vmw_logger/
logger.rs

1static LOGGER: VMWLogger = VMWLogger::new();
2
3fn default_formatter(buffer: &mut dyn core::fmt::Write, record: &log::Record) -> Result<(), core::fmt::Error> {
4    writeln!(
5        buffer,
6        "[{}:{} - {}] {}",
7        record.file().unwrap_or("<unknown>"),
8        record.line().unwrap_or(0),
9        record.level(),
10        record.args(),
11    )
12}
13
14struct VMWLogger;
15
16impl VMWLogger {
17    const fn new() -> Self {
18        Self
19    }
20}
21
22impl core::fmt::Write for VMWLogger {
23    fn write_str(&mut self, s: &str) -> core::fmt::Result {
24        // credits: jessie
25        for c in s.chars() {
26            unsafe {
27                core::arch::asm!(r#"
28                    xchg rbx, {0}
29                    mov eax, 0x564D5868
30                    mov edx, 0x5658
31                    mov ecx, 0x19
32                    in eax, dx
33                    xchg rbx, {0}
34                "#,
35                // input is rbx, but llvm is annoying so
36                // we just use a temp register and xchg them
37                in(reg) c as usize,
38                out("rax") _,
39                out("rdx") _,
40                out("rcx") _,
41                );
42            }
43        }
44
45        Ok(())
46    }
47}
48
49impl log::Log for VMWLogger {
50    fn enabled(&self, _m: &log::Metadata) -> bool {
51        // credits: jessie
52        unsafe {
53            // invokes the 'get_version' command of the vmware backdoor
54            // if ebx is not the magic value the backdoor isn't present
55            let mut rbx: u64 = 0;
56            core::arch::asm!(r#"
57                xchg rbx, {_rbx}
58                xchg {_rbp}, rbp
59                xor rbp, rbp
60                mov eax, 0x564D5868
61                mov edx, 0x5658
62                mov ecx, 0xA
63                in eax, dx
64                xchg rbp, {_rbp}
65                xchg rbx, {_rbx}
66            "#,
67                in("rax") 0x564D5868,
68                _rbx = inout(reg) rbx,
69                in("rcx") 0xA,
70                in("rdx") 0x5658,
71                _rbp = in(reg) 0u64,
72                in("rdi") 0,
73                in("rsi") 0,
74            );
75            rbx == 0x564D5868
76        }
77    }
78
79    fn log(&self, record: &log::Record) {
80        let _ = default_formatter(&mut VMWLogger::new(), record); // lol
81    }
82
83    fn flush(&self) {}
84}
85
86pub struct Builder {
87    filter: log::LevelFilter,
88}
89
90impl Builder {
91    /// Create a builder for fine-tuning logger.
92    pub fn new() -> Self {
93        Self {
94            filter: log::LevelFilter::Info,
95        }
96    }
97
98    /// Set the level filter.
99    pub fn filter(mut self, filter: log::LevelFilter) -> Self {
100        self.filter = filter;
101        self
102    }
103
104    /// Setup a logger based on the configuration.
105    pub fn setup(self) {
106        log::set_logger(&LOGGER).unwrap();
107
108        log::set_max_level(self.filter);
109    }
110}
111
112pub fn builder() -> Builder {
113    Builder::new()
114}
115
116pub fn init() {
117    builder().filter(log::LevelFilter::Info).setup();
118}
119
120pub fn init_with_filter(filter: log::LevelFilter) {
121    builder().filter(filter).setup();
122}
vmw_logger/logger.rs

vmw_logger/
logger.rs
