[thirdparty/glibc.git] / elf / pldd-xx.c

/* Copyright (C) 2011-2024 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/>.  */

#define E(name) E_(name, CLASS)
#define E_(name, cl) E__(name, cl)
#define E__(name, cl) name##cl
#define EW(type) EW_(Elf, CLASS, type)
#define EW_(e, w, t) EW__(e, w, _##t)
#define EW__(e, w, t) e##w##t

#include <dl-r_debug.h>

struct E(link_map)
{
  EW(Addr) l_addr;
  EW(Addr) l_name;
  EW(Addr) l_ld;
  EW(Addr) l_next;
  EW(Addr) l_prev;
  EW(Addr) l_real;
  Lmid_t l_ns;
  EW(Addr) l_libname;
};
#if CLASS == __ELF_NATIVE_CLASS
_Static_assert (offsetof (struct link_map, l_addr)
		== offsetof (struct E(link_map), l_addr), "l_addr");
_Static_assert (offsetof (struct link_map, l_name)
		== offsetof (struct E(link_map), l_name), "l_name");
_Static_assert (offsetof (struct link_map, l_next)
		== offsetof (struct E(link_map), l_next), "l_next");
#endif


struct E(libname_list)
{
  EW(Addr) name;
  EW(Addr) next;
};
#if CLASS == __ELF_NATIVE_CLASS
_Static_assert (offsetof (struct libname_list, name)
		== offsetof (struct E(libname_list), name), "name");
_Static_assert (offsetof (struct libname_list, next)
		== offsetof (struct E(libname_list), next), "next");
#endif

struct E(r_debug)
{
  int r_version;
#if CLASS == 64
  int pad;
#endif
  EW(Addr) r_map;
};
#if CLASS == __ELF_NATIVE_CLASS
_Static_assert (offsetof (struct r_debug, r_version)
		== offsetof (struct E(r_debug), r_version), "r_version");
_Static_assert (offsetof (struct r_debug, r_map)
		== offsetof (struct E(r_debug), r_map), "r_map");
#endif


static int

E(find_maps) (const char *exe, int memfd, pid_t pid, void *auxv,
	      size_t auxv_size)
{
  EW(Addr) phdr = 0;
  unsigned int phnum = 0;
  unsigned int phent = 0;

  EW(auxv_t) *auxvXX = (EW(auxv_t) *) auxv;
  for (int i = 0; i < auxv_size / sizeof (EW(auxv_t)); ++i)
    switch (auxvXX[i].a_type)
      {
      case AT_PHDR:
	phdr = auxvXX[i].a_un.a_val;
	break;
      case AT_PHNUM:
	phnum = auxvXX[i].a_un.a_val;
	break;
      case AT_PHENT:
	phent = auxvXX[i].a_un.a_val;
	break;
      default:
	break;
      }

  if (phdr == 0 || phnum == 0 || phent == 0)
    error (EXIT_FAILURE, 0, gettext ("cannot find program header of process"));

  EW(Phdr) *p = xmalloc (phnum * phent);
  if (pread (memfd, p, phnum * phent, phdr) != phnum * phent)
    error (EXIT_FAILURE, 0, gettext ("cannot read program header"));

  /* Determine the load offset.  We need this for interpreting the
     other program header entries so we do this in a separate loop.
     Fortunately it is the first time unless someone does something
     stupid when linking the application.  */
  EW(Addr) offset = 0;
  for (unsigned int i = 0; i < phnum; ++i)
    if (p[i].p_type == PT_PHDR)
      {
	offset = phdr - p[i].p_vaddr;
	break;
      }

  EW(Addr) list = 0;
  char *interp = NULL;
  for (unsigned int i = 0; i < phnum; ++i)
    if (p[i].p_type == PT_DYNAMIC)
      {
	EW(Dyn) *dyn = xmalloc (p[i].p_filesz);
	if (pread (memfd, dyn, p[i].p_filesz, offset + p[i].p_vaddr)
	    != p[i].p_filesz)
	  error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));

	/* Search for the struct r_debug.  */
	for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
	  {
	    EW(Addr) off = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
	    off = E(r_debug_offset) (&dyn[j], memfd, off);
	    if (off != 0)
	      {
		struct E(r_debug) r;
		if (pread (memfd, &r, sizeof (r), off)
		    != sizeof (r))
		  error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));

		if (r.r_map != 0)
		  {
		    list = r.r_map;
		    break;
		  }
	      }
	  }

	free (dyn);
	break;
      }
    else if (p[i].p_type == PT_INTERP)
      {
	interp = xmalloc (p[i].p_filesz);
	if (pread (memfd, interp, p[i].p_filesz, offset + p[i].p_vaddr)
	    != p[i].p_filesz)
	  error (EXIT_FAILURE, 0, gettext ("cannot read program interpreter"));
      }

  if (list == 0)
    {
      if (interp == NULL)
	{
	  // XXX check whether the executable itself is the loader
	  exit (EXIT_FAILURE);
	}

      // XXX perhaps try finding ld.so and _r_debug in it
      exit (EXIT_FAILURE);
    }

  free (p);
  free (interp);

  /* Print the PID and program name first.  */
  printf ("%lu:\t%s\n", (unsigned long int) pid, exe);

  /* Iterate over the list of objects and print the information.  */
  struct scratch_buffer tmpbuf;
  scratch_buffer_init (&tmpbuf);
  int status = 0;
  do
    {
      struct E(link_map) m;
      if (pread (memfd, &m, sizeof (m), list) != sizeof (m))
	error (EXIT_FAILURE, 0, gettext ("cannot read link map"));

      EW(Addr) name_offset = m.l_name;
      while (1)
	{
	  ssize_t n = pread (memfd, tmpbuf.data, tmpbuf.length, name_offset);
	  if (n == -1)
	    error (EXIT_FAILURE, 0, gettext ("cannot read object name"));

	  if (memchr (tmpbuf.data, '\0', n) != NULL)
	    break;

	  if (!scratch_buffer_grow (&tmpbuf))
	    error (EXIT_FAILURE, 0,
		   gettext ("cannot allocate buffer for object name"));
	}

      /* The m.l_name and m.l_libname.name for loader linkmap points to same
	 values (since BZ#387 fix).  Trying to use l_libname name as the
	 shared object name might lead to an infinite loop (BZ#18035).  */

      /* Skip over the executable.  */
      if (((char *)tmpbuf.data)[0] != '\0')
	printf ("%s\n", (char *)tmpbuf.data);

      list = m.l_next;
    }
  while (list != 0);

  scratch_buffer_free (&tmpbuf);
  return status;
}


#undef CLASS
Commit	Line	Data
dff8da6b	1	/* Copyright (C) 2011-2024 Free Software Foundation, Inc.
11988f8f	2	This file is part of the GNU C Library.
11988f8f UD	3
	4	The GNU C Library is free software; you can redistribute it and/or
	5	modify it under the terms of the GNU Lesser General Public
	6	License as published by the Free Software Foundation; either
	7	version 2.1 of the License, or (at your option) any later version.
	8
	9	The GNU C Library is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	12	Lesser General Public License for more details.
	13
	14	You should have received a copy of the GNU Lesser General Public
59ba27a6	15	License along with the GNU C Library; if not, see
5a82c748	16	<https://www.gnu.org/licenses/>. */
11988f8f UD	17
	18	#define E(name) E_(name, CLASS)
	19	#define E_(name, cl) E__(name, cl)
	20	#define E__(name, cl) name##cl
	21	#define EW(type) EW_(Elf, CLASS, type)
	22	#define EW_(e, w, t) EW__(e, w, _##t)
	23	#define EW__(e, w, t) e##w##t
	24
3fb18fd8 L	25	#include <dl-r_debug.h>
3fb18fd8 L	26
11988f8f UD	27	struct E(link_map)
	28	{
	29	EW(Addr) l_addr;
	30	EW(Addr) l_name;
	31	EW(Addr) l_ld;
	32	EW(Addr) l_next;
	33	EW(Addr) l_prev;
	34	EW(Addr) l_real;
	35	Lmid_t l_ns;
	36	EW(Addr) l_libname;
	37	};
	38	#if CLASS == __ELF_NATIVE_CLASS
1a4c2735 AZ	39	_Static_assert (offsetof (struct link_map, l_addr)
	40	== offsetof (struct E(link_map), l_addr), "l_addr");
	41	_Static_assert (offsetof (struct link_map, l_name)
	42	== offsetof (struct E(link_map), l_name), "l_name");
	43	_Static_assert (offsetof (struct link_map, l_next)
	44	== offsetof (struct E(link_map), l_next), "l_next");
11988f8f UD	45	#endif
	46
	47
	48	struct E(libname_list)
	49	{
	50	EW(Addr) name;
	51	EW(Addr) next;
	52	};
	53	#if CLASS == __ELF_NATIVE_CLASS
1a4c2735 AZ	54	_Static_assert (offsetof (struct libname_list, name)
	55	== offsetof (struct E(libname_list), name), "name");
	56	_Static_assert (offsetof (struct libname_list, next)
	57	== offsetof (struct E(libname_list), next), "next");
11988f8f UD	58	#endif
	59
	60	struct E(r_debug)
	61	{
	62	int r_version;
c5305d88 UD	63	#if CLASS == 64
	64	int pad;
	65	#endif
11988f8f UD	66	EW(Addr) r_map;
	67	};
	68	#if CLASS == __ELF_NATIVE_CLASS
1a4c2735 AZ	69	_Static_assert (offsetof (struct r_debug, r_version)
	70	== offsetof (struct E(r_debug), r_version), "r_version");
	71	_Static_assert (offsetof (struct r_debug, r_map)
	72	== offsetof (struct E(r_debug), r_map), "r_map");
11988f8f UD	73	#endif
	74
	75
	76	static int
c5305d88	77
1a4c2735 AZ	78	E(find_maps) (const char exe, int memfd, pid_t pid, void auxv,
1a4c2735 AZ	79	size_t auxv_size)
11988f8f UD	80	{
	81	EW(Addr) phdr = 0;
	82	unsigned int phnum = 0;
	83	unsigned int phent = 0;
	84
	85	EW(auxv_t) auxvXX = (EW(auxv_t) ) auxv;
	86	for (int i = 0; i < auxv_size / sizeof (EW(auxv_t)); ++i)
	87	switch (auxvXX[i].a_type)
	88	{
	89	case AT_PHDR:
	90	phdr = auxvXX[i].a_un.a_val;
	91	break;
	92	case AT_PHNUM:
	93	phnum = auxvXX[i].a_un.a_val;
	94	break;
	95	case AT_PHENT:
	96	phent = auxvXX[i].a_un.a_val;
	97	break;
	98	default:
	99	break;
	100	}
	101
	102	if (phdr == 0 \|\| phnum == 0 \|\| phent == 0)
	103	error (EXIT_FAILURE, 0, gettext ("cannot find program header of process"));
	104
1a4c2735 AZ	105	EW(Phdr) p = xmalloc (phnum phent);
	106	if (pread (memfd, p, phnum * phent, phdr) != phnum * phent)
	107	error (EXIT_FAILURE, 0, gettext ("cannot read program header"));
11988f8f UD	108
	109	/* Determine the load offset. We need this for interpreting the
	110	other program header entries so we do this in a separate loop.
	111	Fortunately it is the first time unless someone does something
	112	stupid when linking the application. */
	113	EW(Addr) offset = 0;
	114	for (unsigned int i = 0; i < phnum; ++i)
	115	if (p[i].p_type == PT_PHDR)
	116	{
	117	offset = phdr - p[i].p_vaddr;
	118	break;
	119	}
	120
	121	EW(Addr) list = 0;
	122	char *interp = NULL;
	123	for (unsigned int i = 0; i < phnum; ++i)
	124	if (p[i].p_type == PT_DYNAMIC)
	125	{
	126	EW(Dyn) *dyn = xmalloc (p[i].p_filesz);
1a4c2735	127	if (pread (memfd, dyn, p[i].p_filesz, offset + p[i].p_vaddr)
11988f8f	128	!= p[i].p_filesz)
1a4c2735	129	error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
11988f8f	130
3fb18fd8	131	/* Search for the struct r_debug. */
11988f8f	132	for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
3fb18fd8 L	133	{
	134	EW(Addr) off = offset + p[i].p_vaddr + sizeof (EW(Dyn)) * j;
	135	off = E(r_debug_offset) (&dyn[j], memfd, off);
	136	if (off != 0)
	137	{
	138	struct E(r_debug) r;
	139	if (pread (memfd, &r, sizeof (r), off)
	140	!= sizeof (r))
	141	error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
	142
	143	if (r.r_map != 0)
	144	{
	145	list = r.r_map;
	146	break;
	147	}
	148	}
	149	}
11988f8f UD	150
	151	free (dyn);
	152	break;
	153	}
	154	else if (p[i].p_type == PT_INTERP)
	155	{
1a4c2735 AZ	156	interp = xmalloc (p[i].p_filesz);
1a4c2735 AZ	157	if (pread (memfd, interp, p[i].p_filesz, offset + p[i].p_vaddr)
11988f8f	158	!= p[i].p_filesz)
1a4c2735	159	error (EXIT_FAILURE, 0, gettext ("cannot read program interpreter"));
11988f8f UD	160	}
	161
	162	if (list == 0)
	163	{
	164	if (interp == NULL)
	165	{
	166	// XXX check whether the executable itself is the loader
1a4c2735	167	exit (EXIT_FAILURE);
11988f8f UD	168	}
	169
	170	// XXX perhaps try finding ld.so and _r_debug in it
1a4c2735	171	exit (EXIT_FAILURE);
11988f8f UD	172	}
11988f8f UD	173
1a4c2735 AZ	174	free (p);
	175	free (interp);
	176
11988f8f UD	177	/* Print the PID and program name first. */
	178	printf ("%lu:\t%s\n", (unsigned long int) pid, exe);
	179
	180	/* Iterate over the list of objects and print the information. */
7b8399f4 FW	181	struct scratch_buffer tmpbuf;
	182	scratch_buffer_init (&tmpbuf);
	183	int status = 0;
11988f8f UD	184	do
	185	{
	186	struct E(link_map) m;
1a4c2735 AZ	187	if (pread (memfd, &m, sizeof (m), list) != sizeof (m))
1a4c2735 AZ	188	error (EXIT_FAILURE, 0, gettext ("cannot read link map"));
11988f8f UD	189
11988f8f UD	190	EW(Addr) name_offset = m.l_name;
11988f8f UD	191	while (1)
11988f8f UD	192	{
1a4c2735	193	ssize_t n = pread (memfd, tmpbuf.data, tmpbuf.length, name_offset);
11988f8f	194	if (n == -1)
1a4c2735	195	error (EXIT_FAILURE, 0, gettext ("cannot read object name"));
11988f8f	196
7b8399f4	197	if (memchr (tmpbuf.data, '\0', n) != NULL)
11988f8f UD	198	break;
11988f8f UD	199
7b8399f4	200	if (!scratch_buffer_grow (&tmpbuf))
1a4c2735 AZ	201	error (EXIT_FAILURE, 0,
1a4c2735 AZ	202	gettext ("cannot allocate buffer for object name"));
11988f8f UD	203	}
11988f8f UD	204
1a4c2735 AZ	205	/* The m.l_name and m.l_libname.name for loader linkmap points to same
	206	values (since BZ#387 fix). Trying to use l_libname name as the
	207	shared object name might lead to an infinite loop (BZ#18035). */
11988f8f UD	208
11988f8f UD	209	/* Skip over the executable. */
7b8399f4 FW	210	if (((char *)tmpbuf.data)[0] != '\0')
7b8399f4 FW	211	printf ("%s\n", (char *)tmpbuf.data);
11988f8f UD	212
	213	list = m.l_next;
	214	}
	215	while (list != 0);
	216
7b8399f4 FW	217	scratch_buffer_free (&tmpbuf);
7b8399f4 FW	218	return status;
11988f8f UD	219	}
	220
	221
	222	#undef CLASS