xref: /freebsd/sys/compat/linux/linux_elf.c (revision 77013d11e6483b970af25e13c9b892075742f7e5)
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/systm.h>
45 #include <sys/exec.h>
46 #include <sys/imgact.h>
47 #include <sys/imgact_elf.h>
48 #include <sys/kernel.h>
49 #include <sys/proc.h>
50 #include <sys/procfs.h>
51 #include <sys/ptrace.h>
52 #include <sys/sbuf.h>
53 #include <sys/sysent.h>
54 #include <sys/user.h>
55 #include <sys/vnode.h>
56 
57 #include <machine/elf.h>
58 
59 #if __ELF_WORD_SIZE == 32
60 #define linux_pt_regset linux_pt_regset32
61 #define bsd_to_linux_regset bsd_to_linux_regset32
62 #include <machine/../linux32/linux.h>
63 #else
64 #include <machine/../linux/linux.h>
65 #endif
66 #include <compat/linux/linux_elf.h>
67 #include <compat/linux/linux_emul.h>
68 #include <compat/linux/linux_misc.h>
69 
70 /* This adds "linux32_" and "linux64_" prefixes. */
71 #define	__linuxN(x)	__CONCAT(__CONCAT(__CONCAT(linux,__ELF_WORD_SIZE),_),x)
72 
73 #define	LINUX_NT_AUXV	6
74 
75 static void __linuxN(note_fpregset)(void *, struct sbuf *, size_t *);
76 static void __linuxN(note_prpsinfo)(void *, struct sbuf *, size_t *);
77 static void __linuxN(note_prstatus)(void *, struct sbuf *, size_t *);
78 static void __linuxN(note_threadmd)(void *, struct sbuf *, size_t *);
79 static void __linuxN(note_nt_auxv)(void *, struct sbuf *, size_t *);
80 
81 void
82 __linuxN(prepare_notes)(struct thread *td, struct note_info_list *list,
83     size_t *sizep)
84 {
85 	struct proc *p;
86 	struct thread *thr;
87 	size_t size;
88 
89 	p = td->td_proc;
90 	size = 0;
91 
92 	/*
93 	 * To have the debugger select the right thread (LWP) as the initial
94 	 * thread, we dump the state of the thread passed to us in td first.
95 	 * This is the thread that causes the core dump and thus likely to
96 	 * be the right thread one wants to have selected in the debugger.
97 	 */
98 	thr = td;
99 	while (thr != NULL) {
100 		size += __elfN(register_note)(td, list,
101 		    NT_PRSTATUS, __linuxN(note_prstatus), thr);
102 		size += __elfN(register_note)(td, list,
103 		    NT_PRPSINFO, __linuxN(note_prpsinfo), p);
104 		size += __elfN(register_note)(td, list,
105 		    LINUX_NT_AUXV, __linuxN(note_nt_auxv), p);
106 		size += __elfN(register_note)(td, list,
107 		    NT_FPREGSET, __linuxN(note_fpregset), thr);
108 		size += __elfN(register_note)(td, list,
109 		    -1, __linuxN(note_threadmd), thr);
110 
111 		thr = thr == td ? TAILQ_FIRST(&p->p_threads) :
112 		    TAILQ_NEXT(thr, td_plist);
113 		if (thr == td)
114 			thr = TAILQ_NEXT(thr, td_plist);
115 	}
116 
117 	*sizep = size;
118 }
119 
120 typedef struct linux_elf_prstatus linux_elf_prstatus_t;
121 #if __ELF_WORD_SIZE == 32
122 typedef struct prpsinfo32 linux_elf_prpsinfo_t;
123 typedef struct fpreg32 linux_elf_prfpregset_t;
124 #else
125 typedef prpsinfo_t linux_elf_prpsinfo_t;
126 typedef prfpregset_t linux_elf_prfpregset_t;
127 #endif
128 
129 static void
130 __linuxN(note_prpsinfo)(void *arg, struct sbuf *sb, size_t *sizep)
131 {
132 	struct sbuf sbarg;
133 	size_t len;
134 	char *cp, *end;
135 	struct proc *p;
136 	linux_elf_prpsinfo_t *psinfo;
137 	int error;
138 
139 	p = arg;
140 	if (sb != NULL) {
141 		KASSERT(*sizep == sizeof(*psinfo), ("invalid size"));
142 		psinfo = malloc(sizeof(*psinfo), M_TEMP, M_ZERO | M_WAITOK);
143 		psinfo->pr_version = PRPSINFO_VERSION;
144 		psinfo->pr_psinfosz = sizeof(linux_elf_prpsinfo_t);
145 		strlcpy(psinfo->pr_fname, p->p_comm, sizeof(psinfo->pr_fname));
146 		PROC_LOCK(p);
147 		if (p->p_args != NULL) {
148 			len = sizeof(psinfo->pr_psargs) - 1;
149 			if (len > p->p_args->ar_length)
150 				len = p->p_args->ar_length;
151 			memcpy(psinfo->pr_psargs, p->p_args->ar_args, len);
152 			PROC_UNLOCK(p);
153 			error = 0;
154 		} else {
155 			_PHOLD(p);
156 			PROC_UNLOCK(p);
157 			sbuf_new(&sbarg, psinfo->pr_psargs,
158 			    sizeof(psinfo->pr_psargs), SBUF_FIXEDLEN);
159 			error = proc_getargv(curthread, p, &sbarg);
160 			PRELE(p);
161 			if (sbuf_finish(&sbarg) == 0)
162 				len = sbuf_len(&sbarg) - 1;
163 			else
164 				len = sizeof(psinfo->pr_psargs) - 1;
165 			sbuf_delete(&sbarg);
166 		}
167 		if (error || len == 0)
168 			strlcpy(psinfo->pr_psargs, p->p_comm,
169 			    sizeof(psinfo->pr_psargs));
170 		else {
171 			KASSERT(len < sizeof(psinfo->pr_psargs),
172 			    ("len is too long: %zu vs %zu", len,
173 			    sizeof(psinfo->pr_psargs)));
174 			cp = psinfo->pr_psargs;
175 			end = cp + len - 1;
176 			for (;;) {
177 				cp = memchr(cp, '\0', end - cp);
178 				if (cp == NULL)
179 					break;
180 				*cp = ' ';
181 			}
182 		}
183 		psinfo->pr_pid = p->p_pid;
184 		sbuf_bcat(sb, psinfo, sizeof(*psinfo));
185 		free(psinfo, M_TEMP);
186 	}
187 	*sizep = sizeof(*psinfo);
188 }
189 
190 static void
191 __linuxN(note_prstatus)(void *arg, struct sbuf *sb, size_t *sizep)
192 {
193 	struct thread *td;
194 	linux_elf_prstatus_t *status;
195 #if __ELF_WORD_SIZE == 32
196 	struct reg32 pr_reg;
197 #else
198 	struct reg pr_reg;
199 #endif
200 
201 	td = arg;
202 	if (sb != NULL) {
203 		KASSERT(*sizep == sizeof(*status), ("invalid size"));
204 		status = malloc(sizeof(*status), M_TEMP, M_ZERO | M_WAITOK);
205 
206 		/*
207 		 * XXX: Some fields missing.
208 		 */
209 		status->pr_cursig = td->td_proc->p_sig;
210 		status->pr_pid = td->td_tid;
211 
212 #if __ELF_WORD_SIZE == 32
213 		fill_regs32(td, &pr_reg);
214 #else
215 		fill_regs(td, &pr_reg);
216 #endif
217 		bsd_to_linux_regset(&pr_reg, &status->pr_reg);
218 		sbuf_bcat(sb, status, sizeof(*status));
219 		free(status, M_TEMP);
220 	}
221 	*sizep = sizeof(*status);
222 }
223 
224 static void
225 __linuxN(note_fpregset)(void *arg, struct sbuf *sb, size_t *sizep)
226 {
227 	struct thread *td;
228 	linux_elf_prfpregset_t *fpregset;
229 
230 	td = arg;
231 	if (sb != NULL) {
232 		KASSERT(*sizep == sizeof(*fpregset), ("invalid size"));
233 		fpregset = malloc(sizeof(*fpregset), M_TEMP, M_ZERO | M_WAITOK);
234 #if __ELF_WORD_SIZE == 32
235 		fill_fpregs32(td, fpregset);
236 #else
237 		fill_fpregs(td, fpregset);
238 #endif
239 		sbuf_bcat(sb, fpregset, sizeof(*fpregset));
240 		free(fpregset, M_TEMP);
241 	}
242 	*sizep = sizeof(*fpregset);
243 }
244 
245 /*
246  * Allow for MD specific notes, as well as any MD
247  * specific preparations for writing MI notes.
248  */
249 static void
250 __linuxN(note_threadmd)(void *arg, struct sbuf *sb, size_t *sizep)
251 {
252 	struct thread *td;
253 	void *buf;
254 	size_t size;
255 
256 	td = arg;
257 	size = *sizep;
258 	if (size != 0 && sb != NULL)
259 		buf = malloc(size, M_TEMP, M_ZERO | M_WAITOK);
260 	else
261 		buf = NULL;
262 	size = 0;
263 	__elfN(dump_thread)(td, buf, &size);
264 	KASSERT(sb == NULL || *sizep == size, ("invalid size"));
265 	if (size != 0 && sb != NULL)
266 		sbuf_bcat(sb, buf, size);
267 	free(buf, M_TEMP);
268 	*sizep = size;
269 }
270 
271 static void
272 __linuxN(note_nt_auxv)(void *arg, struct sbuf *sb, size_t *sizep)
273 {
274 	struct proc *p;
275 	size_t size;
276 
277 	p = arg;
278 	if (sb == NULL) {
279 		size = 0;
280 		sb = sbuf_new(NULL, NULL, LINUX_AT_COUNT * sizeof(Elf_Auxinfo),
281 		    SBUF_FIXEDLEN);
282 		sbuf_set_drain(sb, sbuf_count_drain, &size);
283 		PHOLD(p);
284 		proc_getauxv(curthread, p, sb);
285 		PRELE(p);
286 		sbuf_finish(sb);
287 		sbuf_delete(sb);
288 		*sizep = size;
289 	} else {
290 		PHOLD(p);
291 		proc_getauxv(curthread, p, sb);
292 		PRELE(p);
293 	}
294 }
295