#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 "missing.h"

#include "util.h"

#include "set.h"

#include "sd-daemon.h"

#include "ioprio.h"

#include "readahead-common.h"

#define MINCORE_VEC_SIZE (READAHEAD_FILE_SIZE_MAX/PAGE_SIZE)

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

struct stat st;

void *start = MAP_FAILED;

uint8_t vec[MINCORE_VEC_SIZE];

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) {

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

r = -errno;

goto finish;

}

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

r = k;

goto finish;

}

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;

}

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

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

r = -errno;

goto finish;

}

fputs(fn, pack);

fputc('\n', pack);

pages = l / PAGE_SIZE;

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,

FD_SIGNAL,

_FD_MAX

};

struct pollfd pollfd[_FD_MAX];

int fanotify_fd = -1, signal_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;

assert(root);

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, 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;

}

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;

sd_notify(0,

"READY=1\n"

"STATUS=Collecting readahead data");

log_debug("Collecting...");

for (;;) {

union {

struct fanotify_event_metadata metadata;

char buffer[4096];

} data;

ssize_t n;

struct fanotify_event_metadata *m;

if (poll(pollfd, _FD_MAX, -1) < 0) {

if (errno == EINTR)

continue;

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

r = -errno;

goto finish;

}

if (pollfd[FD_SIGNAL].revents != 0)

break;

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

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

continue;

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

r = -errno;

goto finish;

}

m = &data.metadata;

while (FAN_EVENT_OK(m, n)) {

if (m->pid != my_pid && m->fd >= 0) {

char fn[PATH_MAX];

int k;

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

char_array_0(fn);

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

if (hashmap_get(files, p))

/* Already read */

free(p);

else {

unsigned long ul;

ul = fd_first_block(m->fd);

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

if (k != -EEXIST)

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

free(p);

}

}

} else

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

}

if (m->fd)

close_nointr_nofail(m->fd);

m = FAN_EVENT_NEXT(m, n);

}

}

if (fanotify_fd >= 0) {

close_nointr_nofail(fanotify_fd);

fanotify_fd = -1;

}

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

on_ssd = fs_on_ssd(root);

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

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 SSD, just write things out in the order the

HASHMAP_FOREACH_KEY(q, p, files, i)

pack_file(pack, p);

} 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_ULONG(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);

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 (pack) {

fclose(pack);

unlink(pack_fn_new);

}

free(pack_fn_new);

free(pack_fn);

while ((p = hashmap_steal_first_key(files)))

free(q);

hashmap_free(files);

return r;

}

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

/* log_set_target(LOG_TARGET_SYSLOG_OR_KMSG); */

log_parse_environment();

log_open();

log_set_max_level(LOG_DEBUG);

if (collect("/") < 0)

return 1;

return 0;

}