Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
493 | 99.80% | 3 | 75.00% | |
1 | 0.20% | 1 | 25.00% | |
Total | 494 | 4 |
Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Benjamin Gray | 493 | 99.80% | 3 | 75.00% |
Colin Ian King | 1 | 0.20% | 1 | 25.00% |
Total | 494 | 4 |
// SPDX-License-Identifier: GPL-2.0-or-later #include <errno.h> #include <stddef.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/prctl.h> #include "dexcr.h" #include "utils.h" static void die(const char *msg) { printf("%s\n", msg); exit(1); } static void help(void) { printf("Invoke a provided program with a custom DEXCR on-exec reset value\n" "\n" "usage: chdexcr [CHDEXCR OPTIONS] -- PROGRAM [ARGS...]\n" "\n" "Each configurable DEXCR aspect is exposed as an option.\n" "\n" "The normal option sets the aspect in the DEXCR. The --no- variant\n" "clears that aspect. For example, --ibrtpd sets the IBRTPD aspect bit,\n" "so indirect branch prediction will be disabled in the provided program.\n" "Conversely, --no-ibrtpd clears the aspect bit, so indirect branch\n" "prediction may occur.\n" "\n" "CHDEXCR OPTIONS:\n"); for (int i = 0; i < ARRAY_SIZE(aspects); i++) { const struct dexcr_aspect *aspect = &aspects[i]; if (aspect->prctl == -1) continue; printf(" --%-6s / --no-%-6s : %s\n", aspect->opt, aspect->opt, aspect->desc); } } static const struct dexcr_aspect *opt_to_aspect(const char *opt) { for (int i = 0; i < ARRAY_SIZE(aspects); i++) if (aspects[i].prctl != -1 && !strcmp(aspects[i].opt, opt)) return &aspects[i]; return NULL; } static int apply_option(const char *option) { const struct dexcr_aspect *aspect; const char *opt = NULL; const char *set_prefix = "--"; const char *clear_prefix = "--no-"; unsigned long ctrl = 0; int err; if (!strcmp(option, "-h") || !strcmp(option, "--help")) { help(); exit(0); } /* Strip out --(no-) prefix and determine ctrl value */ if (!strncmp(option, clear_prefix, strlen(clear_prefix))) { opt = &option[strlen(clear_prefix)]; ctrl |= PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC; } else if (!strncmp(option, set_prefix, strlen(set_prefix))) { opt = &option[strlen(set_prefix)]; ctrl |= PR_PPC_DEXCR_CTRL_SET_ONEXEC; } if (!opt || !*opt) return 1; aspect = opt_to_aspect(opt); if (!aspect) die("unknown aspect"); err = pr_set_dexcr(aspect->prctl, ctrl); if (err) die("failed to apply option"); return 0; } int main(int argc, char *const argv[]) { int i; if (!dexcr_exists()) die("DEXCR not detected on this hardware"); for (i = 1; i < argc; i++) if (apply_option(argv[i])) break; if (i < argc && !strcmp(argv[i], "--")) i++; if (i >= argc) die("missing command"); execvp(argv[i], &argv[i]); perror("execve"); return errno; }