glibc/dlfcn/tst-dlinfo-phdr.c
Florian Weimer 28ea43f8d6 dlfcn: Implement the RTLD_DI_PHDR request type for dlinfo
The information is theoretically available via dl_iterate_phdr as
well, but that approach is very slow if there are many shared
objects.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@rehdat.com>
(cherry picked from commit d056c21213)
2022-05-11 19:17:47 +02:00

126 lines
3.8 KiB
C

/* Test for dlinfo (RTLD_DI_PHDR).
Copyright (C) 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/>. */
#include <dlfcn.h>
#include <link.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <sys/auxv.h>
#include <support/check.h>
#include <support/xdlfcn.h>
/* Used to verify that the program header array appears as expected
among the dl_iterate_phdr callback invocations. */
struct dlip_callback_args
{
struct link_map *l; /* l->l_addr is used to find the object. */
const ElfW(Phdr) *phdr; /* Expected program header pointed. */
int phnum; /* Expected program header count. */
bool found; /* True if l->l_addr has been found. */
};
static int
dlip_callback (struct dl_phdr_info *dlpi, size_t size, void *closure)
{
TEST_COMPARE (sizeof (*dlpi), size);
struct dlip_callback_args *args = closure;
if (dlpi->dlpi_addr == args->l->l_addr)
{
TEST_VERIFY (!args->found);
args->found = true;
TEST_VERIFY (args->phdr == dlpi->dlpi_phdr);
TEST_COMPARE (args->phnum, dlpi->dlpi_phnum);
}
return 0;
}
static int
do_test (void)
{
/* Avoid a copy relocation. */
struct r_debug *debug = xdlsym (RTLD_DEFAULT, "_r_debug");
struct link_map *l = (struct link_map *) debug->r_map;
TEST_VERIFY_EXIT (l != NULL);
do
{
printf ("info: checking link map %p (%p) for \"%s\"\n",
l, l->l_phdr, l->l_name);
/* Cause dlerror () to return an error message. */
dlsym (RTLD_DEFAULT, "does-not-exist");
/* Use the extension that link maps are valid dlopen handles. */
const ElfW(Phdr) *phdr;
int phnum = dlinfo (l, RTLD_DI_PHDR, &phdr);
TEST_VERIFY (phnum >= 0);
/* Verify that the error message has been cleared. */
TEST_COMPARE_STRING (dlerror (), NULL);
TEST_VERIFY (phdr == l->l_phdr);
TEST_COMPARE (phnum, l->l_phnum);
/* Check that we can find PT_DYNAMIC among the array. */
{
bool dynamic_found = false;
for (int i = 0; i < phnum; ++i)
if (phdr[i].p_type == PT_DYNAMIC)
{
dynamic_found = true;
TEST_COMPARE ((ElfW(Addr)) l->l_ld, l->l_addr + phdr[i].p_vaddr);
}
TEST_VERIFY (dynamic_found);
}
/* Check that dl_iterate_phdr finds the link map with the same
program headers. */
{
struct dlip_callback_args args =
{
.l = l,
.phdr = phdr,
.phnum = phnum,
.found = false,
};
TEST_COMPARE (dl_iterate_phdr (dlip_callback, &args), 0);
TEST_VERIFY (args.found);
}
if (l->l_prev == NULL)
{
/* This is the executable, so the information is also
available via getauxval. */
TEST_COMPARE_STRING (l->l_name, "");
TEST_VERIFY (phdr == (const ElfW(Phdr) *) getauxval (AT_PHDR));
TEST_COMPARE (phnum, getauxval (AT_PHNUM));
}
l = l->l_next;
}
while (l != NULL);
return 0;
}
#include <support/test-driver.c>