tool/tserver.c - chromium/deps/sqlite.git - Git at Google

 /*
 ** 2017 June 7
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 **
 ** Simple multi-threaded server used for informal testing of concurrency
 ** between connections in different threads. Listens for tcp/ip connections
 ** on port 9999 of the 127.0.0.1 interface only. To build:
 **
 **   gcc -g $(TOP)/tool/tserver.c sqlite3.o -lpthread -o tserver
 **
 ** To run using "x.db" as the db file:
 **
 **   ./tserver x.db
 **
 ** To connect, open a client socket on port 9999 and start sending commands.
 ** Commands are either SQL - which must be terminated by a semi-colon, or
 ** dot-commands, which must be terminated by a newline. If an SQL statement
 ** is seen, it is prepared and added to an internal list.
 **
 ** Dot-commands are:
 **
 **   .list                    Display all SQL statements in the list.
 **   .quit                    Disconnect.
 **   .run                     Run all SQL statements in the list.
 **   .repeats N               Configure the number of repeats per ".run".
 **   .seconds N               Configure the number of seconds to ".run" for.
 **
 ** Example input:
 **
 **   BEGIN;
 **     INSERT INTO t1 VALUES(randomblob(10), randomblob(100));
 **     INSERT INTO t1 VALUES(randomblob(10), randomblob(100));
 **     INSERT INTO t1 VALUES(randomblob(10), randomblob(100));
 **   COMMIT;
 **   .repeats 100000
 **   .run
 **
 */
 #define TSERVER_PORTNUMBER 9999

 #include <arpa/inet.h>
 #include <assert.h>
 #include <pthread.h>
 #include <signal.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 #include <sys/time.h>
 #include <unistd.h>

 #include "sqlite3.h"

 /* Database used by this server */
 static char *zDatabaseName = 0;

 typedef struct ClientCtx ClientCtx;
 struct ClientCtx {
   sqlite3 *db;                    /* Database handle for this client */
   int fd;                         /* Client fd */
   int nRepeat;                    /* Number of times to repeat SQL */
   int nSecond;                    /* Number of seconds to run for */
   sqlite3_stmt **apPrepare;       /* Array of prepared statements */
   int nPrepare;                   /* Valid size of apPrepare[] */
   int nAlloc;                     /* Allocated size of apPrepare[] */
 };

 static int is_eol(int i){
   return (i=='\n' || i=='\r');
 }
 static int is_whitespace(int i){
   return (i==' ' || i=='\t' || is_eol(i));
 }

 static void trim_string(const char **pzStr, int *pnStr){
   const char *zStr = *pzStr;
   int nStr = *pnStr;

   while( nStr>0 && is_whitespace(zStr[0]) ){
     zStr++;
     nStr--;
   }
   while( nStr>0 && is_whitespace(zStr[nStr-1]) ){
     nStr--;
   }

   *pzStr = zStr;
   *pnStr = nStr;
 }

 static int send_message(ClientCtx *p, const char *zFmt, ...){
   char *zMsg;
   va_list ap;                             /* Vararg list */
   va_start(ap, zFmt);
   int res = -1;

   zMsg = sqlite3_vmprintf(zFmt, ap);
   if( zMsg ){
     res = write(p->fd, zMsg, strlen(zMsg));
   }
   sqlite3_free(zMsg);
   va_end(ap);

   return (res<0);
 }

 static int handle_some_sql(ClientCtx *p, const char *zSql, int nSql){
   const char *zTail = zSql;
   int nTail = nSql;
   int rc = SQLITE_OK;

   while( rc==SQLITE_OK ){
     if( p->nPrepare>=p->nAlloc ){
       int nByte = (p->nPrepare+32) * sizeof(sqlite3_stmt*);
       sqlite3_stmt **apNew = sqlite3_realloc(p->apPrepare, nByte);
       if( apNew ){
         p->apPrepare = apNew;
         p->nAlloc = p->nPrepare+32;
       }else{
         rc = SQLITE_NOMEM;
         break;
       }
     }
     rc = sqlite3_prepare_v2(
         p->db, zTail, nTail, &p->apPrepare[p->nPrepare], &zTail
     );
     if( rc!=SQLITE_OK ){
       send_message(p, "error - %s\n", sqlite3_errmsg(p->db));
       rc = 1;
       break;
     }
     if( p->apPrepare[p->nPrepare]==0 ){
       break;
     }
     p->nPrepare++;
     nTail = nSql - (zTail-zSql);
     rc = send_message(p, "ok (%d SQL statements)\n", p->nPrepare);
   }

   return rc;
 }

 static sqlite3_int64 get_timer(void){
   struct timeval t;
   gettimeofday(&t, 0);
   return ((sqlite3_int64)t.tv_usec / 1000) + ((sqlite3_int64)t.tv_sec * 1000);
 }

 static void clear_sql(ClientCtx *p){
   int j;
   for(j=0; j<p->nPrepare; j++){
     sqlite3_finalize(p->apPrepare[j]);
   }
   p->nPrepare = 0;
 }

 static int handle_dot_command(ClientCtx *p, const char *zCmd, int nCmd){
   assert( zCmd[0]=='.' );
   int n;
   int rc = 0;
   const char *z = &zCmd[1];
   const char *zArg;
   int nArg;

   for(n=0; n<(nCmd-1); n++){
     if( is_whitespace(z[n]) ) break;
   }

   zArg = &z[n];
   nArg = nCmd-n;
   trim_string(&zArg, &nArg);

   if( n>=1 && n<=4 && 0==strncmp(z, "list", n) ){
     int i;
     for(i=0; rc==0 && i<p->nPrepare; i++){
       const char *zSql = sqlite3_sql(p->apPrepare[i]);
       int nSql = strlen(zSql);
       trim_string(&zSql, &nSql);
       rc = send_message(p, "%d: %.*s\n", i, nSql, zSql);
     }
   }

   else if( n>=1 && n<=4 && 0==strncmp(z, "quit", n) ){
     rc = 1;
   }

   else if( n>=2 && n<=7 && 0==strncmp(z, "repeats", n) ){
     if( nArg ){
       p->nRepeat = strtol(zArg, 0, 0);
       if( p->nRepeat>0 ) p->nSecond = 0;
     }
     rc = send_message(p, "ok (repeat=%d)\n", p->nRepeat);
   }

   else if( n>=2 && n<=3 && 0==strncmp(z, "run", n) ){
     int i, j;
     int nBusy = 0;
     sqlite3_int64 t0 = get_timer();
     sqlite3_int64 t1 = t0;
     int nT1 = 0;
     int nTBusy1 = 0;

     for(j=0; (p->nRepeat<=0 || j<p->nRepeat) && rc==SQLITE_OK; j++){
       sqlite3_int64 t2;

       for(i=0; i<p->nPrepare && rc==SQLITE_OK; i++){
         sqlite3_stmt *pStmt = p->apPrepare[i];

         /* Execute the statement */
         while( sqlite3_step(pStmt)==SQLITE_ROW );
         rc = sqlite3_reset(pStmt);

         if( (rc & 0xFF)==SQLITE_BUSY ){
           if( sqlite3_get_autocommit(p->db)==0 ){
             sqlite3_exec(p->db, "ROLLBACK", 0, 0, 0);
           }
           nBusy++;
           rc = SQLITE_OK;
           break;
         }
         else if( rc!=SQLITE_OK ){
           send_message(p, "error - %s\n", sqlite3_errmsg(p->db));
         }
       }

       t2 = get_timer();
       if( t2>=(t1+1000) ){
         int nMs = (t2 - t1);
         int nDone = (j+1 - nBusy - nT1);

         rc = send_message(
             p, "(%d done @ %d per second, %d busy)\n",
             nDone, (1000*nDone + nMs/2) / nMs, nBusy - nTBusy1
         );
         t1 = t2;
         nT1 = j+1 - nBusy;
         nTBusy1 = nBusy;
         if( p->nSecond>0 && (p->nSecond*1000)<=t1-t0 ) break;
       }
     }

     if( rc==SQLITE_OK ){
       send_message(p, "ok (%d/%d SQLITE_BUSY)\n", nBusy, j);
     }
     clear_sql(p);
   }

   else if( n>=1 && n<=7 && 0==strncmp(z, "seconds", n) ){
     if( nArg ){
       p->nSecond = strtol(zArg, 0, 0);
       if( p->nSecond>0 ) p->nRepeat = 0;
     }
     rc = send_message(p, "ok (repeat=%d)\n", p->nRepeat);
   }

   else{
     send_message(p,
         "unrecognized dot command: %.*s\n"
         "should be \"list\", \"run\", \"repeats\", or \"seconds\"\n", n, z
     );
     rc = 1;
   }

   return rc;
 }

 static void *handle_client(void *pArg){
   char zCmd[32*1024];             /* Read buffer */
   int nCmd = 0;                   /* Valid bytes in zCmd[] */
   int res;                        /* Result of read() call */
   int rc = SQLITE_OK;
   int j;

   ClientCtx ctx;
   memset(&ctx, 0, sizeof(ClientCtx));

   ctx.fd = (int)(intptr_t)pArg;
   ctx.nRepeat = 1;
   rc = sqlite3_open(zDatabaseName, &ctx.db);
   if( rc!=SQLITE_OK ){
     fprintf(stderr, "sqlite3_open(): %s\n", sqlite3_errmsg(ctx.db));
     return 0;
   }

   while( rc==SQLITE_OK ){
     int i;
     int iStart;
     int nConsume;
     res = read(ctx.fd, &zCmd[nCmd], sizeof(zCmd)-nCmd-1);
     if( res<=0 ) break;
     nCmd += res;
     if( nCmd>=sizeof(zCmd)-1 ){
       fprintf(stderr, "oversized (>32KiB) message\n");
       res = 0;
       break;
     }
     zCmd[nCmd] = '\0';

     do {
       nConsume = 0;

       /* Gobble up any whitespace */
       iStart = 0;
       while( is_whitespace(zCmd[iStart]) ) iStart++;

       if( zCmd[iStart]=='.' ){
         /* This is a dot-command. Search for end-of-line. */
         for(i=iStart; i<nCmd; i++){
           if( is_eol(zCmd[i]) ){
             rc = handle_dot_command(&ctx, &zCmd[iStart], i-iStart);
             nConsume = i+1;
             break;
           }
         }
       }else{

         int iSemi;
         char c = 0;
         for(iSemi=iStart; iSemi<nCmd; iSemi++){
           if( zCmd[iSemi]==';' ){
             c = zCmd[iSemi+1];
             zCmd[iSemi+1] = '\0';
             break;
           }
         }

         if( iSemi<nCmd ){
           if( sqlite3_complete(zCmd) ){
             rc = handle_some_sql(&ctx, zCmd, iSemi+1);
             nConsume = iSemi+1;
           }

           if( c ){
             zCmd[iSemi+1] = c;
           }
         }
       }

       if( nConsume>0 ){
         nCmd = nCmd-nConsume;
         if( nCmd>0 ){
           memmove(zCmd, &zCmd[nConsume], nCmd);
         }
       }
     }while( rc==SQLITE_OK && nConsume>0 );
   }

   fprintf(stdout, "Client %d disconnects\n", ctx.fd);
   close(ctx.fd);
   clear_sql(&ctx);
   sqlite3_free(ctx.apPrepare);
   sqlite3_close(ctx.db);
   return 0;
 }

 int main(int argc, char *argv[]) {
   sqlite3 *db;
   int sfd;
   int rc;
   int yes = 1;
   struct sockaddr_in server;

   /* Ignore SIGPIPE. Otherwise the server exits if a client disconnects
   ** abruptly.  */
   signal(SIGPIPE, SIG_IGN);

   if( argc!=2 ){
     fprintf(stderr, "Usage: %s DATABASE\n", argv[0]);
     return 1;
   }
   zDatabaseName = argv[1];

   rc = sqlite3_open(zDatabaseName, &db);
   if( rc!=SQLITE_OK ){
     fprintf(stderr, "sqlite3_open(): %s\n", sqlite3_errmsg(db));
     return 1;
   }

   rc = sqlite3_exec(db, "SELECT * FROM sqlite_master", 0, 0, 0);
   if( rc!=SQLITE_OK ){
     fprintf(stderr, "sqlite3_exec(): %s\n", sqlite3_errmsg(db));
     return 1;
   }

   sfd = socket(AF_INET, SOCK_STREAM, 0);
   if( sfd<0 ){
     fprintf(stderr, "socket() failed\n");
     return 1;
   }

   rc = setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
   if( rc<0 ){
     perror("setsockopt");
     return 1;
   }

   memset(&server, 0, sizeof(server));
   server.sin_family = AF_INET;
   server.sin_addr.s_addr = inet_addr("127.0.0.1");
   server.sin_port = htons(TSERVER_PORTNUMBER);

   rc = bind(sfd, (struct sockaddr *)&server, sizeof(struct sockaddr));
   if( rc<0 ){
     fprintf(stderr, "bind() failed\n");
     return 1;
   }

   rc = listen(sfd, 8);
   if( rc<0 ){
     fprintf(stderr, "listen() failed\n");
     return 1;
   }

   while( 1 ){
     pthread_t tid;
     int cfd = accept(sfd, NULL, NULL);
     if( cfd<0 ){
       perror("accept()");
       return 1;
     }

     fprintf(stdout, "Client %d connects\n", cfd);
     rc = pthread_create(&tid, NULL, handle_client, (void*)(intptr_t)cfd);
     if( rc!=0 ){
       perror("pthread_create()");
       return 1;
     }

     pthread_detach(tid);
   }

   return 0;
 }
	/*
	** 2017 June 7
	**
	** The author disclaims copyright to this source code. In place of
	** a legal notice, here is a blessing:
	**
	** May you do good and not evil.
	** May you find forgiveness for yourself and forgive others.
	** May you share freely, never taking more than you give.
	**
	*************************************************************************
	**
	** Simple multi-threaded server used for informal testing of concurrency
	** between connections in different threads. Listens for tcp/ip connections
	** on port 9999 of the 127.0.0.1 interface only. To build:
	**
	** gcc -g $(TOP)/tool/tserver.c sqlite3.o -lpthread -o tserver
	**
	** To run using "x.db" as the db file:
	**
	** ./tserver x.db
	**
	** To connect, open a client socket on port 9999 and start sending commands.
	** Commands are either SQL - which must be terminated by a semi-colon, or
	** dot-commands, which must be terminated by a newline. If an SQL statement
	** is seen, it is prepared and added to an internal list.
	**
	** Dot-commands are:
	**
	** .list Display all SQL statements in the list.
	** .quit Disconnect.
	** .run Run all SQL statements in the list.
	** .repeats N Configure the number of repeats per ".run".
	** .seconds N Configure the number of seconds to ".run" for.
	**
	** Example input:
	**
	** BEGIN;
	** INSERT INTO t1 VALUES(randomblob(10), randomblob(100));
	** INSERT INTO t1 VALUES(randomblob(10), randomblob(100));
	** INSERT INTO t1 VALUES(randomblob(10), randomblob(100));
	** COMMIT;
	** .repeats 100000
	** .run
	**
	*/
	#define TSERVER_PORTNUMBER 9999

	#include <arpa/inet.h>
	#include <assert.h>
	#include <pthread.h>
	#include <signal.h>
	#include <stdint.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/socket.h>
	#include <sys/time.h>
	#include <unistd.h>

	#include "sqlite3.h"

	/* Database used by this server */
	static char *zDatabaseName = 0;

	typedef struct ClientCtx ClientCtx;
	struct ClientCtx {
	sqlite3 db; / Database handle for this client */
	int fd; /* Client fd */
	int nRepeat; /* Number of times to repeat SQL */
	int nSecond; /* Number of seconds to run for */
	sqlite3_stmt *apPrepare; / Array of prepared statements */
	int nPrepare; /* Valid size of apPrepare[] */
	int nAlloc; /* Allocated size of apPrepare[] */
	};

	static int is_eol(int i){
	return (i=='\n' \|\| i=='\r');
	}
	static int is_whitespace(int i){
	return (i==' ' \|\| i=='\t' \|\| is_eol(i));
	}

	static void trim_string(const char *pzStr, int pnStr){
	const char zStr = pzStr;
	int nStr = *pnStr;

	while( nStr>0 && is_whitespace(zStr[0]) ){
	zStr++;
	nStr--;
	}
	while( nStr>0 && is_whitespace(zStr[nStr-1]) ){
	nStr--;
	}

	*pzStr = zStr;
	*pnStr = nStr;
	}

	static int send_message(ClientCtx p, const char zFmt, ...){
	char *zMsg;
	va_list ap; /* Vararg list */
	va_start(ap, zFmt);
	int res = -1;

	zMsg = sqlite3_vmprintf(zFmt, ap);
	if( zMsg ){
	res = write(p->fd, zMsg, strlen(zMsg));
	}
	sqlite3_free(zMsg);
	va_end(ap);

	return (res<0);
	}

	static int handle_some_sql(ClientCtx p, const char zSql, int nSql){
	const char *zTail = zSql;
	int nTail = nSql;
	int rc = SQLITE_OK;

	while( rc==SQLITE_OK ){
	if( p->nPrepare>=p->nAlloc ){
	int nByte = (p->nPrepare+32) * sizeof(sqlite3_stmt*);
	sqlite3_stmt **apNew = sqlite3_realloc(p->apPrepare, nByte);
	if( apNew ){
	p->apPrepare = apNew;
	p->nAlloc = p->nPrepare+32;
	}else{
	rc = SQLITE_NOMEM;
	break;
	}
	}
	rc = sqlite3_prepare_v2(
	p->db, zTail, nTail, &p->apPrepare[p->nPrepare], &zTail
	);
	if( rc!=SQLITE_OK ){
	send_message(p, "error - %s\n", sqlite3_errmsg(p->db));
	rc = 1;
	break;
	}
	if( p->apPrepare[p->nPrepare]==0 ){
	break;
	}
	p->nPrepare++;
	nTail = nSql - (zTail-zSql);
	rc = send_message(p, "ok (%d SQL statements)\n", p->nPrepare);
	}

	return rc;
	}

	static sqlite3_int64 get_timer(void){
	struct timeval t;
	gettimeofday(&t, 0);
	return ((sqlite3_int64)t.tv_usec / 1000) + ((sqlite3_int64)t.tv_sec * 1000);
	}

	static void clear_sql(ClientCtx *p){
	int j;
	for(j=0; j<p->nPrepare; j++){
	sqlite3_finalize(p->apPrepare[j]);
	}
	p->nPrepare = 0;
	}

	static int handle_dot_command(ClientCtx p, const char zCmd, int nCmd){
	assert( zCmd[0]=='.' );
	int n;
	int rc = 0;
	const char *z = &zCmd[1];
	const char *zArg;
	int nArg;

	for(n=0; n<(nCmd-1); n++){
	if( is_whitespace(z[n]) ) break;
	}

	zArg = &z[n];
	nArg = nCmd-n;
	trim_string(&zArg, &nArg);

	if( n>=1 && n<=4 && 0==strncmp(z, "list", n) ){
	int i;
	for(i=0; rc==0 && i<p->nPrepare; i++){
	const char *zSql = sqlite3_sql(p->apPrepare[i]);
	int nSql = strlen(zSql);
	trim_string(&zSql, &nSql);
	rc = send_message(p, "%d: %.*s\n", i, nSql, zSql);
	}
	}

	else if( n>=1 && n<=4 && 0==strncmp(z, "quit", n) ){
	rc = 1;
	}

	else if( n>=2 && n<=7 && 0==strncmp(z, "repeats", n) ){
	if( nArg ){
	p->nRepeat = strtol(zArg, 0, 0);
	if( p->nRepeat>0 ) p->nSecond = 0;
	}
	rc = send_message(p, "ok (repeat=%d)\n", p->nRepeat);
	}

	else if( n>=2 && n<=3 && 0==strncmp(z, "run", n) ){
	int i, j;
	int nBusy = 0;
	sqlite3_int64 t0 = get_timer();
	sqlite3_int64 t1 = t0;
	int nT1 = 0;
	int nTBusy1 = 0;

	for(j=0; (p->nRepeat<=0 \|\| j<p->nRepeat) && rc==SQLITE_OK; j++){
	sqlite3_int64 t2;

	for(i=0; i<p->nPrepare && rc==SQLITE_OK; i++){
	sqlite3_stmt *pStmt = p->apPrepare[i];

	/* Execute the statement */
	while( sqlite3_step(pStmt)==SQLITE_ROW );
	rc = sqlite3_reset(pStmt);

	if( (rc & 0xFF)==SQLITE_BUSY ){
	if( sqlite3_get_autocommit(p->db)==0 ){
	sqlite3_exec(p->db, "ROLLBACK", 0, 0, 0);
	}
	nBusy++;
	rc = SQLITE_OK;
	break;
	}
	else if( rc!=SQLITE_OK ){
	send_message(p, "error - %s\n", sqlite3_errmsg(p->db));
	}
	}

	t2 = get_timer();
	if( t2>=(t1+1000) ){
	int nMs = (t2 - t1);
	int nDone = (j+1 - nBusy - nT1);

	rc = send_message(
	p, "(%d done @ %d per second, %d busy)\n",
	nDone, (1000*nDone + nMs/2) / nMs, nBusy - nTBusy1
	);
	t1 = t2;
	nT1 = j+1 - nBusy;
	nTBusy1 = nBusy;
	if( p->nSecond>0 && (p->nSecond*1000)<=t1-t0 ) break;
	}
	}

	if( rc==SQLITE_OK ){
	send_message(p, "ok (%d/%d SQLITE_BUSY)\n", nBusy, j);
	}
	clear_sql(p);
	}

	else if( n>=1 && n<=7 && 0==strncmp(z, "seconds", n) ){
	if( nArg ){
	p->nSecond = strtol(zArg, 0, 0);
	if( p->nSecond>0 ) p->nRepeat = 0;
	}
	rc = send_message(p, "ok (repeat=%d)\n", p->nRepeat);
	}

	else{
	send_message(p,
	"unrecognized dot command: %.*s\n"
	"should be \"list\", \"run\", \"repeats\", or \"seconds\"\n", n, z
	);
	rc = 1;
	}

	return rc;
	}

	static void handle_client(void pArg){
	char zCmd[321024]; / Read buffer */
	int nCmd = 0; /* Valid bytes in zCmd[] */
	int res; /* Result of read() call */
	int rc = SQLITE_OK;
	int j;

	ClientCtx ctx;
	memset(&ctx, 0, sizeof(ClientCtx));

	ctx.fd = (int)(intptr_t)pArg;
	ctx.nRepeat = 1;
	rc = sqlite3_open(zDatabaseName, &ctx.db);
	if( rc!=SQLITE_OK ){
	fprintf(stderr, "sqlite3_open(): %s\n", sqlite3_errmsg(ctx.db));
	return 0;
	}

	while( rc==SQLITE_OK ){
	int i;
	int iStart;
	int nConsume;
	res = read(ctx.fd, &zCmd[nCmd], sizeof(zCmd)-nCmd-1);
	if( res<=0 ) break;
	nCmd += res;
	if( nCmd>=sizeof(zCmd)-1 ){
	fprintf(stderr, "oversized (>32KiB) message\n");
	res = 0;
	break;
	}
	zCmd[nCmd] = '\0';

	do {
	nConsume = 0;

	/* Gobble up any whitespace */
	iStart = 0;
	while( is_whitespace(zCmd[iStart]) ) iStart++;

	if( zCmd[iStart]=='.' ){
	/* This is a dot-command. Search for end-of-line. */
	for(i=iStart; i<nCmd; i++){
	if( is_eol(zCmd[i]) ){
	rc = handle_dot_command(&ctx, &zCmd[iStart], i-iStart);
	nConsume = i+1;
	break;
	}
	}
	}else{

	int iSemi;
	char c = 0;
	for(iSemi=iStart; iSemi<nCmd; iSemi++){
	if( zCmd[iSemi]==';' ){
	c = zCmd[iSemi+1];
	zCmd[iSemi+1] = '\0';
	break;
	}
	}

	if( iSemi<nCmd ){
	if( sqlite3_complete(zCmd) ){
	rc = handle_some_sql(&ctx, zCmd, iSemi+1);
	nConsume = iSemi+1;
	}

	if( c ){
	zCmd[iSemi+1] = c;
	}
	}
	}

	if( nConsume>0 ){
	nCmd = nCmd-nConsume;
	if( nCmd>0 ){
	memmove(zCmd, &zCmd[nConsume], nCmd);
	}
	}
	}while( rc==SQLITE_OK && nConsume>0 );
	}

	fprintf(stdout, "Client %d disconnects\n", ctx.fd);
	close(ctx.fd);
	clear_sql(&ctx);
	sqlite3_free(ctx.apPrepare);
	sqlite3_close(ctx.db);
	return 0;
	}

	int main(int argc, char *argv[]) {
	sqlite3 *db;
	int sfd;
	int rc;
	int yes = 1;
	struct sockaddr_in server;

	/* Ignore SIGPIPE. Otherwise the server exits if a client disconnects
	** abruptly. */
	signal(SIGPIPE, SIG_IGN);

	if( argc!=2 ){
	fprintf(stderr, "Usage: %s DATABASE\n", argv[0]);
	return 1;
	}
	zDatabaseName = argv[1];

	rc = sqlite3_open(zDatabaseName, &db);
	if( rc!=SQLITE_OK ){
	fprintf(stderr, "sqlite3_open(): %s\n", sqlite3_errmsg(db));
	return 1;
	}

	rc = sqlite3_exec(db, "SELECT * FROM sqlite_master", 0, 0, 0);
	if( rc!=SQLITE_OK ){
	fprintf(stderr, "sqlite3_exec(): %s\n", sqlite3_errmsg(db));
	return 1;
	}

	sfd = socket(AF_INET, SOCK_STREAM, 0);
	if( sfd<0 ){
	fprintf(stderr, "socket() failed\n");
	return 1;
	}

	rc = setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
	if( rc<0 ){
	perror("setsockopt");
	return 1;
	}

	memset(&server, 0, sizeof(server));
	server.sin_family = AF_INET;
	server.sin_addr.s_addr = inet_addr("127.0.0.1");
	server.sin_port = htons(TSERVER_PORTNUMBER);

	rc = bind(sfd, (struct sockaddr *)&server, sizeof(struct sockaddr));
	if( rc<0 ){
	fprintf(stderr, "bind() failed\n");
	return 1;
	}

	rc = listen(sfd, 8);
	if( rc<0 ){
	fprintf(stderr, "listen() failed\n");
	return 1;
	}

	while( 1 ){
	pthread_t tid;
	int cfd = accept(sfd, NULL, NULL);
	if( cfd<0 ){
	perror("accept()");
	return 1;
	}

	fprintf(stdout, "Client %d connects\n", cfd);
	rc = pthread_create(&tid, NULL, handle_client, (void*)(intptr_t)cfd);
	if( rc!=0 ){
	perror("pthread_create()");
	return 1;
	}

	pthread_detach(tid);
	}

	return 0;
	}