Add finger demo to redbean and fix regression

This change fixes a regression in unix.connect() caused by the recent
addition of UNIX domain sockets. The BSD finger command has been added
to third_party for fun and profit. A new demo has been added to redbean
showing how a protocol as simple as finger can be implemented.

libc/runtime/__utmpxname.S

@@ -0,0 +1,28 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/macros.internal.h"
+
+__utmpxname:
+	.errno
+	mov	ENOTSUP(%rip),%edx
+	mov	%edx,(%rax)
+	ret
+	.endfn	__utmpxname,globl
+	.alias	__utmpxname,utmpname
+	.alias	__utmpxname,utmpxname

libc/runtime/utmp.h

@@ -0,0 +1,47 @@
+#ifndef COSMOPOLITAN_LIBC_RUNTIME_UTMP_H_
+#define COSMOPOLITAN_LIBC_RUNTIME_UTMP_H_
+#include "libc/calls/weirdtypes.h"
+#include "libc/runtime/utmpx.h"
+
+#define ACCOUNTING  9
+#define UT_NAMESIZE 32
+#define UT_HOSTSIZE 256
+#define UT_LINESIZE 32
+
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+struct lastlog {
+  time_t ll_time;
+  char ll_line[UT_LINESIZE];
+  char ll_host[UT_HOSTSIZE];
+};
+
+#define ut_time       ut_tv.tv_sec
+#define ut_name       ut_user
+#define ut_addr       ut_addr_v6[0]
+#define utmp          utmpx
+#define e_exit        __e_exit
+#define e_termination __e_termination
+
+int login_tty(int);
+int utmpname(const char *);
+struct utmp *getutent(void);
+struct utmp *getutid(const struct utmp *);
+struct utmp *getutline(const struct utmp *);
+struct utmp *pututline(const struct utmp *);
+void endutent(void);
+void setutent(void);
+void updwtmp(const char *, const struct utmp *);
+
+#define _PATH_UTMP "/dev/null/utmp"
+#define _PATH_WTMP "/dev/null/wtmp"
+
+#define UTMP_FILE     _PATH_UTMP
+#define WTMP_FILE     _PATH_WTMP
+#define UTMP_FILENAME _PATH_UTMP
+#define WTMP_FILENAME _PATH_WTMP
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_RUNTIME_UTMP_H_ */

libc/runtime/utmpx.h

@@ -0,0 +1,51 @@
+#ifndef COSMOPOLITAN_LIBC_RUNTIME_UTMPX_H_
+#define COSMOPOLITAN_LIBC_RUNTIME_UTMPX_H_
+#include "libc/calls/struct/timeval.h"
+#include "libc/calls/weirdtypes.h"
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+struct utmpx {
+  short ut_type;
+  pid_t ut_pid;
+  char ut_line[32];
+  char ut_id[4];
+  char ut_user[32];
+  char ut_host[256];
+  struct {
+    short __e_termination;
+    short __e_exit;
+  } ut_exit;
+  long ut_session;
+  struct timeval ut_tv;
+  unsigned ut_addr_v6[4];
+  char __unused[20];
+};
+
+void endutxent(void);
+struct utmpx *getutxent(void);
+struct utmpx *getutxid(const struct utmpx *);
+struct utmpx *getutxline(const struct utmpx *);
+struct utmpx *pututxline(const struct utmpx *);
+void setutxent(void);
+
+#if defined(_BSD_SOURCE) || defined(_GNU_SOURCE)
+#define e_exit        __e_exit
+#define e_termination __e_termination
+void updwtmpx(const char *, const struct utmpx *);
+int utmpxname(const char *);
+#endif
+
+#define EMPTY         0
+#define RUN_LVL       1
+#define BOOT_TIME     2
+#define NEW_TIME      3
+#define OLD_TIME      4
+#define INIT_PROCESS  5
+#define LOGIN_PROCESS 6
+#define USER_PROCESS  7
+#define DEAD_PROCESS  8
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_LIBC_RUNTIME_UTMPX_H_ */