| Message ID | 20220103230433.1907240-3-hjl.tools@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | Properly align all PT_LOAD segments with tests | expand |
On 03/01/2022 20:04, H.J. Lu wrote: > Add tst-p_alignmod1-edit to edit the copy of tst-alignmod3.so to reduce > p_align of the first PT_LOAD segment by half and verify that the shared > library is mapped with the maximum p_align of all PT_LOAD segments. > --- > elf/Makefile | 18 ++++++ > elf/tst-elf-edit.h | 126 +++++++++++++++++++++++++++++++++++++ > elf/tst-p_align1.c | 27 ++++++++ > elf/tst-p_alignmod1-edit.c | 34 ++++++++++ > 4 files changed, 205 insertions(+) > create mode 100644 elf/tst-elf-edit.h > create mode 100644 elf/tst-p_align1.c > create mode 100644 elf/tst-p_alignmod1-edit.c > > diff --git a/elf/Makefile b/elf/Makefile > index 883578ee36..9c831faac1 100644 > --- a/elf/Makefile > +++ b/elf/Makefile > @@ -403,6 +403,13 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ > tst-dl_find_object-mod8 \ > tst-dl_find_object-mod9 \ > > +ifeq (yes,$(build-shared)) > +tests += \ > + tst-p_alignmod1-edit \ > + tst-p_align1 \ > + > +endif > + > # Most modules build with _ISOMAC defined, but those filtered out > # depend on internal headers. > modules-names-tests = $(filter-out ifuncmod% tst-tlsmod%,\ > @@ -2079,3 +2086,14 @@ CFLAGS-tst-dl_find_object-mod6.c += -funwind-tables > CFLAGS-tst-dl_find_object-mod7.c += -funwind-tables > CFLAGS-tst-dl_find_object-mod8.c += -funwind-tables > CFLAGS-tst-dl_find_object-mod9.c += -funwind-tables > + > +$(objpfx)tst-p_align1: $(objpfx)tst-p_alignmod1.so > + > +# Make a copy of tst-alignmod3.so and lower p_align of the first PT_LOAD > +# segment. > +$(objpfx)tst-p_alignmod1.so: $(objpfx)tst-p_alignmod1-edit \ > + $(objpfx)tst-alignmod3.so tst-alignmod3.so is only provided in the last patch, I think it would be better to move to this patch as tst-alignmod-base and it instead by copying and changing on each test. > + rm -f $@ > + cp $(objpfx)tst-alignmod3.so $@ > + $(test-wrapper-env) $(run-program-env) $(rtld-prefix) \ > + $(objpfx)tst-p_alignmod1-edit $@ > diff --git a/elf/tst-elf-edit.h b/elf/tst-elf-edit.h > new file mode 100644 > index 0000000000..ce98cf012c > --- /dev/null > +++ b/elf/tst-elf-edit.h > @@ -0,0 +1,126 @@ > +/* Update p_align of the first PT_LOAD segment. > + Copyright (C) 2021 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 <stdio.h> > +#include <stdbool.h> > +#include <unistd.h> > +#include <fcntl.h> > +#include <link.h> > +#include <error.h> > +#include <errno.h> > +#include <sys/stat.h> > +#include <sys/mman.h> > + > +const char *file_name; > + > +static size_t update_p_align (size_t); > + > +int > +main (int argc, char ** argv) > +{ > + if (argc != 2) > + { > + printf ("Usage: %s: file\n", argv[0]); > + return 0; > + } > + > + file_name = argv[1]; > + struct stat statbuf; > + int errno_saved; > + > + if (stat (file_name, &statbuf) < 0) > + error (1, errno, "%s: not exist", file_name); > + > + ElfW(Ehdr) *ehdr; > + > + if (statbuf.st_size < sizeof (*ehdr)) > + error (1, 0, "%s: too small", file_name); > + > + int fd = open (file_name, O_RDWR); > + if (fd < 0) > + error (1, errno, "%s: can't open", file_name); > + > + /* Map in the whole file. */ > + void *base = mmap (NULL, statbuf.st_size, PROT_READ | PROT_WRITE, > + MAP_SHARED, fd, 0); > + if (base == MAP_FAILED) > + { > + errno_saved = errno; > + close (fd); > + error (1, errno_saved, "%s: failed to map", file_name); > + } > + > + ehdr = (ElfW(Ehdr) *) base; > + if (ehdr->e_ident[EI_MAG0] != ELFMAG0 > + || ehdr->e_ident[EI_MAG1] != ELFMAG1 > + || ehdr->e_ident[EI_MAG2] != ELFMAG2 > + || ehdr->e_ident[EI_MAG3] != ELFMAG3) > + { > + close (fd); > + error (1, 0, "%s: bad ELF header", file_name); > + } > + > + if (ehdr->e_type != ET_DYN) > + { > + close (fd); > + error (1, 0, "%s: not shared library", file_name); > + } > + > + bool unsupported_class = true; > + switch (ehdr->e_ident[EI_CLASS]) > + { > + default: > + break; > + > + case ELFCLASS32: > + unsupported_class = __ELF_NATIVE_CLASS != 32; > + break; > + > + case ELFCLASS64: > + unsupported_class = __ELF_NATIVE_CLASS != 64; > + break; > + } > + > + if (unsupported_class) > + { > + close (fd); > + error (1, 0, "%s: unsupported ELF class: %d", > + file_name, ehdr->e_ident[EI_CLASS]); > + } > + > + size_t phdr_size = sizeof (ElfW(Phdr)) * ehdr->e_phentsize; > + if (statbuf.st_size < (ehdr->e_phoff + phdr_size)) > + { > + close (fd); > + error (1, 0, "%s: too small", file_name); > + } > + > + ElfW(Phdr) *phdr = (ElfW(Phdr) *) (base + ehdr->e_phoff); > + for (int i = 0; i < ehdr->e_phnum; i++, phdr++) > + if (phdr->p_type == PT_LOAD) > + { > + /* Update p_align of the first PT_LOAD segment. */ > + phdr->p_align = update_p_align (phdr->p_align); > + break; > + } > + > + munmap (base, statbuf.st_size); > + close (fd); > + > + return 0; > +} Look ok, although I think it would be simpler to build it once and use an argument of how to change the alignment instead of build once binary per test. I am not if it is worth to use libsupport here. > diff --git a/elf/tst-p_align1.c b/elf/tst-p_align1.c > new file mode 100644 > index 0000000000..cab9793220 > --- /dev/null > +++ b/elf/tst-p_align1.c > @@ -0,0 +1,27 @@ > +/* Check different alignments of PT_LOAD segments in a shared library. > + Copyright (C) 2021 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/>. */ > + > +extern int do_load_test (void); The do_load_test is defined as returning void on elf/tst-alignmod3.c, but it redefined here as returning 'int'. This is causing a failure on aarch64. Maybe it would better to move it to a proper header. > + > +static int > +do_test (void) > +{ > + return do_load_test (); > +} > + > +#include <support/test-driver.c> And I think 'is_aligned' from sysdeps/generic/tst-stack-align.h seems to have the inverted semantic that makes things confusing (elf/tst-alignmod3.c check if it is equal to 0 to actually check if pointer is aligned). Maybe it would be better to return bool and 'true' if the pointer is indeed aligned (similar to what IS_ALIGNED/PTR_IS_ALIGNED internal macros do). bool __attribute__ ((weak, noclone, noinline)) is_aligned (void *p, int align) { return (((uintptr_t) p) & (align - 1)) == 0; } > diff --git a/elf/tst-p_alignmod1-edit.c b/elf/tst-p_alignmod1-edit.c > new file mode 100644 > index 0000000000..2aa0e7ccdd > --- /dev/null > +++ b/elf/tst-p_alignmod1-edit.c > @@ -0,0 +1,34 @@ > +/* Reduce p_align of the first PT_LOAD segment by half. > + Copyright (C) 2021 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 "tst-elf-edit.h" > + > +/* Reduce p_align by half. */ > + > +static size_t > +update_p_align (size_t p_align) > +{ > + size_t pagesize = sysconf (_SC_PAGESIZE); > + size_t new_p_align = p_align >> 1; > + > + if (new_p_align < pagesize) > + error (1, 0, "%s: new p_align (0x%zx) < page size (0x%zx)", > + file_name, new_p_align, pagesize); > + > + return new_p_align; > +}
On Tue, Jan 18, 2022 at 8:26 AM Adhemerval Zanella <adhemerval.zanella@linaro.org> wrote: > > > > On 03/01/2022 20:04, H.J. Lu wrote: > > Add tst-p_alignmod1-edit to edit the copy of tst-alignmod3.so to reduce > > p_align of the first PT_LOAD segment by half and verify that the shared > > library is mapped with the maximum p_align of all PT_LOAD segments. > > --- > > elf/Makefile | 18 ++++++ > > elf/tst-elf-edit.h | 126 +++++++++++++++++++++++++++++++++++++ > > elf/tst-p_align1.c | 27 ++++++++ > > elf/tst-p_alignmod1-edit.c | 34 ++++++++++ > > 4 files changed, 205 insertions(+) > > create mode 100644 elf/tst-elf-edit.h > > create mode 100644 elf/tst-p_align1.c > > create mode 100644 elf/tst-p_alignmod1-edit.c > > > > diff --git a/elf/Makefile b/elf/Makefile > > index 883578ee36..9c831faac1 100644 > > --- a/elf/Makefile > > +++ b/elf/Makefile > > @@ -403,6 +403,13 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ > > tst-dl_find_object-mod8 \ > > tst-dl_find_object-mod9 \ > > > > +ifeq (yes,$(build-shared)) > > +tests += \ > > + tst-p_alignmod1-edit \ > > + tst-p_align1 \ > > + > > +endif > > + > > # Most modules build with _ISOMAC defined, but those filtered out > > # depend on internal headers. > > modules-names-tests = $(filter-out ifuncmod% tst-tlsmod%,\ > > @@ -2079,3 +2086,14 @@ CFLAGS-tst-dl_find_object-mod6.c += -funwind-tables > > CFLAGS-tst-dl_find_object-mod7.c += -funwind-tables > > CFLAGS-tst-dl_find_object-mod8.c += -funwind-tables > > CFLAGS-tst-dl_find_object-mod9.c += -funwind-tables > > + > > +$(objpfx)tst-p_align1: $(objpfx)tst-p_alignmod1.so > > + > > +# Make a copy of tst-alignmod3.so and lower p_align of the first PT_LOAD > > +# segment. > > +$(objpfx)tst-p_alignmod1.so: $(objpfx)tst-p_alignmod1-edit \ > > + $(objpfx)tst-alignmod3.so > > tst-alignmod3.so is only provided in the last patch, I think it would be better > to move to this patch as tst-alignmod-base, not and it instead by copying and changing > on each test. It is tst-alignmod3.so, not tst-p_alignmod3.so. In any case, I added tst-p_alignmod-base.so. > > + rm -f $@ > > + cp $(objpfx)tst-alignmod3.so $@ > > + $(test-wrapper-env) $(run-program-env) $(rtld-prefix) \ > > + $(objpfx)tst-p_alignmod1-edit $@ > > diff --git a/elf/tst-elf-edit.h b/elf/tst-elf-edit.h > > new file mode 100644 > > index 0000000000..ce98cf012c > > --- /dev/null > > +++ b/elf/tst-elf-edit.h > > @@ -0,0 +1,126 @@ > > +/* Update p_align of the first PT_LOAD segment. > > + Copyright (C) 2021 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 <stdio.h> > > +#include <stdbool.h> > > +#include <unistd.h> > > +#include <fcntl.h> > > +#include <link.h> > > +#include <error.h> > > +#include <errno.h> > > +#include <sys/stat.h> > > +#include <sys/mman.h> > > + > > +const char *file_name; > > + > > +static size_t update_p_align (size_t); > > + > > +int > > +main (int argc, char ** argv) > > +{ > > + if (argc != 2) > > + { > > + printf ("Usage: %s: file\n", argv[0]); > > + return 0; > > + } > > + > > + file_name = argv[1]; > > + struct stat statbuf; > > + int errno_saved; > > + > > + if (stat (file_name, &statbuf) < 0) > > + error (1, errno, "%s: not exist", file_name); > > + > > + ElfW(Ehdr) *ehdr; > > + > > + if (statbuf.st_size < sizeof (*ehdr)) > > + error (1, 0, "%s: too small", file_name); > > + > > + int fd = open (file_name, O_RDWR); > > + if (fd < 0) > > + error (1, errno, "%s: can't open", file_name); > > + > > + /* Map in the whole file. */ > > + void *base = mmap (NULL, statbuf.st_size, PROT_READ | PROT_WRITE, > > + MAP_SHARED, fd, 0); > > + if (base == MAP_FAILED) > > + { > > + errno_saved = errno; > > + close (fd); > > + error (1, errno_saved, "%s: failed to map", file_name); > > + } > > + > > + ehdr = (ElfW(Ehdr) *) base; > > + if (ehdr->e_ident[EI_MAG0] != ELFMAG0 > > + || ehdr->e_ident[EI_MAG1] != ELFMAG1 > > + || ehdr->e_ident[EI_MAG2] != ELFMAG2 > > + || ehdr->e_ident[EI_MAG3] != ELFMAG3) > > + { > > + close (fd); > > + error (1, 0, "%s: bad ELF header", file_name); > > + } > > + > > + if (ehdr->e_type != ET_DYN) > > + { > > + close (fd); > > + error (1, 0, "%s: not shared library", file_name); > > + } > > + > > + bool unsupported_class = true; > > + switch (ehdr->e_ident[EI_CLASS]) > > + { > > + default: > > + break; > > + > > + case ELFCLASS32: > > + unsupported_class = __ELF_NATIVE_CLASS != 32; > > + break; > > + > > + case ELFCLASS64: > > + unsupported_class = __ELF_NATIVE_CLASS != 64; > > + break; > > + } > > + > > + if (unsupported_class) > > + { > > + close (fd); > > + error (1, 0, "%s: unsupported ELF class: %d", > > + file_name, ehdr->e_ident[EI_CLASS]); > > + } > > + > > + size_t phdr_size = sizeof (ElfW(Phdr)) * ehdr->e_phentsize; > > + if (statbuf.st_size < (ehdr->e_phoff + phdr_size)) > > + { > > + close (fd); > > + error (1, 0, "%s: too small", file_name); > > + } > > + > > + ElfW(Phdr) *phdr = (ElfW(Phdr) *) (base + ehdr->e_phoff); > > + for (int i = 0; i < ehdr->e_phnum; i++, phdr++) > > + if (phdr->p_type == PT_LOAD) > > + { > > + /* Update p_align of the first PT_LOAD segment. */ > > + phdr->p_align = update_p_align (phdr->p_align); > > + break; > > + } > > + > > + munmap (base, statbuf.st_size); > > + close (fd); > > + > > + return 0; > > +} > > Look ok, although I think it would be simpler to build it once and use an > argument of how to change the alignment instead of build once binary > per test. I am not if it is worth to use libsupport here. This can be more flexible than an argument. I prefer to keep it ASIS. > > diff --git a/elf/tst-p_align1.c b/elf/tst-p_align1.c > > new file mode 100644 > > index 0000000000..cab9793220 > > --- /dev/null > > +++ b/elf/tst-p_align1.c > > @@ -0,0 +1,27 @@ > > +/* Check different alignments of PT_LOAD segments in a shared library. > > + Copyright (C) 2021 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/>. */ > > + > > +extern int do_load_test (void); > > The do_load_test is defined as returning void on elf/tst-alignmod3.c, > but it redefined here as returning 'int'. This is causing a failure > on aarch64. > > Maybe it would better to move it to a proper header. Done. > > + > > +static int > > +do_test (void) > > +{ > > + return do_load_test (); > > +} > > + > > +#include <support/test-driver.c> > > And I think 'is_aligned' from sysdeps/generic/tst-stack-align.h > seems to have the inverted semantic that makes things confusing > (elf/tst-alignmod3.c check if it is equal to 0 to actually check > if pointer is aligned). > > Maybe it would be better to return bool and 'true' if the pointer > is indeed aligned (similar to what IS_ALIGNED/PTR_IS_ALIGNED > internal macros do). Fixed. > bool > __attribute__ ((weak, noclone, noinline)) > is_aligned (void *p, int align) > { > return (((uintptr_t) p) & (align - 1)) == 0; > } > > > diff --git a/elf/tst-p_alignmod1-edit.c b/elf/tst-p_alignmod1-edit.c > > new file mode 100644 > > index 0000000000..2aa0e7ccdd > > --- /dev/null > > +++ b/elf/tst-p_alignmod1-edit.c > > @@ -0,0 +1,34 @@ > > +/* Reduce p_align of the first PT_LOAD segment by half. > > + Copyright (C) 2021 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 "tst-elf-edit.h" > > + > > +/* Reduce p_align by half. */ > > + > > +static size_t > > +update_p_align (size_t p_align) > > +{ > > + size_t pagesize = sysconf (_SC_PAGESIZE); > > + size_t new_p_align = p_align >> 1; > > + > > + if (new_p_align < pagesize) > > + error (1, 0, "%s: new p_align (0x%zx) < page size (0x%zx)", > > + file_name, new_p_align, pagesize); > > + > > + return new_p_align; > > +} Thanks.
diff --git a/elf/Makefile b/elf/Makefile index 883578ee36..9c831faac1 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -403,6 +403,13 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \ tst-dl_find_object-mod8 \ tst-dl_find_object-mod9 \ +ifeq (yes,$(build-shared)) +tests += \ + tst-p_alignmod1-edit \ + tst-p_align1 \ + +endif + # Most modules build with _ISOMAC defined, but those filtered out # depend on internal headers. modules-names-tests = $(filter-out ifuncmod% tst-tlsmod%,\ @@ -2079,3 +2086,14 @@ CFLAGS-tst-dl_find_object-mod6.c += -funwind-tables CFLAGS-tst-dl_find_object-mod7.c += -funwind-tables CFLAGS-tst-dl_find_object-mod8.c += -funwind-tables CFLAGS-tst-dl_find_object-mod9.c += -funwind-tables + +$(objpfx)tst-p_align1: $(objpfx)tst-p_alignmod1.so + +# Make a copy of tst-alignmod3.so and lower p_align of the first PT_LOAD +# segment. +$(objpfx)tst-p_alignmod1.so: $(objpfx)tst-p_alignmod1-edit \ + $(objpfx)tst-alignmod3.so + rm -f $@ + cp $(objpfx)tst-alignmod3.so $@ + $(test-wrapper-env) $(run-program-env) $(rtld-prefix) \ + $(objpfx)tst-p_alignmod1-edit $@ diff --git a/elf/tst-elf-edit.h b/elf/tst-elf-edit.h new file mode 100644 index 0000000000..ce98cf012c --- /dev/null +++ b/elf/tst-elf-edit.h @@ -0,0 +1,126 @@ +/* Update p_align of the first PT_LOAD segment. + Copyright (C) 2021 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 <stdio.h> +#include <stdbool.h> +#include <unistd.h> +#include <fcntl.h> +#include <link.h> +#include <error.h> +#include <errno.h> +#include <sys/stat.h> +#include <sys/mman.h> + +const char *file_name; + +static size_t update_p_align (size_t); + +int +main (int argc, char ** argv) +{ + if (argc != 2) + { + printf ("Usage: %s: file\n", argv[0]); + return 0; + } + + file_name = argv[1]; + struct stat statbuf; + int errno_saved; + + if (stat (file_name, &statbuf) < 0) + error (1, errno, "%s: not exist", file_name); + + ElfW(Ehdr) *ehdr; + + if (statbuf.st_size < sizeof (*ehdr)) + error (1, 0, "%s: too small", file_name); + + int fd = open (file_name, O_RDWR); + if (fd < 0) + error (1, errno, "%s: can't open", file_name); + + /* Map in the whole file. */ + void *base = mmap (NULL, statbuf.st_size, PROT_READ | PROT_WRITE, + MAP_SHARED, fd, 0); + if (base == MAP_FAILED) + { + errno_saved = errno; + close (fd); + error (1, errno_saved, "%s: failed to map", file_name); + } + + ehdr = (ElfW(Ehdr) *) base; + if (ehdr->e_ident[EI_MAG0] != ELFMAG0 + || ehdr->e_ident[EI_MAG1] != ELFMAG1 + || ehdr->e_ident[EI_MAG2] != ELFMAG2 + || ehdr->e_ident[EI_MAG3] != ELFMAG3) + { + close (fd); + error (1, 0, "%s: bad ELF header", file_name); + } + + if (ehdr->e_type != ET_DYN) + { + close (fd); + error (1, 0, "%s: not shared library", file_name); + } + + bool unsupported_class = true; + switch (ehdr->e_ident[EI_CLASS]) + { + default: + break; + + case ELFCLASS32: + unsupported_class = __ELF_NATIVE_CLASS != 32; + break; + + case ELFCLASS64: + unsupported_class = __ELF_NATIVE_CLASS != 64; + break; + } + + if (unsupported_class) + { + close (fd); + error (1, 0, "%s: unsupported ELF class: %d", + file_name, ehdr->e_ident[EI_CLASS]); + } + + size_t phdr_size = sizeof (ElfW(Phdr)) * ehdr->e_phentsize; + if (statbuf.st_size < (ehdr->e_phoff + phdr_size)) + { + close (fd); + error (1, 0, "%s: too small", file_name); + } + + ElfW(Phdr) *phdr = (ElfW(Phdr) *) (base + ehdr->e_phoff); + for (int i = 0; i < ehdr->e_phnum; i++, phdr++) + if (phdr->p_type == PT_LOAD) + { + /* Update p_align of the first PT_LOAD segment. */ + phdr->p_align = update_p_align (phdr->p_align); + break; + } + + munmap (base, statbuf.st_size); + close (fd); + + return 0; +} diff --git a/elf/tst-p_align1.c b/elf/tst-p_align1.c new file mode 100644 index 0000000000..cab9793220 --- /dev/null +++ b/elf/tst-p_align1.c @@ -0,0 +1,27 @@ +/* Check different alignments of PT_LOAD segments in a shared library. + Copyright (C) 2021 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/>. */ + +extern int do_load_test (void); + +static int +do_test (void) +{ + return do_load_test (); +} + +#include <support/test-driver.c> diff --git a/elf/tst-p_alignmod1-edit.c b/elf/tst-p_alignmod1-edit.c new file mode 100644 index 0000000000..2aa0e7ccdd --- /dev/null +++ b/elf/tst-p_alignmod1-edit.c @@ -0,0 +1,34 @@ +/* Reduce p_align of the first PT_LOAD segment by half. + Copyright (C) 2021 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 "tst-elf-edit.h" + +/* Reduce p_align by half. */ + +static size_t +update_p_align (size_t p_align) +{ + size_t pagesize = sysconf (_SC_PAGESIZE); + size_t new_p_align = p_align >> 1; + + if (new_p_align < pagesize) + error (1, 0, "%s: new p_align (0x%zx) < page size (0x%zx)", + file_name, new_p_align, pagesize); + + return new_p_align; +}