diff options
| -rw-r--r-- | dlfcn/Makefile | 4 | ||||
| -rw-r--r-- | dlfcn/dlfcn.h | 7 | ||||
| -rw-r--r-- | dlfcn/dlinfo.c | 13 | ||||
| -rw-r--r-- | dlfcn/tst-dlinfo-phdr.c | 125 | ||||
| -rw-r--r-- | manual/dynlink.texi | 15 |
5 files changed, 159 insertions, 5 deletions
diff --git a/dlfcn/Makefile b/dlfcn/Makefile index 6e0a014d99..3255ba02c5 100644 --- a/dlfcn/Makefile +++ b/dlfcn/Makefile @@ -73,6 +73,10 @@ tststatic3-ENV = $(tststatic-ENV) tststatic4-ENV = $(tststatic-ENV) tststatic5-ENV = $(tststatic-ENV) +tests-internal += \ + tst-dlinfo-phdr \ + # tests-internal + ifneq (,$(CXX)) modules-names += bug-atexit3-lib else diff --git a/dlfcn/dlfcn.h b/dlfcn/dlfcn.h index b5cd5c5238..a3af6051d4 100644 --- a/dlfcn/dlfcn.h +++ b/dlfcn/dlfcn.h @@ -164,7 +164,12 @@ enum segment, or if the calling thread has not allocated a block for it. */ RTLD_DI_TLS_DATA = 10, - RTLD_DI_MAX = 10 + /* Treat ARG as const ElfW(Phdr) **, and store the address of the + program header array at that location. The dlinfo call returns + the number of program headers in the array. */ + RTLD_DI_PHDR = 11, + + RTLD_DI_MAX = 11 }; diff --git a/dlfcn/dlinfo.c b/dlfcn/dlinfo.c index 068db5260c..0fbe670d67 100644 --- a/dlfcn/dlinfo.c +++ b/dlfcn/dlinfo.c @@ -28,6 +28,10 @@ struct dlinfo_args void *handle; int request; void *arg; + + /* This is the value that is returned from dlinfo if no error is + signaled. */ + int result; }; static void @@ -40,6 +44,7 @@ dlinfo_doit (void *argsblock) { case RTLD_DI_CONFIGADDR: default: + args->result = -1; _dl_signal_error (0, NULL, NULL, N_("unsupported dlinfo request")); break; @@ -75,6 +80,11 @@ dlinfo_doit (void *argsblock) *(void **) args->arg = data; break; } + + case RTLD_DI_PHDR: + *(const ElfW(Phdr) **) args->arg = l->l_phdr; + args->result = l->l_phnum; + break; } } @@ -82,7 +92,8 @@ static int dlinfo_implementation (void *handle, int request, void *arg) { struct dlinfo_args args = { handle, request, arg }; - return _dlerror_run (&dlinfo_doit, &args) ? -1 : 0; + _dlerror_run (&dlinfo_doit, &args); + return args.result; } #ifdef SHARED diff --git a/dlfcn/tst-dlinfo-phdr.c b/dlfcn/tst-dlinfo-phdr.c new file mode 100644 index 0000000000..a15a7d48eb --- /dev/null +++ b/dlfcn/tst-dlinfo-phdr.c @@ -0,0 +1,125 @@ +/* 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> diff --git a/manual/dynlink.texi b/manual/dynlink.texi index bc3b779b69..6a4a50d3f0 100644 --- a/manual/dynlink.texi +++ b/manual/dynlink.texi @@ -30,9 +30,9 @@ location @var{arg}, based on @var{request}. The @var{handle} argument must be a pointer returned by @code{dlopen} or @code{dlmopen}; it must not have been closed by @code{dlclose}. -On success, @code{dlinfo} returns 0. If there is an error, the function -returns @math{-1}, and @code{dlerror} can be used to obtain a -corresponding error message. +On success, @code{dlinfo} returns 0 for most request types; exceptions +are noted below. If there is an error, the function returns @math{-1}, +and @code{dlerror} can be used to obtain a corresponding error message. The following operations are defined for use with @var{request}: @@ -84,6 +84,15 @@ This request writes the TLS module ID for the shared object @var{handle} to @code{*@var{arg}}. The argument @var{arg} must be the address of an object of type @code{size_t}. The module ID is zero if the object does not have an associated TLS block. + +@item RTLD_DI_PHDR +This request writes the address of the program header array to +@code{*@var{arg}}. The argument @var{arg} must be the address of an +object of type @code{const ElfW(Phdr) *} (that is, +@code{const Elf32_Phdr *} or @code{const Elf64_Phdr *}, as appropriate +for the current architecture). For this request, the value returned by +@code{dlinfo} is the number of program headers in the program header +array. @end vtable The @code{dlinfo} function is a GNU extension. |