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-rw-r--r--src/binfmt/binfmt.c264
-rw-r--r--src/binfmt/meson.build17
2 files changed, 281 insertions, 0 deletions
diff --git a/src/binfmt/binfmt.c b/src/binfmt/binfmt.c
new file mode 100644
index 0000000..d21f3f7
--- /dev/null
+++ b/src/binfmt/binfmt.c
@@ -0,0 +1,264 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <getopt.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "alloc-util.h"
+#include "binfmt-util.h"
+#include "build.h"
+#include "conf-files.h"
+#include "constants.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "log.h"
+#include "main-func.h"
+#include "pager.h"
+#include "path-util.h"
+#include "pretty-print.h"
+#include "string-util.h"
+#include "strv.h"
+
+static CatFlags arg_cat_flags = CAT_CONFIG_OFF;
+static PagerFlags arg_pager_flags = 0;
+static bool arg_unregister = false;
+
+static int delete_rule(const char *rulename) {
+ const char *fn = strjoina("/proc/sys/fs/binfmt_misc/", rulename);
+ return write_string_file(fn, "-1", WRITE_STRING_FILE_DISABLE_BUFFER);
+}
+
+static int apply_rule(const char *filename, unsigned line, const char *rule) {
+ assert(filename);
+ assert(line > 0);
+ assert(rule);
+ assert(rule[0]);
+
+ _cleanup_free_ char *rulename = NULL;
+ int r;
+
+ rulename = strdupcspn(rule + 1, CHAR_TO_STR(rule[0]));
+ if (!rulename)
+ return log_oom();
+
+ if (!filename_is_valid(rulename) ||
+ STR_IN_SET(rulename, "register", "status"))
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "%s:%u: Rule name '%s' is not valid, refusing.",
+ filename, line, rulename);
+ r = delete_rule(rulename);
+ if (r < 0 && r != -ENOENT)
+ log_warning_errno(r, "%s:%u: Failed to delete rule '%s', ignoring: %m",
+ filename, line, rulename);
+ if (r >= 0)
+ log_debug("%s:%u: Rule '%s' deleted.", filename, line, rulename);
+
+ r = write_string_file("/proc/sys/fs/binfmt_misc/register", rule, WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ return log_error_errno(r, "%s:%u: Failed to add binary format '%s': %m",
+ filename, line, rulename);
+
+ log_debug("%s:%u: Binary format '%s' registered.", filename, line, rulename);
+ return 0;
+}
+
+static int apply_file(const char *filename, bool ignore_enoent) {
+ _cleanup_fclose_ FILE *f = NULL;
+ _cleanup_free_ char *pp = NULL;
+ int r;
+
+ assert(filename);
+
+ r = search_and_fopen(filename, "re", NULL, (const char**) CONF_PATHS_STRV("binfmt.d"), &f, &pp);
+ if (r < 0) {
+ if (ignore_enoent && r == -ENOENT)
+ return 0;
+
+ return log_error_errno(r, "Failed to open file '%s': %m", filename);
+ }
+
+ log_debug("Applying %s%s", pp, special_glyph(SPECIAL_GLYPH_ELLIPSIS));
+ for (unsigned line = 1;; line++) {
+ _cleanup_free_ char *text = NULL;
+ int k;
+
+ k = read_stripped_line(f, LONG_LINE_MAX, &text);
+ if (k < 0)
+ return log_error_errno(k, "Failed to read file '%s': %m", pp);
+ if (k == 0)
+ break;
+
+ if (isempty(text))
+ continue;
+ if (strchr(COMMENTS, text[0]))
+ continue;
+
+ RET_GATHER(r, apply_rule(filename, line, text));
+ }
+
+ return r;
+}
+
+static int cat_config(char **files) {
+ pager_open(arg_pager_flags);
+
+ return cat_files(NULL, files, arg_cat_flags);
+}
+
+static int help(void) {
+ _cleanup_free_ char *link = NULL;
+ int r;
+
+ r = terminal_urlify_man("systemd-binfmt.service", "8", &link);
+ if (r < 0)
+ return log_oom();
+
+ printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
+ "Registers binary formats with the kernel.\n\n"
+ " -h --help Show this help\n"
+ " --version Show package version\n"
+ " --cat-config Show configuration files\n"
+ " --tldr Show non-comment parts of configuration\n"
+ " --no-pager Do not pipe output into a pager\n"
+ " --unregister Unregister all existing entries\n"
+ "\nSee the %s for details.\n",
+ program_invocation_short_name,
+ link);
+
+ return 0;
+}
+
+static int parse_argv(int argc, char *argv[]) {
+ enum {
+ ARG_VERSION = 0x100,
+ ARG_CAT_CONFIG,
+ ARG_TLDR,
+ ARG_NO_PAGER,
+ ARG_UNREGISTER,
+ };
+
+ static const struct option options[] = {
+ { "help", no_argument, NULL, 'h' },
+ { "version", no_argument, NULL, ARG_VERSION },
+ { "cat-config", no_argument, NULL, ARG_CAT_CONFIG },
+ { "tldr", no_argument, NULL, ARG_TLDR },
+ { "no-pager", no_argument, NULL, ARG_NO_PAGER },
+ { "unregister", no_argument, NULL, ARG_UNREGISTER },
+ {}
+ };
+
+ int c;
+
+ assert(argc >= 0);
+ assert(argv);
+
+ while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
+
+ switch (c) {
+
+ case 'h':
+ return help();
+
+ case ARG_VERSION:
+ return version();
+
+ case ARG_CAT_CONFIG:
+ arg_cat_flags = CAT_CONFIG_ON;
+ break;
+
+ case ARG_TLDR:
+ arg_cat_flags = CAT_TLDR;
+ break;
+
+ case ARG_NO_PAGER:
+ arg_pager_flags |= PAGER_DISABLE;
+ break;
+
+ case ARG_UNREGISTER:
+ arg_unregister = true;
+ break;
+
+ case '?':
+ return -EINVAL;
+
+ default:
+ assert_not_reached();
+ }
+
+ if ((arg_unregister || arg_cat_flags != CAT_CONFIG_OFF) && argc > optind)
+ return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
+ "Positional arguments are not allowed with --cat-config/--tldr or --unregister.");
+
+ return 1;
+}
+
+static int binfmt_mounted_warn(void) {
+ int r;
+
+ r = binfmt_mounted();
+ if (r < 0)
+ return log_error_errno(r, "Failed to check if /proc/sys/fs/binfmt_misc is mounted: %m");
+ if (r == 0)
+ log_debug("/proc/sys/fs/binfmt_misc is not mounted in read-write mode, skipping.");
+
+ return r;
+}
+
+static int run(int argc, char *argv[]) {
+ int r;
+
+ r = parse_argv(argc, argv);
+ if (r <= 0)
+ return r;
+
+ log_setup();
+
+ umask(0022);
+
+ r = 0;
+
+ if (arg_unregister)
+ return disable_binfmt();
+
+ if (argc > optind) {
+ r = binfmt_mounted_warn();
+ if (r <= 0)
+ return r;
+
+ for (int i = optind; i < argc; i++)
+ RET_GATHER(r, apply_file(argv[i], false));
+
+ } else {
+ _cleanup_strv_free_ char **files = NULL;
+
+ r = conf_files_list_strv(&files, ".conf", NULL, 0, (const char**) CONF_PATHS_STRV("binfmt.d"));
+ if (r < 0)
+ return log_error_errno(r, "Failed to enumerate binfmt.d files: %m");
+
+ if (arg_cat_flags != CAT_CONFIG_OFF)
+ return cat_config(files);
+
+ r = binfmt_mounted_warn();
+ if (r <= 0)
+ return r;
+
+ /* Flush out all rules */
+ r = write_string_file("/proc/sys/fs/binfmt_misc/status", "-1", WRITE_STRING_FILE_DISABLE_BUFFER);
+ if (r < 0)
+ log_warning_errno(r, "Failed to flush binfmt_misc rules, ignoring: %m");
+ else
+ log_debug("Flushed all binfmt_misc rules.");
+
+ STRV_FOREACH(f, files)
+ RET_GATHER(r, apply_file(*f, true));
+ }
+
+ return r;
+}
+
+DEFINE_MAIN_FUNCTION(run);
diff --git a/src/binfmt/meson.build b/src/binfmt/meson.build
new file mode 100644
index 0000000..4496340
--- /dev/null
+++ b/src/binfmt/meson.build
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+executables += [
+ libexec_template + {
+ 'name' : 'systemd-binfmt',
+ 'public' : true,
+ 'conditions' : ['ENABLE_BINFMT'],
+ 'sources' : files('binfmt.c'),
+ },
+]
+
+if conf.get('ENABLE_BINFMT') == 1
+ install_emptydir(binfmtdir)
+ if install_sysconfdir
+ install_emptydir(sysconfdir / 'binfmt.d')
+ endif
+endif