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core_elf32.c revision 1.35.12.2
      1 /*	$NetBSD: core_elf32.c,v 1.35.12.2 2014/05/22 11:41:02 yamt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2001 Wasabi Systems, Inc.
      5  * All rights reserved.
      6  *
      7  * Written by Jason R. Thorpe for Wasabi Systems, Inc.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *	This product includes software developed for the NetBSD Project by
     20  *	Wasabi Systems, Inc.
     21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22  *    or promote products derived from this software without specific prior
     23  *    written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 /*
     39  * core_elf32.c/core_elf64.c: Support for the Elf32/Elf64 core file format.
     40  */
     41 
     42 #include <sys/cdefs.h>
     43 __KERNEL_RCSID(1, "$NetBSD: core_elf32.c,v 1.35.12.2 2014/05/22 11:41:02 yamt Exp $");
     44 
     45 #ifdef _KERNEL_OPT
     46 #include "opt_coredump.h"
     47 #endif
     48 
     49 #ifndef ELFSIZE
     50 #define	ELFSIZE		32
     51 #endif
     52 
     53 #include <sys/param.h>
     54 #include <sys/systm.h>
     55 #include <sys/proc.h>
     56 #include <sys/vnode.h>
     57 #include <sys/exec.h>
     58 #include <sys/exec_elf.h>
     59 #include <sys/ptrace.h>
     60 #include <sys/kmem.h>
     61 #include <sys/kauth.h>
     62 
     63 #include <machine/reg.h>
     64 
     65 #include <uvm/uvm_extern.h>
     66 
     67 #ifdef COREDUMP
     68 
     69 struct writesegs_state {
     70 	Elf_Phdr *psections;
     71 	proc_t   *p;
     72 	off_t	 secoff;
     73 	size_t   npsections;
     74 };
     75 
     76 /*
     77  * We need to know how big the 'notes' are before we write the main header.
     78  * To avoid problems with double-processing we save the data.
     79  */
     80 struct note_buf {
     81 	struct note_buf  *nb_next;
     82 	unsigned char    nb_data[4096 - sizeof (void *)];
     83 };
     84 
     85 struct note_state {
     86 	struct note_buf  *ns_first;
     87 	struct note_buf  *ns_last;
     88 	unsigned int     ns_count;       /* Of full buffers */
     89 	unsigned int     ns_offset;      /* Write point in last buffer */
     90 };
     91 
     92 static int	ELFNAMEEND(coredump_getseghdrs)(struct uvm_coredump_state *);
     93 
     94 static int	ELFNAMEEND(coredump_notes)(struct lwp *, struct note_state *);
     95 static int	ELFNAMEEND(coredump_note)(struct lwp *, struct note_state *);
     96 
     97 /* The 'note' section names and data are always 4-byte aligned. */
     98 #define	ELFROUNDSIZE	4	/* XXX Should it be sizeof(Elf_Word)? */
     99 
    100 #define elf_process_read_regs	CONCAT(process_read_regs, ELFSIZE)
    101 #define elf_process_read_fpregs	CONCAT(process_read_fpregs, ELFSIZE)
    102 #define elf_reg			CONCAT(process_reg, ELFSIZE)
    103 #define elf_fpreg		CONCAT(process_fpreg, ELFSIZE)
    104 
    105 int
    106 ELFNAMEEND(coredump)(struct lwp *l, struct coredump_iostate *cookie)
    107 {
    108 	Elf_Ehdr ehdr;
    109 	Elf_Shdr shdr;
    110 	Elf_Phdr *psections;
    111 	size_t psectionssize;
    112 	int npsections;
    113 	struct writesegs_state ws;
    114 	off_t notestart;
    115 	size_t notesize;
    116 	int error, i;
    117 
    118 	struct note_state ns;
    119 	struct note_buf *nb;
    120 
    121 	psections = NULL;
    122 
    123 	/* Get all of the notes (mostly all the registers). */
    124 	ns.ns_first = kmem_alloc(sizeof *ns.ns_first, KM_SLEEP);
    125 	ns.ns_last = ns.ns_first;
    126 	ns.ns_count = 0;
    127 	ns.ns_offset = 0;
    128 	error = ELFNAMEEND(coredump_notes)(l, &ns);
    129 	ns.ns_last->nb_next = NULL;
    130 	if (error)
    131 		goto out;
    132 	notesize = ns.ns_count * sizeof nb->nb_data + ns.ns_offset;
    133 
    134 	/*
    135 	 * We have to make a total of 3 passes across the map:
    136 	 *
    137 	 *	1. Count the number of map entries (the number of
    138 	 *	   PT_LOAD sections in the dump).
    139 	 *
    140 	 *	2. Write the P-section headers.
    141 	 *
    142 	 *	3. Write the P-sections.
    143 	 */
    144 
    145 	/* Pass 1: count the entries. */
    146 	npsections = uvm_coredump_count_segs(l->l_proc);
    147 	/* Allow for the PT_NOTE section. */
    148 	npsections++;
    149 
    150 	/* Build the main elf header */
    151 	memset(&ehdr.e_ident[EI_PAD], 0, sizeof(ehdr.e_ident) - EI_PAD);
    152 	memcpy(ehdr.e_ident, ELFMAG, SELFMAG);
    153 #if ELFSIZE == 32
    154 	ehdr.e_ident[EI_CLASS] = ELFCLASS32;
    155 #elif ELFSIZE == 64
    156 	ehdr.e_ident[EI_CLASS] = ELFCLASS64;
    157 #endif
    158 	ehdr.e_ident[EI_DATA] = ELFDEFNNAME(MACHDEP_ENDIANNESS);
    159 	ehdr.e_ident[EI_VERSION] = EV_CURRENT;
    160 	/* XXX Should be the OSABI/ABI version of the executable. */
    161 	ehdr.e_ident[EI_OSABI] = ELFOSABI_SYSV;
    162 	ehdr.e_ident[EI_ABIVERSION] = 0;
    163 
    164 	ehdr.e_type = ET_CORE;
    165 	/* XXX This should be the e_machine of the executable. */
    166 	ehdr.e_machine = ELFDEFNNAME(MACHDEP_ID);
    167 	ehdr.e_version = EV_CURRENT;
    168 	ehdr.e_entry = 0;
    169 	ehdr.e_flags = 0;
    170 	ehdr.e_ehsize = sizeof(ehdr);
    171 	ehdr.e_phentsize = sizeof(Elf_Phdr);
    172 	if (npsections < PN_XNUM) {
    173 		ehdr.e_phnum = npsections;
    174 		ehdr.e_shentsize = 0;
    175 		ehdr.e_shnum = 0;
    176 		ehdr.e_shoff = 0;
    177 		ehdr.e_phoff = sizeof(ehdr);
    178 	} else {
    179 		ehdr.e_phnum = PN_XNUM;
    180 		ehdr.e_shentsize = sizeof(Elf_Shdr);
    181 		ehdr.e_shnum = 1;
    182 		ehdr.e_shoff = sizeof(ehdr);
    183 		ehdr.e_phoff = sizeof(ehdr) + sizeof(shdr);
    184 	}
    185 	ehdr.e_shstrndx = 0;
    186 
    187 #ifdef ELF_MD_COREDUMP_SETUP
    188 	ELF_MD_COREDUMP_SETUP(l, &ehdr);
    189 #endif
    190 
    191 	/* Write out the ELF header. */
    192 	error = coredump_write(cookie, UIO_SYSSPACE, &ehdr, sizeof(ehdr));
    193 	if (error)
    194 		goto out;
    195 
    196 	/* Write out sections, if needed */
    197 	if (npsections >= PN_XNUM) {
    198 		memset(&shdr, 0, sizeof(shdr));
    199 		shdr.sh_type = SHT_NULL;
    200 		shdr.sh_info = npsections;
    201 		error = coredump_write(cookie, UIO_SYSSPACE, &shdr,
    202 		    sizeof(shdr));
    203 		if (error)
    204 			goto out;
    205 	}
    206 
    207 	psectionssize = npsections * sizeof(*psections);
    208 	notestart = ehdr.e_phoff + psectionssize;
    209 
    210 	psections = kmem_zalloc(psectionssize, KM_SLEEP);
    211 
    212 	/* Pass 2: now find the P-section headers. */
    213 	ws.secoff = notestart + notesize;
    214 	ws.psections = psections;
    215 	ws.npsections = npsections - 1;
    216 	ws.p = l->l_proc;
    217 	error = uvm_coredump_walkmap(l->l_proc, ELFNAMEEND(coredump_getseghdrs),
    218 	    &ws);
    219 	if (error)
    220 		goto out;
    221 	if (ws.npsections != 0) {
    222 		/* A section went away */
    223 		error = ENOMEM;
    224 		goto out;
    225 	}
    226 
    227 	/* Add the PT_NOTE header after the P-section headers. */
    228 	ws.psections->p_type = PT_NOTE;
    229 	ws.psections->p_offset = notestart;
    230 	ws.psections->p_vaddr = 0;
    231 	ws.psections->p_paddr = 0;
    232 	ws.psections->p_filesz = notesize;
    233 	ws.psections->p_memsz = 0;
    234 	ws.psections->p_flags = PF_R;
    235 	ws.psections->p_align = ELFROUNDSIZE;
    236 
    237 	/* Write the P-section headers followed by the PT_NOTE header */
    238 	error = coredump_write(cookie, UIO_SYSSPACE, psections, psectionssize);
    239 	if (error)
    240 		goto out;
    241 
    242 #ifdef DIAGNOSTIC
    243 	if (coredump_offset(cookie) != notestart)
    244 		panic("coredump: offset %lld != notestart %lld",
    245 		    (long long) coredump_offset(cookie),
    246 		    (long long) notestart);
    247 #endif
    248 
    249 	/* Write out the notes. */
    250 	for (nb = ns.ns_first; nb != NULL; nb = nb->nb_next) {
    251 		error = coredump_write(cookie, UIO_SYSSPACE, nb->nb_data,
    252 		    nb->nb_next == NULL ? ns.ns_offset : sizeof nb->nb_data);
    253 		if (error)
    254 			goto out;
    255 	}
    256 
    257 	/* Finally, write the sections themselves. */
    258 	for (i = 0; i < npsections - 1; i++) {
    259 		if (psections[i].p_filesz == 0)
    260 			continue;
    261 
    262 #ifdef DIAGNOSTIC
    263 		if (coredump_offset(cookie) != psections[i].p_offset)
    264 			panic("coredump: offset %lld != p_offset[%d] %lld",
    265 			    (long long) coredump_offset(cookie), i,
    266 			    (long long) psections[i].p_filesz);
    267 #endif
    268 
    269 		error = coredump_write(cookie, UIO_USERSPACE,
    270 		    (void *)(vaddr_t)psections[i].p_vaddr,
    271 		    psections[i].p_filesz);
    272 		if (error)
    273 			goto out;
    274 	}
    275 
    276   out:
    277 	if (psections)
    278 		kmem_free(psections, psectionssize);
    279 	while ((nb = ns.ns_first) != NULL) {
    280 		ns.ns_first = nb->nb_next;
    281 		kmem_free(nb, sizeof *nb);
    282 	}
    283 	return (error);
    284 }
    285 
    286 static int
    287 ELFNAMEEND(coredump_getseghdrs)(struct uvm_coredump_state *us)
    288 {
    289 	struct writesegs_state *ws = us->cookie;
    290 	Elf_Phdr phdr;
    291 	vsize_t size, realsize;
    292 	vaddr_t end;
    293 	int error;
    294 
    295 	/* Don't overrun if there are more sections */
    296 	if (ws->npsections == 0)
    297 		return ENOMEM;
    298 	ws->npsections--;
    299 
    300 	size = us->end - us->start;
    301 	realsize = us->realend - us->start;
    302 	end = us->realend;
    303 
    304 	/* Don't bother writing out trailing zeros */
    305 	while (realsize > 0) {
    306 		long buf[1024 / sizeof(long)];
    307 		size_t slen = realsize > sizeof(buf) ? sizeof(buf) : realsize;
    308 		const long *ep;
    309 		int i;
    310 
    311 		end -= slen;
    312 		if ((error = copyin_proc(ws->p, (void *)end, buf, slen)) != 0)
    313 			return error;
    314 
    315 		ep = (const long *) &buf[slen / sizeof(buf[0])];
    316 		for (i = 0, ep--; buf <= ep; ep--, i++) {
    317 			if (*ep)
    318 				break;
    319 		}
    320 		realsize -= i * sizeof(buf[0]);
    321 		if (i * sizeof(buf[0]) < slen)
    322 			break;
    323 	}
    324 
    325 	phdr.p_type = PT_LOAD;
    326 	phdr.p_offset = ws->secoff;
    327 	phdr.p_vaddr = us->start;
    328 	phdr.p_paddr = 0;
    329 	phdr.p_filesz = realsize;
    330 	phdr.p_memsz = size;
    331 	phdr.p_flags = 0;
    332 	if (us->prot & VM_PROT_READ)
    333 		phdr.p_flags |= PF_R;
    334 	if (us->prot & VM_PROT_WRITE)
    335 		phdr.p_flags |= PF_W;
    336 	if (us->prot & VM_PROT_EXECUTE)
    337 		phdr.p_flags |= PF_X;
    338 	phdr.p_align = PAGE_SIZE;
    339 
    340 	ws->secoff += phdr.p_filesz;
    341 	*ws->psections++ = phdr;
    342 
    343 	return (0);
    344 }
    345 
    346 static int
    347 ELFNAMEEND(coredump_notes)(struct lwp *l, struct note_state *ns)
    348 {
    349 	struct proc *p;
    350 	struct netbsd_elfcore_procinfo cpi;
    351 	int error;
    352 	struct lwp *l0;
    353 	sigset_t ss1, ss2;
    354 
    355 	p = l->l_proc;
    356 
    357 	/* First, write an elfcore_procinfo. */
    358 	cpi.cpi_version = NETBSD_ELFCORE_PROCINFO_VERSION;
    359 	cpi.cpi_cpisize = sizeof(cpi);
    360 	cpi.cpi_signo = p->p_sigctx.ps_signo;
    361 	cpi.cpi_sigcode = p->p_sigctx.ps_code;
    362 	cpi.cpi_siglwp = p->p_sigctx.ps_lwp;
    363 
    364 	/*
    365 	 * XXX This should be per-LWP.
    366 	 */
    367 	ss1 = p->p_sigpend.sp_set;
    368 	sigemptyset(&ss2);
    369 	LIST_FOREACH(l0, &p->p_lwps, l_sibling) {
    370 		sigplusset(&l0->l_sigpend.sp_set, &ss1);
    371 		sigplusset(&l0->l_sigmask, &ss2);
    372 	}
    373 	memcpy(&cpi.cpi_sigpend, &ss1, sizeof(cpi.cpi_sigpend));
    374 	memcpy(&cpi.cpi_sigmask, &ss2, sizeof(cpi.cpi_sigmask));
    375 	memcpy(&cpi.cpi_sigignore, &p->p_sigctx.ps_sigignore,
    376 	    sizeof(cpi.cpi_sigignore));
    377 	memcpy(&cpi.cpi_sigcatch, &p->p_sigctx.ps_sigcatch,
    378 	    sizeof(cpi.cpi_sigcatch));
    379 
    380 	cpi.cpi_pid = p->p_pid;
    381 	mutex_enter(proc_lock);
    382 	cpi.cpi_ppid = p->p_pptr->p_pid;
    383 	cpi.cpi_pgrp = p->p_pgid;
    384 	cpi.cpi_sid = p->p_session->s_sid;
    385 	mutex_exit(proc_lock);
    386 
    387 	cpi.cpi_ruid = kauth_cred_getuid(l->l_cred);
    388 	cpi.cpi_euid = kauth_cred_geteuid(l->l_cred);
    389 	cpi.cpi_svuid = kauth_cred_getsvuid(l->l_cred);
    390 
    391 	cpi.cpi_rgid = kauth_cred_getgid(l->l_cred);
    392 	cpi.cpi_egid = kauth_cred_getegid(l->l_cred);
    393 	cpi.cpi_svgid = kauth_cred_getsvgid(l->l_cred);
    394 
    395 	cpi.cpi_nlwps = p->p_nlwps;
    396 	(void)strncpy(cpi.cpi_name, p->p_comm, sizeof(cpi.cpi_name));
    397 	cpi.cpi_name[sizeof(cpi.cpi_name) - 1] = '\0';
    398 
    399 	ELFNAMEEND(coredump_savenote)(ns, ELF_NOTE_NETBSD_CORE_PROCINFO,
    400 	    ELF_NOTE_NETBSD_CORE_NAME, &cpi, sizeof(cpi));
    401 
    402 	/* XXX Add hook for machdep per-proc notes. */
    403 
    404 	/*
    405 	 * Now write the register info for the thread that caused the
    406 	 * coredump.
    407 	 */
    408 	error = ELFNAMEEND(coredump_note)(l, ns);
    409 	if (error)
    410 		return (error);
    411 
    412 	/*
    413 	 * Now, for each LWP, write the register info and any other
    414 	 * per-LWP notes.
    415 	 * Lock in case this is a gcore requested dump.
    416 	 */
    417 	mutex_enter(p->p_lock);
    418 	LIST_FOREACH(l0, &p->p_lwps, l_sibling) {
    419 		if (l0 == l)		/* we've taken care of this thread */
    420 			continue;
    421 		error = ELFNAMEEND(coredump_note)(l0, ns);
    422 		if (error)
    423 			break;
    424 	}
    425 	mutex_exit(p->p_lock);
    426 
    427 	return error;
    428 }
    429 
    430 static int
    431 ELFNAMEEND(coredump_note)(struct lwp *l, struct note_state *ns)
    432 {
    433 	int error;
    434 	char name[64];
    435 	elf_reg intreg;
    436 #ifdef PT_GETFPREGS
    437 	elf_fpreg freg;
    438 	size_t freglen;
    439 #endif
    440 
    441 	snprintf(name, sizeof(name), "%s@%d",
    442 	    ELF_NOTE_NETBSD_CORE_NAME, l->l_lid);
    443 
    444 	error = elf_process_read_regs(l, &intreg);
    445 	if (error)
    446 		return (error);
    447 
    448 	ELFNAMEEND(coredump_savenote)(ns, PT_GETREGS, name, &intreg,
    449 	    sizeof(intreg));
    450 
    451 #ifdef PT_GETFPREGS
    452 	freglen = sizeof(freg);
    453 	error = elf_process_read_fpregs(l, &freg, &freglen);
    454 	if (error)
    455 		return (error);
    456 
    457 	ELFNAMEEND(coredump_savenote)(ns, PT_GETFPREGS, name, &freg, freglen);
    458 #endif
    459 	/* XXX Add hook for machdep per-LWP notes. */
    460 	return (0);
    461 }
    462 
    463 static void
    464 save_note_bytes(struct note_state *ns, const void *data, size_t len)
    465 {
    466 	struct note_buf *nb = ns->ns_last;
    467 	size_t copylen;
    468 	unsigned char *wp;
    469 
    470 	/*
    471 	 * Just copy the data into a buffer list.
    472 	 * All but the last buffer is full.
    473 	 */
    474 	for (;;) {
    475 		copylen = min(len, sizeof nb->nb_data - ns->ns_offset);
    476 		wp = nb->nb_data + ns->ns_offset;
    477 		memcpy(wp, data, copylen);
    478 		if (copylen == len)
    479 			break;
    480 		nb->nb_next = kmem_alloc(sizeof *nb->nb_next, KM_SLEEP);
    481 		nb = nb->nb_next;
    482 		ns->ns_last = nb;
    483 		ns->ns_count++;
    484 		ns->ns_offset = 0;
    485 		len -= copylen;
    486 		data = (const unsigned char *)data + copylen;
    487 	}
    488 
    489 	while (copylen & (ELFROUNDSIZE - 1))
    490 	    wp[copylen++] = 0;
    491 
    492 	ns->ns_offset += copylen;
    493 }
    494 
    495 void
    496 ELFNAMEEND(coredump_savenote)(struct note_state *ns, unsigned int type,
    497     const char *name, void *data, size_t data_len)
    498 {
    499 	Elf_Nhdr nhdr;
    500 
    501 	nhdr.n_namesz = strlen(name) + 1;
    502 	nhdr.n_descsz = data_len;
    503 	nhdr.n_type = type;
    504 
    505 	save_note_bytes(ns, &nhdr, sizeof (nhdr));
    506 	save_note_bytes(ns, name, nhdr.n_namesz);
    507 	save_note_bytes(ns, data, data_len);
    508 }
    509 
    510 #else	/* COREDUMP */
    511 
    512 int
    513 ELFNAMEEND(coredump)(struct lwp *l, void *cookie)
    514 {
    515 
    516 	return ENOSYS;
    517 }
    518 
    519 #endif	/* COREDUMP */
    520