From ce1f37aae46ea95020d7b865f7a80e8abdfad0d8 Mon Sep 17 00:00:00 2001
From: Michael Krelin <hacker@klever.net>
Date: Sat, 29 Jan 2005 21:21:05 +0000
Subject: initial commit into repository

---
(limited to 'lib/sitecing_util.cc')

diff --git a/lib/sitecing_util.cc b/lib/sitecing_util.cc
new file mode 100644
index 0000000..9b6c54e
--- a/dev/null
+++ b/lib/sitecing_util.cc
@@ -0,0 +1,278 @@
+#ifdef USE_PCH
+ #include "pch.h"
+#else
+ #include <sys/stat.h>
+ #include <sys/types.h>
+ #include <unistd.h>
+ #include <fcntl.h>
+ #include <sys/ipc.h>
+ #include <sys/sem.h>
+ #include <errno.h>
+ #include <iostream>
+ #include <fstream>
+ #include <cassert>
+ #include "sitecing/sitecing_util.h"
+#endif
+
+namespace sitecing {
+
+    /*
+     * XXX: all of these utilities could be sheerly optimized.
+     */
+
+    string normalize_path(const string& path,int opts) {
+	const char *s = path.c_str();
+	string rv;
+	string::size_type notslash = 0;
+	if( (*s)=='.' && s[1]=='/' )
+	    s+=2;
+	if(opts&strip_leading_slash)
+	    for(;(*s) && (*s)=='/';s++);
+	for(;*s;s++) {
+	    if( (*s)=='/' ) {
+		if(s[1]=='/')
+		    continue;
+		if(s[1]=='.' && s[2]=='/') {
+		    s+=2;
+		    continue;
+		}
+	    }
+	    if(opts&restrict_dotdot) {
+		if(
+			( rv.empty() && s[0]=='.' && s[1]=='.' && s[2]=='/' )	// "^../"
+			|| ( s[0]=='/' && s[1]=='.' && s[2]=='.' && (s[3]==0 || s[3]=='/') ) // "/..(/|$)"
+		  )
+		    throw utility_restricted_sequence(CODEPOINT,"restricted updir sequence encountered");
+	    }
+	    rv += *s;
+	    if( (*s) != '/' )
+		notslash=rv.length();
+	}
+	if(!(opts&strip_trailing_slash))
+	    notslash++;
+	if(notslash<rv.length())
+	    rv.erase(notslash); // XXX: check the logic of stripping/not strippling trailing slash
+	return rv;
+    }
+
+    string strip_prefix(const string& str,const string& prefix) {
+	if(str.compare(0,prefix.length(),prefix))
+	    throw utility_no_prefix(CODEPOINT,"no such prefix");
+	return str.substr(prefix.length());
+    }
+
+    string strip_suffix(const string& str,const string& suffix) {
+	if(str.compare(str.length()-suffix.length(),suffix.length(),suffix))
+	    throw utility_no_suffix(CODEPOINT,"no such suffix");
+	return str.substr(0,str.length()-suffix.length());
+    }
+
+    string dir_name(const string& filename) {
+	string::size_type sl = filename.find_last_of('/');
+	if(sl==string::npos)
+	    return ""; // no slashes -- no dir.
+	string::size_type nosl = filename.find_last_not_of('/',sl);
+	if(nosl==string::npos)
+	    return ""; // only slashes -- no dir. XXX: only slashes after the last slash... does it mean no dir?
+	return filename.substr(0,nosl+1);
+    }
+
+    void make_path(const string& path,mode_t mode) {
+	struct stat st;
+	for(string::size_type sl=0;sl!=string::npos;sl=path.find('/',sl+1)) {
+	    if(!sl)
+		continue;
+	    string p = path.substr(0,sl);
+	    if(stat(p.c_str(),&st) || !S_ISDIR(st.st_mode)) {
+		if(mkdir(p.c_str(),mode))
+		    throw konforka::exception(CODEPOINT,"failed to mkdir()");
+	    }
+	}
+	if(stat(path.c_str(),&st) || !S_ISDIR(st.st_mode)) {
+	    if(mkdir(path.c_str(),mode))
+		throw konforka::exception(CODEPOINT,"failed to mkdir()");
+	}
+    }
+
+    void file_lock::lock(const string& f) {
+	unlock();
+	fd = open(f.c_str(),O_CREAT|O_RDWR,S_IRUSR|S_IWUSR);
+	if(fd<0)
+	    throw konforka::exception(CODEPOINT,"failed to open/create lockfile");
+	try {
+	    lock();
+	}catch(konforka::exception& ke) {
+	    ke.see(CODEPOINT);
+	    close(fd); fd=-1;
+	    throw;
+	}catch(...) {
+	    close(fd); fd=-1;
+	    throw;
+	}
+    }
+    void file_lock::lock() {
+	assert(fd>=0);
+	struct flock fl;
+	fl.l_type = F_WRLCK;
+	fl.l_whence=SEEK_SET;
+	fl.l_start=fl.l_len=0;
+	for(int tries=3;tries;tries--) {
+	    if(!fcntl(fd,F_SETLK,&fl))
+		return;
+	    sleep(8);
+	}
+	throw konforka::exception(CODEPOINT,"failed to obtain file lock");
+    }
+    void file_lock::unlock() {
+	if(fd<0)
+	    return;
+	struct flock fl;
+	fl.l_type = F_UNLCK;
+	fl.l_whence=SEEK_SET;
+	fl.l_start=fl.l_len=0;
+	int rv = fcntl(fd,F_SETLK,&fl);
+	close(fd);
+	fd=-1;
+	if(rv)
+	    throw konforka::exception(CODEPOINT,"failed to release file lock");
+    }
+
+    void pid_file::set(const string& f,bool u) {
+	ofstream of(f.c_str(),ios::trunc);
+	if(!of)
+	    throw konforka::exception(CODEPOINT,"failed to open file for writing pid");
+	of << getpid() << endl;
+	of.close();
+	file_name = f;
+	unlink_pid = u;
+    }
+    void pid_file::unlink() {
+	if(!unlink_pid)
+	    return;
+	::unlink(file_name.c_str());
+    }
+
+    void semaphore::init() {
+	deinit();
+	semid = semget(IPC_PRIVATE,1,IPC_CREAT|0600);
+	if(semid<0)
+	    throw konforka::exception(CODEPOINT,"failed to semget()");
+	if(semctl(semid,0,SETVAL,1))
+	    throw konforka::exception(CODEPOINT,"failed to semctl()");
+    }
+    void semaphore::deinit() {
+	if(semid<0)
+	    return;
+	semctl(semid,0,IPC_RMID,0);
+    }
+    void semaphore::on() {
+	assert(semid>=0);
+	struct sembuf sb;
+	sb.sem_num=0;
+	sb.sem_op=-1;
+	sb.sem_flg = SEM_UNDO;
+	while(semop(semid,&sb,1)<0) {
+	    if(errno!=EINTR)
+		throw konforka::exception(CODEPOINT,"failed to semop()");
+	}
+    }
+    void semaphore::off() {
+	assert(semid>=0);
+	struct sembuf sb;
+	sb.sem_num=0;
+	sb.sem_op=1;
+	sb.sem_flg = SEM_UNDO;
+	while(semop(semid,&sb,1)<0) {
+	    if(errno!=EINTR)
+		throw konforka::exception(CODEPOINT,"failed to semop()");
+	}
+    }
+
+    void semaphore_lock::lock() {
+	assert(sem);
+	if(locked)
+	    return;
+	sem->on();
+	locked = true;
+    }
+    void semaphore_lock::unlock() {
+	if(!sem)
+	    return;
+	if(!locked)
+	    return;
+	sem->off();
+	locked=false;
+    }
+
+    string combine_path(const string& origin,const string& relative,int opts) {
+	string r = normalize_path(relative,0);
+	string rv;
+	// XXX: what to do if relative is empty is a question, really.
+	if(r.empty()) {
+	    return normalize_path( (opts&origin_is_file)?dir_name(origin):origin ,strip_leading_slash|restrict_dotdot|strip_trailing_slash);
+	}else{
+	    if(r[0]=='/') {
+		r.erase(0,1);
+	    }else{
+		rv = normalize_path((opts&origin_is_file)?dir_name(origin):origin,restrict_dotdot|strip_trailing_slash);
+	    }
+	}
+	string::size_type lsl = rv.rfind('/');
+	for(string::size_type sl=r.find('/');sl!=string::npos;sl=r.find('/')) {
+	    assert(sl!=0);
+	    if(sl==1 && r[0]=='.') {
+		// it's a "./"
+		r.erase(0,2);
+	    }else if(sl==2 && r[0]=='.' && r[1]=='.') {
+		// we have a "../"
+		if(lsl==string::npos) {
+		    if(rv.empty() && (opts&fail_beyond_root))
+			throw utility_beyond_root(CODEPOINT,"went beyond root while combining path");
+		    rv.clear();
+		}else{
+		    rv.erase(lsl);
+		    lsl = rv.rfind('/');
+		}
+		r.erase(0,3);
+	    }else{
+		// we have a "something/"
+		lsl = rv.length();
+		rv += '/';
+		rv += r.substr(0,sl);
+		r.erase(0,sl+1);
+	    }
+	}
+	if(r.empty())
+	    return rv+'/';
+	if(r.length()==2 && r[0]=='.' && r[0]=='.') {
+	    if(lsl==string::npos) {
+		if(rv.empty() & (opts&fail_beyond_root))
+		    throw utility_beyond_root(CODEPOINT,"went beyond root while combining path");
+		return "/";
+	    }else{
+		rv.erase(lsl+1);
+		return rv;
+	    }
+	}
+	rv += '/';
+	rv += r;
+	return rv;
+    }
+
+    void auto_chdir::pushdir(const string& td,bool ap) {
+	char *tmp = get_current_dir_name();
+	assert(tmp);
+	saved_pwd = tmp;
+	free(tmp);
+	autopop=ap;
+	if(chdir(td.c_str()))
+	    throw konforka::exception(CODEPOINT,"failed to chdir()");
+    }
+    void auto_chdir::popdir() {
+	autopop=false;
+	if(chdir(saved_pwd.c_str()))
+	    throw konforka::exception(CODEPOINT,"failed to chdir()");
+	// XXX: or should it be thrown? after all we call it from destructor...
+    }
+
+}
--
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