feature/android 7b3c774bcee: Update Android port

[Po Lu]

branch: feature/android
commit 7b3c774bcee29fa0a13f38a60ddebc6fbdbedd0e
Author: Po Lu <luangruo@yahoo.com>
Commit: Po Lu <luangruo@yahoo.com>

    Update Android port
    
    * exec/config.h.in: Autoheader.
    * exec/configure.ac: Use system extensions.
    (HAVE_PROCESS_VM): Define if process_vm_readv and
    process_vm_writev are available.
    * exec/trace.c (read_memory, user_copy): Implement in terms of
    process_vm if possible.
---
 exec/config.h.in  | 106 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 exec/configure.ac |  13 ++++++-
 exec/trace.c      |  44 ++++++++++++++++++++++-
 3 files changed, 161 insertions(+), 2 deletions(-)

diff --git a/exec/config.h.in b/exec/config.h.in
index c360e54a4ba..6301275fd8a 100644
--- a/exec/config.h.in
+++ b/exec/config.h.in
@@ -52,6 +52,12 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>. */
 /* Define to 1 if you have the <inttypes.h> header file. */
 #undef HAVE_INTTYPES_H
 
+/* Define to 1 if you have the <minix/config.h> header file. */
+#undef HAVE_MINIX_CONFIG_H
+
+/* Define to 1 if process_vm_readv is available. */
+#undef HAVE_PROCESS_VM
+
 /* Define to 1 if stdbool.h conforms to C99. */
 #undef HAVE_STDBOOL_H
 
@@ -85,12 +91,18 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>. */
 /* Define to 1 if you have the <sys/types.h> header file. */
 #undef HAVE_SYS_TYPES_H
 
+/* Define to 1 if you have the <sys/uio.h> header file. */
+#undef HAVE_SYS_UIO_H
+
 /* Define to 1 if the system has the type `uintptr_t'. */
 #undef HAVE_UINTPTR_T
 
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
+/* Define to 1 if you have the <wchar.h> header file. */
+#undef HAVE_WCHAR_H
+
 /* Define to 1 if the system has the type `_Bool'. */
 #undef HAVE__BOOL
 
@@ -168,6 +180,94 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>. */
 /* Define to word type used by tracees. */
 #undef USER_WORD
 
+/* Enable extensions on AIX 3, Interix.  */
+#ifndef _ALL_SOURCE
+# undef _ALL_SOURCE
+#endif
+/* Enable general extensions on macOS.  */
+#ifndef _DARWIN_C_SOURCE
+# undef _DARWIN_C_SOURCE
+#endif
+/* Enable general extensions on Solaris.  */
+#ifndef __EXTENSIONS__
+# undef __EXTENSIONS__
+#endif
+/* Enable GNU extensions on systems that have them.  */
+#ifndef _GNU_SOURCE
+# undef _GNU_SOURCE
+#endif
+/* Enable X/Open compliant socket functions that do not require linking
+   with -lxnet on HP-UX 11.11.  */
+#ifndef _HPUX_ALT_XOPEN_SOCKET_API
+# undef _HPUX_ALT_XOPEN_SOCKET_API
+#endif
+/* Identify the host operating system as Minix.
+   This macro does not affect the system headers' behavior.
+   A future release of Autoconf may stop defining this macro.  */
+#ifndef _MINIX
+# undef _MINIX
+#endif
+/* Enable general extensions on NetBSD.
+   Enable NetBSD compatibility extensions on Minix.  */
+#ifndef _NETBSD_SOURCE
+# undef _NETBSD_SOURCE
+#endif
+/* Enable OpenBSD compatibility extensions on NetBSD.
+   Oddly enough, this does nothing on OpenBSD.  */
+#ifndef _OPENBSD_SOURCE
+# undef _OPENBSD_SOURCE
+#endif
+/* Define to 1 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_SOURCE
+# undef _POSIX_SOURCE
+#endif
+/* Define to 2 if needed for POSIX-compatible behavior.  */
+#ifndef _POSIX_1_SOURCE
+# undef _POSIX_1_SOURCE
+#endif
+/* Enable POSIX-compatible threading on Solaris.  */
+#ifndef _POSIX_PTHREAD_SEMANTICS
+# undef _POSIX_PTHREAD_SEMANTICS
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-5:2014.  */
+#ifndef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+# undef __STDC_WANT_IEC_60559_ATTRIBS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-1:2014.  */
+#ifndef __STDC_WANT_IEC_60559_BFP_EXT__
+# undef __STDC_WANT_IEC_60559_BFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-2:2015.  */
+#ifndef __STDC_WANT_IEC_60559_DFP_EXT__
+# undef __STDC_WANT_IEC_60559_DFP_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-4:2015.  */
+#ifndef __STDC_WANT_IEC_60559_FUNCS_EXT__
+# undef __STDC_WANT_IEC_60559_FUNCS_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TS 18661-3:2015.  */
+#ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
+# undef __STDC_WANT_IEC_60559_TYPES_EXT__
+#endif
+/* Enable extensions specified by ISO/IEC TR 24731-2:2010.  */
+#ifndef __STDC_WANT_LIB_EXT2__
+# undef __STDC_WANT_LIB_EXT2__
+#endif
+/* Enable extensions specified by ISO/IEC 24747:2009.  */
+#ifndef __STDC_WANT_MATH_SPEC_FUNCS__
+# undef __STDC_WANT_MATH_SPEC_FUNCS__
+#endif
+/* Enable extensions on HP NonStop.  */
+#ifndef _TANDEM_SOURCE
+# undef _TANDEM_SOURCE
+#endif
+/* Enable X/Open extensions.  Define to 500 only if necessary
+   to make mbstate_t available.  */
+#ifndef _XOPEN_SOURCE
+# undef _XOPEN_SOURCE
+#endif
+
+
 /* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
    significant byte first (like Motorola and SPARC, unlike Intel). */
 #if defined AC_APPLE_UNIVERSAL_BUILD
@@ -198,6 +298,12 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>. */
 /* Define as a signed integer type capable of holding a process identifier. */
 #undef pid_t
 
+/* Define to `unsigned int' if <sys/types.h> does not define. */
+#undef size_t
+
+/* Define to `int' if <sys/types.h> does not define. */
+#undef ssize_t
+
 /* Define to the type of an unsigned integer type of width exactly 16 bits if
    such a type exists and the standard includes do not define it. */
 #undef uint16_t
diff --git a/exec/configure.ac b/exec/configure.ac
index b948e184896..efefc6c7dbc 100644
--- a/exec/configure.ac
+++ b/exec/configure.ac
@@ -47,6 +47,7 @@ AC_ARG_WITH([reentrancy],
     [Generate library which can be used within a signal handler.])],
   [AC_DEFINE([REENTRANT], [1])])
 
+AC_USE_SYSTEM_EXTENSIONS
 AC_PROG_CC
 AC_PROG_CPP
 AC_PROG_INSTALL
@@ -56,12 +57,22 @@ AC_TYPE_UINT16_T
 AC_TYPE_UINT32_T
 AC_TYPE_UINT64_T
 AC_TYPE_UINTPTR_T
+AC_TYPE_SIZE_T
+AC_TYPE_SSIZE_T
 AC_TYPE_PID_T
 
 AC_HEADER_STDBOOL
 AC_CHECK_FUNCS([getpagesize stpcpy stpncpy])
 AC_CHECK_DECLS([stpcpy, stpncpy])
-AC_CHECK_HEADERS([sys/param.h]) dnl for MIN and MAX
+AC_CHECK_FUNC([process_vm_readv],
+  [AC_CHECK_FUNC([process_vm_writev],
+    [AC_CHECK_DECL([process_vm_readv],
+      [AC_DEFINE([HAVE_PROCESS_VM], [1],
+        [Define to 1 if process_vm_readv is available.])],
+      [], [[
+#include <sys/uio.h>
+      ]])])])
+AC_CHECK_HEADERS([sys/param.h sys/uio.h])
 
 AH_BOTTOM([
 #ifdef HAVE_STDBOOL_H
diff --git a/exec/trace.c b/exec/trace.c
index cb0839c9cd9..8d107696423 100644
--- a/exec/trace.c
+++ b/exec/trace.c
@@ -42,6 +42,10 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include <linux/elf.h> /* for NT_* */
 #endif /* __aarch64__ */
 
+#ifdef HAVE_SYS_UIO_H
+#include <sys/uio.h> /* for process_vm_readv */
+#endif /* HAVE_SYS_UIO_H */
+
 
 
 /* Program tracing functions.
@@ -122,7 +126,10 @@ static struct exec_tracee *tracing_processes;
 
 
 /* Read N bytes from TRACEE's memory, starting at the specified user
-   ADDRESS.  Return its contents in BUFFER.  */
+   ADDRESS.  Return its contents in BUFFER.
+
+   If there are unreadable pages within ADDRESS + N, the contents of
+   BUFFER after the first such page becomes undefined.  */
 
 static void
 read_memory (struct exec_tracee *tracee, char *buffer,
@@ -130,6 +137,25 @@ read_memory (struct exec_tracee *tracee, char *buffer,
 {
   USER_WORD word, n_words, n_bytes, i;
   long rc;
+#ifdef HAVE_PROCESS_VM
+  struct iovec iov, remote;
+
+  /* If `process_vm_readv' is available, use it instead.  */
+
+  iov.iov_base = buffer;
+  iov.iov_len = n;
+  remote.iov_base = (void *) address;
+  remote.iov_len = n;
+
+  /* Return immediately if successful.  As long as some bytes were
+     read, consider the read to have been a success.  */
+
+  if (n <= SSIZE_MAX
+      && ((size_t) process_vm_readv (tracee->pid, &iov, 1,
+                                    &remote, 1, 0) != -1))
+    return;
+
+#endif /* HAVE_PROCESS_VM */
 
   /* First, read entire words from the tracee.  */
   n_words = n & ~(sizeof (USER_WORD) - 1);
@@ -248,6 +274,22 @@ user_copy (struct exec_tracee *tracee, const unsigned char 
*buffer,
 {
   USER_WORD start, end, word;
   unsigned char *bytes;
+#ifdef HAVE_PROCESS_VM
+  struct iovec iov, remote;
+
+  /* Try to use `process_vm_writev' if possible, but fall back to
+     ptrace if something bad happens.  */
+
+  iov.iov_base = (void *) buffer;
+  iov.iov_len = n;
+  remote.iov_base = (void *) address;
+  remote.iov_len = n;
+
+  if (n <= SSIZE_MAX
+      && ((size_t) process_vm_writev (tracee->pid, &iov, 1,
+                                     &remote, 1, 0) == n))
+    return 0;
+#endif /* HAVE_PROCESS_VM */
 
   /* Calculate the start and end positions for the write.  */