/src/systemd/src/shared/osc-context.c

Source
/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <sys/auxv.h>

#include "escape.h"
#include "format-util.h"
#include "hostname-setup.h"
#include "id128-util.h"
#include "osc-context.h"
#include "pidfd-util.h"
#include "process-util.h"
#include "string-util.h"
#include "strv.h"
#include "terminal-util.h"
#include "user-util.h"

/* This currently generates open sequences for OSC 3008 types "boot", "container", "vm", "elevate", "chpriv",
 * "subcontext", "session", "service".
 *
 * NB: Not generated by systemd: "remote" (would have to be generated from the SSH client), "app". */

static int strextend_escaped(char **s, const char *prefix, const char *value) {
        assert(s);
        assert(value);

        if (!strextend(s, prefix))
                return -ENOMEM;

        _cleanup_free_ char *e = xescape(value, ";\\");
        if (!e)
                return -ENOMEM;

        if (!strextend(s, e))
                return -ENOMEM;

        return 0;
}

static int osc_append_identity(char **s) {
        int r;

        assert(s);

        _cleanup_free_ char *u = getusername_malloc();
        if (u) {
                r = strextend_escaped(s, ";user=", u);
                if (r < 0)
                        return r;
        }

        _cleanup_free_ char *h = gethostname_malloc();
        if (h) {
                r = strextend_escaped(s, ";hostname=", h);
                if (r < 0)
                        return r;
        }

        sd_id128_t id;
        if (sd_id128_get_machine(&id) >= 0) {
                r = strextendf(s, ";machineid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id));
                if (r < 0)
                        return r;
        }

        if (sd_id128_get_boot(&id) >= 0) {
                r = strextendf(s, ";bootid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id));
                if (r < 0)
                        return r;
        }

        r = strextendf(s, ";pid=" PID_FMT, getpid_cached());
        if (r < 0)
                return r;

        uint64_t pidfdid;
        if (pidfd_get_inode_id_self_cached(&pidfdid) >= 0) {
                r = strextendf(s, ";pidfdid=%" PRIu64, pidfdid);
                if (r < 0)
                        return r;
        }

        r = strextend_escaped(s, ";comm=", program_invocation_short_name);
        if (r < 0)
                return r;

        return 0;
}

static void osc_context_default_id(sd_id128_t *ret_id) {

        /* Usually we only want one context ID per tool. Since we don't want to store the ID let's just hash
         * one from process credentials */

        struct {
                const char label[32];
                uint64_t pidfdid;
                uint8_t auxval[16];
                pid_t pid;
        } data = {
                .label = "systemd context hash bytes v1",
                .pid = getpid_cached(),
        };

        assert(ret_id);

        memcpy(data.auxval, ULONG_TO_PTR(getauxval(AT_RANDOM)), sizeof(data.auxval));
        (void) pidfd_get_inode_id_self_cached(&data.pidfdid);

        *ret_id = id128_digest(&data, sizeof(data));
}

static int osc_context_intro_raw(sd_id128_t id, char **ret_seq) {
        int r;

        assert(ret_seq);

        _cleanup_free_ char *seq = NULL;
        if (asprintf(&seq, ANSI_OSC "3008;start=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id)) < 0)
                return -ENOMEM;

        r = osc_append_identity(&seq);
        if (r < 0)
                return r;

        *ret_seq = TAKE_PTR(seq);
        return 0;
}

static int osc_context_intro(char **ret_seq, sd_id128_t *ret_context_id) {
        int r;

        assert(ret_seq);

        /* If the user passed us a buffer for the context ID generate a randomized one, since we have a place
         * to store it. The user should pass the ID back to osc_context_close() later on. If the user did not
         * pass us a buffer, we'll use a session ID hashed from process properties that remain stable as long
         * our process exists. It hence also remains stable across reexec and similar. */
        sd_id128_t id;
        if (ret_context_id) {
                r = sd_id128_randomize(&id);
                if (r < 0)
                        return r;
        } else
                osc_context_default_id(&id);

        r = osc_context_intro_raw(id, ret_seq);
        if (r < 0)
                return r;

        if (ret_context_id)
                *ret_context_id = id;

        return 0;
}

static int osc_context_outro(char *_seq, sd_id128_t id, char **ret_seq, sd_id128_t *ret_context_id) {
        _cleanup_free_ char *seq = TAKE_PTR(_seq); /* We take possession of the string no matter what */

        if (ret_seq)
                *ret_seq = TAKE_PTR(seq);
        else {
                fputs(seq, stdout);
                fflush(stdout);
        }

        if (ret_context_id)
                *ret_context_id = id;

        return 0;
}

int osc_context_open_boot(char **ret_seq) {
        int r;

        _cleanup_free_ char *seq = NULL;
        r = osc_context_intro(&seq, /* ret_context_id= */ NULL);
        if (r < 0)
                return r;

        if (!strextend(&seq, ";type=boot" ANSI_ST))
                return -ENOMEM;

        return osc_context_outro(TAKE_PTR(seq), /* context_id= */ SD_ID128_NULL, ret_seq, /* ret_context_id= */ NULL);
}

int osc_context_open_container(const char *name, char **ret_seq, sd_id128_t *ret_context_id) {
        int r;

        _cleanup_free_ char *seq = NULL;
        sd_id128_t id = SD_ID128_NULL;
        r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
        if (r < 0)
                return r;

        if (name) {
                r = strextend_escaped(&seq, ";container=", name);
                if (r < 0)
                        return r;
        }

        if (!strextend(&seq, ";type=container" ANSI_ST))
                return -ENOMEM;

        return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
}

int osc_context_open_vm(const char *name, char **ret_seq, sd_id128_t *ret_context_id) {
        int r;

        assert(name);

        _cleanup_free_ char *seq = NULL;
        sd_id128_t id = SD_ID128_NULL;
        r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
        if (r < 0)
                return r;

        r = strextend_escaped(&seq, ";vm=", name);
        if (r < 0)
                return r;

        if (!strextend(&seq, ";type=vm" ANSI_ST))
                return -ENOMEM;

        return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
}

int osc_context_open_chpriv(const char *target_user, char **ret_seq, sd_id128_t *ret_context_id) {
        int r;

        assert(target_user);

        _cleanup_free_ char *seq = NULL;
        sd_id128_t id = SD_ID128_NULL;
        r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
        if (r < 0)
                return r;

        if (is_this_me(target_user) > 0) {
                if (!strextend(&seq, ";type=subcontext" ANSI_ST))
                        return -ENOMEM;
        } else if (STR_IN_SET(target_user, "root", "0")) {
                if (!strextend(&seq, ";type=elevate" ANSI_ST))
                        return -ENOMEM;
        } else {
                r = strextend_escaped(&seq, ";targetuser=", target_user);
                if (r < 0)
                        return r;

                if (!strextend(&seq, ";type=chpriv" ANSI_ST))
                        return -ENOMEM;
        }

        return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
}

int osc_context_open_session(const char *user, const char *session_id, char **ret_seq, sd_id128_t *ret_context_id) {
        int r;

        _cleanup_free_ char *seq = NULL;
        sd_id128_t id = SD_ID128_NULL;
        r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
        if (r < 0)
                return r;

        if (user) {
                r = strextend_escaped(&seq, ";targetuser=", user);
                if (r < 0)
                        return r;
        }

        if (session_id) {
                r = strextend_escaped(&seq, ";sessionid=", session_id);
                if (r < 0)
                        return r;
        }

        if (!strextend(&seq, ";type=session" ANSI_ST))
                return -ENOMEM;

        return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
}

int osc_context_open_service(const char *unit, sd_id128_t invocation_id, char **ret_seq) {
        int r;

        sd_id128_t id = SD_ID128_NULL;
        r = osc_context_id_from_invocation_id(invocation_id, &id);
        if (r < 0)
                return r;

        _cleanup_free_ char *seq = NULL;
        r = osc_context_intro_raw(id, &seq);
        if (r < 0)
                return r;

        if (unit) {
                r = strextend_escaped(&seq, ";servicename=", unit);
                if (r < 0)
                        return r;
        }

        r = strextendf(&seq, ";invocationid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(invocation_id));
        if (r < 0)
                return r;

        if (!strextend(&seq, ";type=service" ANSI_ST))
                return -ENOMEM;

        return osc_context_outro(TAKE_PTR(seq), id, ret_seq, /* ret_context_id= */ NULL);
}

int osc_context_close(sd_id128_t id, char **ret_seq) {

        if (sd_id128_is_null(id)) {
                /* nil uuid: no session opened */
                if (ret_seq)
                        *ret_seq = NULL;
                return 0;
        }

        if (sd_id128_is_allf(id)) /* max uuid: default session opened */
                osc_context_default_id(&id);

        _cleanup_free_ char *seq = NULL;
        if (asprintf(&seq, ANSI_OSC "3008;end=" SD_ID128_FORMAT_STR ANSI_ST, SD_ID128_FORMAT_VAL(id)) < 0)
                return -ENOMEM;

        return osc_context_outro(TAKE_PTR(seq), SD_ID128_NULL, ret_seq, /* ret_context_id= */ NULL);
}

int osc_context_id_from_invocation_id(sd_id128_t id, sd_id128_t *ret) {
        static const sd_id128_t app_id = SD_ID128_MAKE(5d,63,a5,8d,96,fd,45,d0,a0,f0,63,50,fc,d8,9a,cd);

        assert(ret);

        /* Hash the context id from the invocation id, so that we don't have to store the context id (as long
         * as we have the invocation ID). We don't use the invocation ID literally in order not to make it too
         * easy to cancel our service context because the invocation ID is reported literally via the
         * $INVOCATION_ID env var. */
        return sd_id128_get_app_specific(id, app_id, ret);
}

Coverage Report

Created: 2026-07-30 06:11

Line	Count	Source
1		/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3		#include <sys/auxv.h>
4
5		#include "escape.h"
6		#include "format-util.h"
7		#include "hostname-setup.h"
8		#include "id128-util.h"
9		#include "osc-context.h"
10		#include "pidfd-util.h"
11		#include "process-util.h"
12		#include "string-util.h"
13		#include "strv.h"
14		#include "terminal-util.h"
15		#include "user-util.h"
16
17		/* This currently generates open sequences for OSC 3008 types "boot", "container", "vm", "elevate", "chpriv",
18		* "subcontext", "session", "service".
19		*
20		* NB: Not generated by systemd: "remote" (would have to be generated from the SSH client), "app". */
21
22	0	static int strextend_escaped(char *s, const char prefix, const char *value) {
23	0	assert(s);
24	0	assert(value);
25
26	0	if (!strextend(s, prefix))
27	0	return -ENOMEM;
28
29	0	_cleanup_free_ char *e = xescape(value, ";\\");
30	0	if (!e)
31	0	return -ENOMEM;
32
33	0	if (!strextend(s, e))
34	0	return -ENOMEM;
35
36	0	return 0;
37	0	}
38
39	0	static int osc_append_identity(char **s) {
40	0	int r;
41
42	0	assert(s);
43
44	0	_cleanup_free_ char *u = getusername_malloc();
45	0	if (u) {
46	0	r = strextend_escaped(s, ";user=", u);
47	0	if (r < 0)
48	0	return r;
49	0	}
50
51	0	_cleanup_free_ char *h = gethostname_malloc();
52	0	if (h) {
53	0	r = strextend_escaped(s, ";hostname=", h);
54	0	if (r < 0)
55	0	return r;
56	0	}
57
58	0	sd_id128_t id;
59	0	if (sd_id128_get_machine(&id) >= 0) {
60	0	r = strextendf(s, ";machineid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id));
61	0	if (r < 0)
62	0	return r;
63	0	}
64
65	0	if (sd_id128_get_boot(&id) >= 0) {
66	0	r = strextendf(s, ";bootid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id));
67	0	if (r < 0)
68	0	return r;
69	0	}
70
71	0	r = strextendf(s, ";pid=" PID_FMT, getpid_cached());
72	0	if (r < 0)
73	0	return r;
74
75	0	uint64_t pidfdid;
76	0	if (pidfd_get_inode_id_self_cached(&pidfdid) >= 0) {
77	0	r = strextendf(s, ";pidfdid=%" PRIu64, pidfdid);
78	0	if (r < 0)
79	0	return r;
80	0	}
81
82	0	r = strextend_escaped(s, ";comm=", program_invocation_short_name);
83	0	if (r < 0)
84	0	return r;
85
86	0	return 0;
87	0	}
88
89	0	static void osc_context_default_id(sd_id128_t *ret_id) {
90
91		/* Usually we only want one context ID per tool. Since we don't want to store the ID let's just hash
92		* one from process credentials */
93
94	0	struct {
95	0	const char label[32];
96	0	uint64_t pidfdid;
97	0	uint8_t auxval[16];
98	0	pid_t pid;
99	0	} data = {
100	0	.label = "systemd context hash bytes v1",
101	0	.pid = getpid_cached(),
102	0	};
103
104	0	assert(ret_id);
105
106	0	memcpy(data.auxval, ULONG_TO_PTR(getauxval(AT_RANDOM)), sizeof(data.auxval));
107	0	(void) pidfd_get_inode_id_self_cached(&data.pidfdid);
108
109	0	*ret_id = id128_digest(&data, sizeof(data));
110	0	}
111
112	0	static int osc_context_intro_raw(sd_id128_t id, char **ret_seq) {
113	0	int r;
114
115	0	assert(ret_seq);
116
117	0	_cleanup_free_ char *seq = NULL;
118	0	if (asprintf(&seq, ANSI_OSC "3008;start=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(id)) < 0)
119	0	return -ENOMEM;
120
121	0	r = osc_append_identity(&seq);
122	0	if (r < 0)
123	0	return r;
124
125	0	*ret_seq = TAKE_PTR(seq);
126	0	return 0;
127	0	}
128
129	0	static int osc_context_intro(char *ret_seq, sd_id128_t ret_context_id) {
130	0	int r;
131
132	0	assert(ret_seq);
133
134		/* If the user passed us a buffer for the context ID generate a randomized one, since we have a place
135		* to store it. The user should pass the ID back to osc_context_close() later on. If the user did not
136		* pass us a buffer, we'll use a session ID hashed from process properties that remain stable as long
137		* our process exists. It hence also remains stable across reexec and similar. */
138	0	sd_id128_t id;
139	0	if (ret_context_id) {
140	0	r = sd_id128_randomize(&id);
141	0	if (r < 0)
142	0	return r;
143	0	} else
144	0	osc_context_default_id(&id);
145
146	0	r = osc_context_intro_raw(id, ret_seq);
147	0	if (r < 0)
148	0	return r;
149
150	0	if (ret_context_id)
151	0	*ret_context_id = id;
152
153	0	return 0;
154	0	}
155
156	0	static int osc_context_outro(char _seq, sd_id128_t id, char ret_seq, sd_id128_t ret_context_id) {
157	0	_cleanup_free_ char seq = TAKE_PTR(_seq); / We take possession of the string no matter what */
158
159	0	if (ret_seq)
160	0	*ret_seq = TAKE_PTR(seq);
161	0	else {
162	0	fputs(seq, stdout);
163	0	fflush(stdout);
164	0	}
165
166	0	if (ret_context_id)
167	0	*ret_context_id = id;
168
169	0	return 0;
170	0	}
171
172	0	int osc_context_open_boot(char **ret_seq) {
173	0	int r;
174
175	0	_cleanup_free_ char *seq = NULL;
176	0	r = osc_context_intro(&seq, /* ret_context_id= */ NULL);
177	0	if (r < 0)
178	0	return r;
179
180	0	if (!strextend(&seq, ";type=boot" ANSI_ST))
181	0	return -ENOMEM;
182
183	0	return osc_context_outro(TAKE_PTR(seq), /* context_id= / SD_ID128_NULL, ret_seq, / ret_context_id= */ NULL);
184	0	}
185
186	0	int osc_context_open_container(const char name, char ret_seq, sd_id128_t ret_context_id) {
187	0	int r;
188
189	0	_cleanup_free_ char *seq = NULL;
190	0	sd_id128_t id = SD_ID128_NULL;
191	0	r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
192	0	if (r < 0)
193	0	return r;
194
195	0	if (name) {
196	0	r = strextend_escaped(&seq, ";container=", name);
197	0	if (r < 0)
198	0	return r;
199	0	}
200
201	0	if (!strextend(&seq, ";type=container" ANSI_ST))
202	0	return -ENOMEM;
203
204	0	return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
205	0	}
206
207	0	int osc_context_open_vm(const char name, char ret_seq, sd_id128_t ret_context_id) {
208	0	int r;
209
210	0	assert(name);
211
212	0	_cleanup_free_ char *seq = NULL;
213	0	sd_id128_t id = SD_ID128_NULL;
214	0	r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
215	0	if (r < 0)
216	0	return r;
217
218	0	r = strextend_escaped(&seq, ";vm=", name);
219	0	if (r < 0)
220	0	return r;
221
222	0	if (!strextend(&seq, ";type=vm" ANSI_ST))
223	0	return -ENOMEM;
224
225	0	return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
226	0	}
227
228	0	int osc_context_open_chpriv(const char target_user, char ret_seq, sd_id128_t ret_context_id) {
229	0	int r;
230
231	0	assert(target_user);
232
233	0	_cleanup_free_ char *seq = NULL;
234	0	sd_id128_t id = SD_ID128_NULL;
235	0	r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
236	0	if (r < 0)
237	0	return r;
238
239	0	if (is_this_me(target_user) > 0) {
240	0	if (!strextend(&seq, ";type=subcontext" ANSI_ST))
241	0	return -ENOMEM;
242	0	} else if (STR_IN_SET(target_user, "root", "0")) {
243	0	if (!strextend(&seq, ";type=elevate" ANSI_ST))
244	0	return -ENOMEM;
245	0	} else {
246	0	r = strextend_escaped(&seq, ";targetuser=", target_user);
247	0	if (r < 0)
248	0	return r;
249
250	0	if (!strextend(&seq, ";type=chpriv" ANSI_ST))
251	0	return -ENOMEM;
252	0	}
253
254	0	return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
255	0	}
256
257	0	int osc_context_open_session(const char user, const char session_id, char *ret_seq, sd_id128_t ret_context_id) {
258	0	int r;
259
260	0	_cleanup_free_ char *seq = NULL;
261	0	sd_id128_t id = SD_ID128_NULL;
262	0	r = osc_context_intro(&seq, ret_context_id ? &id : NULL);
263	0	if (r < 0)
264	0	return r;
265
266	0	if (user) {
267	0	r = strextend_escaped(&seq, ";targetuser=", user);
268	0	if (r < 0)
269	0	return r;
270	0	}
271
272	0	if (session_id) {
273	0	r = strextend_escaped(&seq, ";sessionid=", session_id);
274	0	if (r < 0)
275	0	return r;
276	0	}
277
278	0	if (!strextend(&seq, ";type=session" ANSI_ST))
279	0	return -ENOMEM;
280
281	0	return osc_context_outro(TAKE_PTR(seq), id, ret_seq, ret_context_id);
282	0	}
283
284	0	int osc_context_open_service(const char unit, sd_id128_t invocation_id, char *ret_seq) {
285	0	int r;
286
287	0	sd_id128_t id = SD_ID128_NULL;
288	0	r = osc_context_id_from_invocation_id(invocation_id, &id);
289	0	if (r < 0)
290	0	return r;
291
292	0	_cleanup_free_ char *seq = NULL;
293	0	r = osc_context_intro_raw(id, &seq);
294	0	if (r < 0)
295	0	return r;
296
297	0	if (unit) {
298	0	r = strextend_escaped(&seq, ";servicename=", unit);
299	0	if (r < 0)
300	0	return r;
301	0	}
302
303	0	r = strextendf(&seq, ";invocationid=" SD_ID128_FORMAT_STR, SD_ID128_FORMAT_VAL(invocation_id));
304	0	if (r < 0)
305	0	return r;
306
307	0	if (!strextend(&seq, ";type=service" ANSI_ST))
308	0	return -ENOMEM;
309
310	0	return osc_context_outro(TAKE_PTR(seq), id, ret_seq, /* ret_context_id= */ NULL);
311	0	}
312
313	0	int osc_context_close(sd_id128_t id, char **ret_seq) {
314
315	0	if (sd_id128_is_null(id)) {
316		/* nil uuid: no session opened */
317	0	if (ret_seq)
318	0	*ret_seq = NULL;
319	0	return 0;
320	0	}
321
322	0	if (sd_id128_is_allf(id)) /* max uuid: default session opened */
323	0	osc_context_default_id(&id);
324
325	0	_cleanup_free_ char *seq = NULL;
326	0	if (asprintf(&seq, ANSI_OSC "3008;end=" SD_ID128_FORMAT_STR ANSI_ST, SD_ID128_FORMAT_VAL(id)) < 0)
327	0	return -ENOMEM;
328
329	0	return osc_context_outro(TAKE_PTR(seq), SD_ID128_NULL, ret_seq, /* ret_context_id= */ NULL);
330	0	}
331
332	0	int osc_context_id_from_invocation_id(sd_id128_t id, sd_id128_t *ret) {
333	0	static const sd_id128_t app_id = SD_ID128_MAKE(5d,63,a5,8d,96,fd,45,d0,a0,f0,63,50,fc,d8,9a,cd);
334
335	0	assert(ret);
336
337		/* Hash the context id from the invocation id, so that we don't have to store the context id (as long
338		* as we have the invocation ID). We don't use the invocation ID literally in order not to make it too
339		* easy to cancel our service context because the invocation ID is reported literally via the
340		* $INVOCATION_ID env var. */
341	0	return sd_id128_get_app_specific(id, app_id, ret);
342	0	}