[apple/network_cmds.git] / kdumpd.tproj / kdumpd.c

/*
 * Copyright (c) 1983, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static const char copyright[] =
"@(#) Copyright (c) 1983, 1993\n\
        The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

/* Mac OS X kernel core dump server, based on the BSD trivial file
 * transfer protocol server (FreeBSD distribution), with several
 * modifications. This server is *not* compatible with tftp, as the
 * protocol has changed considerably.
 */

/*
 * Based on the trivial file transfer protocol server.
 *
 * The original version included many modifications by Jim Guyton
 * <guyton@rand-unix>.
 */

#include <sys/param.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/types.h>

#include <netinet/in.h>
#include "kdump.h"
#include <arpa/inet.h>

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <netdb.h>
#include <pwd.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include <libkern/OSByteOrder.h>

#include "kdumpsubs.h"

#define TIMEOUT         5

int     peer;
int     rexmtval = TIMEOUT;
int     maxtimeout = 10*TIMEOUT;

#define PKTSIZE SEGSIZE+6
char    buf[PKTSIZE];
char    ackbuf[PKTSIZE];
struct  sockaddr_in from;
socklen_t fromlen;

void    kdump __P((struct kdumphdr *, int));

/*
 * Null-terminated directory prefix list for absolute pathname requests and
 * search list for relative pathname requests.
 *
 * MAXDIRS should be at least as large as the number of arguments that
 * inetd allows (currently 20).
 */
#define MAXDIRS 20
static struct dirlist {
        char    *name;
        int     len;
} dirs[MAXDIRS+1];
static int      suppress_naks;
static int      logging = 1;
static int      ipchroot;

static char *errtomsg __P((int));
static void  nak __P((int));
static char * __P(verifyhost(struct sockaddr_in *));

#define KDP_FEATURE_MASK_STRING         "features"
enum    {KDP_FEATURE_LARGE_CRASHDUMPS = 1};
uint32_t        kdp_crashdump_feature_mask;
uint32_t        kdp_feature_large_crashdumps;

int
main(argc, argv)
        int argc;
        char *argv[];
{
        register struct kdumphdr *tp;
        register int n;
        int ch, on;
        struct sockaddr_in sin;
        char *chroot_dir = NULL;
        struct passwd *nobody;
        char *chuser = "nobody";

        openlog("kdumpd", LOG_PID | LOG_NDELAY, LOG_FTP);
        while ((ch = getopt(argc, argv, "cClns:u:")) != -1) {
                switch (ch) {
                case 'c':
                        ipchroot = 1;
                        break;
                case 'C':
                        ipchroot = 2;
                        break;
                case 'l':
                        logging = 1;
                        break;
                case 'n':
                        suppress_naks = 1;
                        break;
                case 's':
                        chroot_dir = optarg;
                        break;
                case 'u':
                        chuser = optarg;
                        break;
                default:
                        syslog(LOG_WARNING, "ignoring unknown option -%c", ch);
                }
        }

        if (optind < argc) {
                struct dirlist *dirp;

                /* Get list of directory prefixes. Skip relative pathnames. */
                for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
                     optind++) {
                        if (argv[optind][0] == '/') {
                                dirp->name = argv[optind];
                                dirp->len  = strlen(dirp->name);
                                dirp++;
                        }
                }
        }
        else if (chroot_dir) {
                dirs->name = "/";
                dirs->len = 1;
        }
        if (ipchroot && chroot_dir == NULL) {
                syslog(LOG_ERR, "-c requires -s");
                exit(1);
        }

        on = 1;
        if (ioctl(0, FIONBIO, &on) < 0) {
                syslog(LOG_ERR, "ioctl(FIONBIO): %m");
                exit(1);
        }
        fromlen = sizeof (from);
        n = recvfrom(0, buf, sizeof (buf), 0,
            (struct sockaddr *)&from, &fromlen);
        if (n < 0) {
                syslog(LOG_ERR, "recvfrom: %m");
                exit(1);
        }
        /*
         * Now that we have read the message out of the UDP
         * socket, we fork and exit.  Thus, inetd will go back
         * to listening to the kdump port, and the next request
         * to come in will start up a new instance of kdumpd.
         *
         * We do this so that inetd can run kdumpd in "wait" mode.
         * The problem with kdumpd running in "nowait" mode is that
         * inetd may get one or more successful "selects" on the
         * kdump port before we do our receive, so more than one
         * instance of kdumpd may be started up.  Worse, if kdumpd
         * breaks before doing the above "recvfrom", inetd would
         * spawn endless instances, clogging the system.
         */
        {
                int pid;
                int i;
                socklen_t j;

                for (i = 1; i < 20; i++) {
                    pid = fork();
                    if (pid < 0) {
                                sleep(i);
                                /*
                                 * flush out to most recently sent request.
                                 *
                                 * This may drop some requests, but those
                                 * will be resent by the clients when
                                 * they timeout.  The positive effect of
                                 * this flush is to (try to) prevent more
                                 * than one kdumpd being started up to service
                                 * a single request from a single client.
                                 */
                                j = sizeof from;
                                i = recvfrom(0, buf, sizeof (buf), 0,
                                    (struct sockaddr *)&from, &j);
                                if (i > 0) {
                                        n = i;
                                        fromlen = j;
                                }
                    } else {
                                break;
                    }
                }
                if (pid < 0) {
                        syslog(LOG_ERR, "fork: %m");
                        exit(1);
                } else if (pid != 0) {
                        exit(0);
                }
        }

        /*
         * Since we exit here, we should do that only after the above
         * recvfrom to keep inetd from constantly forking should there
         * be a problem.  See the above comment about system clogging.
         */
        if (chroot_dir) {
                if (ipchroot) {
                        char tempchroot[MAXPATHLEN];
                        char *tempaddr;
                        struct stat sb;
                        int statret;

                        tempaddr = inet_ntoa(from.sin_addr);
                        snprintf(tempchroot, sizeof(tempchroot), "%s/%s", chroot_dir, tempaddr);
                        statret = stat(tempchroot, &sb);
                        if ((sb.st_mode & S_IFDIR) &&
                            (statret == 0 || (statret == -1 && ipchroot == 1)))
                                chroot_dir = tempchroot;
                }
                /* Must get this before chroot because /etc might go away */
                if ((nobody = getpwnam(chuser)) == NULL) {
                        syslog(LOG_ERR, "%s: no such user", chuser);
                        exit(1);
                }
                if (chroot(chroot_dir)) {
                        syslog(LOG_ERR, "chroot: %s: %m", chroot_dir);
                        exit(1);
                }
                chdir( "/" );
                setuid(nobody->pw_uid);
        }
        else
          if (0 !=  chdir(dirs->name))
            syslog(LOG_ERR, "chdir%s: %m", dirs->name);

        from.sin_family = AF_INET;
        alarm(0);
        close(0);
        close(1);
        peer = socket(AF_INET, SOCK_DGRAM, 0);
        if (peer < 0) {
                syslog(LOG_ERR, "socket: %m");
                exit(1);
        }
        memset(&sin, 0, sizeof(sin));
        sin.sin_family = AF_INET;
        if (bind(peer, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
                syslog(LOG_ERR, "bind: %m");
                exit(1);
        }
        if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
                syslog(LOG_ERR, "connect: %m");
                exit(1);
        }
        tp = (struct kdumphdr *)buf;
        tp->th_opcode = ntohs(tp->th_opcode);
        if (tp->th_opcode == WRQ)
                kdump(tp, n);
        exit(1);
}

struct formats;
int     validate_access __P((char **, int));

void    recvfile __P((struct formats *));

struct formats {
        char    *f_mode;
        int     (*f_validate) __P((char **, int));

        void    (*f_recv) __P((struct formats *));
        int     f_convert;
} formats[] = {
  { "netascii", validate_access, recvfile, 1 },
  { "octet",    validate_access, recvfile, 0 },
  { 0 }
};

/*
 * Handle initial connection protocol.
 */
void
kdump(tp, size)
        struct kdumphdr *tp;
        int size;
{
        register char *cp;
        int first = 1, ecode;
        register struct formats *pf;
        char *filename, *mode = NULL;

        filename = cp = tp->th_stuff;
again:
        while (cp < buf + size) {
                if (*cp == '\0')
                        break;
                cp++;
        }
        if (*cp != '\0') {
                nak(EBADOP);
                exit(1);
        }
        if (first) {
                mode = ++cp;
                first = 0;
                goto again;
        }
        for (cp = mode; *cp; cp++)
                if (isupper(*cp))
                        *cp = tolower(*cp);

        cp++;
        if (strncmp(KDP_FEATURE_MASK_STRING, cp, sizeof(KDP_FEATURE_MASK_STRING)) == 0) {
                kdp_crashdump_feature_mask = ntohl(*(uint32_t *) (cp + sizeof(KDP_FEATURE_MASK_STRING)));
                kdp_feature_large_crashdumps = kdp_crashdump_feature_mask & KDP_FEATURE_LARGE_CRASHDUMPS;
                syslog(LOG_INFO, "Received feature mask %s:%hx", cp, kdp_crashdump_feature_mask);
        }
        
        for (pf = formats; pf->f_mode; pf++)
                if (strcmp(pf->f_mode, mode) == 0)
                        break;
        if (pf->f_mode == 0) {
                nak(EBADOP);
                exit(1);
        }
        ecode = (*pf->f_validate)(&filename, tp->th_opcode);
        if (logging) {
                syslog(LOG_INFO, "%s: %s request for %s: %s", verifyhost(&from),
                        tp->th_opcode == WRQ ? "write" : "read",
                        filename, errtomsg(ecode));
        }
        if (ecode) {
                /*
                 * Avoid storms of naks to a RRQ broadcast for a relative
                 * bootfile pathname from a diskless Sun.
                 */
                if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
                        exit(0);
                nak(ecode);
                exit(1);
        }
        if (tp->th_opcode == WRQ)
                (*pf->f_recv)(pf);

        exit(0);
}


FILE *file;

/*
 * Validate file access. We only allow storage of files that do not already
 * exist, and that do not include directory specifiers in their pathnames. 
 * This is because kernel coredump filenames should always be of the form 
 * "core-version-IP as dotted quad-random string" as in :
 * core-custom-17.202.40.204-a75b4eec
 * The file is written to the directory supplied as the first argument
 * in inetd.conf
 */

int 
validate_access(char **filep, int mode)
{
  struct stat stbuf;
  int   fd;
  char *filename = *filep;
  static char pathname[MAXPATHLEN]; 

  if (strstr(filename, "/") || strstr(filename, ".."))
    return (EACCESS);
  
  snprintf(pathname, sizeof(pathname), "./%s", filename);

  if (0 == stat(pathname, &stbuf))
    return (EEXIST);
  
  if (errno != ENOENT)
    return (errno);


  fd = open(filename, O_WRONLY|O_CREAT|O_TRUNC);

  if (fd < 0)
    return (errno + 100);
  
  file = fdopen(fd, (mode == RRQ)? "r":"w");
  if (file == NULL) {
    return errno+100;
  }
  if (fchmod(fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) < 0)
    return errno+100;

  return (0);  
}

int     timeout;
jmp_buf timeoutbuf;

void
timer()
{

        timeout += rexmtval;
        if (timeout >= maxtimeout)
          {
            longjmp(timeoutbuf, 2); 
          }
        longjmp(timeoutbuf, 1);
}

void
justquit()
{
        exit(0);
}


/*
 * Receive a file.
 */
void
recvfile(pf)
        struct formats *pf;
{
        struct kdumphdr *dp, *w_init();
        register struct kdumphdr *ap;    /* ack buffer */
        register int n, size;
        volatile unsigned int block;
        volatile unsigned int jmpval = 0;

        signal(SIGALRM, timer);
        dp = w_init();
        ap = (struct kdumphdr *)ackbuf;
        block = 0;
        do {
send_seek_ack:  timeout = 0;
                if (block == 0)
                        ap->th_opcode = htons((u_short)ACK | (kdp_feature_large_crashdumps << 8));
                else
                        ap->th_opcode = htons((u_short)ACK);
                ap->th_block = htonl((unsigned int)block);
                block++;
                jmpval = setjmp(timeoutbuf);
                if (2 == jmpval)
                  {
                    syslog (LOG_ERR, "Timing out and flushing file to disk");
                    goto flushfile;
                  }
send_ack:
                if (send(peer, ackbuf, 6 , 0) != 6) {
                        syslog(LOG_ERR, "write: %m");
                        goto abort;
                }
                write_behind(file, pf->f_convert);
                for ( ; ; ) {
                        alarm(rexmtval);
                        n = recv(peer, dp, PKTSIZE, 0);
                        alarm(0);
                        if (n < 0) {            /* really? */
                                syslog(LOG_ERR, "read: %m");
                                goto abort;
                        }
                        dp->th_opcode = ntohs((u_short)dp->th_opcode);
                        dp->th_block = ntohl((unsigned int)dp->th_block);
                        if (dp->th_opcode == ERROR)
                                goto abort;
                        if (dp->th_opcode == KDP_EOF)
                          {
                            syslog (LOG_ERR, "Received last panic dump packet");
                            goto final_ack;
                          }
                        if (dp->th_opcode == KDP_SEEK)
                          {
                            if (dp->th_block == block)
                              {
                                off_t crashdump_offset = 0;
                                unsigned int tempoff = 0;

                                if (kdp_feature_large_crashdumps) {
                                        crashdump_offset = OSSwapBigToHostInt64((*(uint64_t *)dp->th_data));
#if     DEBUG                                   
                                        syslog(LOG_INFO, "Large offset");
#endif                                  
                                }
                                else {
                                bcopy (dp->th_data, &tempoff, sizeof(unsigned int));
                                crashdump_offset = ntohl(tempoff);
                                }
#if     DEBUG
                                syslog(LOG_INFO, "Seeking to offset 0x%llx\n", crashdump_offset);
#endif
                                errno = 0;
                                lseek(fileno (file), crashdump_offset, SEEK_SET);
                                if (errno)
                                  syslog (LOG_ERR, "lseek: %m");

                                goto send_seek_ack;
                              }
                            (void) synchnet(peer);
                            if (dp->th_block == (block-1))
                              {
                                syslog (LOG_DAEMON|LOG_ERR, "Retransmitting seek ack - current block %hu, received block %hu", block, dp->th_block);
                                goto send_ack;          /* rexmit */
                              }
                          }

                        if (dp->th_opcode == DATA) {
                                if (dp->th_block == block) {
                                        break;   /* normal */
                                }
                                /* Re-synchronize with the other side */
                                (void) synchnet(peer);
                                if (dp->th_block == (block-1))
                                  {
                                    syslog (LOG_DAEMON|LOG_ERR, "Retransmitting ack - current block %hu, received block %hu", block, dp->th_block);
                                    goto send_ack;          /* rexmit */
                                  }
                                else
                                  syslog (LOG_DAEMON|LOG_ERR, "Not retransmitting ack - current block %hu, received block %hu", block, dp->th_block);
                        }
                }

                size = writeit(file, &dp, n - 6, pf->f_convert);
                if (size != (n-6)) {                    /* ahem */
                        if (size < 0) nak(errno + 100);
                        else nak(ENOSPACE);
                        goto abort;
                }
        } while (dp->th_opcode != KDP_EOF);

final_ack:
        ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
        ap->th_block = htonl((unsigned int) (block));
        (void) send(peer, ackbuf, 6, 0);
flushfile:
        write_behind(file, pf->f_convert);
        (void) fclose(file);            /* close data file */
        syslog (LOG_ERR, "file closed, sending final ACK\n");

        signal(SIGALRM, justquit);      /* just quit on timeout */
        alarm(rexmtval);
        n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
        alarm(0);
        if (n >= 6 &&                   /* if read some data */
            dp->th_opcode == DATA &&    /* and got a data block */
            block == dp->th_block) {    /* then my last ack was lost */
                (void) send(peer, ackbuf, 6, 0);     /* resend final ack */
        }
abort:
        return;
}

struct errmsg {
        int     e_code;
        char    *e_msg;
} errmsgs[] = {
        { EUNDEF,       "Undefined error code" },
        { ENOTFOUND,    "File not found" },
        { EACCESS,      "Access violation" },
        { ENOSPACE,     "Disk full or allocation exceeded" },
        { EBADOP,       "Illegal KDUMP operation" },
        { EBADID,       "Unknown transfer ID" },
        { EEXISTS,      "File already exists" },
        { ENOUSER,      "No such user" },
        { -1,           0 }
};

static char *
errtomsg(error)
        int error;
{
        static char buf[20];
        register struct errmsg *pe;
        if (error == 0)
                return "success";
        for (pe = errmsgs; pe->e_code >= 0; pe++)
                if (pe->e_code == error)
                        return pe->e_msg;
        snprintf(buf, sizeof(buf), "error %d", error);
        return buf;
}

/*
 * Send a nak packet (error message).
 * Error code passed in is one of the
 * standard KDUMP codes, or a UNIX errno
 * offset by 100.
 */
static void
nak(error)
        int error;
{
        register struct kdumphdr *tp;
        int length;
        register struct errmsg *pe;

        tp = (struct kdumphdr *)buf;
        tp->th_opcode = htons((u_short)ERROR);
        tp->th_code = htons((unsigned int)error);
        for (pe = errmsgs; pe->e_code >= 0; pe++)
                if (pe->e_code == error)
                        break;
        if (pe->e_code < 0) {
                pe->e_msg = strerror(error - 100);
                tp->th_code = EUNDEF;   /* set 'undef' errorcode */
        }
        strcpy(tp->th_msg, pe->e_msg);
        length = strlen(pe->e_msg);
        tp->th_msg[length] = '\0';
        length += 5;
        if (send(peer, buf, length, 0) != length)
                syslog(LOG_ERR, "nak: %m");
}

static char *
verifyhost(fromp)
        struct sockaddr_in *fromp;
{
        struct hostent *hp;

        hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(fromp->sin_addr),
                fromp->sin_family);
        if(hp)
                return hp->h_name;
        else
                return inet_ntoa(fromp->sin_addr);
}