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/* Copyright (C) 2011-2022 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
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 DT_DEBUG entry. */
for (unsigned int j = 0; j < p[i].p_filesz / sizeof (EW(Dyn)); ++j)
if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
{
struct E(r_debug) r;
if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
!= 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
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