1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3 #include <errno.h>
4 #include <getopt.h>
5 #include <limits.h>
6 #include <stdbool.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <sys/stat.h>
10 #include <sys/types.h>
11
12 #include "alloc-util.h"
13 #include "binfmt-util.h"
14 #include "conf-files.h"
15 #include "def.h"
16 #include "fd-util.h"
17 #include "fileio.h"
18 #include "log.h"
19 #include "main-func.h"
20 #include "pager.h"
21 #include "path-util.h"
22 #include "pretty-print.h"
23 #include "string-util.h"
24 #include "strv.h"
25
26 static bool arg_cat_config = false;
27 static PagerFlags arg_pager_flags = 0;
28 static bool arg_unregister = false;
29
delete_rule(const char * rulename)30 static int delete_rule(const char *rulename) {
31 const char *fn = strjoina("/proc/sys/fs/binfmt_misc/", rulename);
32 return write_string_file(fn, "-1", WRITE_STRING_FILE_DISABLE_BUFFER);
33 }
34
apply_rule(const char * filename,unsigned line,const char * rule)35 static int apply_rule(const char *filename, unsigned line, const char *rule) {
36 assert(filename);
37 assert(line > 0);
38 assert(rule);
39 assert(rule[0]);
40
41 _cleanup_free_ char *rulename = NULL;
42 const char *e;
43 int r;
44
45 e = strchrnul(rule + 1, rule[0]);
46 rulename = strndup(rule + 1, e - rule - 1);
47 if (!rulename)
48 return log_oom();
49
50 if (!filename_is_valid(rulename) ||
51 STR_IN_SET(rulename, "register", "status"))
52 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
53 "%s:%u: Rule name '%s' is not valid, refusing.",
54 filename, line, rulename);
55 r = delete_rule(rulename);
56 if (r < 0 && r != -ENOENT)
57 log_warning_errno(r, "%s:%u: Failed to delete rule '%s', ignoring: %m",
58 filename, line, rulename);
59 if (r >= 0)
60 log_debug("%s:%u: Rule '%s' deleted.", filename, line, rulename);
61
62 r = write_string_file("/proc/sys/fs/binfmt_misc/register", rule, WRITE_STRING_FILE_DISABLE_BUFFER);
63 if (r < 0)
64 return log_error_errno(r, "%s:%u: Failed to add binary format '%s': %m",
65 filename, line, rulename);
66
67 log_debug("%s:%u: Binary format '%s' registered.", filename, line, rulename);
68 return 0;
69 }
70
apply_file(const char * filename,bool ignore_enoent)71 static int apply_file(const char *filename, bool ignore_enoent) {
72 _cleanup_fclose_ FILE *f = NULL;
73 _cleanup_free_ char *pp = NULL;
74 int r;
75
76 assert(filename);
77
78 r = search_and_fopen(filename, "re", NULL, (const char**) CONF_PATHS_STRV("binfmt.d"), &f, &pp);
79 if (r < 0) {
80 if (ignore_enoent && r == -ENOENT)
81 return 0;
82
83 return log_error_errno(r, "Failed to open file '%s': %m", filename);
84 }
85
86 log_debug("Applying %s…", pp);
87 for (unsigned line = 1;; line++) {
88 _cleanup_free_ char *text = NULL;
89 char *p;
90 int k;
91
92 k = read_line(f, LONG_LINE_MAX, &text);
93 if (k < 0)
94 return log_error_errno(k, "Failed to read file '%s': %m", pp);
95 if (k == 0)
96 break;
97
98 p = strstrip(text);
99 if (isempty(p))
100 continue;
101 if (strchr(COMMENTS, p[0]))
102 continue;
103
104 k = apply_rule(filename, line, p);
105 if (k < 0 && r >= 0)
106 r = k;
107 }
108
109 return r;
110 }
111
help(void)112 static int help(void) {
113 _cleanup_free_ char *link = NULL;
114 int r;
115
116 r = terminal_urlify_man("systemd-binfmt.service", "8", &link);
117 if (r < 0)
118 return log_oom();
119
120 printf("%s [OPTIONS...] [CONFIGURATION FILE...]\n\n"
121 "Registers binary formats with the kernel.\n\n"
122 " -h --help Show this help\n"
123 " --version Show package version\n"
124 " --cat-config Show configuration files\n"
125 " --no-pager Do not pipe output into a pager\n"
126 " --unregister Unregister all existing entries\n"
127 "\nSee the %s for details.\n",
128 program_invocation_short_name,
129 link);
130
131 return 0;
132 }
133
parse_argv(int argc,char * argv[])134 static int parse_argv(int argc, char *argv[]) {
135 enum {
136 ARG_VERSION = 0x100,
137 ARG_CAT_CONFIG,
138 ARG_NO_PAGER,
139 ARG_UNREGISTER,
140 };
141
142 static const struct option options[] = {
143 { "help", no_argument, NULL, 'h' },
144 { "version", no_argument, NULL, ARG_VERSION },
145 { "cat-config", no_argument, NULL, ARG_CAT_CONFIG },
146 { "no-pager", no_argument, NULL, ARG_NO_PAGER },
147 { "unregister", no_argument, NULL, ARG_UNREGISTER },
148 {}
149 };
150
151 int c;
152
153 assert(argc >= 0);
154 assert(argv);
155
156 while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0)
157
158 switch (c) {
159
160 case 'h':
161 return help();
162
163 case ARG_VERSION:
164 return version();
165
166 case ARG_CAT_CONFIG:
167 arg_cat_config = true;
168 break;
169
170 case ARG_NO_PAGER:
171 arg_pager_flags |= PAGER_DISABLE;
172 break;
173
174 case ARG_UNREGISTER:
175 arg_unregister = true;
176 break;
177
178 case '?':
179 return -EINVAL;
180
181 default:
182 assert_not_reached();
183 }
184
185 if ((arg_unregister || arg_cat_config) && argc > optind)
186 return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
187 "Positional arguments are not allowed with --cat-config or --unregister");
188
189 return 1;
190 }
191
run(int argc,char * argv[])192 static int run(int argc, char *argv[]) {
193 int r, k;
194
195 r = parse_argv(argc, argv);
196 if (r <= 0)
197 return r;
198
199 log_setup();
200
201 umask(0022);
202
203 r = 0;
204
205 if (arg_unregister)
206 return disable_binfmt();
207
208 if (argc > optind)
209 for (int i = optind; i < argc; i++) {
210 k = apply_file(argv[i], false);
211 if (k < 0 && r >= 0)
212 r = k;
213 }
214 else {
215 _cleanup_strv_free_ char **files = NULL;
216
217 r = conf_files_list_strv(&files, ".conf", NULL, 0, (const char**) CONF_PATHS_STRV("binfmt.d"));
218 if (r < 0)
219 return log_error_errno(r, "Failed to enumerate binfmt.d files: %m");
220
221 if (arg_cat_config) {
222 pager_open(arg_pager_flags);
223
224 return cat_files(NULL, files, 0);
225 }
226
227 /* Flush out all rules */
228 r = write_string_file("/proc/sys/fs/binfmt_misc/status", "-1", WRITE_STRING_FILE_DISABLE_BUFFER);
229 if (r < 0)
230 log_warning_errno(r, "Failed to flush binfmt_misc rules, ignoring: %m");
231 else
232 log_debug("Flushed all binfmt_misc rules.");
233
234 STRV_FOREACH(f, files) {
235 k = apply_file(*f, true);
236 if (k < 0 && r >= 0)
237 r = k;
238 }
239 }
240
241 return r;
242 }
243
244 DEFINE_MAIN_FUNCTION(run);
245