diff options
Diffstat (limited to 'libexec/ld.elf_so/h_r_rel.c')
| -rw-r--r-- | libexec/ld.elf_so/h_r_rel.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/libexec/ld.elf_so/h_r_rel.c b/libexec/ld.elf_so/h_r_rel.c new file mode 100644 index 000000000000..17cece208ebe --- /dev/null +++ b/libexec/ld.elf_so/h_r_rel.c @@ -0,0 +1,147 @@ +/* $NetBSD: h_r_rel.c,v 1.2 2025/12/21 19:08:09 riastradh Exp $ */ + +/*- + * Copyright (c) 2025 The NetBSD Foundation, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS + * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED + * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS + * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__RCSID("$NetBSD: h_r_rel.c,v 1.2 2025/12/21 19:08:09 riastradh Exp $"); + +#include <stddef.h> +#include <stdio.h> + +/* + * When built as position-independent executable, the value of foop and + * foopp should be computed either via R_*_RELATIVE or R_*_REL32 or + * similar, which -- ports that support it -- may be compressed into a + * SHT_RELR section. + * + * One pointer indirection is enough to produce this effect, but we use + * two pointer indirections to increase the probability of a crash in + * case the relocations are done wrong. + */ +static int foo = 0x5f4d7635; +static int *volatile foop = &foo; +static int *volatile *volatile foopp = &foop; + +/* + * The RELR section compresses relocations for adjacent addresses into + * bitmaps of 31 or 63 bits apiece. Create a bunch of consecutive + * addresses to relocate, punctuated by the occasional non-relocated + * address (null), to check for fencepost errors in the bitmap + * iteration. + */ +static int bar[] = { + 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, + 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, + 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, + 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, + 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, + 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, + 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, + 0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f, + 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, + 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, + 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, + 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, + 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, + 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, + 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, + 0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, +}; + +static int *volatile barp[] = { + &bar[0x00], &bar[0x01], &bar[0x02], &bar[0x03], + &bar[0x04], &bar[0x05], &bar[0x06], &bar[0x07], + &bar[0x08], &bar[0x09], &bar[0x0a], &bar[0x0b], + &bar[0x0c], &bar[0x0d], &bar[0x0e], &bar[0x0f], + &bar[0x10], &bar[0x11], &bar[0x12], &bar[0x13], + &bar[0x14], &bar[0x15], &bar[0x16], &bar[0x17], + &bar[0x18], &bar[0x19], &bar[0x1a], &bar[0x1b], + &bar[0x1c], &bar[0x1d], &bar[0x1e], &bar[0x1f], + &bar[0x20], &bar[0x21], &bar[0x22], &bar[0x23], + &bar[0x24], &bar[0x25], &bar[0x26], &bar[0x27], + &bar[0x28], &bar[0x29], &bar[0x2a], &bar[0x2b], + &bar[0x2c], &bar[0x2d], &bar[0x2e], &bar[0x2f], + &bar[0x30], &bar[0x31], &bar[0x32], &bar[0x33], + &bar[0x34], &bar[0x35], &bar[0x36], &bar[0x37], + &bar[0x38], &bar[0x39], &bar[0x3a], &bar[0x3b], + &bar[0x3c], &bar[0x3d], &bar[0x3e], &bar[0x3f], + NULL, &bar[0x41], &bar[0x42], &bar[0x43], /* test a clear bit */ + &bar[0x44], &bar[0x45], &bar[0x46], &bar[0x47], + &bar[0x48], &bar[0x49], &bar[0x4a], &bar[0x4b], + &bar[0x4c], &bar[0x4d], &bar[0x4e], &bar[0x4f], + &bar[0x50], &bar[0x51], &bar[0x52], &bar[0x53], + &bar[0x54], &bar[0x55], &bar[0x56], &bar[0x57], + &bar[0x58], &bar[0x59], &bar[0x5a], &bar[0x5b], + &bar[0x5c], &bar[0x5d], &bar[0x5e], &bar[0x5f], + &bar[0x60], &bar[0x61], &bar[0x62], &bar[0x63], + &bar[0x64], &bar[0x65], &bar[0x66], &bar[0x67], + &bar[0x68], &bar[0x69], &bar[0x6a], &bar[0x6b], + &bar[0x6c], &bar[0x6d], &bar[0x6e], &bar[0x6f], + &bar[0x70], &bar[0x71], &bar[0x72], &bar[0x73], + &bar[0x74], &bar[0x75], &bar[0x76], &bar[0x77], + &bar[0x78], &bar[0x79], &bar[0x7a], &bar[0x7b], + &bar[0x7c], &bar[0x7d], &bar[0x7e], &bar[0x7f], + NULL, /* confirm we stop at the end */ +}; + +static int baz = -0x1adbd477; +static int *volatile bazp = &baz; + +int +main(void) +{ + int i, result = 0; + + if (**foopp != 0x5f4d7635) { + fprintf(stderr, "foo @ %p, foop = %p, *foop = %p," + " **foopp = 0x%x\n", + &foo, foop, *foopp, **foopp); + result |= 1; + } + for (i = 0; i < (int)__arraycount(barp); i++) { + if (i == 0x40 || i == 0x80) { + if (barp[i] != NULL) { + fprintf(stderr, "barp[%u] = %p\n", + i, barp[i]); + } + } else { + if (*barp[i] != i) { + fprintf(stderr, "bar[%u] @ %p, barp[%u] = %p," + " *barp[%u] = %u\n", + i, &bar[i], i, barp[i], i, *barp[i]); + result |= 1; + } + } + } + if (*bazp != -0x1adbd477) { + fprintf(stderr, "baz @ %p, bazp = %p, *bazp = 0x%x\n", + &baz, bazp, *bazp); + result |= 1; + } + + return result; +} |