usr/src/sbin/savecore/savecore.c

/*
 * Copyright (c) 1980, 1986 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
char copyright[] =
"@(#) Copyright (c) 1980, 1986 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)savecore.c  5.14 (Berkeley) %G%";
#endif /* not lint */

/*
 * savecore
 */

#include <stdio.h>
#include <nlist.h>
#include <sys/param.h>
#include <sys/dir.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/file.h>
#include <sys/syslog.h>

#define DAY     (60L*60L*24L)
#define LEEWAY  (3*DAY)

#define eq(a,b) (!strcmp(a,b))
#ifdef vax
#define ok(number) ((number)&0x7fffffff)
#else
#ifdef tahoe
#define ok(number) ((number)&~0xc0000000)
#else
#define ok(number) (number)
#endif
#endif

struct nlist current_nl[] = {   /* namelist for currently running system */
#define X_DUMPDEV       0
        { "_dumpdev" },
#define X_DUMPLO        1
        { "_dumplo" },
#define X_TIME          2
        { "_time" },
#define X_DUMPSIZE      3
        { "_dumpsize" },
#define X_VERSION       4
        { "_version" },
#define X_PANICSTR      5
        { "_panicstr" },
#define X_DUMPMAG       6
        { "_dumpmag" },
        { "" },
};

struct nlist dump_nl[] = {      /* name list for dumped system */
        { "_dumpdev" },         /* entries MUST be the same as */
        { "_dumplo" },          /*      those in current_nl[]  */
        { "_time" },
        { "_dumpsize" },
        { "_version" },
        { "_panicstr" },
        { "_dumpmag" },
        { "" },
};

char    *system;
char    *dirname;                       /* directory to save dumps in */
char    *ddname;                        /* name of dump device */
char    *find_dev();
dev_t   dumpdev;                        /* dump device */
time_t  dumptime;                       /* time the dump was taken */
int     dumplo;                         /* where dump starts on dumpdev */
int     dumpsize;                       /* amount of memory dumped */
int     dumpmag;                        /* magic number in dump */
time_t  now;                            /* current date */
char    *path();
char    *malloc();
char    *ctime();
char    vers[80];
char    core_vers[80];
char    panic_mesg[80];
int     panicstr;
off_t   lseek();
off_t   Lseek();
int     Verbose;
int     force;
int     clear;
extern  int errno;

main(argc, argv)
        char **argv;
        int argc;
{
        char *cp;

        argc--, argv++;
        while (argc > 0 && argv[0][0] == '-') {
                for (cp = &argv[0][1]; *cp; cp++) switch (*cp) {

                case 'f':
                        force++;
                        break;

                case 'v':
                        Verbose++;
                        break;

                case 'c':
                        clear++;
                        break;

                default:
                usage:
                        fprintf(stderr,
                            "usage: savecore [-f] [-v] dirname [ system ]\n");
                        exit(1);
                }
                argc--, argv++;
        }
        if (argc != 1 && argc != 2)
                goto usage;
        dirname = argv[0];
        if (argc == 2)
                system = argv[1];
        openlog("savecore", LOG_ODELAY, LOG_AUTH);
        if (access(dirname, W_OK) < 0) {
                Perror(LOG_ERR, "%s: %m", dirname);
                exit(1);
        }
        read_kmem();
}

dump_exists()
{
        register int dumpfd;
        int word;

        dumpfd = Open(ddname, O_RDONLY);
        Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
        Read(dumpfd, (char *)&word, sizeof (word));
        close(dumpfd);
        if (Verbose && word != dumpmag) {
                printf("dumplo = %d (%d bytes)\n", dumplo/DEV_BSIZE, dumplo);
                printf("magic number mismatch: %x != %x\n", word, dumpmag);
        }
        return (word == dumpmag);
}

clear_dump()
{
        register int dumpfd;
        int zero = 0;

        dumpfd = Open(ddname, O_WRONLY);
        Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
        Write(dumpfd, (char *)&zero, sizeof (zero));
        close(dumpfd);
}

char *
find_dev(dev, type)
        register dev_t dev;
        register int type;
{
        struct stat statb;
        char *dp;

        strcpy(devname, "/dev/");
                if (stat(devname, &statb)) {
                        perror(devname);
                        continue;
                }
                if ((statb.st_mode&S_IFMT) != type)
                        continue;
                if (dev == statb.st_rdev) {
                        dp = malloc(strlen(devname)+1);
                        strcpy(dp, devname);
                        return (dp);
                }
        }
        log(LOG_ERR, "Can't find device %d/%d\n", major(dev), minor(dev));
        exit(1);
        /*NOTREACHED*/
}

int     cursyms[] =
    { X_DUMPDEV, X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
int     dumpsyms[] =
    { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
read_kmem()
{
        register char *cp;
        FILE *fp;
        char *dump_sys;
        int kmem, i;

        dump_sys = system ? system : "/vmunix";
        nlist("/vmunix", current_nl);
        nlist(dump_sys, dump_nl);
        /*
         * Some names we need for the currently running system,
         * others for the system that was running when the dump was made.
         * The values obtained from the current system are used
         * to look for things in /dev/kmem that cannot be found
         * in the dump_sys namelist, but are presumed to be the same
         * (since the disk partitions are probably the same!)
         */
        for (i = 0; cursyms[i] != -1; i++)
                if (current_nl[cursyms[i]].n_value == 0) {
                        log(LOG_ERR, "/vmunix: %s not in namelist\n",
                            current_nl[cursyms[i]].n_name);
                        exit(1);
                }
        for (i = 0; dumpsyms[i] != -1; i++)
                if (dump_nl[dumpsyms[i]].n_value == 0) {
                        log(LOG_ERR, "%s: %s not in namelist\n", dump_sys,
                            dump_nl[dumpsyms[i]].n_name);
                        exit(1);
                }
        kmem = Open("/dev/kmem", O_RDONLY);
        Lseek(kmem, (long)current_nl[X_DUMPDEV].n_value, L_SET);
        Read(kmem, (char *)&dumpdev, sizeof (dumpdev));
        Lseek(kmem, (long)current_nl[X_DUMPLO].n_value, L_SET);
        Read(kmem, (char *)&dumplo, sizeof (dumplo));
        Lseek(kmem, (long)current_nl[X_DUMPMAG].n_value, L_SET);
        Read(kmem, (char *)&dumpmag, sizeof (dumpmag));
        dumplo *= DEV_BSIZE;
        ddname = find_dev(dumpdev, S_IFBLK);
        fp = fdopen(kmem, "r");
        if (fp == NULL) {
                log(LOG_ERR, "Couldn't fdopen kmem\n");
                exit(1);
        }
        if (system)
                return;
        fseek(fp, (long)current_nl[X_VERSION].n_value, L_SET);
        fgets(vers, sizeof (vers), fp);
        fclose(fp);
}

check_kmem()
{
        FILE *fp;
        register char *cp;

        fp = fopen(ddname, "r");
        if (fp == NULL) {
                Perror(LOG_ERR, "%s: %m", ddname);
                exit(1);
        }
        fseek(fp, (off_t)(dumplo+ok(dump_nl[X_VERSION].n_value)), L_SET);
        fgets(core_vers, sizeof (core_vers), fp);
        fclose(fp);
        if (!eq(vers, core_vers) && system == 0) {
                log(LOG_WARNING, "Warning: vmunix version mismatch:\n");
                log(LOG_WARNING, "\t%s\n", vers);
                log(LOG_WARNING, "and\t%s\n", core_vers);
        }
        fp = fopen(ddname, "r");
        fseek(fp, (off_t)(dumplo + ok(dump_nl[X_PANICSTR].n_value)), L_SET);
        fread((char *)&panicstr, sizeof (panicstr), 1, fp);
        if (panicstr) {
                fseek(fp, dumplo + ok(panicstr), L_SET);
                cp = panic_mesg;
                do
                        *cp = getc(fp);
                while (*cp++);
        }
        fclose(fp);
}

get_crashtime()
{
        int dumpfd;
        time_t clobber = (time_t)0;

        dumpfd = Open(ddname, O_RDONLY);
        Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_TIME].n_value)), L_SET);
        Read(dumpfd, (char *)&dumptime, sizeof dumptime);
        close(dumpfd);
        if (dumptime == 0) {
                if (Verbose)
                        printf("Dump time is zero.\n");
                return (0);
        }
        printf("System went down at %s", ctime(&dumptime));
        if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
                printf("dump time is unreasonable\n");
                return (0);
        }
        return (1);
}

char *
path(file)
        char *file;
{
        register char *cp = malloc(strlen(file) + strlen(dirname) + 2);

        (void) strcpy(cp, dirname);
        (void) strcat(cp, "/");
        (void) strcat(cp, file);
        return (cp);
}

check_space()
{
        struct stat dsb;
        register char *ddev;
        int dfd, spacefree;
        struct fs fs;

        if (stat(dirname, &dsb) < 0) {
                Perror(LOG_ERR, "%s: %m", dirname);
                exit(1);
        }
        ddev = find_dev(dsb.st_dev, S_IFBLK);
        dfd = Open(ddev, O_RDONLY);
        Lseek(dfd, SBOFF, L_SET);
        Read(dfd, (char *)&fs, sizeof (fs));
        close(dfd);
        spacefree = freespace(&fs, fs.fs_minfree) * fs.fs_fsize / 1024;
        if (spacefree < read_number("minfree")) {
                log(LOG_WARNING, "Dump omitted, not enough space on device\n");
                return (0);
        }
        if (freespace(&fs, fs.fs_minfree) < 0)
                log(LOG_WARNING,
                    "Dump performed, but free space threshold crossed\n");
        return (1);
}

read_number(fn)
        char *fn;
{
        char lin[80];
        register FILE *fp;

        fp = fopen(path(fn), "r");
        if (fp == NULL)
                return (0);
        if (fgets(lin, 80, fp) == NULL) {
                fclose(fp);
                return (0);
        }
        fclose(fp);
        return (atoi(lin));
}

#define BUFPAGES        (256*1024/NBPG)         /* 1/4 Mb */

save_core()
{
        register int n;
        register char *cp;
        register int ifd, ofd, bounds;
        register FILE *fp;

        cp = malloc(BUFPAGES*NBPG);
        if (cp == 0) {
                fprintf(stderr, "savecore: Can't allocate i/o buffer.\n");
                return;
        }
        bounds = read_number("bounds");
        ifd = Open(system?system:"/vmunix", O_RDONLY);
        while((n = Read(ifd, cp, BUFSIZ)) > 0)
                Write(ofd, cp, n);
        close(ifd);
        close(ofd);
        ifd = Open(ddname, O_RDONLY);
        Lseek(ifd, (off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
        Read(ifd, (char *)&dumpsize, sizeof (dumpsize));
        (void)sprintf(cp, "vmcore.%d", bounds);
        ofd = Create(path(cp), 0644);
        Lseek(ifd, (off_t)dumplo, L_SET);
        log(LOG_NOTICE, "Saving %d bytes of image in vmcore.%d\n",
            NBPG*dumpsize, bounds);
        while (dumpsize > 0) {
                n = Read(ifd, cp,
                    (dumpsize > BUFPAGES ? BUFPAGES : dumpsize) * NBPG);
                if (n == 0) {
                        log(LOG_WARNING, "WARNING: vmcore may be incomplete\n");
                        break;
                }
                Write(ofd, cp, n);
                dumpsize -= n/NBPG;
        }
        close(ifd);
        close(ofd);
        fp = fopen(path("bounds"), "w");
        fprintf(fp, "%d\n", bounds+1);
        fclose(fp);
        free(cp);
}

/*
 * Versions of std routines that exit on error.
 */
Open(name, rw)
        char *name;
        int rw;
{
        int fd;

        fd = open(name, rw);
        if (fd < 0) {
                Perror(LOG_ERR, "%s: %m", name);
                exit(1);
        }
        return (fd);
}

Read(fd, buff, size)
        int fd, size;
        char *buff;
{
        int ret;

        ret = read(fd, buff, size);
        if (ret < 0) {
                Perror(LOG_ERR, "read: %m");
                exit(1);
        }
        return (ret);
}

off_t
Lseek(fd, off, flag)
        int fd, flag;
        long off;
{
        long ret;

        ret = lseek(fd, off, flag);
        if (ret == -1) {
                Perror(LOG_ERR, "lseek: %m");
                exit(1);
        }
        return (ret);
}

Create(file, mode)
        char *file;
        int mode;
{
        register int fd;

        fd = creat(file, mode);
        if (fd < 0) {
                Perror(LOG_ERR, "%s: %m", file);
                exit(1);
        }
        return (fd);
}

Write(fd, buf, size)
        int fd, size;
        char *buf;
{

        if (write(fd, buf, size) < size) {
                Perror(LOG_ERR, "write: %m");
                exit(1);
        }
}

log(level, msg, a1, a2)
        int level;
        char *msg;
{

        fprintf(stderr, msg, a1, a2);
        syslog(level, msg, a1, a2);
}

Perror(level, msg, s)
        int level;
        char *msg;
{
        int oerrno = errno;

        perror(s);
        errno = oerrno;
        syslog(level, msg, s);
}