linux_exec.c revision 1.29
1/*	$NetBSD: linux_exec.c,v 1.29 1998/09/05 14:50:26 christos Exp $	*/
2
3/*-
4 * Copyright (c) 1994 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. All advertising materials mentioning features or use of this software
19 *    must display the following acknowledgement:
20 *        This product includes software developed by the NetBSD
21 *        Foundation, Inc. and its contributors.
22 * 4. Neither the name of The NetBSD Foundation nor the names of its
23 *    contributors may be used to endorse or promote products derived
24 *    from this software without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36 * POSSIBILITY OF SUCH DAMAGE.
37 */
38
39/*
40 * Copyright (c) 1995 Frank van der Linden
41 * All rights reserved.
42 *
43 * Redistribution and use in source and binary forms, with or without
44 * modification, are permitted provided that the following conditions
45 * are met:
46 * 1. Redistributions of source code must retain the above copyright
47 *    notice, this list of conditions and the following disclaimer.
48 * 2. Redistributions in binary form must reproduce the above copyright
49 *    notice, this list of conditions and the following disclaimer in the
50 *    documentation and/or other materials provided with the distribution.
51 * 3. The name of the author may not be used to endorse or promote products
52 *    derived from this software without specific prior written permission
53 *
54 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
55 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
56 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
57 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
58 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
59 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
60 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
61 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
62 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
63 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
64 *
65 * based on exec_aout.c, sunos_exec.c and svr4_exec.c
66 */
67
68#define	ELFSIZE		32				/* XXX should die */
69
70#include <sys/param.h>
71#include <sys/systm.h>
72#include <sys/kernel.h>
73#include <sys/proc.h>
74#include <sys/malloc.h>
75#include <sys/namei.h>
76#include <sys/vnode.h>
77#include <sys/mount.h>
78#include <sys/exec.h>
79#include <sys/exec_elf.h>
80
81#include <sys/mman.h>
82#include <sys/syscallargs.h>
83
84#include <vm/vm.h>
85#include <vm/vm_param.h>
86#include <vm/vm_map.h>
87
88#include <machine/cpu.h>
89#include <machine/reg.h>
90#include <machine/linux_machdep.h>
91
92#include <compat/linux/linux_types.h>
93#include <compat/linux/linux_syscall.h>
94#include <compat/linux/linux_signal.h>
95#include <compat/linux/linux_syscallargs.h>
96#include <compat/linux/linux_util.h>
97#include <compat/linux/linux_exec.h>
98
99static void *linux_aout_copyargs __P((struct exec_package *,
100    struct ps_strings *, void *, void *));
101static int linux_elf32_signature __P((struct proc *p, struct exec_package *,
102    Elf32_Ehdr *));
103
104#define	LINUX_AOUT_AUX_ARGSIZ	2
105#define LINUX_ELF_AUX_ARGSIZ (sizeof(AuxInfo) * 8 / sizeof(char *))
106
107
108const char linux_emul_path[] = "/emul/linux";
109extern int linux_error[];
110extern char linux_sigcode[], linux_esigcode[];
111extern struct sysent linux_sysent[];
112extern char *linux_syscallnames[];
113
114int exec_linux_aout_prep_zmagic __P((struct proc *, struct exec_package *));
115int exec_linux_aout_prep_nmagic __P((struct proc *, struct exec_package *));
116int exec_linux_aout_prep_omagic __P((struct proc *, struct exec_package *));
117int exec_linux_aout_prep_qmagic __P((struct proc *, struct exec_package *));
118
119struct emul emul_linux_aout = {
120	"linux",
121	linux_error,
122	linux_sendsig,
123	LINUX_SYS_syscall,
124	LINUX_SYS_MAXSYSCALL,
125	linux_sysent,
126	linux_syscallnames,
127	LINUX_AOUT_AUX_ARGSIZ,
128	linux_aout_copyargs,
129	linux_setregs,
130	linux_sigcode,
131	linux_esigcode,
132};
133
134struct emul emul_linux_elf = {
135	"linux",
136	linux_error,
137	linux_sendsig,
138	LINUX_SYS_syscall,
139	LINUX_SYS_MAXSYSCALL,
140	linux_sysent,
141	linux_syscallnames,
142	LINUX_ELF_AUX_ARGSIZ,
143	elf32_copyargs,
144	linux_setregs,
145	linux_sigcode,
146	linux_esigcode,
147};
148
149
150static void *
151linux_aout_copyargs(pack, arginfo, stack, argp)
152	struct exec_package *pack;
153	struct ps_strings *arginfo;
154	void *stack;
155	void *argp;
156{
157	char **cpp = stack;
158	char **stk = stack;
159	char *dp, *sp;
160	size_t len;
161	void *nullp = NULL;
162	int argc = arginfo->ps_nargvstr;
163	int envc = arginfo->ps_nenvstr;
164
165	if (copyout(&argc, cpp++, sizeof(argc)))
166		return NULL;
167
168	/* leave room for envp and argv */
169	cpp += 2;
170	if (copyout(&cpp, &stk[1], sizeof (cpp)))
171		return NULL;
172
173	dp = (char *) (cpp + argc + envc + 2);
174	sp = argp;
175
176	/* XXX don't copy them out, remap them! */
177	arginfo->ps_argvstr = cpp; /* remember location of argv for later */
178
179	for (; --argc >= 0; sp += len, dp += len)
180		if (copyout(&dp, cpp++, sizeof(dp)) ||
181		    copyoutstr(sp, dp, ARG_MAX, &len))
182			return NULL;
183
184	if (copyout(&nullp, cpp++, sizeof(nullp)))
185		return NULL;
186
187	if (copyout(&cpp, &stk[2], sizeof (cpp)))
188		return NULL;
189
190	arginfo->ps_envstr = cpp; /* remember location of envp for later */
191
192	for (; --envc >= 0; sp += len, dp += len)
193		if (copyout(&dp, cpp++, sizeof(dp)) ||
194		    copyoutstr(sp, dp, ARG_MAX, &len))
195			return NULL;
196
197	if (copyout(&nullp, cpp++, sizeof(nullp)))
198		return NULL;
199
200	return cpp;
201}
202
203int
204exec_linux_aout_makecmds(p, epp)
205	struct proc *p;
206	struct exec_package *epp;
207{
208	struct exec *linux_ep = epp->ep_hdr;
209	int machtype, magic;
210	int error = ENOEXEC;
211
212	magic = LINUX_N_MAGIC(linux_ep);
213	machtype = LINUX_N_MACHTYPE(linux_ep);
214
215
216	if (machtype != LINUX_MID_MACHINE)
217		return (ENOEXEC);
218
219	switch (magic) {
220	case QMAGIC:
221		error = exec_linux_aout_prep_qmagic(p, epp);
222		break;
223	case ZMAGIC:
224		error = exec_linux_aout_prep_zmagic(p, epp);
225		break;
226	case NMAGIC:
227		error = exec_linux_aout_prep_nmagic(p, epp);
228		break;
229	case OMAGIC:
230		error = exec_linux_aout_prep_omagic(p, epp);
231		break;
232	}
233	if (error == 0)
234		epp->ep_emul = &emul_linux_aout;
235	return error;
236}
237
238/*
239 * Since text starts at 0x400 in Linux ZMAGIC executables, and 0x400
240 * is very likely not page aligned on most architectures, it is treated
241 * as an NMAGIC here. XXX
242 */
243
244int
245exec_linux_aout_prep_zmagic(p, epp)
246	struct proc *p;
247	struct exec_package *epp;
248{
249	struct exec *execp = epp->ep_hdr;
250
251	epp->ep_taddr = LINUX_N_TXTADDR(*execp, ZMAGIC);
252	epp->ep_tsize = execp->a_text;
253	epp->ep_daddr = LINUX_N_DATADDR(*execp, ZMAGIC);
254	epp->ep_dsize = execp->a_data + execp->a_bss;
255	epp->ep_entry = execp->a_entry;
256
257	/* set up command for text segment */
258	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
259	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, ZMAGIC),
260	    VM_PROT_READ|VM_PROT_EXECUTE);
261
262	/* set up command for data segment */
263	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
264	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, ZMAGIC),
265	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
266
267	/* set up command for bss segment */
268	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
269	    epp->ep_daddr + execp->a_data, NULLVP, 0,
270	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
271
272	return exec_aout_setup_stack(p, epp);
273}
274
275/*
276 * exec_aout_prep_nmagic(): Prepare Linux NMAGIC package.
277 * Not different from the normal stuff.
278 */
279
280int
281exec_linux_aout_prep_nmagic(p, epp)
282	struct proc *p;
283	struct exec_package *epp;
284{
285	struct exec *execp = epp->ep_hdr;
286	long bsize, baddr;
287
288	epp->ep_taddr = LINUX_N_TXTADDR(*execp, NMAGIC);
289	epp->ep_tsize = execp->a_text;
290	epp->ep_daddr = LINUX_N_DATADDR(*execp, NMAGIC);
291	epp->ep_dsize = execp->a_data + execp->a_bss;
292	epp->ep_entry = execp->a_entry;
293
294	/* set up command for text segment */
295	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_text,
296	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, NMAGIC),
297	    VM_PROT_READ|VM_PROT_EXECUTE);
298
299	/* set up command for data segment */
300	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn, execp->a_data,
301	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, NMAGIC),
302	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
303
304	/* set up command for bss segment */
305	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
306	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
307	if (bsize > 0)
308		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
309		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
310
311	return exec_aout_setup_stack(p, epp);
312}
313
314/*
315 * exec_aout_prep_omagic(): Prepare Linux OMAGIC package.
316 * Business as usual.
317 */
318
319int
320exec_linux_aout_prep_omagic(p, epp)
321	struct proc *p;
322	struct exec_package *epp;
323{
324	struct exec *execp = epp->ep_hdr;
325	long dsize, bsize, baddr;
326
327	epp->ep_taddr = LINUX_N_TXTADDR(*execp, OMAGIC);
328	epp->ep_tsize = execp->a_text;
329	epp->ep_daddr = LINUX_N_DATADDR(*execp, OMAGIC);
330	epp->ep_dsize = execp->a_data + execp->a_bss;
331	epp->ep_entry = execp->a_entry;
332
333	/* set up command for text and data segments */
334	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_readvn,
335	    execp->a_text + execp->a_data, epp->ep_taddr, epp->ep_vp,
336	    LINUX_N_TXTOFF(*execp, OMAGIC), VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
337
338	/* set up command for bss segment */
339	baddr = roundup(epp->ep_daddr + execp->a_data, NBPG);
340	bsize = epp->ep_daddr + epp->ep_dsize - baddr;
341	if (bsize > 0)
342		NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, bsize, baddr,
343		    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
344
345	/*
346	 * Make sure (# of pages) mapped above equals (vm_tsize + vm_dsize);
347	 * obreak(2) relies on this fact. Both `vm_tsize' and `vm_dsize' are
348	 * computed (in execve(2)) by rounding *up* `ep_tsize' and `ep_dsize'
349	 * respectively to page boundaries.
350	 * Compensate `ep_dsize' for the amount of data covered by the last
351	 * text page.
352	 */
353	dsize = epp->ep_dsize + execp->a_text - roundup(execp->a_text, NBPG);
354	epp->ep_dsize = (dsize > 0) ? dsize : 0;
355	return exec_aout_setup_stack(p, epp);
356}
357
358int
359exec_linux_aout_prep_qmagic(p, epp)
360	struct proc *p;
361	struct exec_package *epp;
362{
363	struct exec *execp = epp->ep_hdr;
364
365	epp->ep_taddr = LINUX_N_TXTADDR(*execp, QMAGIC);
366	epp->ep_tsize = execp->a_text;
367	epp->ep_daddr = LINUX_N_DATADDR(*execp, QMAGIC);
368	epp->ep_dsize = execp->a_data + execp->a_bss;
369	epp->ep_entry = execp->a_entry;
370
371	/*
372	 * check if vnode is in open for writing, because we want to
373	 * demand-page out of it.  if it is, don't do it, for various
374	 * reasons
375	 */
376	if ((execp->a_text != 0 || execp->a_data != 0) &&
377	    epp->ep_vp->v_writecount != 0) {
378#ifdef DIAGNOSTIC
379		if (epp->ep_vp->v_flag & VTEXT)
380			panic("exec: a VTEXT vnode has writecount != 0\n");
381#endif
382		return ETXTBSY;
383	}
384	epp->ep_vp->v_flag |= VTEXT;
385
386	/* set up command for text segment */
387	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_text,
388	    epp->ep_taddr, epp->ep_vp, LINUX_N_TXTOFF(*execp, QMAGIC),
389	    VM_PROT_READ|VM_PROT_EXECUTE);
390
391	/* set up command for data segment */
392	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_pagedvn, execp->a_data,
393	    epp->ep_daddr, epp->ep_vp, LINUX_N_DATOFF(*execp, QMAGIC),
394	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
395
396	/* set up command for bss segment */
397	NEW_VMCMD(&epp->ep_vmcmds, vmcmd_map_zero, execp->a_bss,
398	    epp->ep_daddr + execp->a_data, NULLVP, 0,
399	    VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
400
401	return exec_aout_setup_stack(p, epp);
402}
403
404/*
405 * Take advantage of the fact that all the linux binaries are compiled
406 * with gcc, and gcc sticks in the comment field a signature. Note that
407 * on SVR4 binaries, the gcc signature will follow the OS name signature,
408 * that will not be a problem. We don't bother to read in the string table,
409 * but we check all the progbits headers.
410 */
411static int
412linux_elf32_signature(p, epp, eh)
413	struct proc *p;
414	struct exec_package *epp;
415	Elf32_Ehdr *eh;
416{
417	size_t shsize = sizeof(Elf32_Shdr) * eh->e_shnum;
418	size_t i;
419	static const char signature[] = "\0GCC: (GNU) ";
420	char buf[sizeof(signature) - 1];
421	Elf32_Shdr *sh;
422	int error;
423
424	sh = (Elf32_Shdr *) malloc(shsize, M_TEMP, M_WAITOK);
425
426	if ((error = elf32_read_from(p, epp->ep_vp, eh->e_shoff,
427	    (caddr_t) sh, shsize)) != 0)
428		goto out;
429
430	for (i = 0; i < eh->e_shnum; i++) {
431		Elf32_Shdr *s = &sh[i];
432
433		/*
434		 * Identify candidates for the comment header;
435		 * Header cannot have a load address, or flags and
436		 * it must be large enough.
437		 */
438		if (s->sh_type != Elf_sht_progbits ||
439		    s->sh_addr != 0 ||
440		    s->sh_flags != 0 ||
441		    s->sh_size < sizeof(signature) - 1)
442			continue;
443
444		if ((error = elf32_read_from(p, epp->ep_vp, s->sh_offset,
445		    (caddr_t) buf, sizeof(signature) - 1)) != 0)
446			goto out;
447
448		/*
449		 * error is 0, if the signatures match we are done.
450		 */
451		if (memcmp(buf, signature, sizeof(signature) - 1) == 0)
452			goto out;
453	}
454	error = EFTYPE;
455
456out:
457	free(sh, M_TEMP);
458	return error;
459}
460
461int
462linux_elf32_probe(p, epp, eh, itp, pos)
463	struct proc *p;
464	struct exec_package *epp;
465	Elf32_Ehdr *eh;
466	char *itp;
467	Elf32_Addr *pos;
468{
469	char *bp;
470	int error;
471	size_t len;
472
473	if ((error = linux_elf32_signature(p, epp, eh)) != 0)
474		return error;
475
476	if (itp[0]) {
477		if ((error = emul_find(p, NULL, linux_emul_path, itp, &bp, 0)))
478			return error;
479		if ((error = copystr(bp, itp, MAXPATHLEN, &len)))
480			return error;
481		free(bp, M_TEMP);
482	}
483	epp->ep_emul = &emul_linux_elf;
484	*pos = ELF32_NO_ADDR;
485	return 0;
486}
487
488/*
489 * The Linux system call to load shared libraries, a.out version. The
490 * a.out shared libs are just files that are mapped onto a fixed
491 * address in the process' address space. The address is given in
492 * a_entry. Read in the header, set up some VM commands and run them.
493 *
494 * Yes, both text and data are mapped at once, so we're left with
495 * writeable text for the shared libs. The Linux crt0 seemed to break
496 * sometimes when data was mapped seperately. It munmapped a uselib()
497 * of ld.so by hand, which failed with shared text and data for ld.so
498 * Yuck.
499 *
500 * Because of the problem with ZMAGIC executables (text starts
501 * at 0x400 in the file, but needs to be mapped at 0), ZMAGIC
502 * shared libs are not handled very efficiently :-(
503 */
504
505int
506linux_sys_uselib(p, v, retval)
507	struct proc *p;
508	void *v;
509	register_t *retval;
510{
511	struct linux_sys_uselib_args /* {
512		syscallarg(char *) path;
513	} */ *uap = v;
514	caddr_t sg;
515	long bsize, dsize, tsize, taddr, baddr, daddr;
516	struct nameidata ni;
517	struct vnode *vp;
518	struct exec hdr;
519	struct exec_vmcmd_set vcset;
520	int i, magic, error;
521	size_t rem;
522
523	sg = stackgap_init(p->p_emul);
524	LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
525
526	NDINIT(&ni, LOOKUP, FOLLOW, UIO_USERSPACE, SCARG(uap, path), p);
527
528	if ((error = namei(&ni)))
529		return error;
530
531	vp = ni.ni_vp;
532
533	if ((error = vn_rdwr(UIO_READ, vp, (caddr_t) &hdr, LINUX_AOUT_HDR_SIZE,
534			     0, UIO_SYSSPACE, IO_NODELOCKED, p->p_ucred,
535			     &rem, p))) {
536		vrele(vp);
537		return error;
538	}
539
540	if (rem != 0) {
541		vrele(vp);
542		return ENOEXEC;
543	}
544
545	if (LINUX_N_MACHTYPE(&hdr) != LINUX_MID_MACHINE)
546		return ENOEXEC;
547
548	magic = LINUX_N_MAGIC(&hdr);
549	taddr = hdr.a_entry & (~(NBPG - 1));
550	tsize = hdr.a_text;
551	daddr = taddr + tsize;
552	dsize = hdr.a_data + hdr.a_bss;
553
554	if ((hdr.a_text != 0 || hdr.a_data != 0) && vp->v_writecount != 0) {
555		vrele(vp);
556                return ETXTBSY;
557        }
558	vp->v_flag |= VTEXT;
559
560	vcset.evs_cnt = 0;
561	vcset.evs_used = 0;
562
563	NEW_VMCMD(&vcset,
564		  magic == ZMAGIC ? vmcmd_map_readvn : vmcmd_map_pagedvn,
565		  hdr.a_text + hdr.a_data, taddr,
566		  vp, LINUX_N_TXTOFF(hdr, magic),
567		  VM_PROT_READ|VM_PROT_EXECUTE|VM_PROT_WRITE);
568
569	baddr = roundup(daddr + hdr.a_data, NBPG);
570	bsize = daddr + dsize - baddr;
571        if (bsize > 0) {
572                NEW_VMCMD(&vcset, vmcmd_map_zero, bsize, baddr,
573                    NULLVP, 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE);
574	}
575
576	for (i = 0; i < vcset.evs_used && !error; i++) {
577		struct exec_vmcmd *vcp;
578
579		vcp = &vcset.evs_cmds[i];
580		error = (*vcp->ev_proc)(p, vcp);
581	}
582
583	kill_vmcmds(&vcset);
584
585	vrele(vp);
586
587	return error;
588}
589
590/*
591 * Execve(2). Just check the alternate emulation path, and pass it on
592 * to the NetBSD execve().
593 */
594int
595linux_sys_execve(p, v, retval)
596	struct proc *p;
597	void *v;
598	register_t *retval;
599{
600	struct linux_sys_execve_args /* {
601		syscallarg(char *) path;
602		syscallarg(char **) argv;
603		syscallarg(char **) envp;
604	} */ *uap = v;
605	struct sys_execve_args ap;
606	caddr_t sg;
607
608	sg = stackgap_init(p->p_emul);
609	LINUX_CHECK_ALT_EXIST(p, &sg, SCARG(uap, path));
610
611	SCARG(&ap, path) = SCARG(uap, path);
612	SCARG(&ap, argp) = SCARG(uap, argp);
613	SCARG(&ap, envp) = SCARG(uap, envp);
614
615	return sys_execve(p, &ap, retval);
616}
617