106 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2#ifndef _GNU_SOURCE3#define _GNU_SOURCE4#endif5#include <link.h>6#include <stdio.h>7#include <stdlib.h>8#include <stdbool.h>9#include "../kselftest.h"10 11struct Statistics {12 unsigned long long load_address;13 unsigned long long alignment;14 bool interp;15};16 17int ExtractStatistics(struct dl_phdr_info *info, size_t size, void *data)18{19 struct Statistics *stats = (struct Statistics *) data;20 int i;21 22 if (info->dlpi_name != NULL && info->dlpi_name[0] != '\0') {23 // Ignore headers from other than the executable.24 return 2;25 }26 27 stats->load_address = (unsigned long long) info->dlpi_addr;28 stats->alignment = 0;29 30 for (i = 0; i < info->dlpi_phnum; i++) {31 unsigned long long align;32 33 if (info->dlpi_phdr[i].p_type == PT_INTERP) {34 stats->interp = true;35 continue;36 }37 38 if (info->dlpi_phdr[i].p_type != PT_LOAD)39 continue;40 41 align = info->dlpi_phdr[i].p_align;42 43 if (align > stats->alignment)44 stats->alignment = align;45 }46 47 return 1; // Terminate dl_iterate_phdr.48}49 50int main(int argc, char **argv)51{52 struct Statistics extracted = { };53 unsigned long long misalign, pow2;54 bool interp_needed;55 char buf[1024];56 FILE *maps;57 int ret;58 59 ksft_print_header();60 ksft_set_plan(4);61 62 /* Dump maps file for debugging reference. */63 maps = fopen("/proc/self/maps", "r");64 if (!maps)65 ksft_exit_fail_msg("FAILED: /proc/self/maps: %s\n", strerror(errno));66 while (fgets(buf, sizeof(buf), maps)) {67 ksft_print_msg("%s", buf);68 }69 fclose(maps);70 71 /* Walk the program headers. */72 ret = dl_iterate_phdr(ExtractStatistics, &extracted);73 if (ret != 1)74 ksft_exit_fail_msg("FAILED: dl_iterate_phdr\n");75 76 /* Report our findings. */77 ksft_print_msg("load_address=%#llx alignment=%#llx\n",78 extracted.load_address, extracted.alignment);79 80 /* If we're named with ".static." we expect no INTERP. */81 interp_needed = strstr(argv[0], ".static.") == NULL;82 83 /* Were we built as expected? */84 ksft_test_result(interp_needed == extracted.interp,85 "%s INTERP program header %s\n",86 interp_needed ? "Wanted" : "Unwanted",87 extracted.interp ? "seen" : "missing");88 89 /* Did we find an alignment? */90 ksft_test_result(extracted.alignment != 0,91 "Alignment%s found\n", extracted.alignment ? "" : " NOT");92 93 /* Is the alignment sane? */94 pow2 = extracted.alignment & (extracted.alignment - 1);95 ksft_test_result(pow2 == 0,96 "Alignment is%s a power of 2: %#llx\n",97 pow2 == 0 ? "" : " NOT", extracted.alignment);98 99 /* Is the load address aligned? */100 misalign = extracted.load_address & (extracted.alignment - 1);101 ksft_test_result(misalign == 0, "Load Address is %saligned (%#llx)\n",102 misalign ? "MIS" : "", misalign);103 104 ksft_finished();105}106