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
|
/*
* Copyright (c) 2020-2022, the SerenityOS developers.
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <signal.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
// Supposed to use volatile everywhere here but good lord does C++ make that a pain
volatile sig_atomic_t saved_signal;
volatile siginfo_t saved_siginfo;
volatile ucontext_t saved_ucontext;
siginfo_t* sig_info_addr;
ucontext_t* ucontext_addr;
void* stack_ptr;
bool volatile signal_was_delivered = false;
static void signal_handler(int sig, siginfo_t* sig_info, void* u_context)
{
stack_ptr = __builtin_frame_address(0);
signal_was_delivered = true;
saved_signal = sig;
// grumble grumble, assignment operator on volatile types not a thing
// grumble grumble more, can't memcpy voltile either, that casts away volatile
// grumble grumble even more, can't std::copy to volatile.
// screw it, just write all the fields
sig_info_addr = sig_info;
saved_siginfo.si_status = sig_info->si_status;
saved_siginfo.si_signo = sig_info->si_signo;
saved_siginfo.si_code = sig_info->si_code;
saved_siginfo.si_pid = sig_info->si_pid;
saved_siginfo.si_uid = sig_info->si_uid;
saved_siginfo.si_value.sival_int = sig_info->si_value.sival_int;
auto user_context = (ucontext_t*)u_context;
ucontext_addr = user_context;
saved_ucontext.uc_link = user_context->uc_link;
saved_ucontext.uc_sigmask = user_context->uc_sigmask;
saved_ucontext.uc_stack.ss_sp = user_context->uc_stack.ss_sp;
saved_ucontext.uc_stack.ss_size = user_context->uc_stack.ss_size;
saved_ucontext.uc_stack.ss_flags = user_context->uc_stack.ss_flags;
// saved_ucontext.uc_mcontext = user_context->uc_mcontext;
}
static int print_signal_results()
{
if (!signal_was_delivered) {
fprintf(stderr, "Where was my signal bro?\n");
return 2;
}
sig_atomic_t read_the_signal = saved_signal;
siginfo_t read_the_siginfo = {};
read_the_siginfo.si_status = saved_siginfo.si_status;
read_the_siginfo.si_signo = saved_siginfo.si_signo;
read_the_siginfo.si_code = saved_siginfo.si_code;
read_the_siginfo.si_pid = saved_siginfo.si_pid;
read_the_siginfo.si_uid = saved_siginfo.si_uid;
read_the_siginfo.si_value.sival_int = saved_siginfo.si_value.sival_int;
ucontext_t read_the_ucontext = {};
read_the_ucontext.uc_link = saved_ucontext.uc_link;
read_the_ucontext.uc_sigmask = saved_ucontext.uc_sigmask;
read_the_ucontext.uc_stack.ss_sp = saved_ucontext.uc_stack.ss_sp;
read_the_ucontext.uc_stack.ss_size = saved_ucontext.uc_stack.ss_size;
read_the_ucontext.uc_stack.ss_flags = saved_ucontext.uc_stack.ss_flags;
// read_the_ucontext.uc_mcontext = saved_ucontext.uc_mcontext;
printf("Handled signal: %d\n", read_the_signal);
printf("Stack sorta started as %p\n", stack_ptr);
printf("Siginfo was stored at %p:\n", sig_info_addr);
printf("\tsi_signo: %d\n", read_the_siginfo.si_signo);
printf("\tsi_code, %x\n", read_the_siginfo.si_code);
printf("\tsi_pid, %d\n", read_the_siginfo.si_pid);
printf("\tsi_uid, %d\n", read_the_siginfo.si_uid);
printf("\tsi_status, %x\n", read_the_siginfo.si_status);
printf("\tsi_value.sival_int, %x\n", read_the_siginfo.si_value.sival_int);
printf("ucontext was stored at %p:\n", ucontext_addr);
printf("\tuc_link, %p\n", read_the_ucontext.uc_link);
printf("\tuc_sigmask, %d\n", read_the_ucontext.uc_sigmask);
printf("\tuc_stack.ss_sp, %p\n", read_the_ucontext.uc_stack.ss_sp);
printf("\tuc_stack.ss_size, %zu\n", read_the_ucontext.uc_stack.ss_size);
printf("\tuc_stack.ss_flags, %d\n", read_the_ucontext.uc_stack.ss_flags);
// printf("\tuc_mcontext, %d\n", read_the_ucontext.uc_mcontext);
return 0;
}
int main()
{
struct sigaction action = {};
action.sa_flags = SA_SIGINFO;
sigemptyset(&action.sa_mask);
action.sa_sigaction = signal_handler;
for (size_t i = 0; i < NSIG; ++i)
(void)sigaction(i, &action, nullptr);
printf("Sleeping for a long time waiting for kill -<N> %d\n", getpid());
sleep(1000);
return print_signal_results();
}
|
