merovingian.c

一个内存数据库的源代码这是服务器端还有客户端

#line 54 "/export/scratch0/monet/monet.GNU.64.64.d.14791/MonetDB5/src/tools/merovingian.mx"
#include "mal_config.h"
#include "merovingian.h"
/*#include "mal_sabaoth.h"*/
#include <stdlib.h> /* exit */
#include <stdarg.h>	/* variadic stuff */
#include <stdio.h> /* fprintf */
#include <sys/types.h>
#include <unistd.h>
#include <string.h> /* strdup, strerror */
#include <errno.h>
#ifdef _MSC_VER
#include <process.h>

#define snprintf _snprintf
#define vsnprintf _vsnprintf
#endif

typedef char* str;
typedef char* err;

#define freeErr(X) free(X)
#define getErrMsg(X) X
#define NO_ERR (err)0

static size_t _merovingian_log_cnt = 0;

/**
 * Tries to log the given string and formatting parameter stuff.  This
 * function may decide how to log it, e.g. syslog, it's own logfile or
 * stderr.
 *
 * Currently this method just spits everything it gets to stderr.
 */
static void
merlog(str fmt, ...)
{
	va_list ap;
	char message[4096];
	int len;

	va_start(ap, fmt);

	len = snprintf(message, 4095, "[merovingian]:%lld ", (long long int)_merovingian_log_cnt++);
	len += vsnprintf(message + len, 4095 - len, fmt, ap);
	message[len] = '\0';

	/* trim trailing newlines */
	while (len > 0 && message[--len] == '\n')
		message[len] = '\0';

	fprintf(stderr, "%s\n", message);

	va_end(ap);
}

static str
newErr(str fmt, ...)
{
	va_list ap;
	char message[4096];
	str ret;
	int len;

	va_start(ap, fmt);

	len = vsnprintf(message, 4095, fmt, ap);
	message[len] = '\0';

	va_end(ap);

	ret = malloc(sizeof(char) * (len + 1));
	memcpy(ret, message, len + 1);
	return(ret);
}

/**
 * Fork an Mserver and detach.  The forked Mserver is not a child of
 * this process any more after this function.  Hence, no client pid is
 * maintained or returned.
 */
static err
forkMserver(str database)
{
#ifdef NATIVE_WIN32
	intptr_t rv = 0;
	/*rv = _spawnv(_P_DETACH, ...); FIXME */ (void) database;
	if (rv == -1) {
		/* forking failed somehow */
		return(newErr(strerror(errno)));
	}
	return(NO_ERR);
#else
	pid_t pid;

	pid = fork();
	if (pid == 0) {
		/* child: refork again, such that this child can die, and the
		 * childchild becomes an orphan which init cares for */
		pid = fork();
		if (pid == 0) {
			/* ok, now exec that Mserver we want */
			/*execv(.... mserver --dbname=%s, databse);  FIXME */
			merlog("todo: %s", database);
			return(NO_ERR);
		} else if (pid > 0) {
			/* we are the parent of the childchild, so let's die */
			exit(0);
		} else {
			/* bleh... forking failed :( nothing we can do but log */
			merlog("Forking sub-child failed, no Mserver spawned!");
			exit(1);
		}
	} else if (pid > 0) {
		/* parent: fine, we're done */
		return(NO_ERR);
	}
	/* forking failed somehow */
	return(newErr(strerror(errno)));
#endif
}

int main(int argc, char *argv[]) {
	merlog("Merovingian %s starting ...", MEROV_VERSION);

	if (argc > 1) {
		forkMserver(argv[1]);
	}
}

/* vim:set ts=4 sw=4 noexpandtab: */