[PATCH v3 2/2] elf: Add a test for PT_LOAD segments with mixed p_align
H.J. Lu
hjl.tools@gmail.com
Tue Dec 21 03:16:16 GMT 2021
Add tst-alignmod3-edit to edit the copy of tst-alignmod3.so to lower
p_align of the first PT_LOAD segment and verify that the shared library
is mapped with the maximum p_align of all PT_LOAD segments.
---
elf/Makefile | 18 ++++++
elf/tst-alignmod3-edit.c | 122 +++++++++++++++++++++++++++++++++++++++
elf/tst-p_align1.c | 27 +++++++++
3 files changed, 167 insertions(+)
create mode 100644 elf/tst-alignmod3-edit.c
create mode 100644 elf/tst-p_align1.c
diff --git a/elf/Makefile b/elf/Makefile
index fe42caeb0e..c3402c65b2 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -378,6 +378,13 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
tst-auditmod18 \
tst-audit18mod \
+ifeq (yesyes,$(build-shared)$(run-built-tests))
+tests += \
+ tst-alignmod3-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%,\
@@ -1995,3 +2002,14 @@ $(objpfx)tst-ro-dynamic-mod.so: $(objpfx)tst-ro-dynamic-mod.os \
$(objpfx)tst-ro-dynamic-mod.os
$(objpfx)tst-rtld-run-static.out: $(objpfx)/ldconfig
+
+$(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-alignmod3-edit \
+ $(objpfx)tst-alignmod3.so
+ rm -f $@
+ cp $(objpfx)tst-alignmod3.so $@
+ $(test-wrapper-env) $(run-program-env) $(rtld-prefix) \
+ $(objpfx)tst-alignmod3-edit $@
diff --git a/elf/tst-alignmod3-edit.c b/elf/tst-alignmod3-edit.c
new file mode 100644
index 0000000000..7b7eafbeec
--- /dev/null
+++ b/elf/tst-alignmod3-edit.c
@@ -0,0 +1,122 @@
+/* Lower 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 <link.h>
+#include <error.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+int
+main (int argc, char ** argv)
+{
+ if (argc != 2)
+ {
+ printf ("Usage: %s: file\n", argv[0]);
+ return 0;
+ }
+
+ const char *file_name = argv[1];
+ ElfW(Ehdr) ehdr;
+ struct stat statbuf;
+ int errno_saved;
+
+ if (stat (file_name, &statbuf) < 0)
+ error (1, errno, "%s: not exist \n", file_name);
+
+ if (statbuf.st_size < sizeof (ehdr))
+ error (1, 0, "%s: too small\n", file_name);
+
+ FILE *file = fopen (file_name, "r+b");
+ if (file == NULL)
+ error (1, 0, "%s: cann't open\n", file_name);
+
+ /* Read in the identity array. */
+ if (fread (&ehdr, sizeof (ehdr), 1, file) != 1)
+ {
+ errno_saved = errno;
+ fclose (file);
+ error (1, errno_saved,
+ "%s: can't read in ELF header\n", file_name);
+ }
+
+ 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)
+ {
+ fclose (file);
+ error (1, 0, "%s: bad ELF header\n", file_name);
+ }
+
+ if (ehdr.e_type != ET_DYN)
+ {
+ fclose (file);
+ error (1, 0, "%s: not shared library\n", file_name);
+ }
+
+ /* We only support 32 bit and 64 bit ELF files. */
+ switch (ehdr.e_ident[EI_CLASS])
+ {
+ default:
+ fclose (file);
+ error (1, 0, "%s: unsupported ELF class: %d\n",
+ file_name, ehdr.e_ident[EI_CLASS]);
+ break;
+
+ case ELFCLASS32:
+ case ELFCLASS64:
+ break;
+ }
+
+ size_t phdr_size = sizeof (ElfW(Phdr)) * ehdr.e_phentsize;
+ if (statbuf.st_size < (ehdr.e_phoff + phdr_size))
+ {
+ fclose (file);
+ error (1, 0, "%s: too small\n", file_name);
+ }
+
+ /* Map in ELF program header table. */
+ void *base = mmap (NULL, ehdr.e_phoff + phdr_size,
+ PROT_READ | PROT_WRITE, MAP_SHARED,
+ fileno (file), 0);
+ if (base == MAP_FAILED)
+ {
+ errno_saved = errno;
+ fclose (file);
+ error (1, errno_saved,
+ "%s: failed to map in program header table\n",
+ 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)
+ {
+ /* Reduce p_align of the first PT_LOAD segment by half. */
+ phdr->p_align = phdr->p_align >> 1;
+ break;
+ }
+
+ fclose (file);
+ munmap (base, phdr_size);
+
+ 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>
--
2.33.1
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