remote_access.c

一个用在mips体系结构中的操作系统

/*
 * Copyright (C) 1996-1998 by the Board of Trustees
 *    of Leland Stanford Junior University.
 * 
 * This file is part of the SimOS distribution. 
 * See LICENSE file for terms of the license. 
 *
 */

/*
 * remote_access.c - Routines to provide remote access to SimOS files.
 */

#include "sim.h"

#include <stdio.h>
#include <sys/types.h>
#ifndef __alpha
#ifndef i386
#include <sys/unistd.h>
#include <sys/ioccom.h>
#include <sys/filio.h>
#endif
#endif
#include <sys/mman.h>
#include <sys/file.h>
#include <sys/signal.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <unistd.h>
#ifndef linux
#include <sys/socket.h>
#include <netinet/in.h>
#endif
#include <sys/param.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>

#include "remote_access.h"
#include "sim_error.h"
#include "simutil.h"
#include "rmtaccess.h"

extern char *MemFileDir;


#define RMT_MAXHOSTNAMELEN 64
#define RMT_MAXCONN 64

enum {RMT_DISK = 0, RMT_CPT, RMT_END};
static char server[RMT_END][RMT_MAXHOSTNAMELEN];
static struct sockaddr_in rmt_addr[RMT_END];
static char cpt_rootname[MAX_PATH_LENGTH];

/* --------------------------------------- */

static int StartRequest(struct sockaddr_in *rmtsrv, int cmd, char *arg, int argsize);
static int ReadForSure(int fd, byte *buf, int size);
static int CopyFile(int infd, int outfd);

/*
 * Simrmt_init -Initialized access to a remote checkpoint. 
 *    returns < 0 on error, 1 if sucessful.
 */
int
Simrmt_cptinit(char *fullname, char *rootname)
{
   int port;
   struct hostent *host;

    /*
     * We assume that the root pathname encodes the host and port as follows:
     *    hostname:port:masterlog_root
     */
    if (sscanf(fullname, "%[^:]:%d:%s", server[RMT_CPT], &port, rootname) != 3) {
       Sim_Warning("Simrmt_init: Bad remote checkpoint name <%s>\n", fullname);
       return -1;
    }
    /*
     * Fill in the internet address to be used in later calls. 
     */
    strcpy(cpt_rootname, rootname);
    host = gethostbyname(server[RMT_CPT]);
    if (!host) {
        perror( "Simrmt_init:gethostbyname bad host");
	Sim_Warning("Bad hostname %s\n", server[RMT_CPT]);
	return -1;
    }
    rmt_addr[RMT_CPT].sin_family = host->h_addrtype;
    bcopy(host->h_addr, (char *) &rmt_addr[RMT_CPT].sin_addr, host->h_length);
    rmt_addr[RMT_CPT].sin_port = htons((short)port);
    
    return 1;
}

/*
 * Simrmt_diskinit - Initialize remote disk for access.
 *      Return the open file descriptor.
 */
int 
Simrmt_diskinit(char *remoteName)
{
    int port;
    struct hostent *host;

    /* If no remote name is given, then we are using the remote
       checkpoint server as a remote disk server as well */
    if (remoteName == NULL) {
      return StartRequest(&(rmt_addr[RMT_CPT]), SIMRMT_DISKINIT, (char *) NULL, 0);
    }
    else {
    /*
     * We assume that the remote name encodes the host and port as follows:
     *    $hostname:port
     */
      if (sscanf(remoteName, "$%[^:]:%d", server[RMT_DISK], &port) != 2) {
        Sim_Warning("Simrmt_diskinit: Bad remote disk name <%s>\n", remoteName);
        return -1;
      }
      /*
       * Fill in the internet address to be used in later calls. 
       */
      host = gethostbyname(server[RMT_DISK]);
      if (!host) {
        perror( "Simrmt_diskinit:gethostbyname bad host");
	Sim_Warning("Bad hostname %s\n", server[RMT_DISK]);
	return -1;
      }
      rmt_addr[RMT_DISK].sin_family = host->h_addrtype;
      bcopy(host->h_addr, (char *) &rmt_addr[RMT_DISK].sin_addr, host->h_length);
      rmt_addr[RMT_DISK].sin_port = htons((short)port);

      return StartRequest(&(rmt_addr[RMT_DISK]), SIMRMT_DISKINIT, (char *) NULL, 0);
    }
}

/*
 * Simrmt_access - See if a remote file is readable
 *     Returns: TRUE if file exists and is readable, FALSE otherwise
 */
bool
Simrmt_access(char *pathname)
{
  int fd = StartRequest(&(rmt_addr[RMT_CPT]), SIMRMT_ACCESS, pathname, strlen(pathname));
  if (fd == -1) return FALSE;
  close(fd);
  return TRUE;
}

/*
 * Simrmt_fopen - Open a remote file.
 *     Returns: NULL on error, otherwise the open file pointer
 */
FILE *
Simrmt_fopen(char *pathname)
{
  int fd = StartRequest(&(rmt_addr[RMT_CPT]), SIMRMT_OPEN, pathname, strlen(pathname));
  if (fd < 0) return NULL;
  else return fdopen(fd, "r");
}


/*
 * Simrmt_diskcmd - Send a remote disk command.
 */
int64
Simrmt_diskcmd(int diskfd, int op,
	       int node, int ctrl, int unit,
	       int64 sectorNum,int64 sizeInBytes, 
               byte *buffer) 
{ 
    NetDiskHdr	hdr, rhdr; 
    int  size;
    static 	int reqnum;
     
    reqnum++;
        
    bzero((char *) &hdr, sizeof(hdr));
    hdr.op = (DiskOp)op;
    hdr.node = node;
    hdr.ctrl = ctrl;
    hdr.unit = unit;
    hdr.sectorNum = sectorNum;
    hdr.sizeInBytes = sizeInBytes;
    hdr.reqnum = reqnum;
    

    if( write(diskfd, &hdr,sizeof(hdr))!=sizeof(hdr) ) {
        CPUError("write to rmtaccess server failed\n");
    };
    if( (op == NETDISK_WRITE) || (op == NETDISK_ATTACH) ) {
       if( write(diskfd,buffer,sizeInBytes)!=sizeInBytes) { 
          CPUError("write to rmtaccess server failed\n");
       }
    } 
    
    size = ReadForSure(diskfd, (byte *)&rhdr, sizeof(rhdr));
    if (size != sizeof(rhdr)) {
        perror("simckpt_netdisk:read");
        rhdr.retVal = EIO;
        return rhdr.retVal; 	
    }
    if (rhdr.reqnum != hdr.reqnum) {
        Sim_Warning("Simnetdisk: Bad reqnum (%d)\n", rhdr.reqnum);
    }
    if (((op == NETDISK_READ) || (op == NETDISK_ATTACH)) && (rhdr.retVal > 0)) {
       size = ReadForSure(diskfd, buffer, rhdr.retVal);
       if (size != rhdr.retVal) {
          Sim_Warning("Simnetdisk: Reply packet too small (%d)\n", size);
          rhdr.retVal = EIO;
       } 
    }
    return rhdr.retVal;
}

/*
 * ReadForSure - just like the read() system call execpt it keeps trying
 *               if not enough data was returned by the read or it was interrupted
 *               by a signal.
 */
static int
ReadForSure(int fd, byte *buf, int size)
{
    int a;
    for(a = 0; a < size;) {	
	int ret = read(fd, buf + a, size-a);
	if (ret < 0) {
	   if (errno == EINTR)
	      continue;
	   return -1;
	}
	a += ret;
    }
    return size;
}

/*
 * StartRequest -
 * Establish a connection with the remote server and exchange the specified command
 * with it. 
 * Returns the open connection to the server. < 0 if the connection
 * fails or the command encountes an errors. 
 */
static int
StartRequest(struct sockaddr_in *rmtsrv, int cmd, char *arg, int argsize)
{
    int fd, err;
    RmtAccessStartRequest  req;
    byte ack[8];
    /*
     * Create the TCP socket and send command, returning socket
     * blocks to and from the net disk server.
     */
 
    fd = socket(rmtsrv->sin_family, SOCK_STREAM, IPPROTO_TCP);
    if (fd < 0) {
            perror("Simrmt:StartRequest:socket");
	    return -1;
    }
    if (connect(fd, (struct sockaddr *)rmtsrv, sizeof (*rmtsrv)) < 0) {
            perror("Simrmt:StartRequest:connect");
	    close(fd);
	    return -1;
    } 

    /*
     * format and send the request over the connection.
     */
    req.magic = RMTACCESS_MAGIC;
    req.cmd = (Rmtaccess_op)cmd;
    req.arglen = argsize;
    
    err = write(fd, (char *) &req, sizeof(req));
    if (err != sizeof(req)) {
       perror("Simrmt:StartRequest:write");
       close(fd);
       goto error;
    }
    if (req.arglen > 0) { 
       err = write(fd, arg, req.arglen);
       if (err != req.arglen) {
	  perror("Simrmt:StartRequest:write2");
	 goto error;
       }
    }
    /*
     * Get error code for command: OK\n or Enn 
     */
    err = ReadForSure(fd, ack, 3);
    if (err < 0) {
       perror("Simrmt:StartRequest:ReadForSure ack");
       goto error;
    }
    if ((ack[0] == 'O') && (ack[1] == 'K')) {
       return fd;
    }

 error:
    close(fd);
    return -1;
}

static int
CopyFile(int infd, int outfd)
{
    char buf[8192];
    int cnt, cnt2;
    while(1) {
        cnt = read(infd, buf, sizeof(buf));
        if (cnt == 0) 
            break;
        if (cnt < 0) {
            perror("CopyFile -- read");
            exit(1);
        }
        cnt2 = write(outfd, buf, cnt);
        if (cnt2 != cnt) {
            perror("CopyFile -- write");
            exit(1);
        }
    }
    return 0;
}

/* 
 * Open a file across a remote server and return the FILE ptr
 * The client must close the FILE ptr when done. 
 */
FILE* 
Simrmt_RemoteFileOpen(char *pathName) 
{
   struct hostent *host;
   char hostName[RMT_MAXHOSTNAMELEN];
   int port;
   char fileName[RMT_MAXHOSTNAMELEN];
   int fd;
   struct sockaddr_in rmtsrv;

   if (sscanf(pathName, "%[^:]:%d:%s", hostName, &port, fileName) != 3) {
      Sim_Warning("Simrmt_RemoteFileOpen: Bad remote file name <%s>",
                  pathName);
      return NULL;
   }

   host = gethostbyname(hostName);
   if (!host) {
      perror( "Simrmt_RemoteFileOpen: gethostbyname bad host");
      Sim_Warning("Bad host name %s\n", hostName);
      return NULL;
   }

   bzero((char *) &rmtsrv, sizeof(rmtsrv));
   rmtsrv.sin_family = host->h_addrtype;
   bcopy(host->h_addr, (char *) &(rmtsrv.sin_addr), host->h_length);
   rmtsrv.sin_port = htons((short) port);
    
  fd = StartRequest(&rmtsrv, SIMRMT_OPEN, fileName, strlen(fileName));
  if (fd < 0) {
     return NULL;
  } else {
     return fdopen(fd, "r");
  }
}


/*
 * This routine implements an mmap of a remote file. Currently we do the 
 * dumb thing, which is to copy the file to a temporary local file
 * and then mmaps it. The parameters to the call are exactly the same as
 * for the mmap call, except that you pass a remoteserver filepath instead of
 * of a file descriptor.
 */
void *
Simrmt_mmap(void *addr, size_t len, int prot, int flags, char* pathName, off_t off)
{
   struct stat statbuf;
   struct hostent *host;
   char hostName[RMT_MAXHOSTNAMELEN];
   int port;
   char fileName[RMT_MAXHOSTNAMELEN];
   int fd, tmpfd;
   struct sockaddr_in rmtsrv;
   void *maddr;

   if (sscanf(pathName, "%[^:]:%d:%s", hostName, &port, fileName) != 3) {
      Sim_Warning("Simrmt_mmap: Bad remote file name <%s>",
                  pathName);
      return NULL;
   }

   host = gethostbyname(hostName);
   if (!host) {
      perror( "Simrmt_mmap: gethostbyname bad host");
      Sim_Warning("Bad host name %s\n", hostName);
      return NULL;
   }

   
   rmtsrv.sin_family = host->h_addrtype;
   bcopy(host->h_addr, (char *) &(rmtsrv.sin_addr), host->h_length);
   rmtsrv.sin_port = htons((short) port);
    
   fd = StartRequest(&rmtsrv, SIMRMT_OPEN, fileName, strlen(fileName));
   if (fd < 0) {
      return NULL;
   } 
   
   tmpfd = MakeFile(MemFileDir, NULL, 0, 1);
   CopyFile(fd, tmpfd);
   close(fd);
   
   if (len == 0) {
      /* this means we want to map to the end of file */
      if (fstat(tmpfd, &statbuf) < 0) {
         perror("Simrmt_mmap fstat");
         exit(1);
      }

      len = statbuf.st_size - off;
   }

   if((maddr = mmap(addr, len, prot, flags, tmpfd, off)) == (void *)-1) {
      perror("Simrmt_mmap");
      exit(1);
   }
   close(tmpfd);
   return maddr;
}