#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 <math.h>

#ifdef HAVE_LINUX_BTRFS_H

#include <linux/btrfs.h>

#endif

#ifdef HAVE_FANOTIFY_INIT

#include <sys/fanotify.h>

#endif

#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 ReadaheadShared *shared = NULL;

static usec_t starttime;

#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 = { .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;

uint64_t inode;

size_t l, pages;

bool mapped;

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

assert(pack);

assert(fn);

fd = open(fn, O_RDONLY|O_CLOEXEC|O_NOATIME|O_NOCTTY|O_NOFOLLOW);

if (fd < 0) {

if (errno == ENOENT)

return 0;

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

return 0;

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

r = -errno;

goto finish;

}

k = file_verify(fd, fn, arg_file_size_max, &st);

if (k <= 0) {

r = k;

goto finish;

}

if (on_btrfs)

btrfs_defrag(fd);

l = PAGE_ALIGN(st.st_size);

start = mmap(NULL, l, PROT_READ, MAP_SHARED, fd, 0);

if (start == MAP_FAILED) {

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

r = -errno;

goto finish;

}

pages = l / page_size();

vec = alloca0(pages);

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

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

r = -errno;

goto finish;

}

fputs(fn, pack);

fputc('\n', pack);

/* Store the inode, so that we notice when the file is deleted */

inode = (uint64_t) st.st_ino;

fwrite(&inode, sizeof(inode), 1, 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);

safe_close(fd);

return r;

}

static unsigned long fd_first_block(int fd) {

struct {

struct fiemap fiemap;

struct fiemap_extent extent;

} data = {

.fiemap.fm_length = ~0ULL,

.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;

unsigned long bin;

};

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

const struct item *i, *j;

i = a;

j = b;

/* sort by bin first */

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

return -1;

if (i->bin > j->bin)

return 1;

/* then sort by sector */

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;

uint64_t previous_block_readahead;

bool previous_block_readahead_set = false;

assert(root);

if (asprintf(&pack_fn, "%s/.readahead", root) < 0) {

r = log_oom();

goto finish;

}

starttime = now(CLOCK_MONOTONIC);

/* If there's no pack file yet we lower the kernel readahead

previous_block_readahead_set =

access(pack_fn, F_OK) < 0 &&

block_get_readahead(root, &previous_block_readahead) >= 0 &&

block_set_readahead(root, 8*1024) >= 0;

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;

}

files = hashmap_new(string_hash_func, string_compare_func);

if (!files) {

log_error("Failed to allocate set.");

r = -ENOMEM;

goto finish;

}

fanotify_fd = fanotify_init(FAN_CLOEXEC|FAN_NONBLOCK, O_RDONLY|O_LARGEFILE|O_CLOEXEC|O_NOATIME);

if (fanotify_fd < 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;

}

inotify_fd = open_inotify();

if (inotify_fd < 0) {

r = inotify_fd;

goto finish;

}

not_after = now(CLOCK_MONOTONIC) + arg_timeout;

my_pid = getpid();

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;

}

}

n = read(fanotify_fd, &data, sizeof(data));

if (n < 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[sizeof("/proc/self/fd/") + DECIMAL_STR_MAX(int)];

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);

k = readlink_malloc(fn, &p);

if (k >= 0) {

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

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

hashmap_get(files, p))

/* Not interesting, or

free(p);

else {

unsigned long ul;

usec_t entrytime;

struct item *entry;

entry = new0(struct item, 1);

if (!entry) {

r = log_oom();

goto finish;

}

ul = fd_first_block(m->fd);

entrytime = now(CLOCK_MONOTONIC);

entry->block = ul;

entry->path = strdup(p);

if (!entry->path) {

free(entry);

r = log_oom();

goto finish;

}

entry->bin = (entrytime - starttime) / 2000000;

k = hashmap_put(files, p, entry);

if (k < 0) {

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

free(p);

}

}

} else

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

next_iteration:

safe_close(m->fd);

}

}

done:

fanotify_fd = safe_close(fanotify_fd);

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 && F_TYPE_EQUAL(sfs.f_type, BTRFS_SUPER_MAGIC);

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

if (asprintf(&pack_fn_new, "%s/.readahead.new", root) < 0) {

r = log_oom();

goto finish;

}

pack = fopen(pack_fn_new, "we");

if (!pack) {

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

r = -errno;

goto finish;

}

fputs(CANONICAL_HOST READAHEAD_PACK_FILE_VERSION, 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 {

unsigned n;

/* On rotating media, order things by the block

log_debug("Ordering...");

n = hashmap_size(files);

if (n) {

_cleanup_free_ struct item *ordered;

struct item *j;

unsigned k;

ordered = new(struct item, n);

if (!ordered) {

r = log_oom();

goto finish;

}

j = ordered;

HASHMAP_FOREACH_KEY(q, p, files, i) {

memcpy(j, q, sizeof(struct item));

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);

} else

log_warning("No pack files");

}

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:

safe_close(fanotify_fd);

safe_close(signal_fd);

safe_close(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);

if (previous_block_readahead_set) {

uint64_t bytes;

/* Restore the original kernel readahead setting if we

if (block_get_readahead(root, &bytes) >= 0 && bytes == 8*1024)

block_set_readahead(root, previous_block_readahead);

}

return r;

}

int main_collect(const char *root) {

if (!root)

root = "/";

/* Skip this step on read-only media. Note that we check the

if (fs_on_read_only(root) > 0) {

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

return EXIT_SUCCESS;

}

if (!enough_ram()) {

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

return EXIT_SUCCESS;

}

shared = shared_get();

if (!shared)

return EXIT_FAILURE;

shared->collect = getpid();

__sync_synchronize();

if (collect(root) < 0)

return EXIT_FAILURE;

return EXIT_SUCCESS;

}