Fix known issues which blow up the process after dlopen("libthr.so")

(or loading a dso linked to libthr.so into process which was not
linked against threading library).

- Remove libthr interposers of the libc functions, including
  __error(). Instead, functions calls are indirected through the
  interposing table, similar to how pthread stubs in libc are already
  done.  Libc by default points either to syscall trampolines or to
  existing libc implementations.  On libthr load, libthr rewrites the
  pointers to the cancellable implementations already in libthr.  The
  interposition table is separate from pthreads stubs indirection
  table to not pull pthreads stubs into static binaries.

- Postpone the malloc(3) internal mutexes initialization until libthr
  is loaded.  This avoids recursion between calloc(3) and static
  pthread_mutex_t initialization.

- Reinstall signal handlers with wrapper on libthr load.  The
  _rtld_is_dlopened(3) is used to avoid useless calls to sigaction(2)
  when libthr is statically referenced from the main binary.

In the process, fix openat(2), swapcontext(2) and setcontext(2)
interposing.  The libc symbols were exported at different versions
than libthr interposers.  Export both libc and libthr versions from
libc now, with default set to the higher version from libthr.

Remove unused and disconnected swapcontext(3) userspace implementation
from libc/gen.

No objections from:	deischen
Tested by:	pho, antoine (exp-run) (previous versions)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week

1 files changed, 140 insertions, 20 deletions

diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h
index 40a5f7266709..adf342de4e85 100644
--- a/lib/libc/include/libc_private.h
+++ b/lib/libc/include/libc_private.h
@@ -173,6 +173,61 @@ typedef pthread_func_t pthread_func_entry_t[2];
 
 extern pthread_func_entry_t __thr_jtable[];
 
+extern int *(*__error_selector)(void);
+int	_pthread_mutex_init_calloc_cb_stub(pthread_mutex_t *mutex,
+	    void *(calloc_cb)(__size_t, __size_t));
+
+typedef int (*interpos_func_t)(void);
+interpos_func_t *__libc_interposing_slot(int interposno);
+extern interpos_func_t __libc_interposing[];
+
+enum {
+	INTERPOS_accept,
+	INTERPOS_accept4,
+	INTERPOS_aio_suspend,
+	INTERPOS_close,
+	INTERPOS_connect,
+	INTERPOS_creat,
+	INTERPOS_fcntl,
+	INTERPOS_fsync,
+	INTERPOS_fork,
+	INTERPOS_msync,
+	INTERPOS_nanosleep,
+	INTERPOS_open,
+	INTERPOS_openat,
+	INTERPOS_poll,
+	INTERPOS_pselect,
+	INTERPOS_raise,
+	INTERPOS_recvfrom,
+	INTERPOS_recvmsg,
+	INTERPOS_select,
+	INTERPOS_sendmsg,
+	INTERPOS_sendto,
+	INTERPOS_setcontext,
+	INTERPOS_sigaction,
+	INTERPOS_sigprocmask,
+	INTERPOS_sigsuspend,
+	INTERPOS_sigwait,
+	INTERPOS_sigtimedwait,
+	INTERPOS_sigwaitinfo,
+	INTERPOS_swapcontext,
+	INTERPOS_system,
+	INTERPOS_sleep,
+	INTERPOS_tcdrain,
+	INTERPOS_usleep,
+	INTERPOS_pause,
+	INTERPOS_read,
+	INTERPOS_readv,
+	INTERPOS_wait,
+	INTERPOS_wait3,
+	INTERPOS_wait4,
+	INTERPOS_waitpid,
+	INTERPOS_write,
+	INTERPOS_writev,
+	INTERPOS__pthread_mutex_init_calloc_cb,
+	INTERPOS_MAX
+};
+
 /*
  * yplib internal interfaces
  */
@@ -215,42 +270,107 @@ void _malloc_thread_cleanup(void);
 void _malloc_prefork(void);
 void _malloc_postfork(void);
 
+void _malloc_first_thread(void);
+
 /*
  * Function to clean up streams, called from abort() and exit().
  */
-extern void (*__cleanup)(void) __hidden;
+void (*__cleanup)(void) __hidden;
 
 /*
  * Get kern.osreldate to detect ABI revisions.  Explicitly
  * ignores value of $OSVERSION and caches result.  Prototypes
  * for the wrapped "new" pad-less syscalls are here for now.
  */
-extern int __getosreldate(void);
+int __getosreldate(void);
 #include <sys/_types.h>
-/* Without pad */
-extern __off_t	__sys_lseek(int, __off_t, int);
-extern int	__sys_ftruncate(int, __off_t);
-extern int	__sys_truncate(const char *, __off_t);
-extern __ssize_t __sys_pread(int, void *, __size_t, __off_t);
-extern __ssize_t __sys_pwrite(int, const void *, __size_t, __off_t);
-extern void *	__sys_mmap(void *, __size_t, int, int, int, __off_t);
+#include <sys/_sigset.h>
 
 /* With pad */
-extern __off_t	__sys_freebsd6_lseek(int, int, __off_t, int);
-extern int	__sys_freebsd6_ftruncate(int, int, __off_t);
-extern int	__sys_freebsd6_truncate(const char *, int, __off_t);
-extern __ssize_t __sys_freebsd6_pread(int, void *, __size_t, int, __off_t);
-extern __ssize_t __sys_freebsd6_pwrite(int, const void *, __size_t, int, __off_t);
-extern void *	__sys_freebsd6_mmap(void *, __size_t, int, int, int, int, __off_t);
-
-/* Without back-compat translation */
-extern int	__sys_fcntl(int, int, ...);
+__off_t	__sys_freebsd6_lseek(int, int, __off_t, int);
+int	__sys_freebsd6_ftruncate(int, int, __off_t);
+int	__sys_freebsd6_truncate(const char *, int, __off_t);
+__ssize_t __sys_freebsd6_pread(int, void *, __size_t, int, __off_t);
+__ssize_t __sys_freebsd6_pwrite(int, const void *, __size_t, int, __off_t);
+void *	__sys_freebsd6_mmap(void *, __size_t, int, int, int, int, __off_t);
 
+struct aiocb;
+struct fd_set;
+struct iovec;
+struct msghdr;
+struct pollfd;
+struct rusage;
+struct sigaction;
+struct sockaddr;
 struct timespec;
 struct timeval;
 struct timezone;
-int	__sys_gettimeofday(struct timeval *, struct timezone *);
-int	__sys_clock_gettime(__clockid_t, struct timespec *ts);
+struct __siginfo;
+struct __ucontext;
+int		__sys_aio_suspend(const struct aiocb * const[], int,
+		    const struct timespec *);
+int		__sys_accept(int, struct sockaddr *, __socklen_t *);
+int		__sys_accept4(int, struct sockaddr *, __socklen_t *, int);
+int		__sys_clock_gettime(__clockid_t, struct timespec *ts);
+int		__sys_close(int);
+int		__sys_connect(int, const struct sockaddr *, __socklen_t);
+int		__sys_fcntl(int, int, ...);
+int		__sys_fsync(int);
+__pid_t		__sys_fork(void);
+int		__sys_ftruncate(int, __off_t);
+int		__sys_gettimeofday(struct timeval *, struct timezone *);
+__off_t		__sys_lseek(int, __off_t, int);
+void	       *__sys_mmap(void *, __size_t, int, int, int, __off_t);
+int		__sys_msync(void *, __size_t, int);
+int		__sys_nanosleep(const struct timespec *, struct timespec *);
+int		__sys_open(const char *, int, ...);
+int		__sys_openat(int, const char *, int, ...);
+int		__sys_pselect(int, struct fd_set *, struct fd_set *,
+		    struct fd_set *, const struct timespec *,
+		    const __sigset_t *);
+int		__sys_poll(struct pollfd *, unsigned, int);
+__ssize_t	__sys_pread(int, void *, __size_t, __off_t);
+__ssize_t	__sys_pwrite(int, const void *, __size_t, __off_t);
+__ssize_t	__sys_read(int, void *, __size_t);
+__ssize_t	__sys_readv(int, const struct iovec *, int);
+__ssize_t	__sys_recv(int, void *, __size_t, int);
+__ssize_t	__sys_recvfrom(int, void *, __size_t, int, struct sockaddr *,
+		    __socklen_t *);
+__ssize_t	__sys_recvmsg(int, struct msghdr *, int);
+int		__sys_select(int, struct fd_set *, struct fd_set *,
+		    struct fd_set *, struct timeval *);
+__ssize_t	__sys_sendmsg(int, const struct msghdr *, int);
+__ssize_t	__sys_sendto(int, const void *, __size_t, int,
+		    const struct sockaddr *, __socklen_t);
+int		__sys_setcontext(const struct __ucontext *);
+int		__sys_sigaction(int, const struct sigaction *,
+		    struct sigaction *);
+int		__sys_sigprocmask(int, const __sigset_t *, __sigset_t *);
+int		__sys_sigsuspend(const __sigset_t *);
+int		__sys_sigtimedwait(const __sigset_t *, struct __siginfo *,
+		    const struct timespec *);
+int		__sys_sigwait(const __sigset_t *, int *);
+int		__sys_sigwaitinfo(const __sigset_t *, struct __siginfo *);
+int		__sys_swapcontext(struct __ucontext *,
+		    const struct __ucontext *);
+int		__sys_truncate(const char *, __off_t);
+__pid_t		__sys_wait4(__pid_t, int *, int, struct rusage *);
+__ssize_t	__sys_write(int, const void *, __size_t);
+__ssize_t	__sys_writev(int, const struct iovec *, int);
+
+int		__libc_creat(const char *path, __mode_t mode);
+int		__libc_pause(void);
+int		__libc_raise(int);
+int		__libc_sigwait(const __sigset_t * __restrict,
+		    int * restrict sig);
+int		__libc_system(const char *);
+unsigned int	__libc_sleep(unsigned int);
+int		__libc_tcdrain(int);
+int		__libc_usleep(__useconds_t);
+__pid_t		__libc_wait(int *);
+__pid_t		__libc_wait3(int *, int, struct rusage *);
+__pid_t		__libc_waitpid(__pid_t, int *, int);
+int		__fcntl_compat(int fd, int cmd, ...);
 
 /* execve() with PATH processing to implement posix_spawnp() */
 int _execvpe(const char *, char * const *, char * const *);