81 lines
2.4 KiB
C++
81 lines
2.4 KiB
C++
#include <unistd.h>
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#include <libreborn/libreborn.h>
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#include <string>
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#include <sys/mman.h>
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#include "guest.h"
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// Syscall Method
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static uint32_t trampoline_syscall(const uint32_t id, const uint32_t length, const unsigned char *args) {
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// Make Syscall
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long ret = syscall(TRAMPOLINE_SYSCALL, id, length, args);
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if (ret == -1) {
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// Error
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ERR("Trampoline Error: %s", strerror(errno));
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}
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// Return
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return *(uint32_t *) args;
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}
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// Pipe Method (Native Trampoline Only)
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static int get_pipe(const char *env) {
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const char *value = getenv(env);
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if (value == nullptr) {
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IMPOSSIBLE();
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}
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std::string str = value;
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return std::stoi(str);
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}
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static uint32_t trampoline_pipe(const uint32_t id, const bool allow_early_return, const uint32_t length, const unsigned char *args) {
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// Get Pipes
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static int arguments_pipe = -1;
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static int return_value_pipe = -1;
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if (arguments_pipe == -1) {
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arguments_pipe = get_pipe(TRAMPOLINE_ARGUMENTS_PIPE_ENV);
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return_value_pipe = get_pipe(TRAMPOLINE_RETURN_VALUE_PIPE_ENV);
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}
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// Write Command
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const trampoline_pipe_arguments cmd = {
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.id = id,
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.allow_early_return = allow_early_return,
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.length = length
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};
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if (write(arguments_pipe, &cmd, sizeof(trampoline_pipe_arguments)) != sizeof(trampoline_pipe_arguments)) {
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ERR("Unable To Write Trampoline Command");
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}
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// Write Arguments
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size_t position = 0;
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while (position < length) {
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const ssize_t ret = write(arguments_pipe, args + position, length - position);
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if (ret == -1) {
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ERR("Unable To Write Trampoline Arguments");
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} else {
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position += ret;
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}
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}
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if (allow_early_return) {
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return 0;
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}
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// Return
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uint32_t ret;
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if (read(return_value_pipe, &ret, sizeof(uint32_t)) != sizeof(uint32_t)) {
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ERR("Unable To Read Trampoline Return Value");
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}
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return ret;
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}
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// Main Function
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uint32_t _raw_trampoline(const uint32_t id, const bool allow_early_return, const uint32_t length, const unsigned char *args) {
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// Configure Method
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static int use_syscall = -1;
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if (use_syscall == -1) {
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use_syscall = getenv(TRAMPOLINE_ARGUMENTS_PIPE_ENV) == nullptr;
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}
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// Use Correct Method
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if (use_syscall) {
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return trampoline_syscall(id, length, args);
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} else {
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return trampoline_pipe(id, allow_early_return, length, args);
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}
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}
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