9.94 uname

struct utsname {
    char sysname[65];
    char nodename[65];
    char release[65];
    char version[65];
    char machine[65];
    char domainname[65];
} __attribute__((packed));

int uname(struct utsname *addr);

This syscall writes system information to the passed structure. The strings on the structure are NUL-terminated.