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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <sys/statvfs.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include "alloc-util.h"
#include "coredump-vacuum.h"
#include "dirent-util.h"
#include "fd-util.h"
#include "fs-util.h"
#include "hashmap.h"
#include "macro.h"
#include "memory-util.h"
#include "stat-util.h"
#include "string-util.h"
#include "time-util.h"
#include "user-util.h"
#define DEFAULT_MAX_USE_LOWER (uint64_t) (1ULL*1024ULL*1024ULL) /* 1 MiB */
#define DEFAULT_MAX_USE_UPPER (uint64_t) (4ULL*1024ULL*1024ULL*1024ULL) /* 4 GiB */
#define DEFAULT_KEEP_FREE_UPPER (uint64_t) (4ULL*1024ULL*1024ULL*1024ULL) /* 4 GiB */
#define DEFAULT_KEEP_FREE (uint64_t) (1024ULL*1024ULL) /* 1 MB */
typedef struct VacuumCandidate {
unsigned n_files;
char *oldest_file;
usec_t oldest_mtime;
} VacuumCandidate;
static VacuumCandidate* vacuum_candidate_free(VacuumCandidate *c) {
if (!c)
return NULL;
free(c->oldest_file);
return mfree(c);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(VacuumCandidate*, vacuum_candidate_free);
static Hashmap* vacuum_candidate_hashmap_free(Hashmap *h) {
return hashmap_free_with_destructor(h, vacuum_candidate_free);
}
DEFINE_TRIVIAL_CLEANUP_FUNC(Hashmap*, vacuum_candidate_hashmap_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_safe(p, e - p);
return parse_uid(u, uid);
}
static bool vacuum_necessary(int fd, uint64_t sum, uint64_t keep_free, uint64_t max_use) {
uint64_t fs_size = 0, fs_free = UINT64_MAX;
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 == UINT64_MAX) {
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;
} else
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 == UINT64_MAX) {
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, uint64_t keep_free, uint64_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)
return log_error_errno(errno, "Failed to fstat(): %m");
}
/* 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;
return log_error_errno(errno, "Can't open coredump directory: %m");
}
for (;;) {
_cleanup_(vacuum_candidate_hashmap_freep) Hashmap *h = NULL;
VacuumCandidate *worst = NULL;
uint64_t sum = 0;
rewinddir(d);
FOREACH_DIRENT(de, d, goto fail) {
VacuumCandidate *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_errno(errno, "Failed to stat /var/lib/systemd/coredump/%s: %m", de->d_name);
continue;
}
if (!S_ISREG(st.st_mode))
continue;
if (exclude_fd >= 0 && stat_inode_same(&exclude_st, &st))
continue;
r = hashmap_ensure_allocated(&h, NULL);
if (r < 0)
return log_oom();
t = timespec_load(&st.st_mtim);
c = hashmap_get(h, UID_TO_PTR(uid));
if (c) {
if (t < c->oldest_mtime) {
char *n;
n = strdup(de->d_name);
if (!n)
return log_oom();
free_and_replace(c->oldest_file, n);
c->oldest_mtime = t;
}
} else {
_cleanup_(vacuum_candidate_freep) VacuumCandidate *n = NULL;
n = new0(VacuumCandidate, 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, UID_TO_PTR(uid), n);
if (r < 0)
return log_oom();
c = TAKE_PTR(n);
}
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;
r = unlinkat_deallocate(dirfd(d), worst->oldest_file, 0);
if (r == -ENOENT)
continue;
if (r < 0)
return log_error_errno(r, "Failed to remove file %s: %m", worst->oldest_file);
log_info("Removed old coredump %s.", worst->oldest_file);
}
return 0;
fail:
return log_error_errno(errno, "Failed to read directory: %m");
}
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