1 // Copyright 2016 The Fuchsia Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "userboot-elf.h"
6
7 #include "bootfs.h"
8 #include "util.h"
9
10 #pragma GCC visibility push(hidden)
11
12 #include <elf.h>
13 #include <elfload/elfload.h>
14 #include <zircon/compiler.h>
15 #include <zircon/processargs.h>
16 #include <zircon/syscalls.h>
17 #include <stdbool.h>
18 #include <string.h>
19
20 #pragma GCC visibility pop
21
22 #define INTERP_PREFIX "lib/"
23
load(zx_handle_t log,const char * what,zx_handle_t vmar,zx_handle_t vmo,uintptr_t * interp_off,size_t * interp_len,zx_handle_t * segments_vmar,size_t * stack_size,bool close_vmo,bool return_entry)24 static zx_vaddr_t load(zx_handle_t log, const char* what,
25 zx_handle_t vmar, zx_handle_t vmo,
26 uintptr_t* interp_off, size_t* interp_len,
27 zx_handle_t* segments_vmar, size_t* stack_size,
28 bool close_vmo, bool return_entry) {
29 elf_load_header_t header;
30 uintptr_t phoff;
31 zx_status_t status = elf_load_prepare(vmo, NULL, 0, &header, &phoff);
32 check(log, status, "elf_load_prepare failed");
33
34 elf_phdr_t phdrs[header.e_phnum];
35 status = elf_load_read_phdrs(vmo, phdrs, phoff, header.e_phnum);
36 check(log, status, "elf_load_read_phdrs failed");
37
38 if (interp_off != NULL &&
39 elf_load_find_interp(phdrs, header.e_phnum, interp_off, interp_len))
40 return 0;
41
42 if (stack_size != NULL) {
43 for (size_t i = 0; i < header.e_phnum; ++i) {
44 if (phdrs[i].p_type == PT_GNU_STACK && phdrs[i].p_memsz > 0)
45 *stack_size = phdrs[i].p_memsz;
46 }
47 }
48
49 zx_vaddr_t base, entry;
50 status = elf_load_map_segments(vmar, &header, phdrs, vmo,
51 segments_vmar, &base, &entry);
52 check(log, status, "elf_load_map_segments failed");
53
54 if (close_vmo)
55 zx_handle_close(vmo);
56
57 printl(log, "userboot: loaded %s at %p, entry point %p\n",
58 what, (void*)base, (void*)entry);
59 return return_entry ? entry : base;
60 }
61
elf_load_vmo(zx_handle_t log,zx_handle_t vmar,zx_handle_t vmo)62 zx_vaddr_t elf_load_vmo(zx_handle_t log, zx_handle_t vmar, zx_handle_t vmo) {
63 return load(log, "vDSO", vmar, vmo, NULL, NULL, NULL, NULL, false, false);
64 }
65
66 enum loader_bootstrap_handle_index {
67 BOOTSTRAP_EXEC_VMO,
68 BOOTSTRAP_LOGGER,
69 BOOTSTRAP_PROC,
70 BOOTSTRAP_ROOT_VMAR,
71 BOOTSTRAP_SEGMENTS_VMAR,
72 BOOTSTRAP_THREAD,
73 BOOTSTRAP_LOADER_SVC,
74 BOOTSTRAP_HANDLES
75 };
76
77 #define LOADER_BOOTSTRAP_ENVIRON "LD_DEBUG=1"
78 #define LOADER_BOOTSTRAP_ENVIRON_NUM 1
79
80 struct loader_bootstrap_message {
81 zx_proc_args_t header;
82 uint32_t handle_info[BOOTSTRAP_HANDLES];
83 char env[sizeof(LOADER_BOOTSTRAP_ENVIRON)];
84 };
85
stuff_loader_bootstrap(zx_handle_t log,zx_handle_t proc,zx_handle_t root_vmar,zx_handle_t thread,zx_handle_t to_child,zx_handle_t segments_vmar,zx_handle_t vmo,zx_handle_t * loader_svc)86 static void stuff_loader_bootstrap(zx_handle_t log,
87 zx_handle_t proc, zx_handle_t root_vmar,
88 zx_handle_t thread,
89 zx_handle_t to_child,
90 zx_handle_t segments_vmar,
91 zx_handle_t vmo,
92 zx_handle_t* loader_svc) {
93 struct loader_bootstrap_message msg = {
94 .header = {
95 .protocol = ZX_PROCARGS_PROTOCOL,
96 .version = ZX_PROCARGS_VERSION,
97 .handle_info_off = offsetof(struct loader_bootstrap_message,
98 handle_info),
99 .environ_num = LOADER_BOOTSTRAP_ENVIRON_NUM,
100 .environ_off = offsetof(struct loader_bootstrap_message, env),
101 },
102 .handle_info = {
103 [BOOTSTRAP_EXEC_VMO] = PA_HND(PA_VMO_EXECUTABLE, 0),
104 [BOOTSTRAP_LOGGER] = PA_HND(PA_FDIO_LOGGER, 0),
105 [BOOTSTRAP_PROC] = PA_HND(PA_PROC_SELF, 0),
106 [BOOTSTRAP_ROOT_VMAR] = PA_HND(PA_VMAR_ROOT, 0),
107 [BOOTSTRAP_SEGMENTS_VMAR] = PA_HND(PA_VMAR_LOADED, 0),
108 [BOOTSTRAP_THREAD] = PA_HND(PA_THREAD_SELF, 0),
109 [BOOTSTRAP_LOADER_SVC] = PA_HND(PA_LDSVC_LOADER, 0),
110 },
111 .env = LOADER_BOOTSTRAP_ENVIRON,
112 };
113 zx_handle_t handles[] = {
114 [BOOTSTRAP_EXEC_VMO] = vmo,
115 [BOOTSTRAP_LOGGER] = ZX_HANDLE_INVALID,
116 [BOOTSTRAP_PROC] = ZX_HANDLE_INVALID,
117 [BOOTSTRAP_ROOT_VMAR] = ZX_HANDLE_INVALID,
118 [BOOTSTRAP_SEGMENTS_VMAR] = segments_vmar,
119 [BOOTSTRAP_THREAD] = ZX_HANDLE_INVALID,
120 [BOOTSTRAP_LOADER_SVC] = ZX_HANDLE_INVALID,
121 };
122 check(log, zx_handle_duplicate(log, ZX_RIGHT_SAME_RIGHTS,
123 &handles[BOOTSTRAP_LOGGER]),
124 "zx_handle_duplicate failed");
125 check(log, zx_handle_duplicate(proc, ZX_RIGHT_SAME_RIGHTS,
126 &handles[BOOTSTRAP_PROC]),
127 "zx_handle_duplicate failed");
128 check(log, zx_handle_duplicate(root_vmar, ZX_RIGHT_SAME_RIGHTS,
129 &handles[BOOTSTRAP_ROOT_VMAR]),
130 "zx_handle_duplicate failed");
131 check(log, zx_handle_duplicate(thread, ZX_RIGHT_SAME_RIGHTS,
132 &handles[BOOTSTRAP_THREAD]),
133 "zx_handle_duplicate failed");
134 check(log, zx_channel_create(0, loader_svc,
135 &handles[BOOTSTRAP_LOADER_SVC]),
136 "zx_channel_create failed");
137
138 zx_status_t status = zx_channel_write(
139 to_child, 0, &msg, sizeof(msg), handles, countof(handles));
140 check(log, status,
141 "zx_channel_write of loader bootstrap message failed");
142 }
143
elf_load_bootfs(zx_handle_t log,struct bootfs * fs,zx_handle_t proc,zx_handle_t vmar,zx_handle_t thread,const char * filename,zx_handle_t to_child,size_t * stack_size,zx_handle_t * loader_svc)144 zx_vaddr_t elf_load_bootfs(zx_handle_t log, struct bootfs *fs, zx_handle_t proc,
145 zx_handle_t vmar, zx_handle_t thread,
146 const char* filename, zx_handle_t to_child,
147 size_t* stack_size, zx_handle_t* loader_svc) {
148 zx_handle_t vmo = bootfs_open(log, "program", fs, filename);
149
150 uintptr_t interp_off = 0;
151 size_t interp_len = 0;
152 zx_vaddr_t entry = load(log, filename,
153 vmar, vmo, &interp_off, &interp_len,
154 NULL, stack_size, true, true);
155 if (interp_len > 0) {
156 char interp[sizeof(INTERP_PREFIX) + interp_len];
157 memcpy(interp, INTERP_PREFIX, sizeof(INTERP_PREFIX) - 1);
158 zx_status_t status = zx_vmo_read(
159 vmo, &interp[sizeof(INTERP_PREFIX) - 1],
160 interp_off, interp_len);
161 if (status < 0)
162 fail(log, "zx_vmo_read failed: %d", status);
163 interp[sizeof(INTERP_PREFIX) - 1 + interp_len] = '\0';
164
165 printl(log, "'%s' has PT_INTERP \"%s\"", filename, interp);
166
167 zx_handle_t interp_vmo =
168 bootfs_open(log, "dynamic linker", fs, interp);
169 zx_handle_t interp_vmar;
170 entry = load(log, interp, vmar, interp_vmo,
171 NULL, NULL, &interp_vmar, NULL, true, true);
172
173 stuff_loader_bootstrap(log, proc, vmar, thread, to_child,
174 interp_vmar, vmo, loader_svc);
175 }
176 return entry;
177 }
178