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coredump: add simple coredump vacuuming

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When disk space taken up by coredumps grows beyond a configured limit
start removing the oldest coredump of the user with the most coredumps,
until we get below the limit again.
This commit is contained in:
Lennart Poettering 2014-06-27 18:57:24 +02:00
parent 1f97091d3c
commit 0dc5d23c85
8 changed files with 393 additions and 15 deletions
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1
.gitignore vendored
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@ -142,6 +142,7 @@
/test-cgroup-util
/test-compress
/test-conf-files
/test-coredump-vacuum
/test-daemon
/test-date
/test-device-nodes

16
Makefile.am
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@ -3771,7 +3771,9 @@ systemd_socket_proxyd_LDADD = \
# ------------------------------------------------------------------------------
if ENABLE_COREDUMP
systemd_coredump_SOURCES = \
src/journal/coredump.c
src/journal/coredump.c \
src/journal/coredump-vacuum.c \
src/journal/coredump-vacuum.h
systemd_coredump_LDADD = \
libsystemd-journal-internal.la \
@ -3810,6 +3812,18 @@ coredumpctl_LDADD = \
bin_PROGRAMS += \
coredumpctl
manual_tests += \
test-coredump-vacuum
test_coredump_vacuum_SOURCES = \
src/journal/test-coredump-vacuum.c \
src/journal/coredump-vacuum.c \
src/journal/coredump-vacuum.h
test_coredump_vacuum_LDADD = \
libsystemd-internal.la \
libsystemd-shared.la
dist_bashcompletion_DATA += \
shell-completion/bash/coredumpctl

20
man/coredump.conf.xml
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@ -121,6 +121,23 @@
<listitem><para>The maximum (uncompressed) size in bytes of a
core to be saved.</para></listitem>
</varlistentry>
<varlistentry>
<term><varname>MaxUse=</varname></term>
<term><varname>KeepFree=</varname></term>
<listitem><para>Enforce limits on the disk space taken up by
externally stored coredumps. <option>MaxUse=</option> makes
sure that old coredumps are removed as soon as the total disk
space taken up by coredumps grows beyond this limit (defaults
to 10% of the total disk size). <option>KeepFree=</option>
controls how much disk space to keep free at least (defaults
to 15% of the total disk size). Note that the disk space used
by coredumps might temporarily exceed these limits while
coredumps are processed. Note that old coredumps are also
removed based on on time via
<citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
@ -129,7 +146,8 @@
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
<citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-tmpfiles</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>

272
src/journal/coredump-vacuum.c Normal file
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@ -0,0 +1,272 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/statvfs.h>
#include "util.h"
#include "time-util.h"
#include "hashmap.h"
#include "macro.h"
#include "coredump-vacuum.h"
#define DEFAULT_MAX_USE_LOWER (off_t) (1ULL*1024ULL*1024ULL) /* 1 MiB */
#define DEFAULT_MAX_USE_UPPER (off_t) (4ULL*1024ULL*1024ULL*1024ULL) /* 4 GiB */
#define DEFAULT_KEEP_FREE_UPPER (off_t) (4ULL*1024ULL*1024ULL*1024ULL) /* 4 GiB */
#define DEFAULT_KEEP_FREE (off_t) (1024ULL*1024ULL) /* 1 MB */
struct vacuum_candidate {
unsigned n_files;
char *oldest_file;
usec_t oldest_mtime;
};
static void vacuum_candidate_free(struct vacuum_candidate *c) {
if (!c)
return;
free(c->oldest_file);
free(c);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(struct vacuum_candidate*, vacuum_candidate_free);
static void vacuum_candidate_hasmap_free(Hashmap *h) {
struct vacuum_candidate *c;
while ((c = hashmap_steal_first(h)))
vacuum_candidate_free(c);
hashmap_free(h);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(Hashmap*, vacuum_candidate_hasmap_free);
static int uid_from_file_name(const char *filename, uid_t *uid) {
const char *p, *e, *u;
p = startswith(filename, "core.");
if (!p)
return -EINVAL;
/* Skip the comm field */
p = strchr(p, '.');
if (!p)
return -EINVAL;
p++;
/* Find end up UID */
e = strchr(p, '.');
if (!e)
return -EINVAL;
u = strndupa(p, e-p);
return parse_uid(u, uid);
}
static bool vacuum_necessary(int fd, off_t sum, off_t keep_free, off_t max_use) {
off_t fs_size = 0, fs_free = (off_t) -1;
struct statvfs sv;
assert(fd >= 0);
if (fstatvfs(fd, &sv) >= 0) {
fs_size = sv.f_frsize * sv.f_blocks;
fs_free = sv.f_frsize * sv.f_bfree;
}
if (max_use == (off_t) -1) {
if (fs_size > 0) {
max_use = PAGE_ALIGN(fs_size / 10); /* 10% */
if (max_use > DEFAULT_MAX_USE_UPPER)
max_use = DEFAULT_MAX_USE_UPPER;
if (max_use < DEFAULT_MAX_USE_LOWER)
max_use = DEFAULT_MAX_USE_LOWER;
}
max_use = DEFAULT_MAX_USE_LOWER;
} else
max_use = PAGE_ALIGN(max_use);
if (max_use > 0 && sum > max_use)
return true;
if (keep_free == (off_t) -1) {
if (fs_size > 0) {
keep_free = PAGE_ALIGN((fs_size * 3) / 20); /* 15% */
if (keep_free > DEFAULT_KEEP_FREE_UPPER)
keep_free = DEFAULT_KEEP_FREE_UPPER;
} else
keep_free = DEFAULT_KEEP_FREE;
} else
keep_free = PAGE_ALIGN(keep_free);
if (keep_free > 0 && fs_free < keep_free)
return true;
return false;
}
int coredump_vacuum(int exclude_fd, off_t keep_free, off_t max_use) {
_cleanup_closedir_ DIR *d = NULL;
struct stat exclude_st;
int r;
if (keep_free <= 0 && max_use <= 0)
return 0;
if (exclude_fd >= 0) {
if (fstat(exclude_fd, &exclude_st) < 0) {
log_error("Failed to fstat(): %m");
return -errno;
}
}
/* This algorithm will keep deleting the oldest file of the
* user with the most coredumps until we are back in the size
* limits. Note that vacuuming for journal files is different,
* because we rely on rate-limiting of the messages there,
* to avoid being flooded. */
d = opendir("/var/lib/systemd/coredump");
if (!d) {
if (errno == ENOENT)
return 0;
log_error("Can't open coredump directory: %m");
return -errno;
}
for (;;) {
_cleanup_(vacuum_candidate_hasmap_freep) Hashmap *h = NULL;
struct vacuum_candidate *worst = NULL;
struct dirent *de;
off_t sum = 0;
rewinddir(d);
FOREACH_DIRENT(de, d, goto fail) {
struct vacuum_candidate *c;
struct stat st;
uid_t uid;
usec_t t;
r = uid_from_file_name(de->d_name, &uid);
if (r < 0)
continue;
if (fstatat(dirfd(d), de->d_name, &st, AT_NO_AUTOMOUNT|AT_SYMLINK_NOFOLLOW) < 0) {
if (errno == ENOENT)
continue;
log_warning("Failed to stat /var/lib/systemd/coredump/%s", de->d_name);
continue;
}
if (!S_ISREG(st.st_mode))
continue;
if (exclude_fd >= 0 &&
exclude_st.st_dev == st.st_dev &&
exclude_st.st_ino == st.st_ino)
continue;
r = hashmap_ensure_allocated(&h, NULL, NULL);
if (r < 0)
return log_oom();
t = timespec_load(&st.st_mtim);
c = hashmap_get(h, UINT32_TO_PTR(uid));
if (c) {
if (t < c->oldest_mtime) {
char *n;
n = strdup(de->d_name);
if (!n)
return log_oom();
free(c->oldest_file);
c->oldest_file = n;
c->oldest_mtime = t;
}
} else {
_cleanup_(vacuum_candidate_freep) struct vacuum_candidate *n = NULL;
n = new0(struct vacuum_candidate, 1);
if (!n)
return log_oom();
n->oldest_file = strdup(de->d_name);
if (!n->oldest_file)
return log_oom();
n->oldest_mtime = t;
r = hashmap_put(h, UINT32_TO_PTR(uid), n);
if (r < 0)
return log_oom();
c = n;
n = NULL;
}
c->n_files++;
if (!worst ||
worst->n_files < c->n_files ||
(worst->n_files == c->n_files && c->oldest_mtime < worst->oldest_mtime))
worst = c;
sum += st.st_blocks * 512;
}
if (!worst)
break;
r = vacuum_necessary(dirfd(d), sum, keep_free, max_use);
if (r <= 0)
return r;
if (unlinkat(dirfd(d), worst->oldest_file, 0) < 0) {
if (errno == ENOENT)
continue;
log_error("Failed to remove file %s: %m", worst->oldest_file);
return -errno;
} else
log_info("Removed old coredump %s.", worst->oldest_file);
}
return 0;
fail:
log_error("Failed to read directory: %m");
return -errno;
}

26
src/journal/coredump-vacuum.h Normal file
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@ -0,0 +1,26 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
#pragma once
/***
This file is part of systemd.
Copyright 2014 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <sys/types.h>
int coredump_vacuum(int exclude_fd, off_t keep_free, off_t max_use);

39
src/journal/coredump.c
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@ -42,6 +42,7 @@
#include "stacktrace.h"
#include "path-util.h"
#include "compress.h"
#include "coredump-vacuum.h"
#ifdef HAVE_ACL
# include <sys/acl.h>
@ -121,10 +122,11 @@ static DEFINE_CONFIG_PARSE_ENUM(config_parse_coredump_compression, coredump_comp
static CoredumpStorage arg_storage = COREDUMP_STORAGE_EXTERNAL;
static CoredumpCompression arg_compression = COREDUMP_COMPRESSION_XZ;
static unsigned arg_compression_level = LZMA_PRESET_DEFAULT;
static off_t arg_process_size_max = PROCESS_SIZE_MAX;
static off_t arg_external_size_max = EXTERNAL_SIZE_MAX;
static size_t arg_journal_size_max = JOURNAL_SIZE_MAX;
static off_t arg_keep_free = (off_t) -1;
static off_t arg_max_use = (off_t) -1;
static int parse_config(void) {
@ -136,6 +138,8 @@ static int parse_config(void) {
{ "Coredump", "ProcessSizeMax", config_parse_iec_off, 0, &arg_process_size_max },
{ "Coredump", "ExternalSizeMax", config_parse_iec_off, 0, &arg_external_size_max },
{ "Coredump", "JournalSizeMax", config_parse_iec_size, 0, &arg_journal_size_max },
{ "Coredump", "KeepFree", config_parse_iec_off, 0, &arg_keep_free },
{ "Coredump", "MaxUse", config_parse_iec_off, 0, &arg_max_use },
{}
};
@ -274,14 +278,14 @@ static int maybe_remove_external_coredump(const char *filename, off_t size) {
return 1;
}
static int save_external_coredump(
const char *info[_INFO_LEN],
uid_t uid,
char **ret_filename,
int *ret_fd,
off_t *ret_size) {
static int save_external_coredump(const char *info[_INFO_LEN],
uid_t uid,
char **ret_filename,
int *ret_fd,
off_t *ret_size) {
_cleanup_free_ char *p = NULL, *t = NULL, *c = NULL, *fn = NULL, *tmp = NULL;
_cleanup_free_ char *p = NULL, *t = NULL, *c = NULL, *fn = NULL, *tmp = NULL, *u = NULL;
_cleanup_close_ int fd = -1;
sd_id128_t boot;
struct stat st;
@ -300,6 +304,10 @@ static int save_external_coredump(const char *info[_INFO_LEN],
if (!p)
return log_oom();
u = filename_escape(info[INFO_UID]);
if (!u)
return log_oom();
t = filename_escape(info[INFO_TIMESTAMP]);
if (!t)
return log_oom();
@ -311,8 +319,9 @@ static int save_external_coredump(const char *info[_INFO_LEN],
}
r = asprintf(&fn,
"/var/lib/systemd/coredump/core.%s." SD_ID128_FORMAT_STR ".%s.%s000000",
"/var/lib/systemd/coredump/core.%s.%s." SD_ID128_FORMAT_STR ".%s.%s000000",
c,
u,
SD_ID128_FORMAT_VAL(boot),
p,
t);
@ -333,12 +342,10 @@ static int save_external_coredump(const char *info[_INFO_LEN],
r = copy_bytes(STDIN_FILENO, fd, arg_process_size_max);
if (r == -E2BIG) {
log_error("Coredump of %s (%s) is larger than configured processing limit, refusing.",
info[INFO_PID], info[INFO_COMM]);
log_error("Coredump of %s (%s) is larger than configured processing limit, refusing.", info[INFO_PID], info[INFO_COMM]);
goto fail;
} else if (IN_SET(r, -EDQUOT, -ENOSPC)) {
log_error("Not enough disk space for coredump of %s (%s), refusing.",
info[INFO_PID], info[INFO_COMM]);
log_error("Not enough disk space for coredump of %s (%s), refusing.", info[INFO_PID], info[INFO_COMM]);
goto fail;
} else if (r < 0) {
log_error("Failed to dump coredump to file: %s", strerror(-r));
@ -646,6 +653,9 @@ int main(int argc, char* argv[]) {
IOVEC_SET_STRING(iovec[j++], "MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1");
IOVEC_SET_STRING(iovec[j++], "PRIORITY=2");
/* Vacuum before we write anything again */
coredump_vacuum(-1, arg_keep_free, arg_max_use);
/* Always stream the coredump to disk, if that's possible */
r = save_external_coredump(info, uid, &filename, &coredump_fd, &coredump_size);
if (r < 0)
@ -666,6 +676,9 @@ int main(int argc, char* argv[]) {
IOVEC_SET_STRING(iovec[j++], coredump_filename);
}
/* Vacuum again, but exclude the coredump we just created */
coredump_vacuum(coredump_fd, arg_keep_free, arg_max_use);
/* Now, let's drop privileges to become the user who owns the
* segfaulted process and allocate the coredump memory under
* his uid. This also ensures that the credentials journald

2
src/journal/coredump.conf
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@ -15,3 +15,5 @@
#ProcessSizeMax=2G
#ExternalSizeMax=2G
#JournalSizeMax=767M
#MaxUse=
#KeepFree=

32
src/journal/test-coredump-vacuum.c Normal file
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@ -0,0 +1,32 @@
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2012 Zbigniew Jędrzejewski-Szmek
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <stdlib.h>
#include "coredump-vacuum.h"
int main(int argc, char *argv[]) {
if (coredump_vacuum(-1, (off_t) -1, 70 * 1024) < 0)
return EXIT_FAILURE;
return EXIT_SUCCESS;
}