);
if (newp != p || _dl_argv[0] != orig_argv0)
{
if (orig_argv0 == (char *) p)
{
if ((char *) newp != _dl_argv[0])
{
assert ((char *) newp < _dl_argv[0]);
_dl_argv[0] = memmove ((char *) newp, _dl_argv[0],
strlen (_dl_argv[0]) + 1);
}
}
else
{
if ((void *) newp != _dl_hurd_data)
memmove (newp, _dl_hurd_data, sizeof (*_dl_hurd_data));
}
}
{
extern void _dl_start_user (void);
/* Unwind the stack to ARGDATA and simulate a return from _dl_start
to the RTLD_START code which will run the user's entry point. */
RETURN_TO (argdata, &_dl_start_user, _dl_hurd_data->user_entry);
}
}
/* Set up so we can do RPCs. */
__mach_init ();
/* Initialize frequently used global variable. */
GLRO(dl_pagesize) = __getpagesize ();
/* See hurd/hurdstartup.c; this deals with getting information
from the exec server and slicing up the arguments.
Then it will call `go', above. */
_hurd_startup (start_argptr, &go);
LOSE;
abort ();
}
void
_dl_sysdep_start_cleanup (void)
{
/* Deallocate the reply port and task port rights acquired by
__mach_init. We are done with them now, and the user will
reacquire them for himself when he wants them. */
__mig_dealloc_reply_port (MACH_PORT_NULL);
__mach_port_deallocate (__mach_task_self (), __mach_host_self_);
__mach_port_deallocate (__mach_task_self (), __mach_task_self_);
}
/* Minimal open/close/mmap/etc. implementation sufficient for initial loading of
shared libraries. These are weak definitions so that when the
dynamic linker re-relocates itself to be user-visible (for -ldl),
it will get the user's definition (i.e. usually libc's).
They also need to be set in the libc and ld section of
sysdeps/mach/hurd/Versions, to be overridable, and in libc.abilist and
ld.abilist to be checked. */
/* This macro checks that the function does not get renamed to be hidden: we do
need these to be overridable by libc's. */
#define check_no_hidden(name) \
__typeof (name) __check_##name##_no_hidden \
__attribute__ ((alias (#name))) \
__attribute_copy__ (name);
/* Open FILE_NAME and return a Hurd I/O for it in *PORT, or return an
error. If STAT is non-zero, stat the file into that stat buffer. */
static error_t
open_file (const char *file_name, int flags,
mach_port_t *port, struct stat64 *stat)
{
enum retry_type doretry;
char retryname[1024]; /* XXX string_t LOSES! */
file_t startdir;
error_t err;
error_t use_init_port (int which, error_t (*operate) (file_t))
{
return (which < _dl_hurd_data->portarraysize
? ((*operate) (_dl_hurd_data->portarray[which]))
: EGRATUITOUS);
}
file_t get_dtable_port (int fd)
{
if ((unsigned int) fd < _dl_hurd_data->dtablesize
&& _dl_hurd_data->dtable[fd] != MACH_PORT_NULL)
{
__mach_port_mod_refs (__mach_task_self (), _dl_hurd_data->dtable[fd],
MACH_PORT_RIGHT_SEND, +1);
return _dl_hurd_data->dtable[fd];
}
errno = EBADF;
return MACH_PORT_NULL;
}
assert (!(flags & ~(O_READ | O_EXEC | O_CLOEXEC)));
flags &= ~O_CLOEXEC;
startdir = _dl_hurd_data->portarray[file_name[0] == '/'
? INIT_PORT_CRDIR : INIT_PORT_CWDIR];
while (file_name[0] == '/')
file_name++;
err = __dir_lookup (startdir, (char *)file_name, flags, 0,
&doretry, retryname, port);
if (!err)
err = __hurd_file_name_lookup_retry (use_init_port, get_dtable_port,
__dir_lookup, doretry, retryname,
O_RDONLY, 0, port);
if (!err && stat)
{
err = __io_stat (*port, stat);
if (err)
__mach_port_deallocate (__mach_task_self (), *port);
}
return err;
}
check_no_hidden(__open);
check_no_hidden (__open64);
check_no_hidden (__open_nocancel);
int weak_function
__open (const char *file_name, int mode, ...)
{
mach_port_t port;
error_t err = open_file (file_name, mode, &port, 0);
if (err)
return __hurd_fail (err);
else
return (int)port;
}
weak_alias (__open, __open64)
weak_alias (__open, __open_nocancel)
check_no_hidden(__close);
check_no_hidden(__close_nocancel);
int weak_function
__close (int fd)
{
if (fd != (int) MACH_PORT_NULL)
__mach_port_deallocate (__mach_task_self (), (mach_port_t) fd);
return 0;
}
weak_alias (__close, __close_nocancel)
check_no_hidden(__pread64);
check_no_hidden(__pread64_nocancel);
__ssize_t weak_function
__pread64 (int fd, void *buf, size_t nbytes, off64_t offset)
{
error_t err;
char *data;
mach_msg_type_number_t nread;
data = buf;
nread = nbytes;
err = __io_read ((mach_port_t) fd, &data, &nread, offset, nbytes);
if (err)
return __hurd_fail (err);
if (data != buf)
{
memcpy (buf, data, nread);
__vm_deallocate (__mach_task_self (), (vm_address_t) data, nread);
}
return nread;
}
libc_hidden_weak (__pread64)
weak_alias (__pread64, __pread64_nocancel)
check_no_hidden(__read);
check_no_hidden(__read_nocancel);
__ssize_t weak_function
__read (int fd, void *buf, size_t nbytes)
{
return __pread64 (fd, buf, nbytes, -1);
}
libc_hidden_weak (__read)
weak_alias (__read, __read_nocancel)
check_no_hidden(__write);
check_no_hidden(__write_nocancel);
__ssize_t weak_function
__write (int fd, const void *buf, size_t nbytes)
{
error_t err;
vm_size_t nwrote;
assert (fd < _hurd_init_dtablesize);
err = __io_write (_hurd_init_dtable[fd], buf, nbytes, -1, &nwrote);
if (err)
return __hurd_fail (err);
return nwrote;
}
libc_hidden_weak (__write)
weak_alias (__write, __write_nocancel)
/* This is only used for printing messages (see dl-misc.c). */
check_no_hidden(__writev);
__ssize_t weak_function
__writev (int fd, const struct iovec *iov, int niov)
{
if (fd >= _hurd_init_dtablesize)
{
errno = EBADF;
return -1;
}
int i;
size_t total = 0;
for (i = 0; i < niov; ++i)
total += iov[i].iov_len;
if (total != 0)
{
char buf[total], *bufp = buf;
error_t err;
vm_size_t nwrote;
for (i = 0; i < niov; ++i)
bufp = (memcpy (bufp, iov[i].iov_base, iov[i].iov_len)
+ iov[i].iov_len);
err = __io_write (_hurd_init_dtable[fd], buf, total, -1, &nwrote);
if (err)
return __hurd_fail (err);
return nwrote;
}
return 0;
}
check_no_hidden(__libc_lseek64);
off64_t weak_function
__libc_lseek64 (int fd, off64_t offset, int whence)
{
error_t err;
err = __io_seek ((mach_port_t) fd, offset, whence, &offset);
if (err)
return __hurd_fail (err);
return offset;
}
check_no_hidden(__mmap);
void *weak_function
__mmap (void *addr, size_t len, int prot, int flags, int fd, off_t offset)
{
error_t err;
vm_prot_t vmprot;
vm_address_t mapaddr;
mach_port_t memobj_rd, memobj_wr;
vmprot = VM_PROT_NONE;
if (prot & PROT_READ)
vmprot |= VM_PROT_READ;
if (prot & PROT_WRITE)
vmprot |= VM_PROT_WRITE;
if (prot & PROT_EXEC)
vmprot |= VM_PROT_EXECUTE;
if (flags & MAP_ANON)
memobj_rd = MACH_PORT_NULL;
else
{
assert (!(flags & MAP_SHARED));
err = __io_map ((mach_port_t) fd, &memobj_rd, &memobj_wr);
if (err)
return __hurd_fail (err), MAP_FAILED;
if (memobj_wr != MACH_PORT_NULL)
__mach_port_deallocate (__mach_task_self (), memobj_wr);
}
mapaddr = (vm_address_t) addr;
err = __vm_map (__mach_task_self (),
&mapaddr, (vm_size_t) len, 0,
!(flags & MAP_FIXED),
memobj_rd,
(vm_offset_t) offset,
flags & (MAP_COPY|MAP_PRIVATE),
vmprot, VM_PROT_ALL,
(flags & MAP_SHARED) ? VM_INHERIT_SHARE : VM_INHERIT_COPY);
if (err == KERN_NO_SPACE && (flags & MAP_FIXED))
{
/* XXX this is not atomic as it is in unix! */
/* The region is already allocated; deallocate it first. */
err = __vm_deallocate (__mach_task_self (), mapaddr, len);
if (! err)
err = __vm_map (__mach_task_self (),
&mapaddr, (vm_size_t) len,
0,
!(flags & MAP_FIXED),
memobj_rd, (vm_offset_t) offset,
flags & (MAP_COPY|MAP_PRIVATE),
vmprot, VM_PROT_ALL,
(flags & MAP_SHARED)
? VM_INHERIT_SHARE : VM_INHERIT_COPY);
}
if ((flags & MAP_ANON) == 0)
__mach_port_deallocate (__mach_task_self (), memobj_rd);
if (err)
return __hurd_fail (err), MAP_FAILED;
return (void *) mapaddr;
}
check_no_hidden(__fstat64);
int weak_function
__fstat64 (int fd, struct stat64 *buf)
{
error_t err;
err = __io_stat ((mach_port_t) fd, buf);
if (err)
return __hurd_fail (err);
return 0;
}
libc_hidden_def (__fstat64)
check_no_hidden(__stat64);
int weak_function
__stat64 (const char *file, struct stat64 *buf)
{
error_t err;
mach_port_t port;
err = open_file (file, 0, &port, buf);
if (err)
return __hurd_fail (err);
__mach_port_deallocate (__mach_task_self (), port);
return 0;
}
libc_hidden_def (__stat64)
/* This function is called by the dynamic linker (rtld.c) to check
whether debugging malloc is allowed even for SUID binaries. This
stub will always fail, which means that malloc-debugging is always
disabled for SUID binaries. */
check_no_hidden(__access);
int weak_function
__access (const char *file, int type)
{
errno = ENOSYS;
return -1;
}
check_no_hidden(__access_noerrno);
int weak_function
__access_noerrno (const char *file, int type)
{
return -1;
}
int
__rtld_execve (const char *file_name, char *const argv[],
char *const envp[])
{
file_t file;
error_t err;
char *args, *env;
size_t argslen, envlen;
mach_port_t *ports = _dl_hurd_data->portarray;
unsigned int portarraysize = _dl_hurd_data->portarraysize;
file_t *dtable = _dl_hurd_data->dtable;
unsigned int dtablesize = _dl_hurd_data->dtablesize;
int *intarray = _dl_hurd_data->intarray;
unsigned int i, j;
mach_port_t *please_dealloc, *pdp;
mach_port_t *portnames = NULL;
mach_msg_type_number_t nportnames = 0;
mach_port_type_t *porttypes = NULL;
mach_msg_type_number_t nporttypes = 0;
int flags;
err = open_file (file_name, O_EXEC, &file, NULL);
if (err)
goto out;
if (argv == NULL)
args = NULL, argslen = 0;
else if (err = __argz_create (argv, &args, &argslen))
goto outfile;
if (envp == NULL)
env = NULL, envlen = 0;
else if (err = __argz_create (envp, &env, &envlen))
goto outargs;
please_dealloc = __alloca ((portarraysize + dtablesize)
* sizeof (mach_port_t));
pdp = please_dealloc;
/* Get all ports that we may not know about and we should thus destroy. */
err = __mach_port_names (__mach_task_self (),
&portnames, &nportnames,
&porttypes, &nporttypes);
if (err)
goto outenv;
if (nportnames != nporttypes)
{
err = EGRATUITOUS;
goto outenv;
}
for (i = 0; i < portarraysize; ++i)
if (ports[i] != MACH_PORT_NULL)
{
*pdp++ = ports[i];
for (j = 0; j < nportnames; j++)
if (portnames[j] == ports[i])
portnames[j] = MACH_PORT_NULL;
}
for (i = 0; i < dtablesize; ++i)
if (dtable[i] != MACH_PORT_NULL)
{
*pdp++ = dtable[i];
for (j = 0; j < nportnames; j++)
if (portnames[j] == dtable[i])
portnames[j] = MACH_PORT_NULL;
}
/* Pack ports to be destroyed together. */
for (i = 0, j = 0; i < nportnames; i++)
{
if (portnames[i] == MACH_PORT_NULL)
continue;
if (j != i)
portnames[j] = portnames[i];
j++;
}
nportnames = j;
flags = 0;
#ifdef EXEC_SIGTRAP
if (__sigismember (&intarray[INIT_TRACEMASK], SIGKILL))
flags |= EXEC_SIGTRAP;
#endif
err = __file_exec_paths (file, __mach_task_self (), flags,
file_name, file_name[0] == '/' ? file_name : "",
args, argslen,
env, envlen,
dtable, MACH_MSG_TYPE_COPY_SEND, dtablesize,
ports, MACH_MSG_TYPE_COPY_SEND, portarraysize,
intarray, INIT_INT_MAX,
please_dealloc, pdp - please_dealloc,
portnames, nportnames);
/* Oh well. Might as well be tidy. */
outenv:
free (env);
outargs:
free (args);
outfile:
__mach_port_deallocate (__mach_task_self (), file);
out:
return err;
}
check_no_hidden(__getpid);
pid_t weak_function
__getpid (void)
{
pid_t pid, ppid;
int orphaned;
if (__proc_getpids (_dl_hurd_data->portarray[INIT_PORT_PROC],
&pid, &ppid, &orphaned))
return -1;
return pid;
}
/* We need this alias to satisfy references from libc_pic.a objects
that were affected by the libc_hidden_proto declaration for __getpid. */
strong_alias (__getpid, __GI___getpid)
/* This is called only in some strange cases trying to guess a value
for $ORIGIN for the executable. The dynamic linker copes with
getcwd failing (dl-object.c), and it's too much hassle to include
the functionality here. (We could, it just requires duplicating or
reusing getcwd.c's code but using our special lookup function as in
`open', above.) */
check_no_hidden(__getcwd);
char *weak_function
__getcwd (char *buf, size_t size)
{
errno = ENOSYS;
return NULL;
}
/* This is used by dl-tunables.c to strdup strings. We can just make this a
mere allocation. */
check_no_hidden(__sbrk);
void *weak_function
__sbrk (intptr_t increment)
{
vm_address_t addr;
if (__vm_allocate (__mach_task_self (), &addr, increment, 1))
return NULL;
return (void *) addr;
}
/* This is only used by hurdlookup for the /dev/fd/nnn magic.
* We avoid pulling the whole libc implementation, and we can keep this hidden. */
unsigned long int weak_function
__strtoul_internal (const char *nptr, char **endptr, int base, int group)
{
assert (base == 0 || base == 10);
assert (group == 0);
return _dl_strtoul (nptr, endptr);
}
/* We need this alias to satisfy references from libc_pic.a objects
that were affected by the libc_hidden_proto declaration for __strtoul_internal. */
strong_alias (__strtoul_internal, __GI___strtoul_internal)
strong_alias (__strtoul_internal, __GI_____strtoul_internal)
check_no_hidden(_exit);
void weak_function attribute_hidden
_exit (int status)
{
__proc_mark_exit (_dl_hurd_data->portarray[INIT_PORT_PROC],
W_EXITCODE (status, 0), 0);
while (__task_terminate (__mach_task_self ()))
__mach_task_self_ = (__mach_task_self) ();
LOSE;
abort ();
}
/* We need this alias to satisfy references from libc_pic.a objects
that were affected by the libc_hidden_proto declaration for _exit. */
strong_alias (_exit, __GI__exit)
/* Try to get a machine dependent instruction which will make the
program crash. This is used in case everything else fails. */
#include <abort-instr.h>
#ifndef ABORT_INSTRUCTION
/* No such instruction is available. */
# define ABORT_INSTRUCTION
#endif
check_no_hidden(abort);
void weak_function
abort (void)
{
/* Try to abort using the system specific command. */
ABORT_INSTRUCTION;
/* If the abort instruction failed, exit. */
_exit (127);
/* If even this fails, make sure we never return. */
while (1)
/* Try for ever and ever. */
ABORT_INSTRUCTION;
}
/* We need this alias to satisfy references from libc_pic.a objects
that were affected by the libc_hidden_proto declaration for abort. */
strong_alias (abort, __GI_abort)
strong_alias (abort, __GI___fortify_fail)
strong_alias (abort, __GI___assert_fail)
strong_alias (abort, __GI___assert_perror_fail)
/* This function is called by interruptible RPC stubs. For initial
dynamic linking, just use the normal mach_msg. Since this defn is
weak, the real defn in libc.so will override it if we are linked into
the user program (-ldl). */
error_t weak_function
_hurd_intr_rpc_mach_msg (mach_msg_header_t *msg,
mach_msg_option_t option,
mach_msg_size_t send_size,
mach_msg_size_t rcv_size,
mach_port_t rcv_name,
mach_msg_timeout_t timeout,
mach_port_t notify)
{
return __mach_msg (msg, option, send_size, rcv_size, rcv_name,
timeout, notify);
}
void
_dl_show_auxv (void)
{
/* There is nothing to print. Hurd has no auxiliary vector. */
}
void weak_function
_dl_init_first (int argc, ...)
{
/* This no-op definition only gets used if libc is not linked in. */
}
#endif /* SHARED */