client/hostinfo_unix: addapt for Apple Silicon M1 / arm64 CPU BOINC#2

- The native arm64 client tries to launch a separate helper program that
  is compiled only for the x86_64 architecture. If successful, this means
  that Rosetta2 is installed and the host can run x86_64 applications, so
  x86_64-apple-darwin is added as an alternative platform. The helper
  program 'detect_rosetta_cpu' gets the feature string for the emulated
  x86_64 CPU (e.g. SSE), and writes it to a file in the BOINC data
  directory. If  this file exists, this file is read in
  hostinfo_unix_mac() and the features of the meulated CPU are
  added to that of the native CPU.

client/cs_platforms.cpp

@@ -53,6 +53,7 @@ extern int compareOSVersionTo(int toMajor, int toMinor);
 
 #include "client_types.h"
 #include "client_state.h"
+#include "client_msgs.h"
 #include "log_flags.h"
 #include "project.h"
 
@@ -72,6 +73,90 @@ void CLIENT_STATE::add_platform(const char* platform) {
 }
 
 
+#if defined (__APPLE__) && defined (__arm64__)
+// detect a possibly emulated x86_64 CPU and its features on a Apple Silicon M1 Mac
+//
+int launch_child_process_to_detect_emulated_cpu() {
+    int prog;
+    char data_dir[MAXPATHLEN];
+    char execpath[MAXPATHLEN];
+    int retval = 0;
+
+    retval = boinc_delete_file(EMULATED_CPU_INFO_FILENAME);
+    if (retval) {
+        msg_printf(0, MSG_INFO,
+            "Failed to delete old %s. error code %d",
+            EMULATED_CPU_INFO_FILENAME, retval
+        );
+    } else {
+        for (;;) {
+            if (!boinc_file_exists(EMULATED_CPU_INFO_FILENAME)) break;
+            boinc_sleep(0.01);
+        }
+    }
+
+
+    // write the EMULATED_CPU_INFO into the BOINC data dir
+    boinc_getcwd(data_dir);
+
+    // the execuable should be in BOINC data dir
+    strncpy(execpath, data_dir, sizeof(execpath));
+    strncat(execpath, "/" EMULATED_CPU_INFO_EXECUTABLE, sizeof(execpath) - strlen(execpath) - 1);
+
+    if (log_flags.coproc_debug) {
+        msg_printf(0, MSG_INFO,
+            "[x86_64-M1] launching child process at %s",
+            execpath
+        );
+    }
+
+    int argc = 1;
+    char* const argv[2] = {
+         const_cast<char *>(execpath),
+         NULL
+    };
+
+    retval = run_program(
+        data_dir,
+        execpath,
+        argc,
+        argv,
+        0,
+        prog
+    );
+
+    if (retval) {
+        if (log_flags.coproc_debug) {
+            msg_printf(0, MSG_INFO,
+                "[x86_64-M1] run_program of child process returned error %d",
+                retval
+            );
+        }
+        return retval;
+    }
+
+    retval = get_exit_status(prog);
+    if (retval) {
+        char buf[200];
+        if (WIFEXITED(retval)) {
+            int code = WEXITSTATUS(retval);
+            snprintf(buf, sizeof(buf), "process exited with status %d: %s", code, strerror(code));
+        } else if (WIFSIGNALED(retval)) {
+            int sig = WTERMSIG(retval);
+            snprintf(buf, sizeof(buf), "process was terminated by signal %d", sig);
+        } else {
+            snprintf(buf, sizeof(buf), "unknown status %d", retval);
+        }
+        msg_printf(0, MSG_INFO,
+            "Emulated CPU detection failed: %s",
+            buf
+        );
+    }
+
+    return retval;
+}
+#endif
+
 // determine the list of supported platforms.
 //
 void CLIENT_STATE::detect_platforms() {
@@ -106,8 +191,9 @@ void CLIENT_STATE::detect_platforms() {
     }
 #elif defined(__arm64__)
     add_platform("arm64-apple-darwin");
-//TODO: Add test for Mac OS Version when Apple Rosetta emulator is removed 
-    add_platform("x86_64-apple-darwin");
+    if (!launch_child_process_to_detect_emulated_cpu()) {
+        add_platform("x86_64-apple-darwin");
+    }
 #else
 #error Mac client now requires a 64-bit system
 #endif

client/detect_rosetta_cpu.cpp

@@ -0,0 +1,44 @@
+// This file is part of BOINC.
+// http://boinc.berkeley.edu
+// Copyright (C) 2020 University of California
+//
+// BOINC is free software; you can redistribute it and/or modify it
+// under the terms of the GNU Lesser General Public License
+// as published by the Free Software Foundation,
+// either version 3 of the License, or (at your option) any later version.
+//
+// BOINC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+// See the GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
+
+// This helper program should is used to detect an emulated x86_64 CPU
+// on Apples arm64 CPUs. It should be compiiled _only_ for x86_64 architecture
+// and writes the feature string of the meulated CPU to a file
+// EMULATED_CPU_INFO_FILENAME in the current working directory.
+
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/sysctl.h>
+
+#include "hostinfo.h"   // for P_FEATURES_SIZE
+#include "filesys.h"    // for boinc_fopen()
+#include "file_names.h" // for EMULATED_CPU_INFO_FILENAME
+
+int main () {
+    size_t len;
+    char features[P_FEATURES_SIZE];
+    FILE*fp;
+
+    len = sizeof(features);
+    sysctlbyname("machdep.cpu.features", features, &len, NULL, 0);
+    if ((fp = boinc_fopen(EMULATED_CPU_INFO_FILENAME, "w"))) {
+        fprintf(fp," %s\n", features);
+        fclose(fp);
+    }
+    return 0;
+}

client/file_names.h

@@ -71,7 +71,9 @@ extern void send_log_after(const char* filename, double t, MIOFILE& mf);
 #define CLIENT_OPAQUE_FILENAME      "client_opaque.txt"
 #define CONFIG_FILE                 "cc_config.xml"
 #define NVC_CONFIG_FILE             "nvc_config.xml"
-#define COPROC_INFO_FILENAME        "coproc_info.xml"
+#define COPROC_INFO_FILENAME        "coproc_info.txt"
+#define EMULATED_CPU_INFO_EXECUTABLE "detect_rosetta_cpu"
+#define EMULATED_CPU_INFO_FILENAME  "emulated_cpu_info.txt"
 #define CPU_BENCHMARKS_FILE_NAME    "cpu_benchmarks"
 #define CREATE_ACCOUNT_FILENAME     "create_account.xml"
 #define DAILY_XFER_HISTORY_FILENAME "daily_xfer_history.xml"

client/hostinfo_unix.cpp

@@ -892,6 +892,24 @@ static void get_cpu_info_mac(HOST_INFO& host) {
 
     sysctlbyname("hw.optional.ucnormal_mem", &feature, &len, NULL, 0);
     if (feature) feature_string += " ucnormal_mem";
+
+    // read features of the emulated CPU if there is a file containing these
+    char fpath[MAXPATHLEN];
+    boinc_getcwd(fpath);
+    strcat(fpath,"/");
+    strcat(fpath,EMULATED_CPU_INFO_FILENAME);
+    if (boinc_file_exists(fpath)) {
+        FILE* fp = boinc_fopen(fpath, "r");
+        if (fp) {
+            fgets(features, sizeof(features), fp);
+	    feature_string += features;
+            fclose(fp);
+        } else if (log_flags.coproc_debug) {
+            msg_printf(0, MSG_INFO, "[x86_64-M1] couldn't open file %s", fpath);
+        }
+    } else if (log_flags.coproc_debug) {
+        msg_printf(0, MSG_INFO, "[x86_64-M1] didn't find file %s", fpath);
+    }
 #endif // defined(__i386__) || defined(__x86_64__)
 
     strncpy(features,feature_string.c_str(),sizeof(features));