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
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
|
/*
* 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/sched.h>
#include <sys/system.h>
#include <sys/errno.h>
#include <sys/vfs.h>
#include <sys/exec.h>
#include <sys/filedesc.h>
#include <sys/signal.h>
#include <sys/loader.h>
#include <sys/cdefs.h>
#include <vm/dynalloc.h>
#include <sys/syslog.h>
#include <string.h>
__MODULE_NAME("exec");
__KERNEL_META("$Hyra$: kern_exec.c, Ian Marco Moffett, "
"exec() implementation");
#define ARG_MAX 1024
/*
* Allocates a buffer in in `res' and fetches
* the args from `argv'
*
* @argv: User argv
* @res: Exec args result.
*
* XXX: res->argp is dynamically allocated, remember
* to free it!
*/
static int
exec_get_args(char **argv, struct exec_args *res)
{
static char *dmmy_envp[] = {NULL};
const size_t ARG_LEN = sizeof(char) * ARG_MAX;
char *argp = NULL;
void *tmp;
struct proc *td;
size_t argp_len = 0;
if (res == NULL)
return -EINVAL;
/* Allocate argp */
res->argp = dynalloc(ARG_LEN);
if (res->argp == NULL)
return -ENOMEM;
td = this_td();
res->vas = td->addrsp;
res->envp = dmmy_envp;
/* Read argv */
copyin((uintptr_t)argv, &argp, sizeof(char *));
for (;;) {
if (argp == NULL) {
res->argp[argp_len] = NULL;
break;
}
/* Fetch this arg and get next argp */
copyinstr((uintptr_t)argp, res->argp[argp_len++], ARG_MAX);
copyin((uintptr_t)++argv, &argp, sizeof(char *));
/* Try to resize the argp buffer */
tmp = dynrealloc(res->argp, ARG_LEN * (argp_len + 1));
if (tmp == NULL) {
dynfree(res->argp);
return -ENOMEM;
}
res->argp = tmp;
}
return 0;
}
/*
* Reset the stack of the process.
*
* @td: Target thread.
* @args: Exec args.
*
* Returns the new stack pointer.
*/
static uintptr_t
exec_set_stack(struct proc *td, struct exec_args args)
{
struct vm_range *stack_range;
uintptr_t stack_top, sp;
stack_range = &td->addr_range[ADDR_RANGE_STACK];
stack_top = stack_range->start + (PROC_STACK_SIZE);
sp = loader_init_stack((void *)stack_top, args);
return sp;
}
/*
* execv() implementation.
*
* @pathname: Path of file to execute.
* @argv: Args.
* @sp_res: Pointer to new stack pointer
*/
static int
execv(char *pathname, char **argv, uintptr_t *sp_res)
{
char *bin = NULL;
struct filedesc *filedes;
struct vm_range *exec_range;
struct exec_args args;
struct proc *td = this_td();
int fd, ret = 0;
int status;
size_t bin_size;
if ((status = exec_get_args(argv, &args)) != 0)
return status;
spinlock_acquire(&td->lock);
fd = open(pathname, O_RDONLY);
if (fd < 0) {
ret = -ENOENT;
goto done;
}
filedes = fd_from_fdnum(td, fd);
if (__unlikely(filedes == NULL)) {
/*
* Should not happen. The kernel might be in some
* erroneous state.
*/
ret = -EIO;
goto done;
}
lseek(fd, 0, SEEK_END);
bin_size = filedes->offset;
lseek(fd, 0, SEEK_SET);
/* Allocate memory for the binary */
bin = dynalloc(bin_size);
if (bin == NULL) {
ret = -ENOMEM;
goto done;
}
/* Read-in the binary */
if ((status = read(fd, bin, bin_size)) < 0) {
ret = status;
goto done;
}
/*
* Unload the current process image. After we do this,
* we cannot return in this state until we replace it.
*
* XXX: This is one of the last things we do in case of
* errors.
*/
exec_range = &td->addr_range[ADDR_RANGE_EXEC];
loader_unload(td->addrsp, exec_range);
/*
* Now we try to load the new program and hope everything
* works... If something goes wrong here then we'll be forced
* to send a SIGSEGV to the thread.
*/
status = loader_load(td->addrsp, bin, &args.auxv, 0, NULL, exec_range);
if (status != 0) {
/* Well shit */
kprintf("exec: Failed to load new process image\n");
signal_raise(td, SIGSEGV);
for (;;);
}
*sp_res = exec_set_stack(td, args);
set_frame_ip(td->tf, args.auxv.at_entry);
done:
/* We are done, cleanup and release the thread */
if (bin != NULL) dynfree(bin);
fd_close_fdnum(td, fd);
dynfree(args.argp);
spinlock_release(&td->lock);
return ret;
}
/*
* Arg0: Pathname
* Arg1: Argv
*/
uint64_t
sys_execv(struct syscall_args *args)
{
uintptr_t sp;
char pathname[PATH_MAX];
char **argv = (char **)args->arg1;
int status;
struct proc *td = this_td();
copyinstr(args->arg0, pathname, PATH_MAX);
if ((status = execv(pathname, argv, &sp)) != 0)
return status;
args->ip = get_frame_ip(td->tf);
args->sp = sp;
return 0;
}
|
