diff options
Diffstat (limited to 'src/binfmt/binfmt.c')
| -rw-r--r-- | src/binfmt/binfmt.c | 264 |
1 files changed, 264 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); |