/*
 * @(#)java_md.c	1.77 10/03/23
 *
 * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

#include "java.h"
#include <dirent.h>
#include <dlfcn.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/types.h>
#include "manifest_info.h"
#include "version_comp.h"

#ifdef __linux__
#include <pthread.h>
#else
#include <thread.h>
#endif

#define JVM_DLL "libjvm.so"
#define JAVA_DLL "libjava.so"

/*
 * If a processor / os combination has the ability to run binaries of
 * two data models and cohabitation of jre/jdk bits with both data
 * models is supported, then DUAL_MODE is defined.  When DUAL_MODE is
 * defined, the architecture names for the narrow and wide version of
 * the architecture are defined in LIBARCH64NAME and LIBARCH32NAME.  Currently
 * only Solaris on sparc/sparcv9 and i586/amd64 is DUAL_MODE; linux
 * i586/amd64 could be defined as DUAL_MODE but that is not the
 * current policy.
 */

#ifndef LIBARCHNAME
#  error "The macro LIBARCHNAME was not defined on the compile line"
#endif

#ifdef __sun
#  define DUAL_MODE
#  ifndef LIBARCH32NAME
#    error "The macro LIBARCH32NAME was not defined on the compile line"
#  endif
#  ifndef LIBARCH64NAME
#    error "The macro LIBARCH64NAME was not defined on the compile line"
#  endif
#  include <sys/systeminfo.h>
#  include <sys/elf.h>
#  include <stdio.h>
#endif

/* pointer to environment */
extern char **environ;

/*
 *      A collection of useful strings. One should think of these as #define
 *      entries, but actual strings can be more efficient (with many compilers).
 */
#ifdef __linux__
static const char *system_dir	= "/usr/java";
static const char *user_dir	= "/java";
#else /* Solaris */
static const char *system_dir	= "/usr/jdk";
static const char *user_dir	= "/jdk";
#endif

/*
 * Flowchart of launcher execs and options processing on unix
 *
 * The selection of the proper vm shared library to open depends on
 * several classes of command line options, including vm "flavor"
 * options (-client, -server) and the data model options, -d32  and
 * -d64, as well as a version specification which may have come from
 * the command line or from the manifest of an executable jar file.
 * The vm selection options are not passed to the running
 * virtual machine; they must be screened out by the launcher.
 *
 * The version specification (if any) is processed first by the
 * platform independent routine SelectVersion.  This may result in
 * the exec of the specified launcher version.
 *
 * Typically, the launcher execs at least once to ensure a suitable
 * LD_LIBRARY_PATH is in effect for the process.  The first exec
 * screens out all the data model options; leaving the choice of data
 * model implicit in the binary selected to run.  However, in case no
 * exec is done, the data model options are screened out before the vm
 * is invoked.
 *
 *  incoming argv ------------------------------
 *  |                                          |
 * \|/                                         |
 * CheckJVMType                                |
 * (removes -client, -server, etc.)            |
 *                                            \|/
 *                                            CreateExecutionEnvironment
 *                                            (removes -d32 and -d64, 
 *                                             determines desired data model,
 *                                             sets up LD_LIBRARY_PATH, 
 *                                             and exec's)
 *                                             |
 *  --------------------------------------------
 *  |
 * \|/
 * exec child 1 incoming argv -----------------
 *  |                                          |
 * \|/                                         |
 * CheckJVMType                                |
 * (removes -client, -server, etc.)            |
 *  |                                         \|/
 *  |                                          CreateExecutionEnvironment
 *  |                                          (verifies desired data model 
 *  |                                           is running and acceptable 
 *  |                                           LD_LIBRARY_PATH;
 *  |                                           no-op in child)
 *  |
 * \|/
 * TranslateDashJArgs...
 * (Prepare to pass args to vm)
 *  |
 *  |
 *  |
 * \|/
 * ParseArguments
 * (ignores -d32 and -d64,
 *  processes version options,
 *  creates argument list for vm, 
 *  etc.)
 * 
 */

static char *SetExecname(char **argv);
static char * GetExecname();
static jboolean GetJVMPath(const char *jrepath, const char *jvmtype,
			   char *jvmpath, jint jvmpathsize, char * arch);
static jboolean GetJREPath(char *path, jint pathsize, char * arch, jboolean speculative);

const char *
GetArch()
{
    return LIBARCHNAME;
}

void
CreateExecutionEnvironment(int *_argcp,
			   char ***_argvp,
			   char jrepath[],
			   jint so_jrepath,
			   char jvmpath[],
			   jint so_jvmpath,
			   char **original_argv) {
  /*
   * First, determine if we are running the desired data model.  If we
   * are running the desired data model, all the error messages
   * associated with calling GetJREPath, ReadKnownVMs, etc. should be
   * output.  However, if we are not running the desired data model,
   * some of the errors should be suppressed since it is more
   * informative to issue an error message based on whether or not the
   * os/processor combination has dual mode capabilities.
   */

    char *execname = NULL;
    int original_argc = *_argcp;
    jboolean jvmpathExists;

    /* Compute the name of the executable */
    execname = SetExecname(*_argvp);

    /* Set the LD_LIBRARY_PATH environment variable, check data model
       flags, and exec process, if needed */
    {
      char *arch	= (char *)GetArch(); /* like sparc or sparcv9 */
      char * jvmtype 	= NULL;
      int argc		= *_argcp;
      char **argv	= original_argv;

      char *runpath	= NULL; /* existing effective LD_LIBRARY_PATH
				   setting */

      int running	=	/* What data model is being ILP32 =>
				   32 bit vm; LP64 => 64 bit vm */
#ifdef _LP64 
	64;
#else
      32;
#endif

      int wanted	= running;	/* What data mode is being
					   asked for? Current model is
					   fine unless another model
					   is asked for */

      char* new_runpath	= NULL; /* desired new LD_LIBRARY_PATH string */
      char* newpath	= NULL; /* path on new LD_LIBRARY_PATH */
      char* lastslash	= NULL;

      char** newenvp	= NULL; /* current environment */

      char** newargv	= NULL;
      int    newargc	= 0;
#ifdef __sun
      char*  dmpath	= NULL;  /* data model specific LD_LIBRARY_PATH,
				    Solaris only */
#endif    

      /*
       * Starting in 1.5, all unix platforms accept the -d32 and -d64
       * options.  On platforms where only one data-model is supported
       * (e.g. ia-64 Linux), using the flag for the other data model is
       * an error and will terminate the program.
       */

      { /* open new scope to declare local variables */
	int i;

	newargv = (char **)JLI_MemAlloc((argc+1) * sizeof(*newargv));
	newargv[newargc++] = argv[0];

	/* scan for data model arguments and remove from argument list;
	   last occurrence determines desired data model */
	for (i=1; i < argc; i++) {

	  if (strcmp(argv[i], "-J-d64") == 0 || strcmp(argv[i], "-d64") == 0) {
	    wanted = 64;
	    continue;
	  }
	  if (strcmp(argv[i], "-J-d32") == 0 || strcmp(argv[i], "-d32") == 0) {
	    wanted = 32;
	    continue;
	  }
	  newargv[newargc++] = argv[i];

#ifdef JAVA_ARGS
	  if (argv[i][0] != '-')
	    continue;
#else
	  if (strcmp(argv[i], "-classpath") == 0 || strcmp(argv[i], "-cp") == 0) {
	    i++;
	    if (i >= argc) break;
	    newargv[newargc++] = argv[i];
	    continue;
	  }
	  if (argv[i][0] != '-') { i++; break; }
#endif
	}

	/* copy rest of args [i .. argc) */
	while (i < argc) {
	  newargv[newargc++] = argv[i++];
	}
	newargv[newargc] = NULL;

	/* 
	 * newargv has all proper arguments here
	 */
    
	argc = newargc;
	argv = newargv;
      }

      /* If the data model is not changing, it is an error if the
	 jvmpath does not exist */
      if (wanted == running) {
	/* Find out where the JRE is that we will be using. */
	if (!GetJREPath(jrepath, so_jrepath, arch, JNI_FALSE) ) {
	  fprintf(stderr, "Error: could not find Java 2 Runtime Environment.\n");
	  exit(2);
	}

	/* Find the specified JVM type */
	if (ReadKnownVMs(jrepath, arch, JNI_FALSE) < 1) {
	  fprintf(stderr, "Error: no known VMs. (check for corrupt jvm.cfg file)\n");
	  exit(1);
	}

	jvmpath[0] = '\0';
	jvmtype = CheckJvmType(_argcp, _argvp, JNI_FALSE);

	if (!GetJVMPath(jrepath, jvmtype, jvmpath, so_jvmpath, arch )) {
	  fprintf(stderr, "Error: no `%s' JVM at `%s'.\n", jvmtype, jvmpath);
	  exit(4);
	}
      } else {  /* do the same speculatively or exit */
#ifdef DUAL_MODE
	if (running != wanted) {
	  /* Find out where the JRE is that we will be using. */
	  if (!GetJREPath(jrepath, so_jrepath, ((wanted==64)?LIBARCH64NAME:LIBARCH32NAME), JNI_TRUE)) {
	    goto EndDataModelSpeculate;
	  }

	  /*
	   * Read in jvm.cfg for target data model and process vm
	   * selection options.
	   */
	  if (ReadKnownVMs(jrepath, ((wanted==64)?LIBARCH64NAME:LIBARCH32NAME), JNI_TRUE) < 1) {
	    goto EndDataModelSpeculate;
	  }
	  jvmpath[0] = '\0';
	  jvmtype = CheckJvmType(_argcp, _argvp, JNI_TRUE);
	  /* exec child can do error checking on the existence of the path */
	  jvmpathExists = GetJVMPath(jrepath, jvmtype, jvmpath, so_jvmpath, 
				     ((wanted==64)?LIBARCH64NAME:LIBARCH32NAME));

	}
      EndDataModelSpeculate: /* give up and let other code report error message */
	;
#else
	fprintf(stderr, "Running a %d-bit JVM is not supported on this platform.\n", wanted);
	exit(1);
#endif
      }

      /*
       * We will set the LD_LIBRARY_PATH as follows:
       *
       *     o		$JVMPATH (directory portion only)
       *     o		$JRE/lib/$LIBARCHNAME
       *     o		$JRE/../lib/$LIBARCHNAME
       *
       * followed by the user's previous effective LD_LIBRARY_PATH, if
       * any.
       */

#ifdef __sun
      /* 
       * Starting in Solaris 7, ld.so.1 supports three LD_LIBRARY_PATH
       * variables:
       *
       * 1. LD_LIBRARY_PATH -- used for 32 and 64 bit searches if
       * data-model specific variables are not set.
       *
       * 2. LD_LIBRARY_PATH_64 -- overrides and replaces LD_LIBRARY_PATH
       * for 64-bit binaries.
       *
       * 3. LD_LIBRARY_PATH_32 -- overrides and replaces LD_LIBRARY_PATH
       * for 32-bit binaries.
       *
       * The vm uses LD_LIBRARY_PATH to set the java.library.path system
       * property.  To shield the vm from the complication of multiple
       * LD_LIBRARY_PATH variables, if the appropriate data model
       * specific variable is set, we will act as if LD_LIBRARY_PATH had
       * the value of the data model specific variant and the data model
       * specific variant will be unset.  Note that the variable for the
       * *wanted* data model must be used (if it is set), not simply the
       * current running data model.
       */

      switch(wanted) {
      case 0:
	if(running == 32) {
	  dmpath = getenv("LD_LIBRARY_PATH_32");
	  wanted = 32;
	}
	else {
	  dmpath = getenv("LD_LIBRARY_PATH_64");
	  wanted = 64;
	}
	break;

      case 32:
	dmpath = getenv("LD_LIBRARY_PATH_32");
	break;

      case 64:
	dmpath = getenv("LD_LIBRARY_PATH_64");
	break;
      
      default:
	fprintf(stderr, "Improper value at line %d.", __LINE__);
	exit(1); /* unknown value in wanted */
	break;
      }
    
      /* 
       * If dmpath is NULL, the relevant data model specific variable is
       * not set and normal LD_LIBRARY_PATH should be used.
       */
      if( dmpath == NULL) {
	runpath = getenv("LD_LIBRARY_PATH");
      }
      else {
	runpath = dmpath;
      }
#else
      /*
       * If not on Solaris, assume only a single LD_LIBRARY_PATH
       * variable.
       */
      runpath = getenv("LD_LIBRARY_PATH");
#endif /* __sun */

#ifdef __linux
      /*
       * On linux, if a binary is running as sgid or suid, glibc sets
       * LD_LIBRARY_PATH to the empty string for security purposes.  (In
       * contrast, on Solaris the LD_LIBRARY_PATH variable for a
       * privileged binary does not lose its settings; but the dynamic
       * linker does apply more scrutiny to the path.) The launcher uses
       * the value of LD_LIBRARY_PATH to prevent an exec loop.
       * Therefore, if we are running sgid or suid, this function's
       * setting of LD_LIBRARY_PATH will be ineffective and we should
       * return from the function now.  Getting the right libraries to
       * be found must be handled through other mechanisms.
       */
      if((getgid() != getegid()) || (getuid() != geteuid()) ) {
	return;
      }
#endif    

      /* runpath contains current effective LD_LIBRARY_PATH setting */

      jvmpath = JLI_StringDup(jvmpath);
      new_runpath = JLI_MemAlloc( ((runpath!=NULL)?strlen(runpath):0) + 
			      2*strlen(jrepath) + 2*strlen(arch) +
			      strlen(jvmpath) + 52);
      newpath = new_runpath + strlen("LD_LIBRARY_PATH=");


      /*
       * Create desired LD_LIBRARY_PATH value for target data model.
       */
      {
	/* remove the name of the .so from the JVM path */
	lastslash = strrchr(jvmpath, '/');
	if (lastslash)
	  *lastslash = '\0';


	/* jvmpath, ((running != wanted)?((wanted==64)?"/"LIBARCH64NAME:"/.."):""), */

	sprintf(new_runpath, "LD_LIBRARY_PATH="
		"%s:"
		"%s/lib/%s:"
		"%s/../lib/%s",
		jvmpath,
#ifdef DUAL_MODE
		jrepath, ((wanted==64)?LIBARCH64NAME:LIBARCH32NAME),
		jrepath, ((wanted==64)?LIBARCH64NAME:LIBARCH32NAME)
#else
		jrepath, arch,
		jrepath, arch
#endif
		);


	/* 
	 * Check to make sure that the prefix of the current path is the 
	 * desired environment variable setting.
	 */
	if (runpath != NULL && 
	    strncmp(newpath, runpath, strlen(newpath))==0 &&
	    (runpath[strlen(newpath)] == 0 || runpath[strlen(newpath)] == ':') &&
	    (running == wanted) /* data model does not have to be changed */
#ifdef __sun
	    && (dmpath == NULL)    /* data model specific variables not set  */
#endif
	    ) {

	  return;

	}
      }
    
      /* 
       * Place the desired environment setting onto the prefix of
       * LD_LIBRARY_PATH.  Note that this prevents any possible infinite
       * loop of execv() because we test for the prefix, above.
       */
      if (runpath != 0) {
	strcat(new_runpath, ":");
	strcat(new_runpath, runpath);
      }
    
      if( putenv(new_runpath) != 0) {
	exit(1); /* problem allocating memory; LD_LIBRARY_PATH not set
		    properly */
      }

      /* 
       * Unix systems document that they look at LD_LIBRARY_PATH only
       * once at startup, so we have to re-exec the current executable
       * to get the changed environment variable to have an effect.
       */

#ifdef __sun
      /*
       * If dmpath is not NULL, remove the data model specific string
       * in the environment for the exec'ed child.
       */

      if( dmpath != NULL)
	(void)UnsetEnv((wanted==32)?"LD_LIBRARY_PATH_32":"LD_LIBRARY_PATH_64");
#endif

      newenvp = environ;

      {
	char *newexec = execname;
#ifdef DUAL_MODE
	/* 
	 * If the data model is being changed, the path to the
	 * executable must be updated accordingly; the executable name
	 * and directory the executable resides in are separate.  In the
	 * case of 32 => 64, the new bits are assumed to reside in, e.g.
	 * "olddir/LIBARCH64NAME/execname"; in the case of 64 => 32,
	 * the bits are assumed to be in "olddir/../execname".  For example,
	 *
	 * olddir/sparcv9/execname
	 * olddir/amd64/execname
	 *
	 * for Solaris SPARC and Linux amd64, respectively.
	 */

	if (running != wanted) {
	  char *oldexec = strcpy(JLI_MemAlloc(strlen(execname) + 1), execname);
	  char *olddir = oldexec;
	  char *oldbase = strrchr(oldexec, '/');

	
	  newexec = JLI_MemAlloc(strlen(execname) + 20);
	  *oldbase++ = 0;
	  sprintf(newexec, "%s/%s/%s", olddir, 
		  ((wanted==64) ? LIBARCH64NAME : ".."), oldbase);
	  argv[0] = newexec;
	} 
#endif

	(void)fflush(stdout);
	(void)fflush(stderr);
	execve(newexec, argv, newenvp);
	perror("execve()");

	fprintf(stderr, "Error trying to exec %s.\n", newexec);
	fprintf(stderr, "Check if file exists and permissions are set correctly.\n");

#ifdef DUAL_MODE
	if (running != wanted) {
	  fprintf(stderr, "Failed to start a %d-bit JVM process from a %d-bit JVM.\n",
		  wanted, running);
#  ifdef __sun

#    ifdef __sparc
	  fprintf(stderr, "Verify all necessary J2SE components have been installed.\n" );
	  fprintf(stderr,
		  "(Solaris SPARC 64-bit components must be installed after 32-bit components.)\n" );
#    else 
	  fprintf(stderr, "Either 64-bit processes are not supported by this platform\n");
	  fprintf(stderr, "or the 64-bit components have not been installed.\n");
#    endif
	}
#  endif
#endif

      }

      exit(1);
    }

}


/*
 * On Solaris VM choosing is done by the launcher (java.c).
 */
static jboolean
GetJVMPath(const char *jrepath, const char *jvmtype,
	   char *jvmpath, jint jvmpathsize, char * arch)
{
    struct stat s;
    
    if (strchr(jvmtype, '/')) {
	sprintf(jvmpath, "%s/" JVM_DLL, jvmtype);
    } else {
	sprintf(jvmpath, "%s/lib/%s/%s/" JVM_DLL, jrepath, arch, jvmtype);
    }
    if (_launcher_debug)
      printf("Does `%s' exist ... ", jvmpath);

    if (stat(jvmpath, &s) == 0) {
	if (_launcher_debug) 
	  printf("yes.\n");
	return JNI_TRUE;
    } else {
	if (_launcher_debug)
	  printf("no.\n");
	return JNI_FALSE;
    }
}

/*
 * Find path to JRE based on .exe's location or registry settings.
 */
static jboolean
GetJREPath(char *path, jint pathsize, char * arch, jboolean speculative)
{
    char libjava[MAXPATHLEN];

    if (GetApplicationHome(path, pathsize)) {
	/* Is JRE co-located with the application? */
	sprintf(libjava, "%s/lib/%s/" JAVA_DLL, path, arch);
	if (access(libjava, F_OK) == 0) {
	    goto found;
	}

	/* Does the app ship a private JRE in <apphome>/jre directory? */
	sprintf(libjava, "%s/jre/lib/%s/" JAVA_DLL, path, arch);
	if (access(libjava, F_OK) == 0) {
	    strcat(path, "/jre");
	    goto found;
	}
    }

    if (!speculative) 
      fprintf(stderr, "Error: could not find " JAVA_DLL "\n");
    return JNI_FALSE;

 found:
    if (_launcher_debug)
      printf("JRE path is %s\n", path);
    return JNI_TRUE;
}

jboolean
LoadJavaVM(const char *jvmpath, InvocationFunctions *ifn)
{
    Dl_info dlinfo;
    void *libjvm;

    if (_launcher_debug) {
	printf("JVM path is %s\n", jvmpath);
    }

    libjvm = dlopen(jvmpath, RTLD_NOW + RTLD_GLOBAL);
    if (libjvm == NULL) {
#if defined(__sparc) && !defined(_LP64) /* i.e. 32-bit sparc */
      FILE * fp;
      Elf32_Ehdr elf_head;
      int count;
      int location;
      
      fp = fopen(jvmpath, "r");
      if(fp == NULL)
	goto error;
    
      /* read in elf header */
      count = fread((void*)(&elf_head), sizeof(Elf32_Ehdr), 1, fp);
      fclose(fp);
      if(count < 1)
	goto error;

      /* 
       * Check for running a server vm (compiled with -xarch=v8plus)
       * on a stock v8 processor.  In this case, the machine type in
       * the elf header would not be included the architecture list
       * provided by the isalist command, which is turn is gotten from
       * sysinfo.  This case cannot occur on 64-bit hardware and thus
       * does not have to be checked for in binaries with an LP64 data
       * model.
       */
      if(elf_head.e_machine == EM_SPARC32PLUS) {
	char buf[257];  /* recommended buffer size from sysinfo man
			   page */
	long length;
	char* location;
	
	length = sysinfo(SI_ISALIST, buf, 257);
	if(length > 0) {
	  location = strstr(buf, "sparcv8plus ");
	  if(location == NULL) {
	    fprintf(stderr, "SPARC V8 processor detected; Server compiler requires V9 or better.\n");
	    fprintf(stderr, "Use Client compiler on V8 processors.\n");
	    fprintf(stderr, "Could not create the Java virtual machine.\n");
	    return JNI_FALSE;
	  }
	}
      }
#endif 
      fprintf(stderr, "dl failure on line %d", __LINE__);
      goto error;
    }

    ifn->CreateJavaVM = (CreateJavaVM_t)
      dlsym(libjvm, "JNI_CreateJavaVM");
    if (ifn->CreateJavaVM == NULL)
	goto error;

    ifn->GetDefaultJavaVMInitArgs = (GetDefaultJavaVMInitArgs_t)
	dlsym(libjvm, "JNI_GetDefaultJavaVMInitArgs");
    if (ifn->GetDefaultJavaVMInitArgs == NULL)
      goto error;

    return JNI_TRUE;

error:
    fprintf(stderr, "Error: failed %s, because %s\n", jvmpath, dlerror());
    return JNI_FALSE;
}

/*
 * If app is "/foo/bin/javac", or "/foo/bin/sparcv9/javac" then put
 * "/foo" into buf.
 */
jboolean
GetApplicationHome(char *buf, jint bufsize)
{
#ifdef __linux__
    char *execname = GetExecname();
    if (execname) {
	strncpy(buf, execname, bufsize-1);
	buf[bufsize-1] = '\0';
    } else {
	return JNI_FALSE;
    }
#else
    Dl_info dlinfo;

    dladdr((void *)GetApplicationHome, &dlinfo);
    if (realpath(dlinfo.dli_fname, buf) == NULL) {
	fprintf(stderr, "Error: realpath(`%s') failed.\n", dlinfo.dli_fname);
	return JNI_FALSE;
    }
#endif

    if (strrchr(buf, '/') == 0) {
	buf[0] = '\0';
	return JNI_FALSE;
    }
    *(strrchr(buf, '/')) = '\0';	/* executable file      */
    if (strlen(buf) < 4 || strrchr(buf, '/') == 0) {
	buf[0] = '\0';
	return JNI_FALSE;
    }
    if (strcmp("/bin", buf + strlen(buf) - 4) != 0) 
	*(strrchr(buf, '/')) = '\0';	/* sparcv9 or amd64     */
    if (strlen(buf) < 4 || strcmp("/bin", buf + strlen(buf) - 4) != 0) {
	buf[0] = '\0';
	return JNI_FALSE;
    }
    *(strrchr(buf, '/')) = '\0';	/* bin                  */

    return JNI_TRUE;
}


/*
 * Return true if the named program exists
 */
static int
ProgramExists(char *name)
{
    struct stat sb;
    if (stat(name, &sb) != 0) return 0;
    if (S_ISDIR(sb.st_mode)) return 0;
    return (sb.st_mode & S_IEXEC) != 0;
}


/*
 * Find a command in a directory, returning the path.
 */
static char *
Resolve(char *indir, char *cmd)
{
    char name[PATH_MAX + 2], *real;

    if ((strlen(indir) + strlen(cmd) + 1)  > PATH_MAX) return 0;
    sprintf(name, "%s%c%s", indir, FILE_SEPARATOR, cmd);
    if (!ProgramExists(name)) return 0;
    real = JLI_MemAlloc(PATH_MAX + 2);
    if (!realpath(name, real)) 
	strcpy(real, name);
    return real;
}


/*
 * Find a path for the executable
 */
static char *
FindExecName(char *program)
{
    char cwdbuf[PATH_MAX+2];
    char *path;
    char *tmp_path;
    char *f;
    char *result = NULL;

    /* absolute path? */
    if (*program == FILE_SEPARATOR || 
	(FILE_SEPARATOR=='\\' && strrchr(program, ':')))
	return Resolve("", program+1);

    /* relative path? */
    if (strrchr(program, FILE_SEPARATOR) != 0) {
	char buf[PATH_MAX+2];
	return Resolve(getcwd(cwdbuf, sizeof(cwdbuf)), program);
    }

    /* from search path? */
    path = getenv("PATH");
    if (!path || !*path) path = ".";
    tmp_path = JLI_MemAlloc(strlen(path) + 2);
    strcpy(tmp_path, path);

    for (f=tmp_path; *f && result==0; ) {
	char *s = f;
	while (*f && (*f != PATH_SEPARATOR)) ++f;
	if (*f) *f++ = 0;
	if (*s == FILE_SEPARATOR)
	    result = Resolve(s, program);
	else {
	    /* relative path element */
	    char dir[2*PATH_MAX];
	    sprintf(dir, "%s%c%s", getcwd(cwdbuf, sizeof(cwdbuf)), 
		    FILE_SEPARATOR, s);
	    result = Resolve(dir, program);
	}
	if (result != 0) break;
    }

    JLI_MemFree(tmp_path);
    return result;
}


/* Store the name of the executable once computed */
static char *execname = NULL;

/*
 * Compute the name of the executable
 *
 * In order to re-exec securely we need the absolute path of the
 * executable. On Solaris getexecname(3c) may not return an absolute
 * path so we use dladdr to get the filename of the executable and
 * then use realpath to derive an absolute path. From Solaris 9
 * onwards the filename returned in DL_info structure from dladdr is
 * an absolute pathname so technically realpath isn't required.
 * On Linux we read the executable name from /proc/self/exe.
 * As a fallback, and for platforms other than Solaris and Linux,
 * we use FindExecName to compute the executable name.
 */
static char *
SetExecname(char **argv)
{
    char* exec_path = NULL;

    if (execname != NULL)	/* Already determined */
	return (execname);
   
#if defined(__sun)
    {
        Dl_info dlinfo;
        if (dladdr((void*)&SetExecname, &dlinfo)) {
	    char *resolved = (char*)JLI_MemAlloc(PATH_MAX+1);
   	    if (resolved != NULL) {
		exec_path = realpath(dlinfo.dli_fname, resolved);
		if (exec_path == NULL) {
		    JLI_MemFree(resolved);
		}
	    }
        }
    }
#elif defined(__linux__)
    {
	const char* self = "/proc/self/exe";
        char buf[PATH_MAX+1];
        int len = readlink(self, buf, PATH_MAX);
        if (len >= 0) {
	    buf[len] = '\0';		/* readlink doesn't nul terminate */
	    exec_path = JLI_StringDup(buf);
	}
    }
#else /* !__sun && !__linux */
    {
        /* Not implemented */
    }
#endif 

    if (exec_path == NULL) {
        exec_path = FindExecName(argv[0]);
    }
    execname = exec_path;
    return exec_path;
}

/*
 * Return the name of the executable.  Used in java_md.c to find the JRE area.
 */
static char *
GetExecname() {
  return execname;
}

void ReportErrorMessage(char * message, jboolean always) {
  if (always) {
    fprintf(stderr, "%s\n", message);
  }
}

void ReportErrorMessage2(char * format, char * string, jboolean always) {
  if (always) {
    fprintf(stderr, format, string);
    fprintf(stderr, "\n");
  }
}

void  ReportExceptionDescription(JNIEnv * env) {
  (*env)->ExceptionDescribe(env);
}

/*
 * Return JNI_TRUE for an option string that has no effect but should
 * _not_ be passed on to the vm; return JNI_FALSE otherwise.  On
 * Solaris SPARC, this screening needs to be done if:
 * 1) LD_LIBRARY_PATH does _not_ need to be reset and
 * 2) -d32 or -d64 is passed to a binary with a matching data model
 *    (the exec in SetLibraryPath removes -d<n> options and points the
 *    exec to the proper binary).  When this exec is not done, these options
 *    would end up getting passed onto the vm.
 */
jboolean RemovableMachineDependentOption(char * option) {
  /*
   * Unconditionally remove both -d32 and -d64 options since only
   * the last such options has an effect; e.g. 
   * java -d32 -d64 -d32 -version
   * is equivalent to 
   * java -d32 -version
   */

  if( (strcmp(option, "-d32")  == 0 ) || 
      (strcmp(option, "-d64")  == 0 ))
    return JNI_TRUE;
  else
    return JNI_FALSE;
}

void PrintMachineDependentOptions() {
      fprintf(stdout,
	"    -d32          use a 32-bit data model if available\n"
	"\n"
	"    -d64          use a 64-bit data model if available\n");
      return;
}

/* 
 * The following methods (down to ServerClassMachine()) answer
 * the question about whether a machine is a "server-class"
 * machine.  A server-class machine is loosely defined as one
 * with 2 or more processors and 2 gigabytes or more physical
 * memory.  The definition of a processor is a physical package,
 * not a hyperthreaded chip masquerading as a multi-processor.
 * The definition of memory is also somewhat fuzzy, since x86
 * machines seem not to report all the memory in their DIMMs, we
 * think because of memory mapping of graphics cards, etc.
 * 
 * This code is somewhat more confused with #ifdef's than we'd
 * like because this file is used by both Solaris and Linux
 * platforms, and so needs to be parameterized for SPARC and
 * i586 hardware.  The other Linux platforms (amd64 and ia64)
 * don't even ask this question, because they only come with
 * server JVMs.  */

# define KB (1024UL)
# define MB (1024UL * KB)
# define GB (1024UL * MB)

/* Compute physical memory by asking the OS */
uint64_t
physical_memory(void) {
  const uint64_t pages     = (uint64_t) sysconf(_SC_PHYS_PAGES);
  const uint64_t page_size = (uint64_t) sysconf(_SC_PAGESIZE);
  const uint64_t result    = pages * page_size;
# define UINT64_FORMAT "%" PRIu64
    
  if (_launcher_debug) {
    printf("pages: " UINT64_FORMAT
           "  page_size: " UINT64_FORMAT
           "  physical memory: " UINT64_FORMAT " (%.3fGB)\n",
           pages, page_size, result, result / (double) GB);
  }
  return result;
}

#if defined(__sun) && defined(__sparc)

/* Methods for solaris-sparc: these are easy. */

/* Ask the OS how many processors there are. */
unsigned long 
physical_processors(void) {
  const unsigned long sys_processors = sysconf(_SC_NPROCESSORS_CONF);

  if (_launcher_debug) {
    printf("sysconf(_SC_NPROCESSORS_CONF): %lu\n", sys_processors);
  }
  return sys_processors;
}

/* The solaris-sparc version of the "server-class" predicate. */
jboolean
solaris_sparc_ServerClassMachine(void) {
  jboolean            result            = JNI_FALSE;
  /* How big is a server class machine? */
  const unsigned long server_processors = 2UL;
  const uint64_t      server_memory     = 2UL * GB;
  const uint64_t      actual_memory     = physical_memory();

  /* Is this a server class machine? */
  if (actual_memory >= server_memory) {
    const unsigned long actual_processors = physical_processors();
    if (actual_processors >= server_processors) {
      result = JNI_TRUE;
    }
  }
  if (_launcher_debug) {
    printf("solaris_" LIBARCHNAME "_ServerClassMachine: %s\n",
           (result == JNI_TRUE ? "JNI_TRUE" : "JNI_FALSE"));
  }
  return result;
}

#endif /* __sun && __sparc */

#if defined(__sun) && defined(i586)

/*
 * A utility method for asking the CPU about itself.
 * There's a corresponding version of linux-i586
 * because the compilers are different.
 */
void 
get_cpuid(uint32_t arg,
          uint32_t* eaxp,
          uint32_t* ebxp,
          uint32_t* ecxp,
          uint32_t* edxp) {
#ifdef _LP64
  asm(
  /* rbx is a callee-saved register */
      " movq    %rbx, %r11  \n"
  /* rdx and rcx are 3rd and 4th argument registers */
      " movq    %rdx, %r10  \n"
      " movq    %rcx, %r9   \n"
      " movl    %edi, %eax  \n"
      " cpuid               \n"
      " movl    %eax, (%rsi)\n"
      " movl    %ebx, (%r10)\n"
      " movl    %ecx, (%r9) \n"
      " movl    %edx, (%r8) \n"
  /* Restore rbx */
      " movq    %r11, %rbx");
#else
  /* EBX is a callee-saved register */
  asm(" pushl   %ebx");
  /* Need ESI for storing through arguments */
  asm(" pushl   %esi");
  asm(" movl    8(%ebp), %eax   \n"
      " cpuid                   \n"
      " movl    12(%ebp), %esi  \n"
      " movl    %eax, (%esi)    \n"
      " movl    16(%ebp), %esi  \n"
      " movl    %ebx, (%esi)    \n"
      " movl    20(%ebp), %esi  \n"
      " movl    %ecx, (%esi)    \n"
      " movl    24(%ebp), %esi  \n"
      " movl    %edx, (%esi)      ");
  /* Restore ESI and EBX */
  asm(" popl    %esi");
  /* Restore EBX */
  asm(" popl    %ebx");
#endif
}

#endif /* __sun && i586 */

#if defined(__linux__) && defined(i586)

/*
 * A utility method for asking the CPU about itself.
 * There's a corresponding version of solaris-i586
 * because the compilers are different.
 */
void 
get_cpuid(uint32_t arg,
          uint32_t* eaxp,
          uint32_t* ebxp,
          uint32_t* ecxp,
          uint32_t* edxp) {
#ifdef _LP64
  __asm__ volatile (/* Instructions */
                    "	movl	%4, %%eax  \n"
                    "	cpuid              \n"
                    "	movl    %%eax, (%0)\n"
                    "	movl    %%ebx, (%1)\n"
                    "	movl    %%ecx, (%2)\n"
                    "	movl    %%edx, (%3)\n"
                    : /* Outputs */
                    : /* Inputs */
                    "r" (eaxp),
                    "r" (ebxp),
                    "r" (ecxp),
                    "r" (edxp),
                    "r" (arg)
                    : /* Clobbers */
                    "%rax", "%rbx", "%rcx", "%rdx", "memory"
                    );
#else
  uint32_t value_of_eax = 0;
  uint32_t value_of_ebx = 0;
  uint32_t value_of_ecx = 0;
  uint32_t value_of_edx = 0;
  __asm__ volatile (/* Instructions */
                        /* ebx is callee-save, so push it */
                    "   pushl   %%ebx      \n"
                    "	movl	%4, %%eax  \n"
                    "	cpuid              \n"
                    "	movl    %%eax, %0  \n"
                    "	movl    %%ebx, %1  \n"
                    "	movl    %%ecx, %2  \n"
                    "	movl    %%edx, %3  \n"
                        /* restore ebx */
                    "   popl    %%ebx      \n"

                    : /* Outputs */
                    "=m" (value_of_eax),
                    "=m" (value_of_ebx),
                    "=m" (value_of_ecx),
                    "=m" (value_of_edx)
                    : /* Inputs */
                    "m" (arg)
                    : /* Clobbers */
                    "%eax", "%ecx", "%edx"
                    );
  *eaxp = value_of_eax;
  *ebxp = value_of_ebx;
  *ecxp = value_of_ecx;
  *edxp = value_of_edx;
#endif
}

#endif /* __linux__ && i586 */

#ifdef i586
/* 
 * Routines shared by solaris-i586 and linux-i586.
 */

enum HyperThreadingSupport_enum {
  hts_supported        =  1,
  hts_too_soon_to_tell =  0,
  hts_not_supported    = -1,
  hts_not_pentium4     = -2,
  hts_not_intel        = -3
};
typedef enum HyperThreadingSupport_enum HyperThreadingSupport;

/* Determine if hyperthreading is supported */
HyperThreadingSupport
hyperthreading_support(void) {
  HyperThreadingSupport result = hts_too_soon_to_tell;
  /* Bits 11 through 8 is family processor id */
# define FAMILY_ID_SHIFT 8
# define FAMILY_ID_MASK 0xf
  /* Bits 23 through 20 is extended family processor id */
# define EXT_FAMILY_ID_SHIFT 20
# define EXT_FAMILY_ID_MASK 0xf
  /* Pentium 4 family processor id */
# define PENTIUM4_FAMILY_ID 0xf
  /* Bit 28 indicates Hyper-Threading Technology support */
# define HT_BIT_SHIFT 28
# define HT_BIT_MASK 1
  uint32_t vendor_id[3] = { 0U, 0U, 0U };
  uint32_t value_of_eax = 0U;
  uint32_t value_of_edx = 0U;
  uint32_t dummy        = 0U;

  /* Yes, this is supposed to be [0], [2], [1] */
  get_cpuid(0, &dummy, &vendor_id[0], &vendor_id[2], &vendor_id[1]);
  if (_launcher_debug) {
    printf("vendor: %c %c %c %c %c %c %c %c %c %c %c %c \n",
           ((vendor_id[0] >>  0) & 0xff), 
           ((vendor_id[0] >>  8) & 0xff), 
           ((vendor_id[0] >> 16) & 0xff), 
           ((vendor_id[0] >> 24) & 0xff), 
           ((vendor_id[1] >>  0) & 0xff), 
           ((vendor_id[1] >>  8) & 0xff), 
           ((vendor_id[1] >> 16) & 0xff), 
           ((vendor_id[1] >> 24) & 0xff), 
           ((vendor_id[2] >>  0) & 0xff), 
           ((vendor_id[2] >>  8) & 0xff), 
           ((vendor_id[2] >> 16) & 0xff), 
           ((vendor_id[2] >> 24) & 0xff));
  }
  get_cpuid(1, &value_of_eax, &dummy, &dummy, &value_of_edx);
  if (_launcher_debug) {
    printf("value_of_eax: 0x%x  value_of_edx: 0x%x\n",
           value_of_eax, value_of_edx);
  }
  if ((((value_of_eax >> FAMILY_ID_SHIFT) & FAMILY_ID_MASK) == PENTIUM4_FAMILY_ID) ||
      (((value_of_eax >> EXT_FAMILY_ID_SHIFT) & EXT_FAMILY_ID_MASK) != 0)) {
    if ((((vendor_id[0] >>  0) & 0xff) == 'G') && 
        (((vendor_id[0] >>  8) & 0xff) == 'e') && 
        (((vendor_id[0] >> 16) & 0xff) == 'n') && 
        (((vendor_id[0] >> 24) & 0xff) == 'u') && 
        (((vendor_id[1] >>  0) & 0xff) == 'i') && 
        (((vendor_id[1] >>  8) & 0xff) == 'n') && 
        (((vendor_id[1] >> 16) & 0xff) == 'e') && 
        (((vendor_id[1] >> 24) & 0xff) == 'I') && 
        (((vendor_id[2] >>  0) & 0xff) == 'n') && 
        (((vendor_id[2] >>  8) & 0xff) == 't') && 
        (((vendor_id[2] >> 16) & 0xff) == 'e') && 
        (((vendor_id[2] >> 24) & 0xff) == 'l')) {
      if (((value_of_edx >> HT_BIT_SHIFT) & HT_BIT_MASK) == HT_BIT_MASK) {
        if (_launcher_debug) {
          printf("Hyperthreading supported\n");
        }
        result = hts_supported;
      } else {
        if (_launcher_debug) {
          printf("Hyperthreading not supported\n");
        }
        result = hts_not_supported;
      }
    } else {
      if (_launcher_debug) {
        printf("Not GenuineIntel\n");
      }
      result = hts_not_intel;
    }
  } else {
    if (_launcher_debug) {
      printf("not Pentium 4 or extended\n");
    }
    result = hts_not_pentium4;
  }
  return result;
}

/* Determine how many logical processors there are per CPU */
unsigned int
logical_processors_per_package(void) {
  /*
   * After CPUID with EAX==1, register EBX bits 23 through 16 
   * indicate the number of logical processors per package
   */
# define NUM_LOGICAL_SHIFT 16
# define NUM_LOGICAL_MASK 0xff
  unsigned int result                        = 1U;
  const HyperThreadingSupport hyperthreading = hyperthreading_support();
  
  if (hyperthreading == hts_supported) {
    uint32_t value_of_ebx = 0U;
    uint32_t dummy        = 0U;

    get_cpuid(1, &dummy, &value_of_ebx, &dummy, &dummy);
    result = (value_of_ebx >> NUM_LOGICAL_SHIFT) & NUM_LOGICAL_MASK;
    if (_launcher_debug) {
      printf("logical processors per package: %u\n", result);
    }
  }
  return result;
}

/* Compute the number of physical processors, not logical processors */
unsigned long 
physical_processors(void) {
  const long sys_processors = sysconf(_SC_NPROCESSORS_CONF);
  unsigned long result      = sys_processors;

  if (_launcher_debug) {
    printf("sysconf(_SC_NPROCESSORS_CONF): %lu\n", sys_processors);
  }
  if (sys_processors > 1) {
    unsigned int logical_processors = logical_processors_per_package();
    if (logical_processors > 1) {
      result = (unsigned long) sys_processors / logical_processors;
    }
  }
  if (_launcher_debug) {
    printf("physical processors: %lu\n", result);
  }
  return result;
}

#endif /* i586 */

#if defined(__sun) && defined(i586)

/* The definition of a server-class machine for solaris-i586/amd64 */
jboolean
solaris_i586_ServerClassMachine(void) {
  jboolean            result            = JNI_FALSE;
  /* How big is a server class machine? */
  const unsigned long server_processors = 2UL;
  const uint64_t      server_memory     = 2UL * GB;
  /*
   * We seem not to get our full complement of memory.
   *     We allow some part (1/8?) of the memory to be "missing",
   *     based on the sizes of DIMMs, and maybe graphics cards.
   */
  const uint64_t      missing_memory    = 256UL * MB;
  const uint64_t      actual_memory     = physical_memory();

  /* Is this a server class machine? */
  if (actual_memory >= (server_memory - missing_memory)) {
    const unsigned long actual_processors = physical_processors();
    if (actual_processors >= server_processors) {
      result = JNI_TRUE;
    }
  }
  if (_launcher_debug) {
    printf("solaris_" LIBARCHNAME "_ServerClassMachine: %s\n",
           (result == JNI_TRUE ? "true" : "false"));
  }
  return result;
}

#endif /* __sun && i586 */

#if defined(__linux__) && defined(i586)

/* The definition of a server-class machine for linux-i586 */
jboolean
linux_i586_ServerClassMachine(void) {
  jboolean            result            = JNI_FALSE;
  /* How big is a server class machine? */
  const unsigned long server_processors = 2UL;
  const uint64_t      server_memory     = 2UL * GB;
  /*
   * We seem not to get our full complement of memory.
   *     We allow some part (1/8?) of the memory to be "missing",
   *     based on the sizes of DIMMs, and maybe graphics cards.
   */
  const uint64_t      missing_memory    = 256UL * MB;
  const uint64_t      actual_memory     = physical_memory();

  /* Is this a server class machine? */
  if (actual_memory >= (server_memory - missing_memory)) {
    const unsigned long actual_processors = physical_processors();
    if (actual_processors >= server_processors) {
      result = JNI_TRUE;
    }
  }
  if (_launcher_debug) {
    printf("linux_" LIBARCHNAME "_ServerClassMachine: %s\n",
           (result == JNI_TRUE ? "true" : "false"));
  }
  return result;
}

#endif /* __linux__ && i586 */

/* Dispatch to the platform-specific definition of "server-class" */
jboolean
ServerClassMachine(void) {
  jboolean result = JNI_FALSE;
#if   defined(NEVER_ACT_AS_SERVER_CLASS_MACHINE)
  result = JNI_FALSE;
#elif defined(ALWAYS_ACT_AS_SERVER_CLASS_MACHINE)
  result = JNI_TRUE;
#elif defined(__sun) && defined(__sparc)
  result = solaris_sparc_ServerClassMachine();
#elif defined(__sun) && defined(i586)
  result = solaris_i586_ServerClassMachine();
#elif defined(__linux__) && defined(i586)
  result = linux_i586_ServerClassMachine();
#else
  if (_launcher_debug) {
    printf("ServerClassMachine: returns default value of %s\n",
           (result == JNI_TRUE ? "true" : "false"));
  }
#endif
  return result;
}

/*
 *	Since using the file system as a registry is a bit risky, perform
 *	additional sanity checks on the identified directory to validate
 *	it as a valid jre/sdk.
 *
 *	Return 0 if the tests fail; otherwise return non-zero (true).
 *
 *	Note that checking for anything more than the existence of an
 *	executable object at bin/java relative to the path being checked
 *	will break the regression tests.
 */
static int
CheckSanity(char *path, char *dir)
{
    char    buffer[PATH_MAX];

    if (strlen(path) + strlen(dir) + 11 > PATH_MAX)
	return (0);	/* Silently reject "impossibly" long paths */

    (void)strcat(strcat(strcat(strcpy(buffer, path), "/"), dir), "/bin/java");
    return ((access(buffer, X_OK) == 0) ? 1 : 0);
}

/*
 *	Determine if there is an acceptable JRE in the directory dirname.
 *	Upon locating the "best" one, return a fully qualified path to
 *	it. "Best" is defined as the most advanced JRE meeting the
 *	constraints contained in the manifest_info. If no JRE in this
 *	directory meets the constraints, return NULL.
 *
 *	Note that we don't check for errors in reading the directory
 *	(which would be done by checking errno).  This is because it
 *	doesn't matter if we get an error reading the directory, or
 *	we just don't find anything interesting in the directory.  We
 *	just return NULL in either case.
 *
 *	The historical names of j2sdk and j2re were changed to jdk and
 *	jre respecively as part of the 1.5 rebranding effort.  Since the
 *	former names are legacy on Linux, they must be recognized for
 *	all time.  Fortunately, this is a minor cost.
 */
static char
*ProcessDir(manifest_info *info, char *dirname)
{
    DIR	    *dirp;
    struct dirent *dp;
    char    *best = NULL;
    int     offset;
    int	    best_offset = 0;
    char    *ret_str = NULL;
    char    buffer[PATH_MAX];

    if ((dirp = opendir(dirname)) == NULL)
	return (NULL);

    do {
	if ((dp = readdir(dirp)) != NULL) {
	    offset = 0;
	    if ((strncmp(dp->d_name, "jre", 3) == 0) ||
	        (strncmp(dp->d_name, "jdk", 3) == 0))
		offset = 3;
	    else if (strncmp(dp->d_name, "j2re", 4) == 0)
		offset = 4;
	    else if (strncmp(dp->d_name, "j2sdk", 5) == 0)
		offset = 5;
	    if (offset > 0) {
	    	if ((JLI_AcceptableRelease(dp->d_name + offset,
		    info->jre_version)) && CheckSanity(dirname, dp->d_name))
	    	    if ((best == NULL) || (JLI_ExactVersionId(
		      dp->d_name + offset, best + best_offset) > 0)) {
			if (best != NULL)
			    JLI_MemFree(best);
			best = JLI_StringDup(dp->d_name);
			best_offset = offset;
		    }
	    }
	}
    } while (dp != NULL);
    (void) closedir(dirp);
    if (best == NULL)
	return (NULL);
    else {
	ret_str = JLI_MemAlloc(strlen(dirname) + strlen(best) + 2);
	ret_str = strcat(strcat(strcpy(ret_str, dirname), "/"), best);
	JLI_MemFree(best);
	return (ret_str);
    }
}

/*
 *	This is the global entry point. It examines the host for the optimal
 *	JRE to be used by scanning a set of directories.  The set of directories
 *	is platform dependent and can be overridden by the environment
 *	variable JAVA_VERSION_PATH.
 *
 *	This routine itself simply determines the set of appropriate
 *	directories before passing control onto ProcessDir().
 */
char*
LocateJRE(manifest_info* info)
{
    char	*path;
    char	*home;
    char	*target = NULL;
    char	*dp;
    char	*cp;

    /*
     * Start by getting JAVA_VERSION_PATH
     */
    if (info->jre_restrict_search)
	path = JLI_StringDup(system_dir);
    else if ((path = getenv("JAVA_VERSION_PATH")) != NULL)
	path = JLI_StringDup(path);
    else
	if ((home = getenv("HOME")) != NULL) {
	    path = (char *)JLI_MemAlloc(strlen(home) + strlen(system_dir) +
		strlen(user_dir) + 2);
	    path = strcat(strcat(strcat(strcpy(path, home),
	        user_dir), ":"), system_dir);
	} else
	    path = JLI_StringDup(system_dir);

    /*
     * Step through each directory on the path. Terminate the scan with
     * the first directory with an acceptable JRE.
     */
    cp = dp = path;
    while (dp != NULL) {
	cp = strchr(dp, (int)':');
	if (cp != NULL)
	    *cp = (char)NULL;
	if ((target = ProcessDir(info, dp)) != NULL)
	    break;
	dp = cp;
	if (dp != NULL)
	    dp++;
    }
    JLI_MemFree(path);
    return (target);
}

/*
 * Given a path to a jre to execute, this routine checks if this process
 * is indeed that jre.  If not, it exec's that jre.
 *
 * We want to actually check the paths rather than just the version string
 * built into the executable, so that given version specification (and
 * JAVA_VERSION_PATH) will yield the exact same Java environment, regardless
 * of the version of the arbitrary launcher we start with.
 */
void
ExecJRE(char *jre, char **argv)
{
    char    wanted[PATH_MAX];
    char    *execname;
    char    *progname;

    /*
     * Resolve the real path to the directory containing the selected JRE.
     */
    if (realpath(jre, wanted) == NULL) {
	fprintf(stderr, "Unable to resolve %s\n", jre);
	exit(1);
    }

    /*
     * Resolve the real path to the currently running launcher.
     */
    execname = SetExecname(argv);
    if (execname == NULL) {
	fprintf(stderr, "Unable to resolve current executable\n");
	exit(1);
    }

    /*
     * If the path to the selected JRE directory is a match to the initial
     * portion of the path to the currently executing JRE, we have a winner!
     * If so, just return.
     */
    if (strncmp(wanted, execname, strlen(wanted)) == 0)
	return;			/* I am the droid you were looking for */

    /*
     * If this isn't the selected version, exec the selected version.
     */
#ifdef JAVA_ARGS  /* javac, jar and friends. */
    progname = "java";
#else             /* java, oldjava, javaw and friends */
#ifdef PROGNAME
    progname = PROGNAME;
#else
    progname = *argv;
    if ((s = strrchr(progname, FILE_SEPARATOR)) != 0) {
        progname = s + 1;
    }
#endif /* PROGNAME */
#endif /* JAVA_ARGS */

    /*
     * This should never happen (because of the selection code in SelectJRE),
     * but check for "impossibly" long path names just because buffer overruns
     * can be so deadly.
     */
    if (strlen(wanted) + strlen(progname) + 6 > PATH_MAX) {
	fprintf(stderr, "Path length exceeds maximum length (PATH_MAX)\n");
	exit(1);
    }

    /*
     * Construct the path and exec it.
     */
    (void)strcat(strcat(wanted, "/bin/"), progname);
    argv[0] = progname;
    if (_launcher_debug) {
	int i;
	printf("ReExec Command: %s (%s)\n", wanted, argv[0]);
	printf("ReExec Args:");
	for (i = 1; argv[i] != NULL; i++)
	    printf(" %s", argv[i]);
	printf("\n");
    }
    (void)fflush(stdout);
    (void)fflush(stderr);
    execv(wanted, argv);
    perror("execv()");
    fprintf(stderr, "Exec of %s failed\n", wanted);
    exit(1);
}

/*
 * "Borrowed" from Solaris 10 where the unsetenv() function is being added
 * to libc thanks to SUSv3 (Standard Unix Specification, version 3). As
 * such, in the fullness of time this will appear in libc on all relevant
 * Solaris/Linux platforms and maybe even the Windows platform.  At that
 * time, this stub can be removed.
 *
 * This implementation removes the environment locking for multithreaded
 * applications.  (We don't have access to these mutexes within libc and
 * the launcher isn't multithreaded.)  Note that what remains is platform
 * independent, because it only relies on attributes that a POSIX environment
 * defines.
 *
 * Returns 0 on success, -1 on failure.
 *
 * Also removed was the setting of errno.  The only value of errno set
 * was EINVAL ("Invalid Argument").
 */

/*
 * s1(environ) is name=value
 * s2(name) is name(not the form of name=value).
 * if names match, return value of 1, else return 0
 */
static int
match_noeq(const char *s1, const char *s2)
{
	while (*s1 == *s2++) {
		if (*s1++ == '=')
			return (1);
	}
	if (*s1 == '=' && s2[-1] == '\0')
		return (1);
	return (0);
}

/*
 * added for SUSv3 standard
 *
 * Delete entry from environ.
 * Do not free() memory!  Other threads may be using it.
 * Keep it around forever.
 */
static int
borrowed_unsetenv(const char *name)
{
	long	idx;		/* index into environ */

	if (name == NULL || *name == '\0' ||
	    strchr(name, '=') != NULL) {
		return (-1);
	}

	for (idx = 0; environ[idx] != NULL; idx++) {
		if (match_noeq(environ[idx], name))
			break;
	}
	if (environ[idx] == NULL) {
		/* name not found but still a success */
		return (0);
	}
	/* squeeze up one entry */
	do {
		environ[idx] = environ[idx+1];
	} while (environ[++idx] != NULL);

	return (0);
}
/* --- End of "borrowed" code --- */

/*
 * Wrapper for unsetenv() function.
 */
int
UnsetEnv(char *name)
{
    return(borrowed_unsetenv(name));
}

/* --- Splash Screen shared library support --- */

static const char* SPLASHSCREEN_SO = "libsplashscreen.so";

static void* hSplashLib = NULL;

void* SplashProcAddress(const char* name) {
    if (!hSplashLib) { 
        hSplashLib = dlopen(SPLASHSCREEN_SO, RTLD_LAZY | RTLD_GLOBAL); 
    }
    if (hSplashLib) { 
        void* sym = dlsym(hSplashLib, name); 
        return sym;
    } else { 
        return NULL; 
    }
}

void SplashFreeLibrary() {
    if (hSplashLib) {
        dlclose(hSplashLib);
        hSplashLib = NULL;
    }
}

const char *
jlong_format_specifier() {
    return "%lld";
}

/*
 * Block current thread and continue execution in a new thread
 */
int
ContinueInNewThread(int (JNICALL *continuation)(void *), jlong stack_size, void * args) {
    int rslt;
#ifdef __linux__
    pthread_t tid;
    pthread_attr_t attr;
    pthread_attr_init(&attr);
    pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);

    if (stack_size > 0) {
      pthread_attr_setstacksize(&attr, stack_size);
    }

    if (pthread_create(&tid, &attr, (void *(*)(void*))continuation, (void*)args) == 0) {
      void * tmp;
      pthread_join(tid, &tmp);
      rslt = (int)tmp;
    } else {
     /*
      * Continue execution in current thread if for some reason (e.g. out of
      * memory/LWP)  a new thread can't be created. This will likely fail
      * later in continuation as JNI_CreateJavaVM needs to create quite a
      * few new threads, anyway, just give it a try..
      */
      rslt = continuation(args);
    }

    pthread_attr_destroy(&attr);
#else
    thread_t tid;
    long flags = 0;
    if (thr_create(NULL, stack_size, (void *(*)(void *))continuation, args, flags, &tid) == 0) {
      void * tmp;
      thr_join(tid, NULL, &tmp);
      rslt = (int)tmp;
    } else {
      /* See above. Continue in current thread if thr_create() failed */
      rslt = continuation(args);
    }
#endif
    return rslt;
}

/* Coarse estimation of number of digits assuming the worst case is a 64-bit pid. */
#define MAX_PID_STR_SZ   20

void SetJavaLauncherPlatformProps() {
   /* Linux only */
#ifdef __linux__
    const char *substr = "-Dsun.java.launcher.pid=";
    char *pid_prop_str = (char *)JLI_MemAlloc(strlen(substr) + MAX_PID_STR_SZ + 1);
    sprintf(pid_prop_str, "%s%d", substr, getpid());
    AddOption(pid_prop_str, NULL);
#endif
}
