This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH 2/2] elf: Fix pldd (BZ#18035)
On 17/04/2019 01:05, Carlos O'Donell wrote:
> On 4/16/19 5:27 PM, Adhemerval Zanella wrote:
>> Since 9182aa67994 (Fix vDSO l_name for GDB's, BZ#387) the initial link_map
>> for executable itself and loader will have both l_name and l_libname->name
>> holding the same value due:
>
> Thanks for tracking this down!
>
> Please post v2:
> - consider removal of more braces.
> - add a comment where the old code was removed to warn against looking
> at l_libname and the problem therein.
> - consider adjusted comment.
I will sent it, thanks for reviewing it.
>
>>
>> elf/dl-object.c
>>
>> 95 new->l_name = *realname ? realname : (char *) newname->name + libname_len - 1;
>>
>> Since newname->name points to new->l_libname->name.
>>
>> This leads to pldd to an infinite call at:
>>
>> elf/pldd-xx.c
>>
>> 203 again:
>> 204 while (1)
>> 205 {
>> 206 ssize_t n = pread64 (memfd, tmpbuf.data, tmpbuf.length, name_offset);
>>
>> 228 /* Try the l_libname element. */
>> 229 struct E(libname_list) ln;
>> 230 if (pread64 (memfd, &ln, sizeof (ln), m.l_libname) == sizeof (ln))
>> 231 {
>> 232 name_offset = ln.name;
>> 233 goto again;
>> 234 }
>>
>> Since the value at ln.name (l_libname->name) will be the same as previously
>> read. The straightforward fix is just avoid the check and read the new list
>> entry.
>>
>> I checked also against binaries issues with old loaders with fix for BZ#387,
>> and pldd could dump the shared objects.
>>
>> Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and
>> powerpc64le-linux-gnu.
>>
>> [BZ #18035]
>> * elf/Makefile (tests-container): Add tst-pldd.
>> * elf/pldd-xx.c: Use _Static_assert in of pldd_assert.
>> (E(find_maps)): Avoid use alloca, use default read file operations
>> instead of explicit LFS names, and fix infinite loop.
>> * elf/pldd.c: Explicit set _FILE_OFFSET_BITS, cleanup headers.
>> (get_process_info): Use _Static_assert instead of assert, use default
>> directory operations instead of explicit LFS names, and free some
>> leadek pointers.
>> * elf/tst-pldd.c: New file.
>> * elf/tst-pldd.root/tst-pldd.script: Likewise.
>
> This has a lot of unrelated cleanup to pldd which does much more than just
> fix pldd. However, the cleanups are all OK IMO, and if someone needs to
> backport just the required fix, they can do the removal of t
Right, the fix itself is quite simple for a backport (more below).
>
>
>> ---
>> elf/Makefile | 1 +
>> elf/pldd-xx.c | 106 ++++++++++-----------------
>> elf/pldd.c | 64 ++++++++--------
>> elf/tst-pldd.c | 118 ++++++++++++++++++++++++++++++
>> elf/tst-pldd.root/tst-pldd.script | 1 +
>> posix/tst-pldd.c | 9 +++
>> 6 files changed, 196 insertions(+), 103 deletions(-)
>> create mode 100644 elf/tst-pldd.c
>> create mode 100644 elf/tst-pldd.root/tst-pldd.script
>> create mode 100644 posix/tst-pldd.c
>>
>> diff --git a/elf/Makefile b/elf/Makefile
>> index 310a37cc13..0b4a877880 100644
>> --- a/elf/Makefile
>> +++ b/elf/Makefile
>> @@ -194,6 +194,7 @@ tests-internal += loadtest unload unload2 circleload1 \
>> tst-tls3 tst-tls6 tst-tls7 tst-tls8 tst-dlmopen2 \
>> tst-ptrguard1 tst-stackguard1 tst-libc_dlvsym \
>> tst-create_format1
>> +tests-container += tst-pldd
>
> OK.
>
>> ifeq ($(build-hardcoded-path-in-tests),yes)
>> tests += tst-dlopen-aout
>> tst-dlopen-aout-no-pie = yes
>> diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
>> index 547f840ee1..53858b9932 100644
>> --- a/elf/pldd-xx.c
>> +++ b/elf/pldd-xx.c
>> @@ -23,10 +23,6 @@
>> #define EW_(e, w, t) EW__(e, w, _##t)
>> #define EW__(e, w, t) e##w##t
>> -#define pldd_assert(name, exp) \
>> - typedef int __assert_##name[((exp) != 0) - 1]
>> -
>> -
>
> OK.
>
>> struct E(link_map)
>> {
>> EW(Addr) l_addr;
>> @@ -39,12 +35,12 @@ struct E(link_map)
>> EW(Addr) l_libname;
>> };
>> #if CLASS == __ELF_NATIVE_CLASS
>> -pldd_assert (l_addr, (offsetof (struct link_map, l_addr)
>> - == offsetof (struct E(link_map), l_addr)));
>> -pldd_assert (l_name, (offsetof (struct link_map, l_name)
>> - == offsetof (struct E(link_map), l_name)));
>> -pldd_assert (l_next, (offsetof (struct link_map, l_next)
>> - == offsetof (struct E(link_map), l_next)));
>> +_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");
>
> OK.
>
>> #endif
>> @@ -54,10 +50,10 @@ struct E(libname_list)
>> EW(Addr) next;
>> };
>> #if CLASS == __ELF_NATIVE_CLASS
>> -pldd_assert (name, (offsetof (struct libname_list, name)
>> - == offsetof (struct E(libname_list), name)));
>> -pldd_assert (next, (offsetof (struct libname_list, next)
>> - == offsetof (struct E(libname_list), next)));
>> +_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");
>
> OK.
>
>> #endif
>> struct E(r_debug)
>> @@ -69,16 +65,17 @@ struct E(r_debug)
>> EW(Addr) r_map;
>> };
>> #if CLASS == __ELF_NATIVE_CLASS
>> -pldd_assert (r_version, (offsetof (struct r_debug, r_version)
>> - == offsetof (struct E(r_debug), r_version)));
>> -pldd_assert (r_map, (offsetof (struct r_debug, r_map)
>> - == offsetof (struct E(r_debug), r_map)));
>> +_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");
>
> OK.
>
>> #endif
>> static int
>> -E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> +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;
>> @@ -104,12 +101,9 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> if (phdr == 0 || phnum == 0 || phent == 0)
>> error (EXIT_FAILURE, 0, gettext ("cannot find program header of process"));
>> - EW(Phdr) *p = alloca (phnum * phent);
>> - if (pread64 (memfd, p, phnum * phent, phdr) != phnum * phent)
>> - {
>> - error (0, 0, gettext ("cannot read program header"));
>> - return EXIT_FAILURE;
>> - }
>> + EW(Phdr) *p = xmalloc (phnum * phent);
>> + if (pread (memfd, p, phnum * phent, phdr) != phnum * phent)
>> + error (EXIT_FAILURE, 0, gettext ("cannot read program header"));
>
> OK.
>
>> /* Determine the load offset. We need this for interpreting the
>> other program header entries so we do this in a separate loop.
>> @@ -129,11 +123,10 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> if (p[i].p_type == PT_DYNAMIC)
>> {
>> EW(Dyn) *dyn = xmalloc (p[i].p_filesz);
>> - if (pread64 (memfd, dyn, p[i].p_filesz, offset + p[i].p_vaddr)
>> + if (pread (memfd, dyn, p[i].p_filesz, offset + p[i].p_vaddr)
>
> OK.
>
>> != p[i].p_filesz)
>> {
>> - error (0, 0, gettext ("cannot read dynamic section"));
>> - return EXIT_FAILURE;
>> + error (EXIT_FAILURE, 0, gettext ("cannot read dynamic section"));
>
> OK. Consider removing braces?
Ack.
>
>> }
>> /* Search for the DT_DEBUG entry. */
>> @@ -141,11 +134,10 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> if (dyn[j].d_tag == DT_DEBUG && dyn[j].d_un.d_ptr != 0)
>> {
>> struct E(r_debug) r;
>> - if (pread64 (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
>> + if (pread (memfd, &r, sizeof (r), dyn[j].d_un.d_ptr)
>
> OK.
>
>> != sizeof (r))
>> {
>> - error (0, 0, gettext ("cannot read r_debug"));
>> - return EXIT_FAILURE;
>> + error (EXIT_FAILURE, 0, gettext ("cannot read r_debug"));
>
> OK. Consider removing braces?
Ack.
>
>> }
>> if (r.r_map != 0)
>> @@ -160,12 +152,11 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> }
>> else if (p[i].p_type == PT_INTERP)
>> {
>> - interp = alloca (p[i].p_filesz);
>> - if (pread64 (memfd, interp, p[i].p_filesz, offset + p[i].p_vaddr)
>> + interp = xmalloc (p[i].p_filesz);
>> + if (pread (memfd, interp, p[i].p_filesz, offset + p[i].p_vaddr)
>
> OK.
>
>> != p[i].p_filesz)
>> {
>> - error (0, 0, gettext ("cannot read program interpreter"));
>> - return EXIT_FAILURE;
>> + error (EXIT_FAILURE, 0, gettext ("cannot read program interpreter"));
>
> OK. Consider removing braces?
Ack.
>
>> }
>> }
>> @@ -174,14 +165,16 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> if (interp == NULL)
>> {
>> // XXX check whether the executable itself is the loader
>> - return EXIT_FAILURE;
>> + exit (EXIT_FAILURE);
>
> OK.
>
>> }
>> // XXX perhaps try finding ld.so and _r_debug in it
>> -
>> - return EXIT_FAILURE;
>> + exit (EXIT_FAILURE);
>
> OK.
>
>> }
>> + free (p);
>> + free (interp);
>
> OK. Both were changed from alloca to xmalloc.
>
>> +
>> /* Print the PID and program name first. */
>> printf ("%lu:\t%s\n", (unsigned long int) pid, exe);
>> @@ -192,46 +185,22 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> do
>> {
>> struct E(link_map) m;
>> - if (pread64 (memfd, &m, sizeof (m), list) != sizeof (m))
>> - {
>> - error (0, 0, gettext ("cannot read link map"));
>> - status = EXIT_FAILURE;
>> - goto out;
>> - }
>> + if (pread (memfd, &m, sizeof (m), list) != sizeof (m))
>> + error (EXIT_FAILURE, 0, gettext ("cannot read link map"));
>
> OK.
>
>> EW(Addr) name_offset = m.l_name;
>> - again:
>> while (1)
>> {
>> - ssize_t n = pread64 (memfd, tmpbuf.data, tmpbuf.length, name_offset);
>> + ssize_t n = pread (memfd, tmpbuf.data, tmpbuf.length, name_offset);
>> if (n == -1)
>> - {
>> - error (0, 0, gettext ("cannot read object name"));
>> - status = EXIT_FAILURE;
>> - goto out;
>> - }
>> + error (EXIT_FAILURE, 0, gettext ("cannot read object name"));
>
> OK.
>
>> if (memchr (tmpbuf.data, '\0', n) != NULL)
>> break;
>> if (!scratch_buffer_grow (&tmpbuf))
>> - {
>> - error (0, 0, gettext ("cannot allocate buffer for object name"));
>> - status = EXIT_FAILURE;
>> - goto out;
>> - }
>> - }
>> -
>> - if (((char *)tmpbuf.data)[0] == '\0' && name_offset == m.l_name
>> - && m.l_libname != 0)
>> - {
>> - /* Try the l_libname element. */
>> - struct E(libname_list) ln;
>> - if (pread64 (memfd, &ln, sizeof (ln), m.l_libname) == sizeof (ln))
>> - {
>> - name_offset = ln.name;
>> - goto again;
>> - }
>> + error (EXIT_FAILURE, 0,
>> + gettext ("cannot allocate buffer for object name"));
>
> This is the real fix right? We remove the iteration into l_libname?
> Why was this code ever needed in the first place?
Yes, the core issue is l_name and l_libname->name for loaders linkmap
points to same value since BZ#387 fix. This makes 'm.l_libname' being
the same address as the m.l_name, thus creating an infinite loop. A more
self-contained patch would be:
---
diff --git a/elf/pldd-xx.c b/elf/pldd-xx.c
index 547f840ee1..995a731d43 100644
--- a/elf/pldd-xx.c
+++ b/elf/pldd-xx.c
@@ -200,7 +200,6 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
}
EW(Addr) name_offset = m.l_name;
- again:
while (1)
{
ssize_t n = pread64 (memfd, tmpbuf.data, tmpbuf.length, name_offset);
@@ -222,18 +221,6 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
}
}
- if (((char *)tmpbuf.data)[0] == '\0' && name_offset == m.l_name
- && m.l_libname != 0)
- {
- /* Try the l_libname element. */
- struct E(libname_list) ln;
- if (pread64 (memfd, &ln, sizeof (ln), m.l_libname) == sizeof (ln))
- {
- name_offset = ln.name;
- goto again;
- }
- }
-
/* Skip over the executable. */
if (((char *)tmpbuf.data)[0] != '\0')
printf ("%s\n", (char *)tmpbuf.data);
---
>
>> }
>> /* Skip over the executable. */
>> @@ -242,7 +211,6 @@ E(find_maps) (pid_t pid, void *auxv, size_t auxv_size)
>> }
>> while (list != 0);
>> - out:
>
> OK.
>
>> scratch_buffer_free (&tmpbuf);
>> return status;
>> }
>> diff --git a/elf/pldd.c b/elf/pldd.c
>> index f3fac4e487..69629bd5d2 100644
>> --- a/elf/pldd.c
>> +++ b/elf/pldd.c
>> @@ -17,23 +17,17 @@
>> License along with the GNU C Library; if not, see
>> <http://www.gnu.org/licenses/>. */
>> -#include <alloca.h>
>> +#define _FILE_OFFSET_BITS 64
>> +
>> #include <argp.h>
>> -#include <assert.h>
>> #include <dirent.h>
>> -#include <elf.h>
>> -#include <errno.h>
>> #include <error.h>
>> #include <fcntl.h>
>> #include <libintl.h>
>> -#include <link.h>
>> -#include <stddef.h>
>> #include <stdio.h>
>> #include <stdlib.h>
>> -#include <string.h>
>> #include <unistd.h>
>> #include <sys/ptrace.h>
>> -#include <sys/stat.h>
>
> OK.
>
>> #include <sys/wait.h>
>> #include <scratch_buffer.h>
>> @@ -76,14 +70,9 @@ static struct argp argp =
>> options, parse_opt, args_doc, doc, NULL, more_help, NULL
>> };
>> -// File descriptor of /proc/*/mem file.
>> -static int memfd;
>> -
>> -/* Name of the executable */
>> -static char *exe;
>
> OK.
>
>> /* Local functions. */
>> -static int get_process_info (int dfd, long int pid);
>> +static int get_process_info (const char *exe, int dfd, long int pid);
>
> OK.
>
>> static void wait_for_ptrace_stop (long int pid);
>> @@ -102,8 +91,10 @@ main (int argc, char *argv[])
>> return 1;
>> }
>> - assert (sizeof (pid_t) == sizeof (int)
>> - || sizeof (pid_t) == sizeof (long int));
>> + _Static_assert (sizeof (pid_t) == sizeof (int)
>> + || sizeof (pid_t) == sizeof (long int),
>> + "sizeof (pid_t) != sizeof (int) or sizeof (long int)");
>
> OK.
>
>> +
>> char *endp;
>> errno = 0;
>> long int pid = strtol (argv[remaining], &endp, 10);
>> @@ -119,25 +110,24 @@ main (int argc, char *argv[])
>> if (dfd == -1)
>> error (EXIT_FAILURE, errno, gettext ("cannot open %s"), buf);
>> - struct scratch_buffer exebuf;
>> - scratch_buffer_init (&exebuf);
>> + /* Name of the executable */
>> + struct scratch_buffer exe;
>> + scratch_buffer_init (&exe);
>> ssize_t nexe;
>> while ((nexe = readlinkat (dfd, "exe",
>> - exebuf.data, exebuf.length)) == exebuf.length)
>> + exe.data, exe.length)) == exe.length)
>
> OK.
>
>> {
>> - if (!scratch_buffer_grow (&exebuf))
>> + if (!scratch_buffer_grow (&exe))
>
> OK.
>
>> {
>> nexe = -1;
>> break;
>> }
>> }
>> if (nexe == -1)
>> - exe = (char *) "<program name undetermined>";
>> + /* Default stack allocation is at least 1024. */
>> + snprintf (exe.data, exe.length, "<program name undetermined>");
>
> OK.
>
>> else
>> - {
>> - exe = exebuf.data;
>> - exe[nexe] = '\0';
>> - }
>> + ((char*)exe.data)[nexe] = '\0';
>
> OK.
>
>> /* Stop all threads since otherwise the list of loaded modules might
>> change while we are reading it. */
>> @@ -155,8 +145,8 @@ main (int argc, char *argv[])
>> error (EXIT_FAILURE, errno, gettext ("cannot prepare reading %s/task"),
>> buf);
>> - struct dirent64 *d;
>> - while ((d = readdir64 (dir)) != NULL)
>> + struct dirent *d;
>> + while ((d = readdir (dir)) != NULL)
>> {
>> if (! isdigit (d->d_name[0]))
>> continue;
>> @@ -182,7 +172,7 @@ main (int argc, char *argv[])
>> wait_for_ptrace_stop (tid);
>> - struct thread_list *newp = alloca (sizeof (*newp));
>> + struct thread_list *newp = xmalloc (sizeof (*newp));
>
> OK.
>
>> newp->tid = tid;
>> newp->next = thread_list;
>> thread_list = newp;
>> @@ -190,17 +180,22 @@ main (int argc, char *argv[])
>> closedir (dir);
>> - int status = get_process_info (dfd, pid);
>> + if (thread_list == NULL)
>> + error (EXIT_FAILURE, 0, gettext ("no valid %s/task entries"), buf);
>> +
>> + int status = get_process_info (exe.data, dfd, pid);
>
> OK.
>
>> - assert (thread_list != NULL);
>> do
>> {
>> ptrace (PTRACE_DETACH, thread_list->tid, NULL, NULL);
>> + struct thread_list *prev = thread_list;
>> thread_list = thread_list->next;
>> + free (prev);
>
> OK.
>
>> }
>> while (thread_list != NULL);
>> close (dfd);
>> + scratch_buffer_free (&exe);
>
> OK.
>
>> return status;
>> }
>> @@ -281,9 +276,10 @@ warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n\
>> static int
>> -get_process_info (int dfd, long int pid)
>> +get_process_info (const char *exe, int dfd, long int pid)
>> {
>> - memfd = openat (dfd, "mem", O_RDONLY);
>> + /* File descriptor of /proc/<pid>/mem file. */
>> + int memfd = openat (dfd, "mem", O_RDONLY);
>> if (memfd == -1)
>> goto no_info;
>> @@ -333,9 +329,9 @@ get_process_info (int dfd, long int pid)
>> int retval;
>> if (e_ident[EI_CLASS] == ELFCLASS32)
>> - retval = find_maps32 (pid, auxv, auxv_size);
>> + retval = find_maps32 (exe, memfd, pid, auxv, auxv_size);
>> else
>> - retval = find_maps64 (pid, auxv, auxv_size);
>> + retval = find_maps64 (exe, memfd, pid, auxv, auxv_size);
>
> OK.
>
>> free (auxv);
>> close (memfd);
>> diff --git a/elf/tst-pldd.c b/elf/tst-pldd.c
>> new file mode 100644
>> index 0000000000..9b568ca4eb
>> --- /dev/null
>> +++ b/elf/tst-pldd.c
>> @@ -0,0 +1,118 @@
>> +/* Basic tests for pldd program.
>
> OK.
>
>> + Copyright (C) 2019 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
>> + <http://www.gnu.org/licenses/>. */
>> +
>> +#include <stdio.h>
>> +#include <string.h>
>> +#include <unistd.h>
>> +#include <stdint.h>
>> +#include <libgen.h>
>> +#include <stdbool.h>
>> +
>> +#include <array_length.h>
>> +#include <gnu/lib-names.h>
>> +
>> +#include <support/subprocess.h>
>> +#include <support/capture_subprocess.h>
>> +#include <support/check.h>
>> +
>> +static void
>> +target_process (void *arg)
>> +{
>> + pause ();
>> +}
>> +
>> +/* The test runs on container because currently pldd does not support trace
>> + a binary issues with loader itself (as with testrun.sh). */
>
> Suggest:
>
> /* The test runs in a container because pldd does not support tracing
> a binary started by the loader iself (as with testrun.sh). */
Ack.
>
>> +
>> +static int
>> +do_test (void)
>> +{
>> + /* Create a copy of current test to check with pldd. */
>> + struct support_subprocess target = support_subprocess (target_process, NULL);
>> +
>> + /* Run 'pldd' on test subprocess. */
>> + struct support_capture_subprocess pldd;
>> + {
>> + /* Three digits per byte plus null terminator. */
>> + char pid[3 * sizeof (uint32_t) + 1];
>> + snprintf (pid, array_length (pid), "%d", target.pid);
>> +
>> + const char prog[] = "/usr/bin/pldd";
>> +
>> + pldd = support_capture_subprogram (prog,
>> + (char *const []) { (char *) prog, pid, NULL });
>> +
>> + support_capture_subprocess_check (&pldd, "pldd", 0, sc_allow_stdout);
>> + }
>> +
>> + /* Check 'pldd' output. The test is expected to be linked against only
>> + loader and libc. */
>> + {
>> + pid_t pid;
>> + char buffer[512];
>> +#define STRINPUT(size) "%" # size "s"
>> +
>> + FILE *out = fmemopen (pldd.out.buffer, pldd.out.length, "r");
>> + TEST_VERIFY (out != NULL);
>> +
>> + /* First line is in the form of <pid>: <full path of executable> */
>> + TEST_COMPARE (fscanf (out, "%u: " STRINPUT (512), &pid, buffer), 2);
>> +
>> + TEST_COMPARE (pid, target.pid);
>> + TEST_COMPARE (strcmp (basename (buffer), "tst-pldd"), 0);
>> +
>> + /* It expects only one loader and libc loaded by the program. */
>> + bool interpreter_found = false, libc_found = false;
>> + while (fgets (buffer, array_length (buffer), out) != NULL)
>> + {
>> + /* Ignore vDSO. */
>> + if (buffer[0] != '/')
>> + continue;
>> +
>> + /* Remove newline so baseline (buffer) can compare against the
>> + LD_SO and LIBC_SO macros unmodified. */
>> + if (buffer[strlen(buffer)-1] == '\n')
>> + buffer[strlen(buffer)-1] = '\0';
>> +
>> + if (strcmp (basename (buffer), LD_SO) == 0)
>> + {
>> + TEST_COMPARE (interpreter_found, false);
>> + interpreter_found = true;
>> + continue;
>> + }
>> +
>> + if (strcmp (basename (buffer), LIBC_SO) == 0)
>> + {
>> + TEST_COMPARE (libc_found, false);
>> + libc_found = true;
>> + continue;
>> + }
>> + }
>> + TEST_COMPARE (interpreter_found, true);
>> + TEST_COMPARE (libc_found, true);
>> +
>> + fclose (out);
>> + }
>> +
>> + support_capture_subprocess_free (&pldd);
>> + support_process_terminate (&target);
>> +
>> + return 0;
>> +}
>> +
>> +#include <support/test-driver.c>
>
> OK.
>
>> diff --git a/elf/tst-pldd.root/tst-pldd.script b/elf/tst-pldd.root/tst-pldd.script
>> new file mode 100644
>> index 0000000000..5a197b2ed0
>> --- /dev/null
>> +++ b/elf/tst-pldd.root/tst-pldd.script
>> @@ -0,0 +1 @@
>> +cp $B/elf/pldd $I/bin/pldd
>
> OK.
>
>> diff --git a/posix/tst-pldd.c b/posix/tst-pldd.c
>> new file mode 100644
>> index 0000000000..edff4b9d07
>> --- /dev/null
>> +++ b/posix/tst-pldd.c
>> @@ -0,0 +1,9 @@
>> +#include <unistd.h>
>> +#include <stdio.h>
>> +
>> +int main (int argc, char *argv[])
>> +{
>> + printf ("pid=%d\n", (int) getpid());
>> + pause ();
>> + return 0;
>> +}
>
> OK.
This is in fact an artifact that should not be on this patch, I will remove it.