freebsd-nq/sbin/savecore/savecore.c
Peter Wemm 241ca2287a Banish hard-coded KERNBASE references from savecore. Dynamically
adjust to whatever kernbase is in the kernel that we are dumping.
2001-08-24 09:26:17 +00:00

789 lines
18 KiB
C

/*-
* Copyright (c) 1986, 1992, 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) 1986, 1992, 1993\n\
The Regents of the University of California. All rights reserved.\n";
#endif /* not lint */
#ifndef lint
#if 0
static char sccsid[] = "@(#)savecore.c 8.3 (Berkeley) 1/2/94";
#endif
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
#include <vm/pmap.h>
#include <dirent.h>
#include <fcntl.h>
#include <nlist.h>
#include <paths.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "zopen.h"
#ifdef __alpha__
#define ok(number) ALPHA_K0SEG_TO_PHYS(number)
#endif
#ifdef __i386__
#define ok(number) ((number) - kernbase)
#endif
struct nlist current_nl[] = { /* Namelist for currently running system. */
#define X_DUMPLO 0
{ "_dumplo" },
#define X_TIME 1
{ "_time_second" },
#define X_DUMPSIZE 2
{ "_dumpsize" },
#define X_VERSION 3
{ "_version" },
#define X_PANICSTR 4
{ "_panicstr" },
#define X_DUMPMAG 5
{ "_dumpmag" },
#define X_KERNBASE 6
{ "_kernbase" },
{ "" },
};
int cursyms[] = { X_DUMPLO, X_VERSION, X_DUMPMAG, -1 };
int dumpsyms[] = { X_TIME, X_DUMPSIZE, X_VERSION, X_PANICSTR, X_DUMPMAG, -1 };
struct nlist dump_nl[] = { /* Name list for dumped system. */
{ "_dumplo" }, /* Entries MUST be the same as */
{ "_time_second" }, /* those in current_nl[]. */
{ "_dumpsize" },
{ "_version" },
{ "_panicstr" },
{ "_dumpmag" },
{ "_kernbase" },
{ "" },
};
/* Types match kernel declarations. */
u_long dumpmag; /* magic number in dump */
/* Based on kernel variables, but with more convenient types. */
off_t dumplo; /* where dump starts on dumpdev */
off_t dumpsize; /* amount of memory dumped */
char *kernel; /* user-specified kernel */
char *savedir; /* directory to save dumps in */
char ddname[MAXPATHLEN]; /* name of dump device */
dev_t dumpdev; /* dump device */
int dumpfd; /* read/write descriptor on char dev */
time_t now; /* current date */
char panic_mesg[1024]; /* panic message */
int panicstr; /* flag: dump was caused by panic */
char vers[1024]; /* version of kernel that crashed */
#ifdef __i386__
u_long kernbase; /* offset of kvm to core file */
#endif
int clear, compress, force, verbose; /* flags */
int keep; /* keep dump on device */
void check_kmem __P((void));
int check_space __P((void));
void clear_dump __P((void));
void DumpRead __P((int fd, void *bp, int size, off_t off, int flag));
void DumpWrite __P((int fd, void *bp, int size, off_t off, int flag));
int dump_exists __P((void));
void find_dev __P((dev_t));
int get_crashtime __P((void));
void get_dumpsize __P((void));
void kmem_setup __P((void));
void log __P((int, char *, ...)) __printflike(2, 3);
void Lseek __P((int, off_t, int));
int Open __P((const char *, int rw));
int Read __P((int, void *, int));
void save_core __P((void));
void usage __P((void));
void Write __P((int, void *, int));
int
main(argc, argv)
int argc;
char *argv[];
{
int ch;
openlog("savecore", LOG_PERROR, LOG_DAEMON);
while ((ch = getopt(argc, argv, "cdfkN:vz")) != -1)
switch(ch) {
case 'c':
clear = 1;
break;
case 'd': /* Not documented. */
case 'v':
verbose = 1;
break;
case 'f':
force = 1;
break;
case 'k':
keep = 1;
break;
case 'N':
kernel = optarg;
break;
case 'z':
compress = 1;
break;
case '?':
default:
usage();
}
argc -= optind;
argv += optind;
if (!clear) {
if (argc != 1 && argc != 2)
usage();
savedir = argv[0];
}
if (argc == 2)
kernel = argv[1];
(void)time(&now);
kmem_setup();
if (clear) {
clear_dump();
exit(0);
}
if (!dump_exists() && !force)
exit(1);
check_kmem();
if (panicstr)
syslog(LOG_ALERT, "reboot after panic: %s", panic_mesg);
else
syslog(LOG_ALERT, "reboot");
get_dumpsize();
if ((!get_crashtime() || !check_space()) && !force)
exit(1);
save_core();
if (!keep)
clear_dump();
exit(0);
}
void
kmem_setup()
{
int kmem, i;
const char *dump_sys;
size_t len;
long kdumplo; /* block number where dump starts on dumpdev */
char *p;
/*
* 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!)
*/
if ((nlist(getbootfile(), current_nl)) == -1)
syslog(LOG_ERR, "%s: nlist: %m", getbootfile());
for (i = 0; cursyms[i] != -1; i++)
if (current_nl[cursyms[i]].n_value == 0) {
syslog(LOG_ERR, "%s: %s not in namelist",
getbootfile(), current_nl[cursyms[i]].n_name);
exit(1);
}
dump_sys = kernel ? kernel : getbootfile();
if ((nlist(dump_sys, dump_nl)) == -1)
syslog(LOG_ERR, "%s: nlist: %m", dump_sys);
for (i = 0; dumpsyms[i] != -1; i++)
if (dump_nl[dumpsyms[i]].n_value == 0) {
syslog(LOG_ERR, "%s: %s not in namelist",
dump_sys, dump_nl[dumpsyms[i]].n_name);
exit(1);
}
#ifdef __i386__
if (dump_nl[X_KERNBASE].n_value != 0)
kernbase = dump_nl[X_KERNBASE].n_value;
else
kernbase = KERNBASE;
#endif
len = sizeof dumpdev;
if (sysctlbyname("kern.dumpdev", &dumpdev, &len, NULL, 0) == -1) {
syslog(LOG_ERR, "sysctl: kern.dumpdev: %m");
exit(1);
}
if (dumpdev == NODEV) {
syslog(LOG_WARNING, "no core dump (no dumpdev)");
exit(1);
}
kmem = Open(_PATH_KMEM, O_RDONLY);
Lseek(kmem, (off_t)current_nl[X_DUMPLO].n_value, L_SET);
(void)Read(kmem, &kdumplo, sizeof(kdumplo));
dumplo = (off_t)kdumplo * DEV_BSIZE;
if (verbose)
(void)printf("dumplo = %lld (%ld * %d)\n",
(long long)dumplo, kdumplo, DEV_BSIZE);
Lseek(kmem, (off_t)current_nl[X_DUMPMAG].n_value, L_SET);
(void)Read(kmem, &dumpmag, sizeof(dumpmag));
find_dev(dumpdev);
dumpfd = Open(ddname, O_RDWR);
if (kernel)
return;
lseek(kmem, (off_t)current_nl[X_VERSION].n_value, SEEK_SET);
Read(kmem, vers, sizeof(vers));
vers[sizeof(vers) - 1] = '\0';
p = strchr(vers, '\n');
if (p)
p[1] = '\0';
/* Don't fclose(fp), we use kmem later. */
}
void
check_kmem()
{
char core_vers[1024], *p;
DumpRead(dumpfd, core_vers, sizeof(core_vers),
(off_t)(dumplo + ok(dump_nl[X_VERSION].n_value)), L_SET);
core_vers[sizeof(core_vers) - 1] = '\0';
p = strchr(core_vers, '\n');
if (p)
p[1] = '\0';
if (strcmp(vers, core_vers) && kernel == 0)
syslog(LOG_WARNING,
"warning: %s version mismatch:\n\t\"%s\"\nand\t\"%s\"\n",
getbootfile(), vers, core_vers);
DumpRead(dumpfd, &panicstr, sizeof(panicstr),
(off_t)(dumplo + ok(dump_nl[X_PANICSTR].n_value)), L_SET);
if (panicstr) {
DumpRead(dumpfd, panic_mesg, sizeof(panic_mesg),
(off_t)(dumplo + ok(panicstr)), L_SET);
}
}
/*
* Clear the magic number in the dump header.
*/
void
clear_dump()
{
int newdumpmag;
newdumpmag = 0;
DumpWrite(dumpfd, &newdumpmag, sizeof(newdumpmag),
(off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
close(dumpfd);
}
/*
* Check if a dump exists by looking for a magic number in the dump
* header.
*/
int
dump_exists()
{
int newdumpmag;
DumpRead(dumpfd, &newdumpmag, sizeof(newdumpmag),
(off_t)(dumplo + ok(dump_nl[X_DUMPMAG].n_value)), L_SET);
if (newdumpmag != dumpmag) {
if (verbose)
syslog(LOG_WARNING, "magic number mismatch (%x != %x)",
newdumpmag, dumpmag);
syslog(LOG_WARNING, "no core dump");
return (0);
}
return (1);
}
char buf[1024 * 1024];
#define BLOCKSIZE (1<<12)
#define BLOCKMASK (~(BLOCKSIZE-1))
/*
* Save the core dump.
*/
void
save_core()
{
register FILE *fp;
register int bounds, ifd, nr, nw;
int hs, he; /* start and end of hole */
char path[MAXPATHLEN];
mode_t oumask;
/*
* Get the current number and update the bounds file. Do the update
* now, because may fail later and don't want to overwrite anything.
*/
(void)snprintf(path, sizeof(path), "%s/bounds", savedir);
if ((fp = fopen(path, "r")) == NULL)
goto err1;
if (fgets(buf, sizeof(buf), fp) == NULL) {
if (ferror(fp))
err1: syslog(LOG_WARNING, "%s: %m", path);
bounds = 0;
} else
bounds = atoi(buf);
if (fp != NULL)
(void)fclose(fp);
if ((fp = fopen(path, "w")) == NULL)
syslog(LOG_ERR, "%s: %m", path);
else {
(void)fprintf(fp, "%d\n", bounds + 1);
(void)fclose(fp);
}
/* Create the core file. */
oumask = umask(S_IRWXG|S_IRWXO); /* Restrict access to the core file.*/
(void)snprintf(path, sizeof(path), "%s/vmcore.%d%s",
savedir, bounds, compress ? ".Z" : "");
if (compress)
fp = zopen(path, "w", 0);
else
fp = fopen(path, "w");
if (fp == NULL) {
syslog(LOG_ERR, "%s: %m", path);
exit(1);
}
(void)umask(oumask);
/* Seek to the start of the core. */
Lseek(dumpfd, (off_t)dumplo, L_SET);
/* Copy the core file. */
syslog(LOG_NOTICE, "writing %score to %s",
compress ? "compressed " : "", path);
for (; dumpsize > 0; dumpsize -= nr) {
(void)printf("%6dK\r", dumpsize / 1024);
(void)fflush(stdout);
nr = read(dumpfd, buf, MIN(dumpsize, sizeof(buf)));
if (nr <= 0) {
if (nr == 0)
syslog(LOG_WARNING,
"WARNING: EOF on dump device");
else
syslog(LOG_ERR, "%s: %m", ddname);
goto err2;
}
for (nw = 0; nw < nr; nw = he) {
/* find a contiguous block of zeroes */
for (hs = nw; hs < nr; hs += BLOCKSIZE) {
for (he = hs; he < nr && buf[he] == 0; ++he)
/* nothing */ ;
/* is the hole long enough to matter? */
if (he >= hs + BLOCKSIZE)
break;
}
/* back down to a block boundary */
he &= BLOCKMASK;
/*
* 1) Don't go beyond the end of the buffer.
* 2) If the end of the buffer is less than
* BLOCKSIZE bytes away, we're at the end
* of the file, so just grab what's left.
*/
if (hs + BLOCKSIZE > nr)
hs = he = nr;
/*
* At this point, we have a partial ordering:
* nw <= hs <= he <= nr
* If hs > nw, buf[nw..hs] contains non-zero data.
* If he > hs, buf[hs..he] is all zeroes.
*/
if (hs > nw)
if (fwrite(buf + nw, hs - nw, 1, fp) != 1)
break;
if (he > hs)
if (fseek(fp, he - hs, SEEK_CUR) == -1)
break;
}
if (nw != nr) {
syslog(LOG_ERR, "%s: %m", path);
err2: syslog(LOG_WARNING,
"WARNING: vmcore may be incomplete");
(void)printf("\n");
exit(1);
}
}
(void)fclose(fp);
/* Copy the kernel. */
ifd = Open(kernel ? kernel : getbootfile(), O_RDONLY);
(void)snprintf(path, sizeof(path), "%s/kernel.%d%s",
savedir, bounds, compress ? ".Z" : "");
if (compress)
fp = zopen(path, "w", 0);
else
fp = fopen(path, "w");
if (fp == NULL) {
syslog(LOG_ERR, "%s: %m", path);
exit(1);
}
syslog(LOG_NOTICE, "writing %skernel to %s",
compress ? "compressed " : "", path);
while ((nr = read(ifd, buf, sizeof(buf))) > 0) {
nw = fwrite(buf, 1, nr, fp);
if (nw != nr) {
syslog(LOG_ERR, "%s: %m", path);
syslog(LOG_WARNING,
"WARNING: kernel may be incomplete");
exit(1);
}
}
if (nr < 0) {
syslog(LOG_ERR, "%s: %m", kernel ? kernel : getbootfile());
syslog(LOG_WARNING,
"WARNING: kernel may be incomplete");
exit(1);
}
(void)fclose(fp);
close(ifd);
}
/*
* Verify that the specified device node exists and matches the
* specified device.
*/
int
verify_dev(name, dev)
char *name;
register dev_t dev;
{
struct stat sb;
if (lstat(name, &sb) == -1)
return (-1);
if (!S_ISCHR(sb.st_mode) || sb.st_rdev != dev)
return (-1);
return (0);
}
/*
* Find the dump device.
*
* 1) try devname(3); see if it returns something sensible
* 2) scan /dev for the desired node
* 3) as a last resort, try to create the node we need
*/
void
find_dev(dev)
register dev_t dev;
{
struct dirent *ent;
char *dn, *dnp;
DIR *d;
strcpy(ddname, _PATH_DEV);
dnp = ddname + sizeof _PATH_DEV - 1;
if ((dn = devname(dev, S_IFCHR)) != NULL) {
strcpy(dnp, dn);
if (verify_dev(ddname, dev) == 0)
return;
}
if ((d = opendir(_PATH_DEV)) != NULL) {
while ((ent = readdir(d))) {
strcpy(dnp, ent->d_name);
if (verify_dev(ddname, dev) == 0) {
closedir(d);
return;
}
}
closedir(d);
}
strcpy(dnp, "dump");
if (mknod(ddname, S_IFCHR|S_IRUSR|S_IWUSR, dev) == 0)
return;
syslog(LOG_ERR, "can't find device %d/%#x", major(dev), minor(dev));
exit(1);
}
/*
* Extract the date and time of the crash from the dump header, and
* make sure it looks sane (within one week of current date and time).
*/
int
get_crashtime()
{
time_t dumptime; /* Time the dump was taken. */
DumpRead(dumpfd, &dumptime, sizeof(dumptime),
(off_t)(dumplo + ok(dump_nl[X_TIME].n_value)), L_SET);
if (dumptime == 0) {
if (verbose)
syslog(LOG_ERR, "dump time is zero");
return (0);
}
(void)printf("savecore: system went down at %s", ctime(&dumptime));
#define LEEWAY (7 * 86400)
if (dumptime < now - LEEWAY || dumptime > now + LEEWAY) {
(void)printf("dump time is unreasonable\n");
return (0);
}
return (1);
}
/*
* Extract the size of the dump from the dump header.
*/
void
get_dumpsize()
{
int kdumpsize;
/* Read the dump size. */
DumpRead(dumpfd, &kdumpsize, sizeof(kdumpsize),
(off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
dumpsize = kdumpsize * getpagesize();
}
/*
* Check that sufficient space is available on the disk that holds the
* save directory.
*/
int
check_space()
{
register FILE *fp;
const char *tkernel;
off_t minfree, spacefree, totfree, kernelsize, needed;
struct stat st;
struct statfs fsbuf;
char buf[100], path[MAXPATHLEN];
tkernel = kernel ? kernel : getbootfile();
if (stat(tkernel, &st) < 0) {
syslog(LOG_ERR, "%s: %m", tkernel);
exit(1);
}
kernelsize = st.st_blocks * S_BLKSIZE;
if (statfs(savedir, &fsbuf) < 0) {
syslog(LOG_ERR, "%s: %m", savedir);
exit(1);
}
spacefree = ((off_t) fsbuf.f_bavail * fsbuf.f_bsize) / 1024;
totfree = ((off_t) fsbuf.f_bfree * fsbuf.f_bsize) / 1024;
(void)snprintf(path, sizeof(path), "%s/minfree", savedir);
if ((fp = fopen(path, "r")) == NULL)
minfree = 0;
else {
if (fgets(buf, sizeof(buf), fp) == NULL)
minfree = 0;
else
minfree = atoi(buf);
(void)fclose(fp);
}
needed = (dumpsize + kernelsize) / 1024;
if (((minfree > 0) ? spacefree : totfree) - needed < minfree) {
syslog(LOG_WARNING,
"no dump, not enough free space on device (%lld available, need %lld)",
(long long)(minfree > 0 ? spacefree : totfree),
(long long)needed);
return (0);
}
if (spacefree - needed < 0)
syslog(LOG_WARNING,
"dump performed, but free space threshold crossed");
return (1);
}
int
Open(name, rw)
const char *name;
int rw;
{
int fd;
if ((fd = open(name, rw, 0)) < 0) {
syslog(LOG_ERR, "%s: %m", name);
exit(1);
}
return (fd);
}
int
Read(fd, bp, size)
int fd, size;
void *bp;
{
int nr;
nr = read(fd, bp, size);
if (nr != size) {
syslog(LOG_ERR, "read: %m");
exit(1);
}
return (nr);
}
void
Lseek(fd, off, flag)
int fd, flag;
off_t off;
{
off_t ret;
ret = lseek(fd, off, flag);
if (ret == -1) {
syslog(LOG_ERR, "lseek: %m");
exit(1);
}
}
/*
* DumpWrite and DumpRead block io requests to the * dump device.
*/
#define DUMPBUFSIZE 8192
void
DumpWrite(fd, bp, size, off, flag)
int fd, size, flag;
void *bp;
off_t off;
{
unsigned char buf[DUMPBUFSIZE], *p, *q;
off_t pos;
int i, j;
if (flag != L_SET) {
syslog(LOG_ERR, "lseek: not LSET");
exit(2);
}
q = bp;
while (size) {
pos = off & ~(DUMPBUFSIZE - 1);
Lseek(fd, pos, flag);
(void)Read(fd, buf, sizeof(buf));
j = off & (DUMPBUFSIZE - 1);
p = buf + j;
i = size;
if (i > DUMPBUFSIZE - j)
i = DUMPBUFSIZE - j;
memcpy(p, q, i);
Lseek(fd, pos, flag);
(void)Write(fd, buf, sizeof(buf));
size -= i;
q += i;
off += i;
}
}
void
DumpRead(fd, bp, size, off, flag)
int fd, size, flag;
void *bp;
off_t off;
{
unsigned char buf[DUMPBUFSIZE], *p, *q;
off_t pos;
int i, j;
if (flag != L_SET) {
syslog(LOG_ERR, "lseek: not LSET");
exit(2);
}
q = bp;
while (size) {
pos = off & ~(DUMPBUFSIZE - 1);
Lseek(fd, pos, flag);
(void)Read(fd, buf, sizeof(buf));
j = off & (DUMPBUFSIZE - 1);
p = buf + j;
i = size;
if (i > DUMPBUFSIZE - j)
i = DUMPBUFSIZE - j;
memcpy(q, p, i);
size -= i;
q += i;
off += i;
}
}
void
Write(fd, bp, size)
int fd, size;
void *bp;
{
int n;
if ((n = write(fd, bp, size)) < size) {
syslog(LOG_ERR, "write: %m");
exit(1);
}
}
void
usage()
{
(void)syslog(LOG_ERR, "usage: savecore [-cfkvz] [-N system] directory");
exit(1);
}