In linux client, Added code to detect capability to run 64-bit binaries

from 32-bit BOINC client, and capability to run 32-bit binaries on a 64-bit 
linux system.


svn path=/trunk/boinc/; revision=17617

checkin_notes

@@ -3076,4 +3076,11 @@ Charlie 17 Mar 2009
     mac_build/
         boinc.xcodeproj/
             project.pbxproj
-    
+   
+Eric K  17 Mar 2009
+    - Linux: client: Added code to detect capability to run 64-bit binaries
+        from 32-bit BOINC client, and capability to run 32-bit binaries on 
+	a 64-bit linux system.
+
+    client/
+        cs_platforms.cpp

client/cs_platforms.cpp

@@ -46,6 +46,7 @@ LPFN_ISWOW64PROCESS fnIsWow64Process;
 #include "client_state.h"
 #include "error_numbers.h"
 #include "log_flags.h"
+#include "filesys.h"
 #include "str_util.h"
 #include "util.h"
 
@@ -103,6 +104,105 @@ void CLIENT_STATE::detect_platforms() {
     // Supported on all 3 Mac architectures
     add_platform("powerpc-apple-darwin");
 
+#elif defined(__linux__) && ( defined(__i386__) || defined(__x86_64__) )
+    // Let's try to support both 32 and 64 bit applications in one client
+    // regardless of whether it is a 32 or 64 bit client
+    const char *uname[]={"/bin/uname","/usr/bin/uname",0};
+    int eno=0, support64=0, support32=0;
+    FILE *f;
+    char cmdline[256];
+    cmdline[0]=0;
+
+    // find the 'uname' executable
+    do {
+        if (boinc_file_exists(uname[eno])) break; 
+    } while (uname[++eno] != 0);
+    // run it and check the kernel machine architecture.
+    if ( uname[eno] != 0 ) {
+        strlcpy(cmdline,uname[eno],256);
+        strlcat(cmdline," -m",256);
+        if ((f=popen(cmdline,"r"))) {
+            while (!std::feof(f)) {
+	        fgets(cmdline,256,f);
+		if (strstr(cmdline,"x86_64")) support64=1;
+	    }
+	    pclose(f);
+	}
+        if (!support64) {
+	    // we're running on a 32 bit kernel, so we will assume
+	    // we are i686-pc-linux-gnu only.
+	    support32=1;
+	} else {
+	    // we're running on a 64 bit kernel.
+	    // Now comes the hard part.  How to tell whether we can run
+	    // 32-bit binaries.
+#if defined(__i386__) && !defined(__x86_64__)
+            // If we're a 32 bit binary, then we obviously can.
+	    support32=1;
+#else
+            // If we're a 64 bit binary, the check is a bit harder.
+	    // We'll use the file command to check installation of
+	    // 32 bit libraries or executables.
+	    const char *file[]={"/usr/bin/file","/bin/file",0};
+	    const char *libdir[]={"/lib","/lib32","/lib/32","/usr/lib","/usr/lib32","/usr/lib/32"};
+	    const int nlibdirs=sizeof(libdir)/sizeof(char *);
+	    
+
+            // find 'file'
+            eno=0;
+            do {
+                if (boinc_file_exists(file[eno])) break; 
+            } while (file[++eno] != 0);
+	    // now try to find a 32-bit C library.
+	    if (file[eno] != 0) {
+	        int i;
+	        for (i=0;i<nlibdirs;i++) {
+	            struct dirent *entry;
+	            DIR *a=opendir(libdir[i]);
+		    // if dir doesn't exist, do to the next one
+		    if ( a == 0 ) continue;
+		    // dir exists. read each entry until you find a 32bit lib
+		    while ((support32 == 0) && ((entry=readdir(a)) != 0)) {
+		        strlcpy(cmdline,file[eno],256);
+		        strlcat(cmdline," -L ",256);
+		        strlcat(cmdline,libdir[i],256);
+		        strlcat(cmdline,"/",256);
+		        strlcat(cmdline,entry->d_name,256);
+		        if ((f=popen(cmdline,"r"))) {
+                            while (!std::feof(f)) {
+	                        fgets(cmdline,256,f);
+			        // If the library is 32-bit ELF, then we're
+			        // golden.
+		                if (strstr(cmdline,"ELF") && 
+			            strstr(cmdline,"32-bit")) support32=1;
+	                    }
+			    pclose(f);
+		        }  
+		    }
+		    closedir(a);
+		    if (support32) break;
+                 }
+	     }
+#endif
+	 }
+    }
+
+    if (support64) {
+       add_platform("x86_64-pc-linux-gnu");
+    }
+    if (support32) {
+       add_platform("i686-pc-linux-gnu");
+    }
+
+    if (!(support64 || support32)) {
+        // Something went wrong. Assume HOSTTYPE and HOSTTYPEALT
+	// are correct
+        add_platform(HOSTTYPE);
+#ifdef HOSTTYPEALT
+        add_platform(HOSTTYPEALT);
+#endif
+    }
+
 #elif defined(sun)
     // Check if we can run 64-bit binaries...
     // this assumes there isn't a 64-bit only solaris.  (Every 64-bit solaris can run 32 bit binaries)
@@ -169,7 +269,7 @@ void CLIENT_STATE::detect_platforms() {
 
 #endif  // !defined(UNKNOWN_SOLARIS_PROCESSOR)
 
-#else  // defined(sun)
+#else                   
     // Any other platform, fall back to the previous method
     add_platform(HOSTTYPE);
 #ifdef HOSTTYPEALT