1/*-
2 * Copyright (c) 2015 Nuxi, https://nuxi.nl/
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 */
25
26#include <sys/cdefs.h>
27__FBSDID("$FreeBSD$");
28
29#include <sys/param.h>
30#include <sys/imgact.h>
31#include <sys/kernel.h>
32#include <sys/module.h>
33#include <sys/proc.h>
34#include <sys/smp.h>
35#include <sys/sysctl.h>
36#include <sys/sysent.h>
37#include <sys/systm.h>
38
39#include <contrib/cloudabi/cloudabi32_types.h>
40
41#include <compat/cloudabi/cloudabi_util.h>
42
43#include <compat/cloudabi32/cloudabi32_util.h>
44
45extern char _binary_cloudabi32_vdso_o_start[];
46extern char _binary_cloudabi32_vdso_o_end[];
47
48register_t *
49cloudabi32_copyout_strings(struct image_params *imgp)
50{
51	struct image_args *args;
52	uintptr_t begin;
53	size_t len;
54
55	/* Copy out program arguments. */
56	args = imgp->args;
57	len = args->begin_envv - args->begin_argv;
58	begin = rounddown2(imgp->sysent->sv_usrstack - len, sizeof(register_t));
59	copyout(args->begin_argv, (void *)begin, len);
60	return ((register_t *)begin);
61}
62
63int
64cloudabi32_fixup(register_t **stack_base, struct image_params *imgp)
65{
66	char canarybuf[64], pidbuf[16];
67	Elf32_Auxargs *args;
68	struct thread *td;
69	void *argdata, *canary, *pid;
70	size_t argdatalen;
71	int error;
72
73	/*
74	 * CloudABI executables do not store the FreeBSD OS release
75	 * number in their header. Set the OS release number to the
76	 * latest version of FreeBSD, so that system calls behave as if
77	 * called natively.
78	 */
79	td = curthread;
80	td->td_proc->p_osrel = __FreeBSD_version;
81
82	argdata = *stack_base;
83
84	/* Store canary for stack smashing protection. */
85	arc4rand(canarybuf, sizeof(canarybuf), 0);
86	*stack_base -= howmany(sizeof(canarybuf), sizeof(register_t));
87	canary = *stack_base;
88	error = copyout(canarybuf, canary, sizeof(canarybuf));
89	if (error != 0)
90		return (error);
91
92	/*
93	 * Generate a random UUID that identifies the process. Right now
94	 * we don't store this UUID in the kernel. Ideally, it should be
95	 * exposed through ps(1).
96	 */
97	arc4rand(pidbuf, sizeof(pidbuf), 0);
98	pidbuf[6] = (pidbuf[6] & 0x0f) | 0x40;
99	pidbuf[8] = (pidbuf[8] & 0x3f) | 0x80;
100	*stack_base -= howmany(sizeof(pidbuf), sizeof(register_t));
101	pid = *stack_base;
102	error = copyout(pidbuf, pid, sizeof(pidbuf));
103	if (error != 0)
104		return (error);
105
106	/*
107	 * Compute length of program arguments. As the argument data is
108	 * binary safe, we had to add a trailing null byte in
109	 * exec_copyin_data_fds(). Undo this by reducing the length.
110	 */
111	args = (Elf32_Auxargs *)imgp->auxargs;
112	argdatalen = imgp->args->begin_envv - imgp->args->begin_argv;
113	if (argdatalen > 0)
114		--argdatalen;
115
116	/* Write out an auxiliary vector. */
117	cloudabi32_auxv_t auxv[] = {
118#define	VAL(type, val)	{ .a_type = (type), .a_val = (val) }
119#define	PTR(type, ptr)	{ .a_type = (type), .a_ptr = (uintptr_t)(ptr) }
120		PTR(CLOUDABI_AT_ARGDATA, argdata),
121		VAL(CLOUDABI_AT_ARGDATALEN, argdatalen),
122		VAL(CLOUDABI_AT_BASE, args->base),
123		PTR(CLOUDABI_AT_CANARY, canary),
124		VAL(CLOUDABI_AT_CANARYLEN, sizeof(canarybuf)),
125		VAL(CLOUDABI_AT_NCPUS, mp_ncpus),
126		VAL(CLOUDABI_AT_PAGESZ, args->pagesz),
127		PTR(CLOUDABI_AT_PHDR, args->phdr),
128		VAL(CLOUDABI_AT_PHNUM, args->phnum),
129		PTR(CLOUDABI_AT_PID, pid),
130		PTR(CLOUDABI_AT_SYSINFO_EHDR,
131		    imgp->proc->p_sysent->sv_shared_page_base),
132		VAL(CLOUDABI_AT_TID, td->td_tid),
133#undef VAL
134#undef PTR
135		{ .a_type = CLOUDABI_AT_NULL },
136	};
137	*stack_base -= howmany(sizeof(auxv), sizeof(register_t));
138	error = copyout(auxv, *stack_base, sizeof(auxv));
139	if (error != 0)
140		return (error);
141
142	/* Reserve space for storing the TCB. */
143	*stack_base -= howmany(sizeof(cloudabi32_tcb_t), sizeof(register_t));
144	return (0);
145}
146
147static int
148cloudabi32_modevent(module_t mod, int type, void *data)
149{
150
151	switch (type) {
152	case MOD_LOAD:
153		cloudabi_vdso_init(cloudabi32_brand.sysvec,
154		    _binary_cloudabi32_vdso_o_start,
155		    _binary_cloudabi32_vdso_o_end);
156		if (elf32_insert_brand_entry(&cloudabi32_brand) < 0) {
157			printf("Failed to add CloudABI ELF brand handler\n");
158			return (EINVAL);
159		}
160		return (0);
161	case MOD_UNLOAD:
162		if (elf32_brand_inuse(&cloudabi32_brand))
163			return (EBUSY);
164		if (elf32_remove_brand_entry(&cloudabi32_brand) < 0) {
165			printf("Failed to remove CloudABI ELF brand handler\n");
166			return (EINVAL);
167		}
168		cloudabi_vdso_destroy(cloudabi32_brand.sysvec);
169		return (0);
170	default:
171		return (EOPNOTSUPP);
172	}
173}
174
175static moduledata_t cloudabi32_module = {
176	"cloudabi32",
177	cloudabi32_modevent,
178	NULL
179};
180
181DECLARE_MODULE_TIED(cloudabi32, cloudabi32_module, SI_SUB_EXEC, SI_ORDER_ANY);
182MODULE_DEPEND(cloudabi32, cloudabi, 1, 1, 1);
183FEATURE(cloudabi32, "CloudABI 32bit support");
184