diff options
Diffstat (limited to 'pk/syscall.c')
| -rw-r--r-- | pk/syscall.c | 87 |
1 files changed, 87 insertions, 0 deletions
diff --git a/pk/syscall.c b/pk/syscall.c index bda4393..3dd0bf7 100644 --- a/pk/syscall.c +++ b/pk/syscall.c @@ -13,6 +13,11 @@ typedef long (*syscall_t)(long, long, long, long, long, long, long); +struct iovec { + void *iov_base; + size_t iov_len; +}; + #define CLOCK_FREQ 1000000000 #define MAX_BUF 512 @@ -566,6 +571,86 @@ int sys_chdir(const char *path) return frontend_syscall(SYS_chdir, kva2pa(kbuf), 0, 0, 0, 0, 0, 0); } +int sys_readlinkat(int dirfd, const char *pathname, char *buf, size_t bufsiz) +{ + if (bufsiz > MAX_BUF) + return -ENOMEM; + + const int kdirfd = at_kfd(dirfd); + if (kdirfd == -1) + return -EBADF; + + char kpathname[MAX_BUF]; + if (!strcpy_from_user(kpathname, pathname, MAX_BUF)) + return -ENAMETOOLONG; + const size_t pathname_len = strlen(kpathname); + + char kbuf[MAX_BUF]; + const ssize_t ret = frontend_syscall(SYS_readlinkat, kdirfd, kva2pa(kpathname), + pathname_len + 1, kva2pa(kbuf), bufsiz, 0, 0); + if (ret < 0) + return ret; + + if (ret > 0) + memcpy_to_user(buf, kbuf, ret); + return ret; +} + +ssize_t sys_readv(int fd, const struct iovec *iov, int iovcnt) +{ + if (iovcnt < 0) + return -EINVAL; + if (iov == NULL) + return -EFAULT; + + file_t * const f = file_get(fd); + if (!f) + return -EBADF; + + ssize_t ret = 0; + for (int cur_iovcnt = 0; cur_iovcnt < iovcnt; ++cur_iovcnt) { + struct iovec kiov; + memcpy_from_user(&kiov, iov + cur_iovcnt, sizeof(struct iovec)); + + // iov_len is too large to be represented in ssize_t + if (kiov.iov_len & (1ULL << (sizeof(kiov.iov_len) * 8 - 1))) { + ret = -EINVAL; + goto out_decref_f; + } + + char *buf = kiov.iov_base; + for (size_t already_read_size = 0; already_read_size < kiov.iov_len; ) { + char kread_buf[MAX_BUF]; + const size_t to_read_size = MIN(kiov.iov_len - already_read_size, sizeof(kread_buf)); + const ssize_t read_res = file_read(f, kread_buf, to_read_size); + if (read_res < 0) { + ret = read_res; + goto out_decref_f; + } + + memcpy_to_user(buf, kread_buf, read_res); + + already_read_size += read_res; + if (read_res < to_read_size) { + ret += already_read_size; + goto out_decref_f; + } + + buf += read_res; + } + + ret += kiov.iov_len; + if (ret < 0) { // ret overflowed + ret = -EINVAL; + goto out_decref_f; + } + } + +out_decref_f: + file_decref(f); + return ret; +} + void sys_tgkill(int tgid, int tid, int sig) { // assume target is current thread @@ -632,6 +717,8 @@ long do_syscall(long a0, long a1, long a2, long a3, long a4, long a5, unsigned l [SYS_rt_sigprocmask] = sys_stub_success, [SYS_clock_gettime] = sys_clock_gettime, [SYS_chdir] = sys_chdir, + [SYS_readlinkat] = sys_readlinkat, + [SYS_readv] = sys_readv, }; const static void* old_syscall_table[] = { |