#include <sys/statvfs.h>

#include "coredump-vacuum.h"

#include "fd-util.h"

#include "hashmap.h"

#include "macro.h"

#include "string-util.h"

#include "time-util.h"

#include "user-util.h"

#include "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 */

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, uint64_t sum, uint64_t keep_free, uint64_t max_use) {

uint64_t fs_size = 0, fs_free = (uint64_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 == (uint64_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;

} 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_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, 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

d = opendir("/var/lib/systemd/coredump");

if (!d) {

if (errno == ENOENT)

return 0;

log_error_errno(errno, "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;

uint64_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);

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_errno(errno, "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_errno(errno, "Failed to read directory: %m");

return -errno;

}