#include <errno.h>

#include <inttypes.h>

#include <fcntl.h>

#include <linux/limits.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/select.h>

#include <sys/time.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#include <linux/fanotify.h>

#include <sys/signalfd.h>

#include <sys/poll.h>

#include <sys/mman.h>

#include <linux/fs.h>

#include <linux/fiemap.h>

#include <sys/ioctl.h>

#include <sys/vfs.h>

#include <getopt.h>

#include <sys/inotify.h>

#include <systemd/sd-daemon.h>

#include "missing.h"

#include "util.h"

#include "set.h"

#include "ioprio.h"

#include "readahead-common.h"

#include "virt.h"

static unsigned arg_files_max = 16*1024;

static off_t arg_file_size_max = READAHEAD_FILE_SIZE_MAX;

static usec_t arg_timeout = 2*USEC_PER_MINUTE;

static ReadaheadShared *shared = NULL;

#define SECTOR_TO_PTR(s) ULONG_TO_PTR((s)+1)

#define PTR_TO_SECTOR(p) (PTR_TO_ULONG(p)-1)

static int btrfs_defrag(int fd) {

struct btrfs_ioctl_vol_args data;

zero(data);

data.fd = fd;

return ioctl(fd, BTRFS_IOC_DEFRAG, &data);

}

static int pack_file(FILE *pack, const char *fn, bool on_btrfs) {

struct stat st;

void *start = MAP_FAILED;

uint8_t *vec;

uint32_t b, c;

size_t l, pages;

bool mapped;

int r = 0, fd = -1, k;

assert(pack);

assert(fn);

if ((fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW)) < 0) {

if (errno == ENOENT)

return 0;

if (errno == EPERM || errno == EACCES)

return 0;

log_warning("open(%s) failed: %m", fn);

r = -errno;

goto finish;

}

if ((k = file_verify(fd, fn, arg_file_size_max, &st)) <= 0) {

r = k;

goto finish;

}

if (on_btrfs)

btrfs_defrag(fd);

l = PAGE_ALIGN(st.st_size);

if ((start = mmap(NULL, l, PROT_READ, MAP_SHARED, fd, 0)) == MAP_FAILED) {

log_warning("mmap(%s) failed: %m", fn);

r = -errno;

goto finish;

}

pages = l / page_size();

vec = alloca(pages);

memset(vec, 0, pages);

if (mincore(start, l, vec) < 0) {

log_warning("mincore(%s) failed: %m", fn);

r = -errno;

goto finish;

}

fputs(fn, pack);

fputc('\n', pack);

mapped = false;

for (c = 0; c < pages; c++) {

bool new_mapped = !!(vec[c] & 1);

if (!mapped && new_mapped)

b = c;

else if (mapped && !new_mapped) {

fwrite(&b, sizeof(b), 1, pack);

fwrite(&c, sizeof(c), 1, pack);

log_debug("%s: page %u to %u", fn, b, c);

}

mapped = new_mapped;

}

/* We don't write any range data if we should read the entire file */

if (mapped && b > 0) {

fwrite(&b, sizeof(b), 1, pack);

fwrite(&c, sizeof(c), 1, pack);

log_debug("%s: page %u to %u", fn, b, c);

}

/* End marker */

b = 0;

fwrite(&b, sizeof(b), 1, pack);

fwrite(&b, sizeof(b), 1, pack);

finish:

if (start != MAP_FAILED)

munmap(start, l);

if (fd >= 0)

close_nointr_nofail(fd);

return r;

}

static unsigned long fd_first_block(int fd) {

struct {

struct fiemap fiemap;

struct fiemap_extent extent;

} data;

zero(data);

data.fiemap.fm_length = ~0ULL;

data.fiemap.fm_extent_count = 1;

if (ioctl(fd, FS_IOC_FIEMAP, &data) < 0)

return 0;

if (data.fiemap.fm_mapped_extents <= 0)

return 0;

if (data.fiemap.fm_extents[0].fe_flags & FIEMAP_EXTENT_UNKNOWN)

return 0;

return (unsigned long) data.fiemap.fm_extents[0].fe_physical;

}

struct item {

const char *path;

unsigned long block;

};

static int qsort_compare(const void *a, const void *b) {

const struct item *i, *j;

i = a;

j = b;

if (i->block < j->block)

return -1;

if (i->block > j->block)

return 1;

return strcmp(i->path, j->path);

}

static int collect(const char *root) {

enum {

FD_FANOTIFY, /* Get the actual fs events */

FD_SIGNAL,

FD_INOTIFY, /* We get notifications to quit early via this fd */

_FD_MAX

};

struct pollfd pollfd[_FD_MAX];

int fanotify_fd = -1, signal_fd = -1, inotify_fd = -1, r = 0;

pid_t my_pid;

Hashmap *files = NULL;

Iterator i;

char *p, *q;

sigset_t mask;

FILE *pack = NULL;

char *pack_fn_new = NULL, *pack_fn = NULL;

bool on_ssd, on_btrfs;

struct statfs sfs;

usec_t not_after;

assert(root);

write_one_line_file("/proc/self/oom_score_adj", "1000");

if (ioprio_set(IOPRIO_WHO_PROCESS, getpid(), IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0)) < 0)

log_warning("Failed to set IDLE IO priority class: %m");

assert_se(sigemptyset(&mask) == 0);

sigset_add_many(&mask, SIGINT, SIGTERM, -1);

assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);

if ((signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC)) < 0) {

log_error("signalfd(): %m");

r = -errno;

goto finish;

}

if (!(files = hashmap_new(string_hash_func, string_compare_func))) {

log_error("Failed to allocate set.");

r = -ENOMEM;

goto finish;

}

if ((fanotify_fd = fanotify_init(FAN_CLOEXEC|FAN_NONBLOCK, O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_NOATIME)) < 0) {

log_error("Failed to create fanotify object: %m");

r = -errno;

goto finish;

}

if (fanotify_mark(fanotify_fd, FAN_MARK_ADD|FAN_MARK_MOUNT, FAN_OPEN, AT_FDCWD, root) < 0) {

log_error("Failed to mark %s: %m", root);

r = -errno;

goto finish;

}

if ((inotify_fd = open_inotify()) < 0) {

r = inotify_fd;

goto finish;

}

not_after = now(CLOCK_MONOTONIC) + arg_timeout;

my_pid = getpid();

zero(pollfd);

pollfd[FD_FANOTIFY].fd = fanotify_fd;

pollfd[FD_FANOTIFY].events = POLLIN;

pollfd[FD_SIGNAL].fd = signal_fd;

pollfd[FD_SIGNAL].events = POLLIN;

pollfd[FD_INOTIFY].fd = inotify_fd;

pollfd[FD_INOTIFY].events = POLLIN;

sd_notify(0,

"READY=1\n"

"STATUS=Collecting readahead data");

log_debug("Collecting...");

if (access("/run/systemd/readahead/cancel", F_OK) >= 0) {

log_debug("Collection canceled");

r = -ECANCELED;

goto finish;

}

if (access("/run/systemd/readahead/done", F_OK) >= 0) {

log_debug("Got termination request");

goto done;

}

for (;;) {

union {

struct fanotify_event_metadata metadata;

char buffer[4096];

} data;

ssize_t n;

struct fanotify_event_metadata *m;

usec_t t;

int h;

if (hashmap_size(files) > arg_files_max) {

log_debug("Reached maximum number of read ahead files, ending collection.");

break;

}

t = now(CLOCK_MONOTONIC);

if (t >= not_after) {

log_debug("Reached maximum collection time, ending collection.");

break;

}

if ((h = poll(pollfd, _FD_MAX, (int) ((not_after - t) / USEC_PER_MSEC))) < 0) {

if (errno == EINTR)

continue;

log_error("poll(): %m");

r = -errno;

goto finish;

}

if (h == 0) {

log_debug("Reached maximum collection time, ending collection.");

break;

}

if (pollfd[FD_SIGNAL].revents) {

log_debug("Got signal.");

break;

}

if (pollfd[FD_INOTIFY].revents) {

uint8_t inotify_buffer[sizeof(struct inotify_event) + FILENAME_MAX];

struct inotify_event *e;

if ((n = read(inotify_fd, &inotify_buffer, sizeof(inotify_buffer))) < 0) {

if (errno == EINTR || errno == EAGAIN)

continue;

log_error("Failed to read inotify event: %m");

r = -errno;

goto finish;

}

e = (struct inotify_event*) inotify_buffer;

while (n > 0) {

size_t step;

if ((e->mask & IN_CREATE) && streq(e->name, "cancel")) {

log_debug("Collection canceled");

r = -ECANCELED;

goto finish;

}

if ((e->mask & IN_CREATE) && streq(e->name, "done")) {

log_debug("Got termination request");

goto done;

}

step = sizeof(struct inotify_event) + e->len;

assert(step <= (size_t) n);

e = (struct inotify_event*) ((uint8_t*) e + step);

n -= step;

}

}

if ((n = read(fanotify_fd, &data, sizeof(data))) < 0) {

if (errno == EINTR || errno == EAGAIN)

continue;

/* fanotify sometimes returns EACCES on read()

if (errno == EACCES)

continue;

log_error("Failed to read event: %m");

r = -errno;

goto finish;

}

for (m = &data.metadata; FAN_EVENT_OK(m, n); m = FAN_EVENT_NEXT(m, n)) {

char fn[PATH_MAX];

int k;

if (m->fd < 0)

goto next_iteration;

if (m->pid == my_pid)

goto next_iteration;

__sync_synchronize();

if (m->pid == shared->replay)

goto next_iteration;

snprintf(fn, sizeof(fn), "/proc/self/fd/%i", m->fd);

char_array_0(fn);

if ((k = readlink_malloc(fn, &p)) >= 0) {

if (startswith(p, "/tmp") ||

endswith(p, " (deleted)") ||

hashmap_get(files, p))

/* Not interesting, or

free(p);

else {

unsigned long ul;

ul = fd_first_block(m->fd);

if ((k = hashmap_put(files, p, SECTOR_TO_PTR(ul))) < 0) {

log_warning("set_put() failed: %s", strerror(-k));

free(p);

}

}

} else

log_warning("readlink(%s) failed: %s", fn, strerror(-k));

next_iteration:

if (m->fd)

close_nointr_nofail(m->fd);

}

}

done:

if (fanotify_fd >= 0) {

close_nointr_nofail(fanotify_fd);

fanotify_fd = -1;

}

log_debug("Writing Pack File...");

on_ssd = fs_on_ssd(root) > 0;

log_debug("On SSD: %s", yes_no(on_ssd));

on_btrfs = statfs(root, &sfs) >= 0 && (long) sfs.f_type == (long) BTRFS_SUPER_MAGIC;

log_debug("On btrfs: %s", yes_no(on_btrfs));

asprintf(&pack_fn, "%s/.readahead", root);

asprintf(&pack_fn_new, "%s/.readahead.new", root);

if (!pack_fn || !pack_fn_new) {

log_error("Out of memory");

r = -ENOMEM;

goto finish;

}

if (!(pack = fopen(pack_fn_new, "we"))) {

log_error("Failed to open pack file: %m");

r = -errno;

goto finish;

}

fputs(CANONICAL_HOST "\n", pack);

putc(on_ssd ? 'S' : 'R', pack);

if (on_ssd || on_btrfs) {

/* On SSD or on btrfs, just write things out in the

HASHMAP_FOREACH_KEY(q, p, files, i)

pack_file(pack, p, on_btrfs);

} else {

struct item *ordered, *j;

unsigned k, n;

/* On rotating media, order things by the block

log_debug("Ordering...");

n = hashmap_size(files);

if (!(ordered = new(struct item, n))) {

log_error("Out of memory");

r = -ENOMEM;

goto finish;

}

j = ordered;

HASHMAP_FOREACH_KEY(q, p, files, i) {

j->path = p;

j->block = PTR_TO_SECTOR(q);

j++;

}

assert(ordered + n == j);

qsort(ordered, n, sizeof(struct item), qsort_compare);

for (k = 0; k < n; k++)

pack_file(pack, ordered[k].path, on_btrfs);

free(ordered);

}

log_debug("Finalizing...");

fflush(pack);

if (ferror(pack)) {

log_error("Failed to write pack file.");

r = -EIO;

goto finish;

}

if (rename(pack_fn_new, pack_fn) < 0) {

log_error("Failed to rename readahead file: %m");

r = -errno;

goto finish;

}

fclose(pack);

pack = NULL;

log_debug("Done.");

finish:

if (fanotify_fd >= 0)

close_nointr_nofail(fanotify_fd);

if (signal_fd >= 0)

close_nointr_nofail(signal_fd);

if (inotify_fd >= 0)

close_nointr_nofail(inotify_fd);

if (pack) {

fclose(pack);

unlink(pack_fn_new);

}

free(pack_fn_new);

free(pack_fn);

while ((p = hashmap_steal_first_key(files)))

free(p);

hashmap_free(files);

return r;

}

static int help(void) {

printf("%s [OPTIONS...] [DIRECTORY]\n\n"

"Collect read-ahead data on early boot.\n\n"

" -h --help Show this help\n"

" --max-files=INT Maximum number of files to read ahead\n"

" --max-file-size=BYTES Maximum size of files to read ahead\n"

" --timeout=USEC Maximum time to spend collecting data\n",

program_invocation_short_name);

return 0;

}

static int parse_argv(int argc, char *argv[]) {

enum {

ARG_FILES_MAX = 0x100,

ARG_FILE_SIZE_MAX,

ARG_TIMEOUT

};

static const struct option options[] = {

{ "help", no_argument, NULL, 'h' },

{ "files-max", required_argument, NULL, ARG_FILES_MAX },

{ "file-size-max", required_argument, NULL, ARG_FILE_SIZE_MAX },

{ "timeout", required_argument, NULL, ARG_TIMEOUT },

{ NULL, 0, NULL, 0 }

};

int c;

assert(argc >= 0);

assert(argv);

while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) {

switch (c) {

case 'h':

help();

return 0;

case ARG_FILES_MAX:

if (safe_atou(optarg, &arg_files_max) < 0 || arg_files_max <= 0) {

log_error("Failed to parse maximum number of files %s.", optarg);

return -EINVAL;

}

break;

case ARG_FILE_SIZE_MAX: {

unsigned long long ull;

if (safe_atollu(optarg, &ull) < 0 || ull <= 0) {

log_error("Failed to parse maximum file size %s.", optarg);

return -EINVAL;

}

arg_file_size_max = (off_t) ull;

break;

}

case ARG_TIMEOUT:

if (parse_usec(optarg, &arg_timeout) < 0 || arg_timeout <= 0) {

log_error("Failed to parse timeout %s.", optarg);

return -EINVAL;

}

break;

case '?':

return -EINVAL;

default:

log_error("Unknown option code %c", c);

return -EINVAL;

}

}

if (optind != argc &&

optind != argc-1) {

help();

return -EINVAL;

}

return 1;

}

int main(int argc, char *argv[]) {

int r;

const char *root;

log_set_target(LOG_TARGET_AUTO);

log_parse_environment();

log_open();

umask(0022);

if ((r = parse_argv(argc, argv)) <= 0)

return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;

root = optind < argc ? argv[optind] : "/";

if (fs_on_read_only(root) > 0) {

log_info("Disabling readahead collector due to read-only media.");

return 0;

}

if (!enough_ram()) {

log_info("Disabling readahead collector due to low memory.");

return 0;

}

if (detect_virtualization(NULL) > 0) {

log_info("Disabling readahead collector due to execution in virtualized environment.");

return 0;

}

if (!(shared = shared_get()))

return 1;

shared->collect = getpid();

__sync_synchronize();

if (collect(root) < 0)

return 1;

return 0;

}