OSV: Allow using a wrapper file to start JVM

0001-Allow-using-a-wrapper-file-to-start-JVM.patch

From 6c920c277f2e02d67a4f45241b080ed7b5ee446e Mon Sep 17 00:00:00 2001
From: Lyor Goldstein <lgoldstein@vmware.com>
Date: Sun, 26 Apr 2015 15:25:11 +0300
Subject: [PATCH] Allow using a wrapper file to start JVM

---
 java/java.cc | 194 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 194 insertions(+)

diff --git a/java/java.cc b/java/java.cc
index 8c14462..c094f39 100644
--- a/java/java.cc
+++ b/java/java.cc
@@ -94,6 +94,195 @@ static void on_vm_stop(JNIEnv *env, jclass clz) {
     attached_env::set_jvm(nullptr);
 }
 
+inline bool is_whitespace(char c) {
+	if ((c == ' ') || (c == '\t')) {
+		return true;
+	} else {
+		return false;
+	}
+}
+
+static char *trim(char *s) {
+	size_t startPos=0, maxPos=strlen(s), endPos=maxPos;
+	for ( ; startPos < endPos; startPos++) {
+		char c=s[startPos];
+		if (!is_whitespace(c)) {
+			break;
+		}
+	}
+	
+	for ( ; endPos > startPos; endPos--) {
+		char c=s[endPos - 1];
+		if (!is_whitespace(c)) {
+			break;
+		}
+	}
+	
+	if ((startPos == 0) && (endPos == maxPos)) {
+		return s;
+	}
+
+	// check if trimmed any characters at end of string
+	if (endPos < maxPos) {
+		s[endPos] = '\0';
+	}
+
+	// check if trimmed any characters at start of string
+	if (startPos > 0) {
+		size_t curPos=0;
+		for ( ; startPos < endPos; startPos++, curPos++) {
+			s[curPos] = s[startPos];
+		}
+		s[curPos] = '\0';
+	}
+	
+	return s;
+}
+
+static int get_values_list(std::map<std::string,std::string> &configMap, const char *prefix, std::vector<std::string> &out) {
+	int index=1;
+	for ( ; ; index++) {
+		std::string	key(prefix);
+		key += std::string(".");
+		key += std::to_string(index);
+		
+		std::map<std::string,std::string>::iterator	it=configMap.find(key);
+		if (it == configMap.end()) {
+			break;
+		}
+		
+		std::string value=it->second;
+		
+		// TODO check if need to strip quotes
+#if 0
+		key += std::string(".stripquotes");
+		if ((it=configMap.find(key)) != configMap.end()) {
+			const char	*s=value.c_str();
+			...strip quotes and replace value ...
+		}
+#endif
+
+		out.push_back(value);
+	}
+
+	return index - 1;
+}
+
+static char *duplicate_wrapper_value(const std::string& str) {
+	const char	*s=str.c_str();
+	return strdup(s);
+}
+
+static int duplicate_wrapper_values(std::vector<std::string>& values, char **argv, int startPos, int numValues) {
+	int	curPos=startPos, index=0;
+	for (index=0; index < numValues; index++, curPos++) {
+		argv[curPos] = duplicate_wrapper_value(values[index]);
+	}
+
+	return curPos;
+}
+
+static int process_wrapper_configuration(std::map<std::string,std::string> &configMap, int& argc, char **&argv) {
+	std::map<std::string,std::string>::iterator	it=configMap.find(std::string("wrapper.java.mainclass"));
+	if (it == configMap.end()) {
+		std::cerr << "java.so: Missing main class specification in wrapper configuration.\n";
+		return 1;
+	}
+
+	std::string					mainClass=it->second;
+	std::vector<std::string>	jvmDefs, appParams, classpath;
+	int							numJvmDefs=get_values_list(configMap, "wrapper.java.additional", jvmDefs);
+	int							numClasspath=get_values_list(configMap, "wrapper.java.classpath", classpath);
+	int							numAppParams=get_values_list(configMap, "wrapper.app.parameter", appParams);
+	int							totalParams=1 /* argv[0] */ + ((numClasspath > 0) ? 2 /* -cp + path */ : 0) + numJvmDefs + 1 /* main class */ + numAppParams + 1 /* last is NULL */;
+	char						**replArgv=(char **) malloc(totalParams * sizeof(char *));
+	replArgv[0] = argv[0];	// argv[0] is the same as the original
+	
+	int	curPos=duplicate_wrapper_values(jvmDefs, replArgv, 1, numJvmDefs);
+	if (numClasspath > 0) {
+		std::string	joined;
+		for (int index=0; index < numClasspath; index++) {
+			std::string	path=classpath[index];
+			if (joined.length() > 0) {
+				joined += std::string(":");	// NOTE: we use the Linux path separator as OSV is Linux-like
+			}
+			
+			joined += path;
+		}
+
+		replArgv[curPos] = strdup("-cp");
+		curPos++;
+		replArgv[curPos] = duplicate_wrapper_value(joined);
+		curPos++;
+	}
+
+	replArgv[curPos] = duplicate_wrapper_value(mainClass);
+	curPos++;
+	curPos = duplicate_wrapper_values(appParams, replArgv, curPos, numAppParams);
+	replArgv[curPos] = NULL;	// mark end
+	
+	argv = replArgv;
+	argc = curPos;
+	return 0;
+}
+
+#define MAX_WRAPPER_LINE_LENGTH	1024
+static int read_wrapper_configuration_file(FILE *fp, int& argc, char **&argv) {
+	char								line[MAX_WRAPPER_LINE_LENGTH + sizeof(int)], *sep;
+	int 								lineNumber=1;
+	std::map<std::string,std::string>	configMap;
+
+	for (lineNumber=1; fgets(line, MAX_WRAPPER_LINE_LENGTH, fp) != NULL; lineNumber++) {
+		line[MAX_WRAPPER_LINE_LENGTH] = '\0';	// just make sure
+		trim(line);
+		
+		// skip empty and/or comment lines
+		if ((line[0] == '\0') || (line[0] == '#')) {
+			continue;
+		}
+		
+		// allow both separators
+		sep = strchr(line, '=');
+		if (sep == NULL) {
+			sep = strchr(line, ':');
+		}
+		
+		if (sep == NULL) {
+			std::cerr << "java.so: Missing name/value separator at line #" << lineNumber  << " of wrapper configuration.\n";
+			return 1;
+		}
+		
+		*sep = '\0';	// create 2 strings
+		
+		std::string	name(line), value(trim(sep + 1));
+		configMap[name] = value;
+	}
+	
+	return process_wrapper_configuration(configMap, argc, argv);
+}
+
+static int read_wrapper_configuration(const char *path, int& argc, char **&argv) {
+	FILE	*fp=fopen(path, "r");
+	if (fp == NULL) {
+        std::cerr << "java.so: Can't open " << path  << " to read wrapper configuration.\n";
+		return 1;
+	}
+
+	int	err=read_wrapper_configuration_file(fp, argc, argv);
+	fclose(fp);
+	return err;
+}
+
+// Based on the http://wrapper.tanukisoftware.com/doc/english/properties.html#name
+static int check_wrapper(int& argc, char **&argv) {
+	// if using the wrapper option then it must be the ONLY one and have EXACTLY one "argument" - the configuration file
+	if ((argc != 3) || (strcmp(argv[1], "--wrapper") != 0)) {
+		return 0;
+	} else {
+		return read_wrapper_configuration(argv[2], argc, argv);
+	}
+}
+
 static int java_main(int argc, char **argv)
 {
     auto prog = elf::get_program();
@@ -131,6 +320,11 @@ static int java_main(int argc, char **argv)
         }
     }
 
+	int err=check_wrapper(argc, argv);
+	if (err != 0) {
+		return err;
+	}
+
     int orig_argc = argc;
     int has_xms = 0, has_xmx = 0;
 
-- 
1.9.5.msysgit.1