mal_sabaoth.c

一个内存数据库的源代码这是服务器端还有客户端

#line 39 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
#include "mal_config.h"
#include "mal_sabaoth.h"
#include <stdio.h> /* fseek, rewind */
#include <unistd.h>	/* unlink and friends */
#include <errno.h>
#include <string.h> /* for getting error messages */
#include <assert.h>


/** the directory where the databases are (aka dbfarm) */
str _sabaoth_internal_dbfarm = NULL;
/** the database which is "active" */
str _sabaoth_internal_dbname = NULL;

static str getFarmPath(str *ret, size_t size, str extra) {
	if (_sabaoth_internal_dbfarm == NULL)
		throw(MAL, "sabaoth.assert", "Sabaoth was not initialised!");

	if (extra == NULL) {
		snprintf(*ret, size, "%s", _sabaoth_internal_dbfarm);
	} else {
		snprintf(*ret, size, "%s%c%s", _sabaoth_internal_dbfarm, DIR_SEP, extra);
	}

	return(MAL_SUCCEED);
}

static str getDBPath(str *ret, size_t size, str extra) {
	if (_sabaoth_internal_dbfarm == NULL)
		throw(MAL, "sabaoth.assert", "Sabaoth was not initialised!");
	if (_sabaoth_internal_dbname == NULL)
		throw(MAL, "sabaoth.assert", "Cannot use this function when no database is active");

	if (extra == NULL) {
		snprintf(*ret, size, "%s%c%s",
				_sabaoth_internal_dbfarm,
				DIR_SEP,
				_sabaoth_internal_dbname);
	} else {
		snprintf(*ret, size, "%s%c%s%c%s",
				_sabaoth_internal_dbfarm,
				DIR_SEP,
				_sabaoth_internal_dbname,
				DIR_SEP,
				extra);
	}

	return(MAL_SUCCEED);
}



#line 92 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
/**
 * Initialises this Sabaoth instance to use the given dbfarm and dbname.
 * dbfarm may be NULL to indicate that there is no active database.  The
 * arguments are copied for internal use.
 */
void SABAOTHinit(str dbfarm, str dbname) {
	size_t len;

	assert(dbfarm != NULL);

	if (_sabaoth_internal_dbfarm != NULL)
		free(_sabaoth_internal_dbfarm);
	if (_sabaoth_internal_dbname != NULL)
		free(_sabaoth_internal_dbname);

	len = strlen(dbfarm) + 1;
	_sabaoth_internal_dbfarm = malloc(sizeof(char) * (len));
	memcpy(_sabaoth_internal_dbfarm, dbfarm, len);
	/* remove trailing slashes */
	while (len > 0 && _sabaoth_internal_dbfarm[len - 1] == '/') {
		_sabaoth_internal_dbfarm[len - 1] = '\0';
		len--;
	}

	if (dbname == NULL) {
		_sabaoth_internal_dbname = NULL;
	} else {
		len = strlen(dbname) + 1;
		_sabaoth_internal_dbname = malloc(sizeof(char) * (len));
		memcpy(_sabaoth_internal_dbname, dbname, len);
	}
}



#line 128 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
#define SCENARIOFILE ".scen"
/**
 * Writes the given language to the scenarios file.  If the file doesn't
 * exist, it is created.  Multiple invocations of this function for the
 * same language are ignored.
 */
str SABAOTHmarchScenario(int *ret, str *lang) {
	FILE *f;
	str buf = alloca(sizeof(char) * 256);	/* should be enough for now */
	int len;
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str tmp;
	(void)ret;

	rethrow("sabaoth.marchScenario", tmp,
			getDBPath(&path, PATHLENGTH, SCENARIOFILE));
	if ((f = fopen(path, "a+")) != NULL) {
		if ((len = fread(buf, 1, 255, f)) > 0) {
			str p;

			buf[len] = '\0';
			/* find newlines and evaluate string */
			while ((p = strchr(buf, '\n')) != NULL) {
				*p = '\0';
				if (strcmp(buf, *lang) == 0) {
					(void)fclose(f);
					return(MAL_SUCCEED);
				}
				buf = p;
			}
		}
		/* append to the file */
		fprintf(f, "%s\n", *lang);
		(void)fflush(f);
		(void)fclose(f);
		return(MAL_SUCCEED);
	}
	throw(IO, "sabaoth.marchScenario", "unable to open file %s", path);
}



#line 171 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
/**
 * Removes the given language from the scenarios file.  If the scenarios
 * file is empty (before or) after removing the language, the file is
 * removed.
 */
str SABAOTHretreatScenario(int *ret, str *lang) {
	FILE *f;
	str buf = alloca(sizeof(char) * 256);	/* should be enough for now */
	int len;
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str tmp;
	(void)ret;

	rethrow("sabaoth.retreatScenario", tmp,
			getDBPath(&path, PATHLENGTH, SCENARIOFILE));
	if ((f = fopen(path, "a+")) != NULL) {
		if ((len = fread(buf, 1, 255, f)) > 0) {
			str p;
			FILE *tmp = tmpfile();
			int written = 0;

			buf[len] = '\0';
			/* find newlines and evaluate string */
			while ((p = strchr(buf, '\n')) != NULL) {
				*p = '\0';
				if (strcmp(buf, *lang) != 0) {
					fprintf(tmp, "%s\n", buf);
					written = 1;
				}
				buf = p;
			}
			if (written != 0) {
				buf = alloca(sizeof(char) * 256);
				/* no idea how to "move" a file by it's fd (sounds
				 * impossible anyway) and tmpnam is so much "DO NOT USE"
				 * that I decided to just copy over the file again... */
				rewind(f);
				fflush(tmp);
				rewind(tmp);
				len = fread(buf, 1, 256, tmp);
				fwrite(buf, 1, len, f);
				fflush(f);
				fclose(f);
				fclose(tmp); /* this should remove it automagically */
				return(MAL_SUCCEED);
			} else {
				(void)fclose(f);
				unlink(path);
				return(MAL_SUCCEED);
			}
		} else if (len == 0) {
			(void)fclose(f);
			unlink(path);
			return(MAL_SUCCEED);
		} else { /* some error */
			str err = strerror(errno);
			(void)fclose(f);
			throw(IO, "sabaoth.retreatScenario",
					"error while reading from file: %s", err);
		}
	}
	throw(IO, "sabaoth.retreatScenario", "unable to open file %s", path);
}



#line 238 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
#define CONNECTIONFILE ".conn"
/**
 * Writes an URI to the connection file based on the given arguments.
 * If the file doesn't exist, it is created.  Multiple invocations of
 * this function for the same arguments are NOT ignored.
 */
str SABAOTHmarchConnection(int *ret, str *host, int *port, bit *ssl) {
	FILE *f;
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str tmp;
	(void)ret;

	rethrow("sabaoth.marchConnection", tmp,
			getDBPath(&path, PATHLENGTH, CONNECTIONFILE));
	if ((f = fopen(path, "a")) != NULL) {
		/* append to the file */
		fprintf(f, "mapi%s:monetdb://%s:%i/\n", *ssl ? "s" : "", *host, *port);
		(void)fflush(f);
		(void)fclose(f);
		return(MAL_SUCCEED);
	}
	throw(IO, "sabaoth.marchConnection",
			"unable to open file %s", path);
}



#line 266 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
/**
 * Removes all known publications of available services.  The function
 * name is a nostalgic phrase from "Defender of the Crown" from the
 * Commodore Amiga age.
 */
str SABAOTHwildRetreat(int *ret) {
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str tmp;
	(void)ret;

	rethrow("sabaoth.wildRetreat", tmp,
			getDBPath(&path, PATHLENGTH, SCENARIOFILE));
	unlink(path);
	rethrow("sabaoth.wildRetreat", tmp,
			getDBPath(&path, PATHLENGTH, CONNECTIONFILE));
	unlink(path);

	return(MAL_SUCCEED);
}



#line 289 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
#define UPLOGFILE ".uplog"
/**
 * Writes a start attempt to the sabaoth start/stop log.  Examination of
 * the log at a later stage might reveal crashes of the server.
 */
str SABAOTHregisterStart(int *ret) {
	/* The sabaoth uplog is in fact a simple two column table that
	 * contains a start time and a stop time.  Start times are followed
	 * by a tab character, while stop times are followed by a newline.
	 * This allows to detect crashes, while sabaoth only appends to the
	 * uplog.
	 */

	FILE *f;
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str tmp;
	(void)ret;

	rethrow("sabaoth.registerStart", tmp,
			getDBPath(&path, PATHLENGTH, UPLOGFILE));
	if ((f = fopen(path, "a")) != NULL) {
		/* append to the file */
		fprintf(f, SZFMT "\t", (size_t)time(NULL));
		(void)fflush(f);
		(void)fclose(f);
		return(MAL_SUCCEED);
	}
	throw(IO, "sabaoth.registerStart", "unable to open file %s", path);
}



#line 322 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
/**
 * Writes a start attempt to the sabaoth start/stop log.  Examination of
 * the log at a later stage might reveal crashes of the server.
 */
str SABAOTHregisterStop(int *ret) {
	/* The sabaoth uplog is in fact a simple two column table that
	 * contains a start time and a stop time.  Start times are followed
	 * by a tab character, while stop times are followed by a newline.
	 * This allows to detect crashes, while sabaoth only appends to the
	 * uplog.
	 */

	FILE *f;
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str tmp;
	(void)ret;

	rethrow("sabaoth.registerStop", tmp,
			getDBPath(&path, PATHLENGTH, UPLOGFILE));
	if ((f = fopen(path, "a")) != NULL) {
		/* append to the file */
		fprintf(f, SZFMT "\n", (size_t)time(NULL));
		(void)fflush(f);
		(void)fclose(f);
		return(MAL_SUCCEED);
	}
	throw(IO, "sabaoth.registerStop", "unable to open file %s", path);
}



#line 380 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/mal/mal_sabaoth.mx"
/**
 */
str SABAOTHgetStatus(sabdb** ret, str dbname) {
	DIR *d;
	struct dirent *e;
	str buf = alloca(sizeof(char) * (PATHLENGTH + 1));
	str data = alloca(sizeof(char) * 8096);
	str path = alloca(sizeof(char) * (PATHLENGTH + 1));
	str p;
	int len;
	FILE *f;
	int fd;

	sabdb* sdb = *ret;
	sdb = NULL;

	buf[PATHLENGTH] = '\0';
	/* scan the parent for directories */
	rethrow("sabaoth.getStatus", p,
			getFarmPath(&path, PATHLENGTH, NULL));
	d = opendir(path);
	while ((e = readdir(d)) != NULL) {
		if (dbname != NULL && strcmp(e->d_name, dbname) != 0)
			continue;

		sdb = malloc(sizeof(sabdb));

		/* store the database name */
		sdb->dbname = strdup(e->d_name);

		/* add scenarios that are supported */
		sdb->scens = NULL;
		snprintf(buf, PATHLENGTH, "%s/%s/%s", path, e->d_name, SCENARIOFILE);
		if ((f = fopen(buf, "r")) != NULL) {
			if ((len = fread(data, 1, 8095, f)) > 0) {
				sablist* np = NULL;
				buf[len] = '\0';
				while ((p = strchr(buf, '\n')) != NULL) {
					*p = '\0';
					if (sdb->scens == NULL) {
						sdb->scens = malloc(sizeof(sablist));
						sdb->scens->val = strdup(buf);
						sdb->scens->next = NULL;
						np = sdb->scens;
					} else {
						np = np->next = malloc(sizeof(sablist));
						np->val = strdup(buf);
						np->next = NULL;
					}
					buf = p + 1;
				}
				/* trailing stuff without an ending newline, is simply
				 * not valid in Sabaoth, so we don't care */
			}
			(void)fclose(f);
		}

		/* add how this server can be reached */
		sdb->conns = NULL;
		snprintf(buf, PATHLENGTH, "%s/%s/%s", path, e->d_name, CONNECTIONFILE);
		if ((f = fopen(buf, "r")) != NULL) {
			if ((len = fread(data, 1, 8095, f)) > 0) {
				sablist* np = NULL;
				buf[len] = '\0';
				while ((p = strchr(buf, '\n')) != NULL) {
					*p = '\0';
					if (sdb->conns == NULL) {
						sdb->conns = malloc(sizeof(sablist));
						sdb->conns->val = strdup(buf);
						sdb->conns->next = NULL;
						np = sdb->conns;
					} else {
						np = np->next = malloc(sizeof(sablist));
						np->val = strdup(buf);
						np->next = NULL;
					}
					buf = p + 1;
				}
				/* trailing stuff without an ending newline, is simply
				 * not valid in Sabaoth, so we don't care */
			}
			(void)fclose(f);
		}

		/* check the state of the server by looking at its gdk lock:
		 * - if we can lock it, the server has crashed or isn't running
		 * - if we can't open it because it's locked, the server is
		 *   running
		 * - to distinguish between a crash and proper shutdown, consult
		 *   the uplog
		 */
		snprintf(buf, PATHLENGTH, "%s/%s/%s", path, e->d_name, ".gdk_lock");
		fd = MT_lockf(buf, F_TLOCK, 4, 1);
		if (fd == -2) {
			/* Locking failed; this can be because the lockfile couldn't
			 * be created.  Probably there is no Mserver running for
			 * that case also.
			 */
			sdb->state = SABdbInactive;
		} else if (fd == -1) {
			/* lock denied, so Mserver is running */
			sdb->state = SABdbRunning;
		} else {
			char *log = alloca(sizeof(char) * (PATHLENGTH + 1));
			log[PATHLENGTH] = '\0';

			/* locking succeed, check for a crash in the uplog */
			close(fd);

			snprintf(log, PATHLENGTH, "%s/%s/%s", path, e->d_name, UPLOGFILE);
			if ((f = fopen(log, "r")) != NULL) {
				(void)fseek(f, -1, SEEK_END);
				if (fread(data, 1, 1, f) != 1) {
					/* the log is corrupt/wrong, assume no crash */
					sdb->state = SABdbInactive;
				} else if (data[0] == '\n') {
					sdb->state = SABdbInactive;
				} else { /* should be \t */
					sdb->state = SABdbCrashed;
				}
				(void)fclose(f);
			} else {
				/* no uplog file? assume no crash */
				sdb->state = SABdbInactive;
			}
			fd = MT_lockf(buf, F_ULOCK, 4, 1);
			if (fd >= 0)
				close(fd);
		}
	}
	(void) closedir(d);

	return(MAL_SUCCEED);
}