Date: Fri, 14 Jun 1996 16:11:42 +0200 From: "Philippe C." <philou@lirmm.fr> To: FreeBSD-gnats-submit@freebsd.org Subject: bin/1322: savecore: incorrect use of minfree Message-ID: <199606141411.QAA01133@pcdif01.lirmm.fr> Resent-Message-ID: <199606141430.HAA18175@freefall.freebsd.org>
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>Number: 1322
>Category: bin
>Synopsis: savecore does not take minfree into account
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Fri Jun 14 07:30:05 PDT 1996
>Last-Modified:
>Originator: Philippe Charnier.
>Organization:
>Release: FreeBSD 2.2-current
>Environment:
>Description:
I finally find a way to send this patch that is on my tree since months using
send-pr. It will not be lost. I real life, my address is charnier@lirmm.fr,
my From: line should lie.
- dumpsize was used (in check_space) before being computed (in
save_core): dumpsize was always 0 in check_space. Compute
dumpsize before calling check_space which need it.
- convert all quantities required for free space computation to a
number of bytes (some of them were in Kbytes, others in bytes,
making result a little bit silly). Minfree is really take into
account now.
- cosmetics changes.
- only dump a core is minfree bytes are left on the disk after
the dump.
>How-To-Repeat:
add only syslog(LOG_INFO,..) part of the patch and crash your kernel
with not enough space in /var/crash
>Fix:
cvs diff: Diffing .
Index: savecore.8
===================================================================
RCS file: /home2h/FreeBSD.cvsroot/src/sbin/savecore/savecore.8,v
retrieving revision 1.3
diff -u -r1.3 savecore.8
--- savecore.8 1994/09/24 00:08:21 1.3
+++ savecore.8 1996/06/13 20:26:05
@@ -65,7 +65,7 @@
Use
.Ar system
as the kernel instead of the running kernel (as determined from
-.Xr getbootfile 3 )
+.Xr getbootfile 3 ).
.It Fl v
Prints out some additional debugging information.
.It Fl z
Index: savecore.c
===================================================================
RCS file: /home2h/FreeBSD.cvsroot/src/sbin/savecore/savecore.c,v
retrieving revision 1.12
diff -u -r1.12 savecore.c
--- savecore.c 1996/05/02 09:07:53 1.12
+++ savecore.c 1996/05/03 18:38:19
@@ -290,6 +290,11 @@
*cp = getc(fp);
while (*cp++ && cp < &panic_mesg[sizeof(panic_mesg)]);
}
+ /* Read the dump size, and convert it to a number of bytes. */
+ (void)fseek(fp,
+ (off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
+ (void)fread(&dumpsize, sizeof(dumpsize), 1, fp);
+ dumpsize *= getpagesize();
/* Don't fclose(fp), we use dumpfd later. */
}
@@ -369,15 +374,10 @@
ifd = dumpfd;
}
- /* Read the dump size. */
- Lseek(dumpfd, (off_t)(dumplo + ok(dump_nl[X_DUMPSIZE].n_value)), L_SET);
- (void)Read(dumpfd, &dumpsize, sizeof(dumpsize));
-
/* Seek to the start of the core. */
Lseek(ifd, (off_t)dumplo, L_SET);
/* Copy the core file. */
- dumpsize *= getpagesize();
syslog(LOG_NOTICE, "writing %score to %s",
compress ? "compressed " : "", path);
for (; dumpsize > 0; dumpsize -= nr) {
@@ -547,28 +547,27 @@
syslog(LOG_ERR, "%s: %m", dirname);
exit(1);
}
- spacefree = (fsbuf.f_bavail * fsbuf.f_bsize) / 1024;
-
+ spacefree = fsbuf.f_bavail * fsbuf.f_bsize;
+ minfree = 0;
(void)snprintf(path, sizeof(path), "%s/minfree", dirname);
- if ((fp = fopen(path, "r")) == NULL)
- minfree = 0;
- else {
- if (fgets(buf, sizeof(buf), fp) == NULL)
- minfree = 0;
- else
- minfree = atoi(buf);
+ if ((fp = fopen(path, "r"))) {
+ if (fgets(buf, sizeof(buf), fp)) minfree = atoi(buf);
(void)fclose(fp);
}
-
- needed = (dumpsize + kernelsize) / 1024;
- if (minfree > 0 && spacefree - needed < minfree) {
- syslog(LOG_WARNING,
- "no dump, not enough free space on device");
+ /* dumpsize, kernelsize, minfree, and spacefree are in bytes */
+ needed = dumpsize + kernelsize; /* minfree? not yet */
+ if (verbose) {
+ syslog(LOG_INFO, "dumpsize: %d", dumpsize);
+ syslog(LOG_INFO, "kernelsize: %d", kernelsize);
+ syslog(LOG_INFO, "minfree: %d", minfree);
+ syslog(LOG_INFO, "spacefree: %d", spacefree);
+ syslog(LOG_INFO, "needed: %d", needed);
+ }
+ /* space left (after the dump) must be greater than minfree */
+ if (spacefree < needed + minfree) {
+ syslog(LOG_WARNING, "no dump, not enough free space on device");
return (0);
}
- if (spacefree - needed < minfree)
- syslog(LOG_WARNING,
- "dump performed, but free space threshold crossed");
return (1);
}
>Audit-Trail:
>Unformatted:
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