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Commit | Line | Data |
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3bda3f17 LP |
1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
2 | ||
3 | #include "errno-util.h" | |
4 | #include "fd-util.h" | |
5 | #include "missing_syscall.h" | |
6 | #include "parse-util.h" | |
7 | #include "pidref.h" | |
8 | #include "process-util.h" | |
a0d1659c | 9 | #include "signal-util.h" |
3bda3f17 LP |
10 | |
11 | int pidref_set_pid(PidRef *pidref, pid_t pid) { | |
12 | int fd; | |
13 | ||
14 | assert(pidref); | |
15 | ||
16 | if (pid < 0) | |
17 | return -ESRCH; | |
18 | if (pid == 0) | |
19 | pid = getpid_cached(); | |
20 | ||
21 | fd = pidfd_open(pid, 0); | |
22 | if (fd < 0) { | |
23 | /* Graceful fallback in case the kernel doesn't support pidfds or is out of fds */ | |
24 | if (!ERRNO_IS_NOT_SUPPORTED(errno) && !ERRNO_IS_PRIVILEGE(errno) && !ERRNO_IS_RESOURCE(errno)) | |
25 | return -errno; | |
26 | ||
27 | fd = -EBADF; | |
28 | } | |
29 | ||
30 | *pidref = (PidRef) { | |
31 | .fd = fd, | |
32 | .pid = pid, | |
33 | }; | |
34 | ||
35 | return 0; | |
36 | } | |
37 | ||
38 | int pidref_set_pidstr(PidRef *pidref, const char *pid) { | |
39 | pid_t nr; | |
40 | int r; | |
41 | ||
42 | assert(pidref); | |
43 | ||
44 | r = parse_pid(pid, &nr); | |
45 | if (r < 0) | |
46 | return r; | |
47 | ||
48 | return pidref_set_pid(pidref, nr); | |
49 | } | |
50 | ||
51 | int pidref_set_pidfd(PidRef *pidref, int fd) { | |
52 | int r; | |
53 | ||
54 | assert(pidref); | |
55 | ||
56 | if (fd < 0) | |
57 | return -EBADF; | |
58 | ||
59 | int fd_copy = fcntl(fd, F_DUPFD_CLOEXEC, 3); | |
60 | if (fd_copy < 0) { | |
61 | pid_t pid; | |
62 | ||
63 | if (!ERRNO_IS_RESOURCE(errno)) | |
64 | return -errno; | |
65 | ||
66 | /* Graceful fallback if we are out of fds */ | |
67 | r = pidfd_get_pid(fd, &pid); | |
68 | if (r < 0) | |
69 | return r; | |
70 | ||
dcfcea6d | 71 | *pidref = PIDREF_MAKE_FROM_PID(pid); |
3bda3f17 LP |
72 | return 0; |
73 | } | |
74 | ||
75 | return pidref_set_pidfd_consume(pidref, fd_copy); | |
76 | } | |
77 | ||
78 | int pidref_set_pidfd_take(PidRef *pidref, int fd) { | |
79 | pid_t pid; | |
80 | int r; | |
81 | ||
82 | assert(pidref); | |
83 | ||
84 | if (fd < 0) | |
85 | return -EBADF; | |
86 | ||
87 | r = pidfd_get_pid(fd, &pid); | |
88 | if (r < 0) | |
89 | return r; | |
90 | ||
91 | *pidref = (PidRef) { | |
92 | .fd = fd, | |
93 | .pid = pid, | |
94 | }; | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | int pidref_set_pidfd_consume(PidRef *pidref, int fd) { | |
100 | int r; | |
101 | ||
102 | r = pidref_set_pidfd_take(pidref, fd); | |
103 | if (r < 0) | |
104 | safe_close(fd); | |
105 | ||
106 | return r; | |
107 | } | |
108 | ||
109 | void pidref_done(PidRef *pidref) { | |
110 | assert(pidref); | |
111 | ||
112 | *pidref = (PidRef) { | |
113 | .fd = safe_close(pidref->fd), | |
114 | }; | |
115 | } | |
116 | ||
83765982 LP |
117 | PidRef *pidref_free(PidRef *pidref) { |
118 | /* Regularly, this is an embedded structure. But sometimes we want it on the heap too */ | |
119 | if (!pidref) | |
120 | return NULL; | |
121 | ||
122 | pidref_done(pidref); | |
123 | return mfree(pidref); | |
124 | } | |
125 | ||
126 | int pidref_dup(const PidRef *pidref, PidRef **ret) { | |
127 | _cleanup_close_ int dup_fd = -EBADF; | |
128 | pid_t dup_pid = 0; | |
129 | ||
130 | assert(ret); | |
131 | ||
132 | /* Allocates a new PidRef on the heap, making it a copy of the specified pidref. This does not try to | |
133 | * acquire a pidfd if we don't have one yet! | |
134 | * | |
135 | * If NULL is passed we'll generate a PidRef that refers to no process. This makes it easy to copy | |
136 | * pidref fields that might or might not reference a process yet. */ | |
137 | ||
138 | if (pidref) { | |
139 | if (pidref->fd >= 0) { | |
140 | dup_fd = fcntl(pidref->fd, F_DUPFD_CLOEXEC, 3); | |
141 | if (dup_fd < 0) { | |
142 | if (!ERRNO_IS_RESOURCE(errno)) | |
143 | return -errno; | |
144 | ||
145 | dup_fd = -EBADF; | |
146 | } | |
147 | } | |
148 | ||
149 | if (pidref->pid > 0) | |
150 | dup_pid = pidref->pid; | |
151 | } | |
152 | ||
153 | PidRef *dup_pidref = new(PidRef, 1); | |
154 | if (!dup_pidref) | |
155 | return -ENOMEM; | |
156 | ||
157 | *dup_pidref = (PidRef) { | |
158 | .fd = TAKE_FD(dup_fd), | |
159 | .pid = dup_pid, | |
160 | }; | |
161 | ||
162 | *ret = TAKE_PTR(dup_pidref); | |
163 | return 0; | |
164 | } | |
165 | ||
166 | int pidref_new_from_pid(pid_t pid, PidRef **ret) { | |
167 | _cleanup_(pidref_freep) PidRef *n = 0; | |
168 | int r; | |
169 | ||
170 | assert(ret); | |
171 | ||
172 | if (pid < 0) | |
173 | return -ESRCH; | |
174 | ||
175 | n = new(PidRef, 1); | |
176 | if (!n) | |
177 | return -ENOMEM; | |
178 | ||
179 | *n = PIDREF_NULL; | |
180 | ||
181 | r = pidref_set_pid(n, pid); | |
182 | if (r < 0) | |
183 | return r; | |
184 | ||
185 | *ret = TAKE_PTR(n); | |
186 | return 0; | |
187 | } | |
188 | ||
44c55e5a | 189 | int pidref_kill(const PidRef *pidref, int sig) { |
3bda3f17 LP |
190 | |
191 | if (!pidref) | |
192 | return -ESRCH; | |
193 | ||
194 | if (pidref->fd >= 0) | |
195 | return RET_NERRNO(pidfd_send_signal(pidref->fd, sig, NULL, 0)); | |
196 | ||
197 | if (pidref->pid > 0) | |
198 | return RET_NERRNO(kill(pidref->pid, sig)); | |
199 | ||
200 | return -ESRCH; | |
201 | } | |
202 | ||
44c55e5a | 203 | int pidref_kill_and_sigcont(const PidRef *pidref, int sig) { |
3bda3f17 LP |
204 | int r; |
205 | ||
206 | r = pidref_kill(pidref, sig); | |
207 | if (r < 0) | |
208 | return r; | |
209 | ||
210 | if (!IN_SET(sig, SIGCONT, SIGKILL)) | |
211 | (void) pidref_kill(pidref, SIGCONT); | |
212 | ||
213 | return 0; | |
214 | } | |
a0d1659c | 215 | |
44c55e5a | 216 | int pidref_sigqueue(const PidRef *pidref, int sig, int value) { |
a0d1659c LP |
217 | |
218 | if (!pidref) | |
219 | return -ESRCH; | |
220 | ||
221 | if (pidref->fd >= 0) { | |
222 | siginfo_t si; | |
223 | ||
224 | /* We can't use structured initialization here, since the structure contains various unions | |
225 | * and these fields lie in overlapping (carefully aligned) unions that LLVM is allergic to | |
226 | * allow assignments to */ | |
227 | zero(si); | |
228 | si.si_signo = sig; | |
229 | si.si_code = SI_QUEUE; | |
230 | si.si_pid = getpid_cached(); | |
231 | si.si_uid = getuid(); | |
232 | si.si_value.sival_int = value; | |
233 | ||
234 | return RET_NERRNO(pidfd_send_signal(pidref->fd, sig, &si, 0)); | |
235 | } | |
236 | ||
237 | if (pidref->pid > 0) | |
238 | return RET_NERRNO(sigqueue(pidref->pid, sig, (const union sigval) { .sival_int = value })); | |
239 | ||
240 | return -ESRCH; | |
241 | } | |
9cb7e49f | 242 | |
bd389293 | 243 | int pidref_verify(const PidRef *pidref) { |
ec8dc835 LP |
244 | int r; |
245 | ||
246 | /* This is a helper that is supposed to be called after reading information from procfs via a | |
247 | * PidRef. It ensures that the PID we track still matches the PIDFD we pin. If this value differs | |
248 | * after a procfs read, we might have read the data from a recycled PID. */ | |
249 | ||
250 | if (!pidref_is_set(pidref)) | |
251 | return -ESRCH; | |
252 | ||
253 | if (pidref->fd < 0) | |
254 | return 0; /* If we don't have a pidfd we cannot validate it, hence we assume it's all OK → return 0 */ | |
255 | ||
256 | r = pidfd_verify_pid(pidref->fd, pidref->pid); | |
257 | if (r < 0) | |
258 | return r; | |
259 | ||
260 | return 1; /* We have a pidfd and it still points to the PID we have, hence all is *really* OK → return 1 */ | |
261 | } | |
262 | ||
9cb7e49f LP |
263 | static void pidref_hash_func(const PidRef *pidref, struct siphash *state) { |
264 | siphash24_compress(&pidref->pid, sizeof(pidref->pid), state); | |
265 | } | |
266 | ||
267 | static int pidref_compare_func(const PidRef *a, const PidRef *b) { | |
268 | return CMP(a->pid, b->pid); | |
269 | } | |
270 | ||
271 | DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR( | |
272 | pidref_hash_ops, | |
273 | PidRef, | |
274 | pidref_hash_func, | |
275 | pidref_compare_func, | |
276 | pidref_free); |