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// See LICENSE for license details.
#include "syscall.h"
#include "htif.h"
#include "byteorder.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <limits.h>
#include <errno.h>
#include <stdlib.h>
#include <assert.h>
#include <termios.h>
#include <sstream>
#include <iostream>
using namespace std::placeholders;
#define RISCV_AT_FDCWD -100
struct riscv_stat
{
uint64_t dev;
uint64_t ino;
uint32_t mode;
uint32_t nlink;
uint32_t uid;
uint32_t gid;
uint64_t rdev;
uint64_t __pad1;
uint64_t size;
uint32_t blksize;
uint32_t __pad2;
uint64_t blocks;
uint64_t atime;
uint64_t __pad3;
uint64_t mtime;
uint64_t __pad4;
uint64_t ctime;
uint64_t __pad5;
uint32_t __unused4;
uint32_t __unused5;
riscv_stat(const struct stat& s)
: dev(s.st_dev), ino(s.st_ino), mode(s.st_mode), nlink(s.st_nlink),
uid(s.st_uid), gid(s.st_gid), rdev(s.st_rdev), __pad1(0),
size(s.st_size), blksize(s.st_blksize), __pad2(0),
blocks(s.st_blocks), atime(s.st_atime), __pad3(0),
mtime(s.st_mtime), __pad4(0), ctime(s.st_ctime), __pad5(0),
__unused4(0), __unused5(0) {}
};
syscall_t::syscall_t(htif_t* htif)
: htif(htif), memif(&htif->memif()), table(2048)
{
table[17] = &syscall_t::sys_getcwd;
table[25] = &syscall_t::sys_fcntl;
table[34] = &syscall_t::sys_mkdirat;
table[35] = &syscall_t::sys_unlinkat;
table[37] = &syscall_t::sys_linkat;
table[38] = &syscall_t::sys_renameat;
table[46] = &syscall_t::sys_ftruncate;
table[48] = &syscall_t::sys_faccessat;
table[49] = &syscall_t::sys_chdir;
table[56] = &syscall_t::sys_openat;
table[57] = &syscall_t::sys_close;
table[62] = &syscall_t::sys_lseek;
table[63] = &syscall_t::sys_read;
table[64] = &syscall_t::sys_write;
table[67] = &syscall_t::sys_pread;
table[68] = &syscall_t::sys_pwrite;
table[79] = &syscall_t::sys_fstatat;
table[80] = &syscall_t::sys_fstat;
table[93] = &syscall_t::sys_exit;
table[1039] = &syscall_t::sys_lstat;
table[2011] = &syscall_t::sys_getmainvars;
register_command(0, std::bind(&syscall_t::handle_syscall, this, _1), "syscall");
int stdin_fd = dup(0), stdout_fd0 = dup(1), stdout_fd1 = dup(1);
if (stdin_fd < 0 || stdout_fd0 < 0 || stdout_fd1 < 0)
throw std::runtime_error("could not dup stdin/stdout");
fds.alloc(stdin_fd); // stdin -> stdin
fds.alloc(stdout_fd0); // stdout -> stdout
fds.alloc(stdout_fd1); // stderr -> stdout
}
std::string syscall_t::do_chroot(const char* fn)
{
if (!chroot.empty() && *fn == '/')
return chroot + fn;
return fn;
}
std::string syscall_t::undo_chroot(const char* fn)
{
if (chroot.empty())
return fn;
if (strncmp(fn, chroot.c_str(), chroot.size()) == 0
&& (chroot.back() == '/' || fn[chroot.size()] == '/'))
return fn + chroot.size() - (chroot.back() == '/');
return "/";
}
void syscall_t::handle_syscall(command_t cmd)
{
if (cmd.payload() & 1) // test pass/fail
{
htif->exitcode = cmd.payload();
if (htif->exit_code())
std::cerr << "*** FAILED *** (tohost = " << htif->exit_code() << ")" << std::endl;
return;
}
else // proxied system call
dispatch(cmd.payload());
cmd.respond(1);
}
reg_t syscall_t::sys_exit(reg_t code, reg_t a1, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
htif->exitcode = code << 1 | 1;
return 0;
}
static reg_t sysret_errno(sreg_t ret)
{
return ret == -1 ? -errno : ret;
}
reg_t syscall_t::sys_read(reg_t fd, reg_t pbuf, reg_t len, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> buf(len);
ssize_t ret = read(fds.lookup(fd), &buf[0], len);
reg_t ret_errno = sysret_errno(ret);
if (ret > 0)
memif->write(pbuf, ret, &buf[0]);
return ret_errno;
}
reg_t syscall_t::sys_pread(reg_t fd, reg_t pbuf, reg_t len, reg_t off, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> buf(len);
ssize_t ret = pread(fds.lookup(fd), &buf[0], len, off);
reg_t ret_errno = sysret_errno(ret);
if (ret > 0)
memif->write(pbuf, ret, &buf[0]);
return ret_errno;
}
reg_t syscall_t::sys_write(reg_t fd, reg_t pbuf, reg_t len, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> buf(len);
memif->read(pbuf, len, &buf[0]);
reg_t ret = sysret_errno(write(fds.lookup(fd), &buf[0], len));
return ret;
}
reg_t syscall_t::sys_pwrite(reg_t fd, reg_t pbuf, reg_t len, reg_t off, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> buf(len);
memif->read(pbuf, len, &buf[0]);
reg_t ret = sysret_errno(pwrite(fds.lookup(fd), &buf[0], len, off));
return ret;
}
reg_t syscall_t::sys_close(reg_t fd, reg_t a1, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
if (close(fds.lookup(fd)) < 0)
return sysret_errno(-1);
fds.dealloc(fd);
return 0;
}
reg_t syscall_t::sys_lseek(reg_t fd, reg_t ptr, reg_t dir, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
return sysret_errno(lseek(fds.lookup(fd), ptr, dir));
}
reg_t syscall_t::sys_fstat(reg_t fd, reg_t pbuf, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
struct stat buf;
reg_t ret = sysret_errno(fstat(fds.lookup(fd), &buf));
if (ret != (reg_t)-1)
{
riscv_stat rbuf(buf);
memif->write(pbuf, sizeof(rbuf), &rbuf);
}
return ret;
}
reg_t syscall_t::sys_fcntl(reg_t fd, reg_t cmd, reg_t arg, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
return sysret_errno(fcntl(fds.lookup(fd), cmd, arg));
}
reg_t syscall_t::sys_ftruncate(reg_t fd, reg_t len, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
return sysret_errno(ftruncate(fds.lookup(fd), len));
}
reg_t syscall_t::sys_lstat(reg_t pname, reg_t len, reg_t pbuf, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> name(len);
memif->read(pname, len, &name[0]);
struct stat buf;
reg_t ret = sysret_errno(lstat(do_chroot(&name[0]).c_str(), &buf));
riscv_stat rbuf(buf);
if (ret != (reg_t)-1)
{
riscv_stat rbuf(buf);
memif->write(pbuf, sizeof(rbuf), &rbuf);
}
return ret;
}
#define AT_SYSCALL(syscall, fd, name, ...) \
(syscall(fds.lookup(fd), int(fd) == RISCV_AT_FDCWD ? do_chroot(name).c_str() : (name), __VA_ARGS__))
reg_t syscall_t::sys_openat(reg_t dirfd, reg_t pname, reg_t len, reg_t flags, reg_t mode, reg_t a5, reg_t a6)
{
std::vector<char> name(len);
memif->read(pname, len, &name[0]);
int fd = sysret_errno(AT_SYSCALL(openat, dirfd, &name[0], flags, mode));
if (fd < 0)
return sysret_errno(-1);
return fds.alloc(fd);
}
reg_t syscall_t::sys_fstatat(reg_t dirfd, reg_t pname, reg_t len, reg_t pbuf, reg_t flags, reg_t a5, reg_t a6)
{
std::vector<char> name(len);
memif->read(pname, len, &name[0]);
struct stat buf;
reg_t ret = sysret_errno(AT_SYSCALL(fstatat, dirfd, &name[0], &buf, flags));
if (ret != (reg_t)-1)
{
riscv_stat rbuf(buf);
memif->write(pbuf, sizeof(rbuf), &rbuf);
}
return ret;
}
reg_t syscall_t::sys_faccessat(reg_t dirfd, reg_t pname, reg_t len, reg_t mode, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> name(len);
memif->read(pname, len, &name[0]);
return sysret_errno(AT_SYSCALL(faccessat, dirfd, &name[0], mode, 0));
}
reg_t syscall_t::sys_renameat(reg_t odirfd, reg_t popath, reg_t olen, reg_t ndirfd, reg_t pnpath, reg_t nlen, reg_t a6)
{
std::vector<char> opath(olen), npath(nlen);
memif->read(popath, olen, &opath[0]);
memif->read(pnpath, nlen, &npath[0]);
return sysret_errno(renameat(fds.lookup(odirfd), int(odirfd) == RISCV_AT_FDCWD ? do_chroot(&opath[0]).c_str() : &opath[0],
fds.lookup(ndirfd), int(ndirfd) == RISCV_AT_FDCWD ? do_chroot(&npath[0]).c_str() : &npath[0]));
}
reg_t syscall_t::sys_linkat(reg_t odirfd, reg_t poname, reg_t olen, reg_t ndirfd, reg_t pnname, reg_t nlen, reg_t flags)
{
std::vector<char> oname(olen), nname(nlen);
memif->read(poname, olen, &oname[0]);
memif->read(pnname, nlen, &nname[0]);
return sysret_errno(linkat(fds.lookup(odirfd), int(odirfd) == RISCV_AT_FDCWD ? do_chroot(&oname[0]).c_str() : &oname[0],
fds.lookup(ndirfd), int(ndirfd) == RISCV_AT_FDCWD ? do_chroot(&nname[0]).c_str() : &nname[0],
flags));
}
reg_t syscall_t::sys_unlinkat(reg_t dirfd, reg_t pname, reg_t len, reg_t flags, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> name(len);
memif->read(pname, len, &name[0]);
return sysret_errno(AT_SYSCALL(unlinkat, dirfd, &name[0], flags));
}
reg_t syscall_t::sys_mkdirat(reg_t dirfd, reg_t pname, reg_t len, reg_t mode, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> name(len);
memif->read(pname, len, &name[0]);
return sysret_errno(AT_SYSCALL(mkdirat, dirfd, &name[0], mode));
}
reg_t syscall_t::sys_getcwd(reg_t pbuf, reg_t size, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<char> buf(size);
char* ret = getcwd(&buf[0], size);
if (ret == NULL)
return sysret_errno(-1);
std::string tmp = undo_chroot(&buf[0]);
if (size <= tmp.size())
return -ENOMEM;
memif->write(pbuf, tmp.size() + 1, &tmp[0]);
return tmp.size() + 1;
}
reg_t syscall_t::sys_getmainvars(reg_t pbuf, reg_t limit, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
std::vector<std::string> args = htif->target_args();
std::vector<uint64_t> words(args.size() + 3);
words[0] = htif->to_target<uint64_t>(args.size());
words[args.size()+1] = 0; // argv[argc] = NULL
words[args.size()+2] = 0; // envp[0] = NULL
size_t sz = (args.size() + 3) * sizeof(words[0]);
for (size_t i = 0; i < args.size(); i++)
{
words[i+1] = htif->to_target<uint64_t>(sz + pbuf);
sz += args[i].length() + 1;
}
std::vector<char> bytes(sz);
memcpy(&bytes[0], &words[0], sizeof(words[0]) * words.size());
for (size_t i = 0; i < args.size(); i++)
strcpy(&bytes[htif->from_target(words[i+1]) - pbuf], args[i].c_str());
if (bytes.size() > limit)
return -ENOMEM;
memif->write(pbuf, bytes.size(), &bytes[0]);
return 0;
}
reg_t syscall_t::sys_chdir(reg_t path, reg_t a1, reg_t a2, reg_t a3, reg_t a4, reg_t a5, reg_t a6)
{
size_t size = 0;
while (memif->read_uint8(path + size++))
;
std::vector<char> buf(size);
for (size_t offset = 0;; offset++)
{
buf[offset] = memif->read_uint8(path + offset);
if (!buf[offset])
break;
}
return sysret_errno(chdir(buf.data()));
}
void syscall_t::dispatch(reg_t mm)
{
reg_t magicmem[8];
memif->read(mm, sizeof(magicmem), magicmem);
reg_t n = htif->from_target(magicmem[0]);
if (n >= table.size() || !table[n])
throw std::runtime_error("bad syscall #" + std::to_string(n));
magicmem[0] = htif->to_target((this->*table[n])(htif->from_target(magicmem[1]), htif->from_target(magicmem[2]), htif->from_target(magicmem[3]), htif->from_target(magicmem[4]), htif->from_target(magicmem[5]), htif->from_target(magicmem[6]), htif->from_target(magicmem[7])));
memif->write(mm, sizeof(magicmem), magicmem);
}
reg_t fds_t::alloc(int fd)
{
reg_t i;
for (i = 0; i < fds.size(); i++)
if (fds[i] == -1)
break;
if (i == fds.size())
fds.resize(i+1);
fds[i] = fd;
return i;
}
void fds_t::dealloc(reg_t fd)
{
fds[fd] = -1;
}
int fds_t::lookup(reg_t fd)
{
if (int(fd) == RISCV_AT_FDCWD)
return AT_FDCWD;
return fd >= fds.size() ? -1 : fds[fd];
}
void syscall_t::set_chroot(const char* where)
{
char buf1[PATH_MAX], buf2[PATH_MAX];
if (getcwd(buf1, sizeof(buf1)) == NULL
|| chdir(where) != 0
|| getcwd(buf2, sizeof(buf2)) == NULL
|| chdir(buf1) != 0)
{
fprintf(stderr, "could not chroot to %s\n", where);
exit(-1);
}
chroot = buf2;
}
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