1206e22f0SChris Kennelly // SPDX-License-Identifier: GPL-2.0-only
2206e22f0SChris Kennelly #ifndef _GNU_SOURCE
3206e22f0SChris Kennelly #define _GNU_SOURCE
4206e22f0SChris Kennelly #endif
5206e22f0SChris Kennelly #include <link.h>
6206e22f0SChris Kennelly #include <stdio.h>
7206e22f0SChris Kennelly #include <stdlib.h>
8*b57a2907SKees Cook #include <stdbool.h>
9c4095067SMuhammad Usama Anjum #include "../kselftest.h"
10206e22f0SChris Kennelly
11206e22f0SChris Kennelly struct Statistics {
12206e22f0SChris Kennelly unsigned long long load_address;
13206e22f0SChris Kennelly unsigned long long alignment;
14*b57a2907SKees Cook bool interp;
15206e22f0SChris Kennelly };
16206e22f0SChris Kennelly
ExtractStatistics(struct dl_phdr_info * info,size_t size,void * data)17206e22f0SChris Kennelly int ExtractStatistics(struct dl_phdr_info *info, size_t size, void *data)
18206e22f0SChris Kennelly {
19206e22f0SChris Kennelly struct Statistics *stats = (struct Statistics *) data;
20206e22f0SChris Kennelly int i;
21206e22f0SChris Kennelly
22206e22f0SChris Kennelly if (info->dlpi_name != NULL && info->dlpi_name[0] != '\0') {
23206e22f0SChris Kennelly // Ignore headers from other than the executable.
24206e22f0SChris Kennelly return 2;
25206e22f0SChris Kennelly }
26206e22f0SChris Kennelly
27206e22f0SChris Kennelly stats->load_address = (unsigned long long) info->dlpi_addr;
28206e22f0SChris Kennelly stats->alignment = 0;
29206e22f0SChris Kennelly
30206e22f0SChris Kennelly for (i = 0; i < info->dlpi_phnum; i++) {
31*b57a2907SKees Cook unsigned long long align;
32*b57a2907SKees Cook
33*b57a2907SKees Cook if (info->dlpi_phdr[i].p_type == PT_INTERP) {
34*b57a2907SKees Cook stats->interp = true;
35*b57a2907SKees Cook continue;
36*b57a2907SKees Cook }
37*b57a2907SKees Cook
38206e22f0SChris Kennelly if (info->dlpi_phdr[i].p_type != PT_LOAD)
39206e22f0SChris Kennelly continue;
40206e22f0SChris Kennelly
41*b57a2907SKees Cook align = info->dlpi_phdr[i].p_align;
42*b57a2907SKees Cook
43*b57a2907SKees Cook if (align > stats->alignment)
44*b57a2907SKees Cook stats->alignment = align;
45206e22f0SChris Kennelly }
46206e22f0SChris Kennelly
47206e22f0SChris Kennelly return 1; // Terminate dl_iterate_phdr.
48206e22f0SChris Kennelly }
49206e22f0SChris Kennelly
main(int argc,char ** argv)50206e22f0SChris Kennelly int main(int argc, char **argv)
51206e22f0SChris Kennelly {
52*b57a2907SKees Cook struct Statistics extracted = { };
53*b57a2907SKees Cook unsigned long long misalign, pow2;
54*b57a2907SKees Cook bool interp_needed;
55*b57a2907SKees Cook char buf[1024];
56*b57a2907SKees Cook FILE *maps;
57206e22f0SChris Kennelly int ret;
58206e22f0SChris Kennelly
59c4095067SMuhammad Usama Anjum ksft_print_header();
60*b57a2907SKees Cook ksft_set_plan(4);
61206e22f0SChris Kennelly
62*b57a2907SKees Cook /* Dump maps file for debugging reference. */
63*b57a2907SKees Cook maps = fopen("/proc/self/maps", "r");
64*b57a2907SKees Cook if (!maps)
65*b57a2907SKees Cook ksft_exit_fail_msg("FAILED: /proc/self/maps: %s\n", strerror(errno));
66*b57a2907SKees Cook while (fgets(buf, sizeof(buf), maps)) {
67*b57a2907SKees Cook ksft_print_msg("%s", buf);
68*b57a2907SKees Cook }
69*b57a2907SKees Cook fclose(maps);
70*b57a2907SKees Cook
71*b57a2907SKees Cook /* Walk the program headers. */
72c4095067SMuhammad Usama Anjum ret = dl_iterate_phdr(ExtractStatistics, &extracted);
73c4095067SMuhammad Usama Anjum if (ret != 1)
74c4095067SMuhammad Usama Anjum ksft_exit_fail_msg("FAILED: dl_iterate_phdr\n");
75c4095067SMuhammad Usama Anjum
76*b57a2907SKees Cook /* Report our findings. */
77*b57a2907SKees Cook ksft_print_msg("load_address=%#llx alignment=%#llx\n",
78*b57a2907SKees Cook extracted.load_address, extracted.alignment);
79206e22f0SChris Kennelly
80*b57a2907SKees Cook /* If we're named with ".static." we expect no INTERP. */
81*b57a2907SKees Cook interp_needed = strstr(argv[0], ".static.") == NULL;
82*b57a2907SKees Cook
83*b57a2907SKees Cook /* Were we built as expected? */
84*b57a2907SKees Cook ksft_test_result(interp_needed == extracted.interp,
85*b57a2907SKees Cook "%s INTERP program header %s\n",
86*b57a2907SKees Cook interp_needed ? "Wanted" : "Unwanted",
87*b57a2907SKees Cook extracted.interp ? "seen" : "missing");
88*b57a2907SKees Cook
89*b57a2907SKees Cook /* Did we find an alignment? */
90*b57a2907SKees Cook ksft_test_result(extracted.alignment != 0,
91*b57a2907SKees Cook "Alignment%s found\n", extracted.alignment ? "" : " NOT");
92*b57a2907SKees Cook
93*b57a2907SKees Cook /* Is the alignment sane? */
94*b57a2907SKees Cook pow2 = extracted.alignment & (extracted.alignment - 1);
95*b57a2907SKees Cook ksft_test_result(pow2 == 0,
96*b57a2907SKees Cook "Alignment is%s a power of 2: %#llx\n",
97*b57a2907SKees Cook pow2 == 0 ? "" : " NOT", extracted.alignment);
98*b57a2907SKees Cook
99*b57a2907SKees Cook /* Is the load address aligned? */
100206e22f0SChris Kennelly misalign = extracted.load_address & (extracted.alignment - 1);
101*b57a2907SKees Cook ksft_test_result(misalign == 0, "Load Address is %saligned (%#llx)\n",
102*b57a2907SKees Cook misalign ? "MIS" : "", misalign);
103206e22f0SChris Kennelly
104c4095067SMuhammad Usama Anjum ksft_finished();
105206e22f0SChris Kennelly }
106