1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
|
/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/loader.h>
#include <sys/cdefs.h>
#include <sys/elf.h>
#include <sys/types.h>
#include <sys/syslog.h>
#include <sys/errno.h>
#include <sys/proc.h>
#include <vm/vm.h>
#include <vm/map.h>
#include <vm/physseg.h>
#include <vm/dynalloc.h>
#include <string.h>
#include <assert.h>
__MODULE_NAME("kern_loader");
__KERNEL_META("$Hyra$: kern_loader.c, Ian Marco Moffett, "
"Kernel ELF loader");
#define pr_trace(fmt, ...) kprintf("loader: " fmt, ##__VA_ARGS__)
#define pr_error(...) pr_trace(__VA_ARGS__)
#define PHDR(hdrptr, IDX) \
(void *)((uintptr_t)hdr + (hdrptr)->e_phoff + (hdrptr->e_phentsize*IDX))
int
loader_unload(struct vas vas, struct vm_range *exec_range)
{
size_t start, end;
start = exec_range->start;
end = exec_range->end;
/* FIXME: Figure out how to free physical memory too */
return vm_map_destroy(vas, start, (end - start));
}
uintptr_t
loader_init_stack(void *stack_top, struct exec_args args)
{
uintptr_t *sp = stack_top;
uintptr_t old_sp = 0;
size_t argc, envc, len;
char **argvp = args.argp;
char **envp = args.envp;
struct auxval auxv = args.auxv;
/* Copy strings */
old_sp = (uintptr_t)sp;
for (argc = 0; argvp[argc] != NULL; ++argc) {
len = strlen(argvp[argc]) + 1;
sp = (void *)((char *)sp - len);
memcpy((char *)sp, argvp[argc], len);
}
for (envc = 0; envp[envc] != NULL; ++envc) {
len = strlen(envp[envc]) + 1;
sp = (void *)((char *)sp - len);
memcpy((char *)sp, envp[envc], len);
}
/* Ensure the stack is aligned */
sp = (void *)__ALIGN_DOWN((uintptr_t)sp, 16);
if (((argc + envc + 1) & 1) != 0)
--sp;
AUXVAL(sp, AT_NULL, 0x0);
AUXVAL(sp, AT_SECURE, 0x0);
AUXVAL(sp, AT_ENTRY, auxv.at_entry);
AUXVAL(sp, AT_PHDR, auxv.at_phdr);
AUXVAL(sp, AT_PHNUM, auxv.at_phnum);
AUXVAL(sp, AT_PAGESIZE, vm_get_page_size());
STACK_PUSH(sp, 0);
/* Copy envp pointers */
sp -= envc;
for (int i = 0; i < envc; ++i) {
len = strlen(envp[i]) + 1;
old_sp -= len;
sp[i] = KERN_TO_USER(old_sp);
}
/* Copy argvp pointers */
STACK_PUSH(sp, 0);
sp -= argc;
for (int i = 0; i < argc; ++i) {
len = strlen(argvp[i]) + 1;
old_sp -= len;
sp[i] = KERN_TO_USER(old_sp);
}
STACK_PUSH(sp, argc);
return (uintptr_t)sp;
}
int loader_load(struct vas vas, const void *dataptr, struct auxval *auxv,
size_t load_base, char **ld_path, struct vm_range *prog_range)
{
const Elf64_Ehdr *hdr = dataptr;
Elf64_Phdr *phdr;
vm_prot_t prot = PROT_USER;
uintptr_t physmem;
size_t misalign, page_count, map_len;
int status;
uintptr_t start_addr = (uintptr_t)-1;
uintptr_t end_addr = 0;
const size_t GRANULE = vm_get_page_size();
void *tmp_ptr;
if (auxv == NULL) {
pr_error("Auxval argument NULL\n");
return -1;
}
if (memcmp(hdr->e_ident, ELFMAG, 4) != 0) {
/* Bad ELF header */
pr_error("ELF header bad! (Magic incorrect)\n");
return -1;
}
/* Parse program headers */
for (size_t i = 0; i < hdr->e_phnum; ++i) {
phdr = PHDR(hdr, i);
switch (phdr->p_type) {
case PT_LOAD:
if (__TEST(phdr->p_flags, PF_W))
prot |= PROT_WRITE;
if (__TEST(phdr->p_flags, PF_X)) {
prot |= PROT_EXEC;
}
misalign = phdr->p_vaddr & (GRANULE - 1);
page_count = __DIV_ROUNDUP(phdr->p_memsz + misalign, GRANULE);
physmem = vm_alloc_pageframe(page_count);
map_len = page_count * GRANULE;
/*
* Now we want to compute the start address of the
* program and the end address.
*/
if (start_addr == (uintptr_t)-1) {
start_addr = phdr->p_vaddr;
}
end_addr = __MAX(end_addr, phdr->p_vaddr + page_count*GRANULE);
/* Do we not have enough page frames? */
if (physmem == 0) {
pr_error("Failed to allocate physical memory\n");
vm_free_pageframe(physmem, page_count);
return -ENOMEM;
}
status = vm_map_create(vas, phdr->p_vaddr + load_base, physmem, prot, map_len);
if (status != 0) {
return status;
}
/* Now we want to copy the data */
tmp_ptr = (void *)((uintptr_t)hdr + phdr->p_offset);
memcpy(PHYS_TO_VIRT(physmem), tmp_ptr, phdr->p_filesz);
break;
case PT_INTERP:
if (ld_path == NULL) {
break;
}
*ld_path = dynalloc(phdr->p_filesz);
if (ld_path == NULL) {
pr_error("Failed to allocate memory for PT_INTERP path\n");
return -ENOMEM;
}
memcpy(*ld_path, (char *)hdr + phdr->p_offset, phdr->p_filesz);
break;
case PT_PHDR:
auxv->at_phdr = phdr->p_vaddr + load_base;
break;
}
}
auxv->at_entry = hdr->e_entry + load_base;
auxv->at_phent = hdr->e_phentsize;
auxv->at_phnum = hdr->e_phnum;
prog_range->start = start_addr;
prog_range->end = end_addr;
return 0;
}
|
