xref: /illumos-gate/usr/src/lib/libproc/common/Pservice.c (revision 8119dad84d6416f13557b0ba8e2aaf9064cbcfd3)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 /*
26  * Copyright (c) 2013 by Delphix. All rights reserved.
27  * Copyright 2023 Oxide Computer Company
28  */
29 
30 #include <stdarg.h>
31 #include <string.h>
32 #include <errno.h>
33 #include "Pcontrol.h"
34 
35 /*
36  * This file implements the process services declared in <proc_service.h>.
37  * This enables libproc to be used in conjunction with libc_db and
38  * librtld_db.  As most of these facilities are already provided by
39  * (more elegant) interfaces in <libproc.h>, we can just call those.
40  *
41  * NOTE: We explicitly do *not* implement the functions ps_kill() and
42  * ps_lrolltoaddr() in this library.  The very existence of these functions
43  * causes libc_db to create an "agent thread" in the target process.
44  * The only way to turn off this behavior is to omit these functions.
45  */
46 
47 #pragma weak ps_pdread = ps_pread
48 #pragma weak ps_ptread = ps_pread
49 #pragma weak ps_pdwrite = ps_pwrite
50 #pragma weak ps_ptwrite = ps_pwrite
51 
52 ps_err_e
53 ps_pdmodel(struct ps_prochandle *P, int *modelp)
54 {
55 	*modelp = P->status.pr_dmodel;
56 	return (PS_OK);
57 }
58 
59 ps_err_e
60 ps_pread(struct ps_prochandle *P, psaddr_t addr, void *buf, size_t size)
61 {
62 	if (P->ops.pop_pread(P, buf, size, addr, P->data) != size)
63 		return (PS_BADADDR);
64 	return (PS_OK);
65 }
66 
67 ps_err_e
68 ps_pwrite(struct ps_prochandle *P, psaddr_t addr, const void *buf, size_t size)
69 {
70 	if (P->ops.pop_pwrite(P, buf, size, addr, P->data) != size)
71 		return (PS_BADADDR);
72 	return (PS_OK);
73 }
74 
75 /*
76  * libc_db calls matched pairs of ps_pstop()/ps_pcontinue()
77  * in the belief that the client may have left the process
78  * running while calling in to the libc_db interfaces.
79  *
80  * We interpret the meaning of these functions to be an inquiry
81  * as to whether the process is stopped, not an action to be
82  * performed to make it stopped.  For similar reasons, we also
83  * return PS_OK for core files in order to allow libc_db to
84  * operate on these as well.
85  */
86 ps_err_e
87 ps_pstop(struct ps_prochandle *P)
88 {
89 	if (P->state != PS_STOP && P->state != PS_DEAD)
90 		return (PS_ERR);
91 	return (PS_OK);
92 }
93 
94 ps_err_e
95 ps_pcontinue(struct ps_prochandle *P)
96 {
97 	if (P->state != PS_STOP && P->state != PS_DEAD)
98 		return (PS_ERR);
99 	return (PS_OK);
100 }
101 
102 /*
103  * ps_lstop() and ps_lcontinue() are not called by any code in libc_db
104  * or librtld_db.  We make them behave like ps_pstop() and ps_pcontinue().
105  */
106 /* ARGSUSED1 */
107 ps_err_e
108 ps_lstop(struct ps_prochandle *P, lwpid_t lwpid)
109 {
110 	if (P->state != PS_STOP && P->state != PS_DEAD)
111 		return (PS_ERR);
112 	return (PS_OK);
113 }
114 
115 /* ARGSUSED1 */
116 ps_err_e
117 ps_lcontinue(struct ps_prochandle *P, lwpid_t lwpid)
118 {
119 	if (P->state != PS_STOP && P->state != PS_DEAD)
120 		return (PS_ERR);
121 	return (PS_OK);
122 }
123 
124 ps_err_e
125 ps_lgetregs(struct ps_prochandle *P, lwpid_t lwpid, prgregset_t regs)
126 {
127 	if (P->state != PS_STOP && P->state != PS_DEAD)
128 		return (PS_ERR);
129 
130 	if (Plwp_getregs(P, lwpid, regs) == 0)
131 		return (PS_OK);
132 
133 	return (PS_BADLID);
134 }
135 
136 ps_err_e
137 ps_lsetregs(struct ps_prochandle *P, lwpid_t lwpid, const prgregset_t regs)
138 {
139 	if (P->state != PS_STOP)
140 		return (PS_ERR);
141 
142 	if (Plwp_setregs(P, lwpid, regs) == 0)
143 		return (PS_OK);
144 
145 	return (PS_BADLID);
146 }
147 
148 ps_err_e
149 ps_lgetfpregs(struct ps_prochandle *P, lwpid_t lwpid, prfpregset_t *regs)
150 {
151 	if (P->state != PS_STOP && P->state != PS_DEAD)
152 		return (PS_ERR);
153 
154 	if (Plwp_getfpregs(P, lwpid, regs) == 0)
155 		return (PS_OK);
156 
157 	return (PS_BADLID);
158 }
159 
160 ps_err_e
161 ps_lsetfpregs(struct ps_prochandle *P, lwpid_t lwpid, const prfpregset_t *regs)
162 {
163 	if (P->state != PS_STOP)
164 		return (PS_ERR);
165 
166 	if (Plwp_setfpregs(P, lwpid, regs) == 0)
167 		return (PS_OK);
168 
169 	return (PS_BADLID);
170 }
171 
172 ps_err_e
173 ps_lgetxregsize(struct ps_prochandle *P, lwpid_t lwpid, int *xrsize)
174 {
175 	char fname[PATH_MAX];
176 	struct stat statb;
177 
178 	if (P->state == PS_DEAD) {
179 		core_info_t *core = P->data;
180 		lwp_info_t *lwp;
181 
182 		for (lwp = list_head(&core->core_lwp_head); lwp != NULL;
183 		    lwp = list_next(&core->core_lwp_head, lwp)) {
184 			if (lwp->lwp_id == lwpid) {
185 				if (lwp->lwp_xregs != NULL &&
186 				    lwp->lwp_xregsize > 0) {
187 					if (lwp->lwp_xregsize >= INT_MAX) {
188 						return (PS_ERR);
189 					}
190 
191 					*xrsize = (int)lwp->lwp_xregsize;
192 				} else {
193 					*xrsize = 0;
194 				}
195 				return (PS_OK);
196 			}
197 		}
198 
199 		return (PS_BADLID);
200 	}
201 
202 	(void) snprintf(fname, sizeof (fname), "%s/%d/lwp/%d/xregs",
203 	    procfs_path, (int)P->status.pr_pid, (int)lwpid);
204 
205 	if (stat(fname, &statb) != 0)
206 		return (PS_BADLID);
207 
208 	if (statb.st_size > INT_MAX)
209 		return (PS_ERR);
210 
211 	*xrsize = (int)statb.st_size;
212 	return (PS_OK);
213 }
214 
215 ps_err_e
216 ps_lgetxregs(struct ps_prochandle *P, lwpid_t lwpid, caddr_t xregs)
217 {
218 	size_t xregsize;
219 	prxregset_t *prx;
220 
221 	if (P->state != PS_STOP && P->state != PS_DEAD)
222 		return (PS_ERR);
223 
224 	if (Plwp_getxregs(P, lwpid, &prx, &xregsize) == 0) {
225 		(void) memcpy(xregs, prx, xregsize);
226 		Plwp_freexregs(P, prx, xregsize);
227 		return (PS_OK);
228 	}
229 
230 	if (errno == ENODATA)
231 		return (PS_NOXREGS);
232 	else if (errno == ENOENT)
233 		return (PS_BADLID);
234 	return (PS_ERR);
235 }
236 
237 ps_err_e
238 ps_lsetxregs(struct ps_prochandle *P, lwpid_t lwpid, caddr_t xregs)
239 {
240 	size_t xregsize = 0;
241 
242 	if (P->state != PS_STOP)
243 		return (PS_ERR);
244 
245 	/*
246 	 * libproc asks the caller for the size of the extended register set.
247 	 * Unfortunately, right now we aren't given the actual size of this
248 	 * ourselves and we don't want to break the ABI that folks have used
249 	 * historically. Therefore, we reach in and ask the structure in a
250 	 * platform-specific way about what this should be. Sorry, this is a bit
251 	 * unfortunate. This really shouldn't be a platform-specific #ifdef.
252 	 *
253 	 * Platforms without xregs can leave xregsize set to zero the kernel
254 	 * will fail with EINVAL.
255 	 */
256 #if defined(__i386) || defined(__amd64)
257 	prxregset_hdr_t *hdr = (prxregset_hdr_t *)xregs;
258 	xregsize = hdr->pr_size;
259 #endif
260 
261 	if (Plwp_setxregs(P, lwpid, (prxregset_t *)xregs, xregsize) == 0)
262 		return (PS_OK);
263 
264 	if (errno == ENOENT)
265 		return (PS_BADLID);
266 	return (PS_ERR);
267 }
268 
269 #if defined(sparc) || defined(__sparc)
270 ps_err_e
271 ps_lsetxregs(struct ps_prochandle *P, lwpid_t lwpid, caddr_t xregs)
272 {
273 	if (P->state != PS_STOP)
274 		return (PS_ERR);
275 
276 	/* LINTED - alignment */
277 	if (Plwp_setxregs(P, lwpid, (prxregset_t *)xregs) == 0)
278 		return (PS_OK);
279 
280 	return (PS_BADLID);
281 }
282 
283 #endif	/* sparc */
284 
285 #if defined(__i386) || defined(__amd64)
286 
287 ps_err_e
288 ps_lgetLDT(struct ps_prochandle *P, lwpid_t lwpid, struct ssd *ldt)
289 {
290 #if defined(__amd64) && defined(_LP64)
291 	if (P->status.pr_dmodel != PR_MODEL_NATIVE) {
292 #endif
293 	prgregset_t regs;
294 	struct ssd *ldtarray;
295 	ps_err_e error;
296 	uint_t gs;
297 	int nldt;
298 	int i;
299 
300 	if (P->state != PS_STOP && P->state != PS_DEAD)
301 		return (PS_ERR);
302 
303 	/*
304 	 * We need to get the ldt entry that matches the
305 	 * value in the lwp's GS register.
306 	 */
307 	if ((error = ps_lgetregs(P, lwpid, regs)) != PS_OK)
308 		return (error);
309 
310 	gs = regs[GS];
311 
312 	if ((nldt = Pldt(P, NULL, 0)) <= 0 ||
313 	    (ldtarray = malloc(nldt * sizeof (struct ssd))) == NULL)
314 		return (PS_ERR);
315 	if ((nldt = Pldt(P, ldtarray, nldt)) <= 0) {
316 		free(ldtarray);
317 		return (PS_ERR);
318 	}
319 
320 	for (i = 0; i < nldt; i++) {
321 		if (gs == ldtarray[i].sel) {
322 			*ldt = ldtarray[i];
323 			break;
324 		}
325 	}
326 	free(ldtarray);
327 
328 	if (i < nldt)
329 		return (PS_OK);
330 #if defined(__amd64) && defined(_LP64)
331 	}
332 #endif
333 
334 	return (PS_ERR);
335 }
336 
337 #endif	/* __i386 || __amd64 */
338 
339 /*
340  * Libthread_db doesn't use this function currently, but librtld_db uses
341  * it for its debugging output.  We turn this on via rd_log if our debugging
342  * switch is on, and then echo the messages sent to ps_plog to stderr.
343  */
344 void
345 ps_plog(const char *fmt, ...)
346 {
347 	va_list ap;
348 
349 	if (_libproc_debug && fmt != NULL && *fmt != '\0') {
350 		va_start(ap, fmt);
351 		(void) vfprintf(stderr, fmt, ap);
352 		va_end(ap);
353 		if (fmt[strlen(fmt) - 1] != '\n')
354 			(void) fputc('\n', stderr);
355 	}
356 }
357 
358 /*
359  * Store a pointer to our internal copy of the aux vector at the address
360  * specified by the caller.  It should not hold on to this data for too long.
361  */
362 ps_err_e
363 ps_pauxv(struct ps_prochandle *P, const auxv_t **aux)
364 {
365 	if (P->auxv == NULL)
366 		Preadauxvec(P);
367 
368 	if (P->auxv == NULL)
369 		return (PS_ERR);
370 
371 	*aux = (const auxv_t *)P->auxv;
372 	return (PS_OK);
373 }
374 
375 ps_err_e
376 ps_pbrandname(struct ps_prochandle *P, char *buf, size_t len)
377 {
378 	return (Pbrandname(P, buf, len) ? PS_OK : PS_ERR);
379 }
380 
381 /*
382  * Search for a symbol by name and return the corresponding address.
383  */
384 ps_err_e
385 ps_pglobal_lookup(struct ps_prochandle *P, const char *object_name,
386     const char *sym_name, psaddr_t *sym_addr)
387 {
388 	GElf_Sym sym;
389 
390 	if (Plookup_by_name(P, object_name, sym_name, &sym) == 0) {
391 		dprintf("pglobal_lookup <%s> -> %p\n",
392 		    sym_name, (void *)(uintptr_t)sym.st_value);
393 		*sym_addr = (psaddr_t)sym.st_value;
394 		return (PS_OK);
395 	}
396 
397 	return (PS_NOSYM);
398 }
399 
400 /*
401  * Search for a symbol by name and return the corresponding symbol
402  * information.  If we're compiled _LP64, we just call Plookup_by_name
403  * and return because ps_sym_t is defined to be an Elf64_Sym, which
404  * is the same as a GElf_Sym.  In the _ILP32 case, we have to convert
405  * Plookup_by_name's result back to a ps_sym_t (which is an Elf32_Sym).
406  */
407 ps_err_e
408 ps_pglobal_sym(struct ps_prochandle *P, const char *object_name,
409     const char *sym_name, ps_sym_t *symp)
410 {
411 #if defined(_ILP32)
412 	GElf_Sym sym;
413 
414 	if (Plookup_by_name(P, object_name, sym_name, &sym) == 0) {
415 		symp->st_name = (Elf32_Word)sym.st_name;
416 		symp->st_value = (Elf32_Addr)sym.st_value;
417 		symp->st_size = (Elf32_Word)sym.st_size;
418 		symp->st_info = ELF32_ST_INFO(
419 		    GELF_ST_BIND(sym.st_info), GELF_ST_TYPE(sym.st_info));
420 		symp->st_other = sym.st_other;
421 		symp->st_shndx = sym.st_shndx;
422 		return (PS_OK);
423 	}
424 
425 #elif defined(_LP64)
426 	if (Plookup_by_name(P, object_name, sym_name, symp) == 0)
427 		return (PS_OK);
428 #endif
429 	return (PS_NOSYM);
430 }
431