xref: /freebsd/sys/compat/linux/linux_elf.c (revision 4731124cace5e7a0224e29784617d2856e5c59ab)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2021 Edward Tomasz Napierala <trasz@FreeBSD.org>
5  * Copyright (c) 2018 Chuck Tuffli
6  * Copyright (c) 2017 Dell EMC
7  * Copyright (c) 2000 David O'Brien
8  * Copyright (c) 1995-1996 Søren Schmidt
9  * Copyright (c) 1996 Peter Wemm
10  * All rights reserved.
11  *
12  * This software was developed by the University of Cambridge Computer
13  * Laboratory as part of the CHERI for Hypervisors and Operating Systems
14  * (CHaOS) project, funded by EPSRC grant EP/V000292/1.
15  *
16  * Redistribution and use in source and binary forms, with or without
17  * modification, are permitted provided that the following conditions
18  * are met:
19  * 1. Redistributions of source code must retain the above copyright
20  *    notice, this list of conditions and the following disclaimer
21  *    in this position and unchanged.
22  * 2. Redistributions in binary form must reproduce the above copyright
23  *    notice, this list of conditions and the following disclaimer in the
24  *    documentation and/or other materials provided with the distribution.
25  * 3. The name of the author may not be used to endorse or promote products
26  *    derived from this software without specific prior written permission
27  *
28  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
29  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
30  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
31  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
32  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
33  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
37  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include <sys/param.h>
44 #include <sys/imgact.h>
45 #include <sys/imgact_elf.h>
46 #include <sys/lock.h>
47 #include <sys/malloc.h>
48 #include <sys/mutex.h>
49 #include <sys/proc.h>
50 #include <sys/procfs.h>
51 #include <sys/reg.h>
52 #include <sys/sbuf.h>
53 
54 #include <machine/elf.h>
55 
56 #if __ELF_WORD_SIZE == 32
57 #define linux_pt_regset linux_pt_regset32
58 #define bsd_to_linux_regset bsd_to_linux_regset32
59 #include <machine/../linux32/linux.h>
60 #else
61 #include <machine/../linux/linux.h>
62 #endif
63 #include <compat/linux/linux_elf.h>
64 #include <compat/linux/linux_emul.h>
65 #include <compat/linux/linux_misc.h>
66 
67 /* This adds "linux32_" and "linux64_" prefixes. */
68 #define	__linuxN(x)	__CONCAT(__CONCAT(__CONCAT(linux,__ELF_WORD_SIZE),_),x)
69 
70 #define	LINUX_NT_AUXV	6
71 
72 static void __linuxN(note_fpregset)(void *, struct sbuf *, size_t *);
73 static void __linuxN(note_prpsinfo)(void *, struct sbuf *, size_t *);
74 static void __linuxN(note_prstatus)(void *, struct sbuf *, size_t *);
75 static void __linuxN(note_threadmd)(void *, struct sbuf *, size_t *);
76 static void __linuxN(note_nt_auxv)(void *, struct sbuf *, size_t *);
77 
78 void
79 __linuxN(prepare_notes)(struct thread *td, struct note_info_list *list,
80     size_t *sizep)
81 {
82 	struct proc *p;
83 	struct thread *thr;
84 	size_t size;
85 
86 	p = td->td_proc;
87 	size = 0;
88 
89 	/*
90 	 * To have the debugger select the right thread (LWP) as the initial
91 	 * thread, we dump the state of the thread passed to us in td first.
92 	 * This is the thread that causes the core dump and thus likely to
93 	 * be the right thread one wants to have selected in the debugger.
94 	 */
95 	thr = td;
96 	while (thr != NULL) {
97 		size += __elfN(register_note)(td, list,
98 		    NT_PRSTATUS, __linuxN(note_prstatus), thr);
99 		size += __elfN(register_note)(td, list,
100 		    NT_PRPSINFO, __linuxN(note_prpsinfo), p);
101 		size += __elfN(register_note)(td, list,
102 		    LINUX_NT_AUXV, __linuxN(note_nt_auxv), p);
103 		size += __elfN(register_note)(td, list,
104 		    NT_FPREGSET, __linuxN(note_fpregset), thr);
105 		size += __elfN(register_note)(td, list,
106 		    -1, __linuxN(note_threadmd), thr);
107 
108 		thr = thr == td ? TAILQ_FIRST(&p->p_threads) :
109 		    TAILQ_NEXT(thr, td_plist);
110 		if (thr == td)
111 			thr = TAILQ_NEXT(thr, td_plist);
112 	}
113 
114 	*sizep = size;
115 }
116 
117 typedef struct linux_elf_prstatus linux_elf_prstatus_t;
118 #if __ELF_WORD_SIZE == 32
119 typedef struct prpsinfo32 linux_elf_prpsinfo_t;
120 typedef struct fpreg32 linux_elf_prfpregset_t;
121 #else
122 typedef prpsinfo_t linux_elf_prpsinfo_t;
123 typedef prfpregset_t linux_elf_prfpregset_t;
124 #endif
125 
126 static void
127 __linuxN(note_prpsinfo)(void *arg, struct sbuf *sb, size_t *sizep)
128 {
129 	struct sbuf sbarg;
130 	size_t len;
131 	char *cp, *end;
132 	struct proc *p;
133 	linux_elf_prpsinfo_t *psinfo;
134 	int error;
135 
136 	p = arg;
137 	if (sb != NULL) {
138 		KASSERT(*sizep == sizeof(*psinfo), ("invalid size"));
139 		psinfo = malloc(sizeof(*psinfo), M_TEMP, M_ZERO | M_WAITOK);
140 		psinfo->pr_version = PRPSINFO_VERSION;
141 		psinfo->pr_psinfosz = sizeof(linux_elf_prpsinfo_t);
142 		strlcpy(psinfo->pr_fname, p->p_comm, sizeof(psinfo->pr_fname));
143 		PROC_LOCK(p);
144 		if (p->p_args != NULL) {
145 			len = sizeof(psinfo->pr_psargs) - 1;
146 			if (len > p->p_args->ar_length)
147 				len = p->p_args->ar_length;
148 			memcpy(psinfo->pr_psargs, p->p_args->ar_args, len);
149 			PROC_UNLOCK(p);
150 			error = 0;
151 		} else {
152 			_PHOLD(p);
153 			PROC_UNLOCK(p);
154 			sbuf_new(&sbarg, psinfo->pr_psargs,
155 			    sizeof(psinfo->pr_psargs), SBUF_FIXEDLEN);
156 			error = proc_getargv(curthread, p, &sbarg);
157 			PRELE(p);
158 			if (sbuf_finish(&sbarg) == 0)
159 				len = sbuf_len(&sbarg) - 1;
160 			else
161 				len = sizeof(psinfo->pr_psargs) - 1;
162 			sbuf_delete(&sbarg);
163 		}
164 		if (error || len == 0)
165 			strlcpy(psinfo->pr_psargs, p->p_comm,
166 			    sizeof(psinfo->pr_psargs));
167 		else {
168 			KASSERT(len < sizeof(psinfo->pr_psargs),
169 			    ("len is too long: %zu vs %zu", len,
170 			    sizeof(psinfo->pr_psargs)));
171 			cp = psinfo->pr_psargs;
172 			end = cp + len - 1;
173 			for (;;) {
174 				cp = memchr(cp, '\0', end - cp);
175 				if (cp == NULL)
176 					break;
177 				*cp = ' ';
178 			}
179 		}
180 		psinfo->pr_pid = p->p_pid;
181 		sbuf_bcat(sb, psinfo, sizeof(*psinfo));
182 		free(psinfo, M_TEMP);
183 	}
184 	*sizep = sizeof(*psinfo);
185 }
186 
187 static void
188 __linuxN(note_prstatus)(void *arg, struct sbuf *sb, size_t *sizep)
189 {
190 	struct thread *td;
191 	linux_elf_prstatus_t *status;
192 #if __ELF_WORD_SIZE == 32
193 	struct reg32 pr_reg;
194 #else
195 	struct reg pr_reg;
196 #endif
197 
198 	td = arg;
199 	if (sb != NULL) {
200 		KASSERT(*sizep == sizeof(*status), ("invalid size"));
201 		status = malloc(sizeof(*status), M_TEMP, M_ZERO | M_WAITOK);
202 
203 		/*
204 		 * XXX: Some fields missing.
205 		 */
206 		status->pr_cursig = td->td_proc->p_sig;
207 		status->pr_pid = td->td_tid;
208 
209 #if __ELF_WORD_SIZE == 32
210 		fill_regs32(td, &pr_reg);
211 #else
212 		fill_regs(td, &pr_reg);
213 #endif
214 		bsd_to_linux_regset(&pr_reg, &status->pr_reg);
215 		sbuf_bcat(sb, status, sizeof(*status));
216 		free(status, M_TEMP);
217 	}
218 	*sizep = sizeof(*status);
219 }
220 
221 static void
222 __linuxN(note_fpregset)(void *arg, struct sbuf *sb, size_t *sizep)
223 {
224 	struct thread *td;
225 	linux_elf_prfpregset_t *fpregset;
226 
227 	td = arg;
228 	if (sb != NULL) {
229 		KASSERT(*sizep == sizeof(*fpregset), ("invalid size"));
230 		fpregset = malloc(sizeof(*fpregset), M_TEMP, M_ZERO | M_WAITOK);
231 #if __ELF_WORD_SIZE == 32
232 		fill_fpregs32(td, fpregset);
233 #else
234 		fill_fpregs(td, fpregset);
235 #endif
236 		sbuf_bcat(sb, fpregset, sizeof(*fpregset));
237 		free(fpregset, M_TEMP);
238 	}
239 	*sizep = sizeof(*fpregset);
240 }
241 
242 /*
243  * Allow for MD specific notes, as well as any MD
244  * specific preparations for writing MI notes.
245  */
246 static void
247 __linuxN(note_threadmd)(void *arg, struct sbuf *sb, size_t *sizep)
248 {
249 	struct thread *td;
250 	void *buf;
251 	size_t size;
252 
253 	td = arg;
254 	size = *sizep;
255 	if (size != 0 && sb != NULL)
256 		buf = malloc(size, M_TEMP, M_ZERO | M_WAITOK);
257 	else
258 		buf = NULL;
259 	size = 0;
260 	__elfN(dump_thread)(td, buf, &size);
261 	KASSERT(sb == NULL || *sizep == size, ("invalid size"));
262 	if (size != 0 && sb != NULL)
263 		sbuf_bcat(sb, buf, size);
264 	free(buf, M_TEMP);
265 	*sizep = size;
266 }
267 
268 static void
269 __linuxN(note_nt_auxv)(void *arg, struct sbuf *sb, size_t *sizep)
270 {
271 	struct proc *p;
272 	size_t size;
273 
274 	p = arg;
275 	if (sb == NULL) {
276 		size = 0;
277 		sb = sbuf_new(NULL, NULL, LINUX_AT_COUNT * sizeof(Elf_Auxinfo),
278 		    SBUF_FIXEDLEN);
279 		sbuf_set_drain(sb, sbuf_count_drain, &size);
280 		PHOLD(p);
281 		proc_getauxv(curthread, p, sb);
282 		PRELE(p);
283 		sbuf_finish(sb);
284 		sbuf_delete(sb);
285 		*sizep = size;
286 	} else {
287 		PHOLD(p);
288 		proc_getauxv(curthread, p, sb);
289 		PRELE(p);
290 	}
291 }
292