diff options
Diffstat (limited to 'src/libudev/libudev-queue-private.c')
| -rw-r--r-- | src/libudev/libudev-queue-private.c | 406 |
1 files changed, 0 insertions, 406 deletions
diff --git a/src/libudev/libudev-queue-private.c b/src/libudev/libudev-queue-private.c deleted file mode 100644 index d5a2b503dd..0000000000 --- a/src/libudev/libudev-queue-private.c +++ /dev/null @@ -1,406 +0,0 @@ -/*** - This file is part of systemd. - - Copyright 2008-2012 Kay Sievers <kay@vrfy.org> - Copyright 2009 Alan Jenkins <alan-jenkins@tuffmail.co.uk> - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -/* - * DISCLAIMER - The file format mentioned here is private to udev/libudev, - * and may be changed without notice. - * - * The udev event queue is exported as a binary log file. - * Each log record consists of a sequence number followed by the device path. - * - * When a new event is queued, its details are appended to the log. - * When the event finishes, a second record is appended to the log - * with the same sequence number but a devpath len of 0. - * - * Example: - * { 0x0000000000000001 } - * { 0x0000000000000001, 0x0019, "/devices/virtual/mem/null" }, - * { 0x0000000000000002, 0x001b, "/devices/virtual/mem/random" }, - * { 0x0000000000000001, 0x0000 }, - * { 0x0000000000000003, 0x0019, "/devices/virtual/mem/zero" }, - * - * Events 2 and 3 are still queued, but event 1 has finished. - * - * The queue does not grow indefinitely. It is periodically re-created - * to remove finished events. Atomic rename() makes this transparent to readers. - * - * The queue file starts with a single sequence number which specifies the - * minimum sequence number in the log that follows. Any events prior to this - * sequence number have already finished. - */ - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <fcntl.h> -#include <dirent.h> -#include <limits.h> -#include <errno.h> -#include <sys/stat.h> -#include <sys/types.h> - -#include "libudev.h" -#include "libudev-private.h" - -static int rebuild_queue_file(struct udev_queue_export *udev_queue_export); - -struct udev_queue_export { - struct udev *udev; - int queued_count; /* number of unfinished events exported in queue file */ - FILE *queue_file; - unsigned long long int seqnum_max; /* earliest sequence number in queue file */ - unsigned long long int seqnum_min; /* latest sequence number in queue file */ - int waste_bytes; /* queue file bytes wasted on finished events */ -}; - -struct udev_queue_export *udev_queue_export_new(struct udev *udev) -{ - struct udev_queue_export *udev_queue_export; - unsigned long long int initial_seqnum; - - if (udev == NULL) - return NULL; - - udev_queue_export = new0(struct udev_queue_export, 1); - if (udev_queue_export == NULL) - return NULL; - udev_queue_export->udev = udev; - - initial_seqnum = udev_get_kernel_seqnum(udev); - udev_queue_export->seqnum_min = initial_seqnum; - udev_queue_export->seqnum_max = initial_seqnum; - - udev_queue_export_cleanup(udev_queue_export); - if (rebuild_queue_file(udev_queue_export) != 0) { - free(udev_queue_export); - return NULL; - } - - return udev_queue_export; -} - -struct udev_queue_export *udev_queue_export_unref(struct udev_queue_export *udev_queue_export) -{ - if (udev_queue_export == NULL) - return NULL; - if (udev_queue_export->queue_file != NULL) - fclose(udev_queue_export->queue_file); - free(udev_queue_export); - return NULL; -} - -void udev_queue_export_cleanup(struct udev_queue_export *udev_queue_export) -{ - if (udev_queue_export == NULL) - return; - unlink("/run/udev/queue.tmp"); - unlink("/run/udev/queue.bin"); -} - -static int skip_to(FILE *file, long offset) -{ - long old_offset; - - /* fseek may drop buffered data, avoid it for small seeks */ - old_offset = ftell(file); - if (offset > old_offset && offset - old_offset <= BUFSIZ) { - size_t skip_bytes = offset - old_offset; - char *buf = alloca(skip_bytes); - - if (fread(buf, skip_bytes, 1, file) != skip_bytes) - return -1; - } - - return fseek(file, offset, SEEK_SET); -} - -struct queue_devpaths { - unsigned int devpaths_first; /* index of first queued event */ - unsigned int devpaths_size; - long devpaths[]; /* seqnum -> offset of devpath in queue file (or 0) */ -}; - -/* - * Returns a table mapping seqnum to devpath file offset for currently queued events. - * devpaths[i] represents the event with seqnum = i + udev_queue_export->seqnum_min. - */ -static struct queue_devpaths *build_index(struct udev_queue_export *udev_queue_export) -{ - struct queue_devpaths *devpaths; - unsigned long long int range; - long devpath_offset; - ssize_t devpath_len; - unsigned long long int seqnum; - unsigned long long int n; - unsigned int i; - - /* seek to the first event in the file */ - rewind(udev_queue_export->queue_file); - udev_queue_read_seqnum(udev_queue_export->queue_file, &seqnum); - - /* allocate the table */ - range = udev_queue_export->seqnum_min - udev_queue_export->seqnum_max; - if (range - 1 > INT_MAX) { - udev_err(udev_queue_export->udev, "queue file overflow\n"); - return NULL; - } - devpaths = malloc0(sizeof(struct queue_devpaths) + (range + 1) * sizeof(long)); - if (devpaths == NULL) - return NULL; - devpaths->devpaths_size = range + 1; - - /* read all records and populate the table */ - for (;;) { - if (udev_queue_read_seqnum(udev_queue_export->queue_file, &seqnum) < 0) - break; - n = seqnum - udev_queue_export->seqnum_max; - if (n >= devpaths->devpaths_size) - goto read_error; - - devpath_offset = ftell(udev_queue_export->queue_file); - devpath_len = udev_queue_skip_devpath(udev_queue_export->queue_file); - if (devpath_len < 0) - goto read_error; - - if (devpath_len > 0) - devpaths->devpaths[n] = devpath_offset; - else - devpaths->devpaths[n] = 0; - } - - /* find first queued event */ - for (i = 0; i < devpaths->devpaths_size; i++) { - if (devpaths->devpaths[i] != 0) - break; - } - devpaths->devpaths_first = i; - - return devpaths; - -read_error: - udev_err(udev_queue_export->udev, "queue file corrupted\n"); - free(devpaths); - return NULL; -} - -static int rebuild_queue_file(struct udev_queue_export *udev_queue_export) -{ - unsigned long long int seqnum; - struct queue_devpaths *devpaths = NULL; - FILE *new_queue_file = NULL; - unsigned int i; - - /* read old queue file */ - if (udev_queue_export->queue_file != NULL) { - devpaths = build_index(udev_queue_export); - if (devpaths != NULL) - udev_queue_export->seqnum_max += devpaths->devpaths_first; - } - if (devpaths == NULL) { - udev_queue_export->queued_count = 0; - udev_queue_export->seqnum_max = udev_queue_export->seqnum_min; - } - - /* create new queue file */ - new_queue_file = fopen("/run/udev/queue.tmp", "w+e"); - if (new_queue_file == NULL) - goto error; - seqnum = udev_queue_export->seqnum_max; - fwrite(&seqnum, 1, sizeof(unsigned long long int), new_queue_file); - - /* copy unfinished events only to the new file */ - if (devpaths != NULL) { - for (i = devpaths->devpaths_first; i < devpaths->devpaths_size; i++) { - char devpath[UTIL_PATH_SIZE]; - int err; - unsigned short devpath_len; - - if (devpaths->devpaths[i] != 0) - { - skip_to(udev_queue_export->queue_file, devpaths->devpaths[i]); - err = udev_queue_read_devpath(udev_queue_export->queue_file, devpath, sizeof(devpath)); - devpath_len = err; - - fwrite(&seqnum, sizeof(unsigned long long int), 1, new_queue_file); - fwrite(&devpath_len, sizeof(unsigned short), 1, new_queue_file); - fwrite(devpath, 1, devpath_len, new_queue_file); - } - seqnum++; - } - free(devpaths); - devpaths = NULL; - } - fflush(new_queue_file); - if (ferror(new_queue_file)) - goto error; - - /* rename the new file on top of the old one */ - if (rename("/run/udev/queue.tmp", "/run/udev/queue.bin") != 0) - goto error; - - if (udev_queue_export->queue_file != NULL) - fclose(udev_queue_export->queue_file); - udev_queue_export->queue_file = new_queue_file; - udev_queue_export->waste_bytes = 0; - - return 0; - -error: - udev_err(udev_queue_export->udev, "failed to create queue file: %m\n"); - udev_queue_export_cleanup(udev_queue_export); - - if (udev_queue_export->queue_file != NULL) { - fclose(udev_queue_export->queue_file); - udev_queue_export->queue_file = NULL; - } - if (new_queue_file != NULL) - fclose(new_queue_file); - - if (devpaths != NULL) - free(devpaths); - udev_queue_export->queued_count = 0; - udev_queue_export->waste_bytes = 0; - udev_queue_export->seqnum_max = udev_queue_export->seqnum_min; - - return -1; -} - -static int write_queue_record(struct udev_queue_export *udev_queue_export, - unsigned long long int seqnum, const char *devpath, size_t devpath_len) -{ - unsigned short len; - - if (udev_queue_export->queue_file == NULL) - return -1; - - if (fwrite(&seqnum, sizeof(unsigned long long int), 1, udev_queue_export->queue_file) != 1) - goto write_error; - - len = (devpath_len < USHRT_MAX) ? devpath_len : USHRT_MAX; - if (fwrite(&len, sizeof(unsigned short), 1, udev_queue_export->queue_file) != 1) - goto write_error; - if (len > 0) { - if (fwrite(devpath, 1, len, udev_queue_export->queue_file) != len) - goto write_error; - } - - /* *must* flush output; caller may fork */ - if (fflush(udev_queue_export->queue_file) != 0) - goto write_error; - - return 0; - -write_error: - /* if we failed half way through writing a record to a file, - we should not try to write any further records to it. */ - udev_err(udev_queue_export->udev, "error writing to queue file: %m\n"); - fclose(udev_queue_export->queue_file); - udev_queue_export->queue_file = NULL; - - return -1; -} - -enum device_state { - DEVICE_QUEUED, - DEVICE_FINISHED, -}; - -static inline size_t queue_record_size(size_t devpath_len) -{ - return sizeof(unsigned long long int) + sizeof(unsigned short int) + devpath_len; -} - -static int update_queue(struct udev_queue_export *udev_queue_export, - struct udev_device *udev_device, enum device_state state) -{ - unsigned long long int seqnum = udev_device_get_seqnum(udev_device); - const char *devpath = NULL; - size_t devpath_len = 0; - int bytes; - int err; - - /* FINISHED records have a zero length devpath */ - if (state == DEVICE_QUEUED) { - devpath = udev_device_get_devpath(udev_device); - devpath_len = strlen(devpath); - } - - /* recover from an earlier failed rebuild */ - if (udev_queue_export->queue_file == NULL) { - if (rebuild_queue_file(udev_queue_export) != 0) - return -1; - } - - /* if we're removing the last event from the queue, that's the best time to rebuild it */ - if (state != DEVICE_QUEUED && udev_queue_export->queued_count == 1) { - /* we don't need to read the old queue file */ - fclose(udev_queue_export->queue_file); - udev_queue_export->queue_file = NULL; - rebuild_queue_file(udev_queue_export); - return 0; - } - - /* try to rebuild the queue files before they grow larger than one page. */ - bytes = ftell(udev_queue_export->queue_file) + queue_record_size(devpath_len); - if ((udev_queue_export->waste_bytes > bytes / 2) && bytes > 4096) - rebuild_queue_file(udev_queue_export); - - /* don't record a finished event, if we already dropped the event in a failed rebuild */ - if (seqnum < udev_queue_export->seqnum_max) - return 0; - - /* now write to the queue */ - if (state == DEVICE_QUEUED) { - udev_queue_export->queued_count++; - udev_queue_export->seqnum_min = seqnum; - } else { - udev_queue_export->waste_bytes += queue_record_size(devpath_len) + queue_record_size(0); - udev_queue_export->queued_count--; - } - err = write_queue_record(udev_queue_export, seqnum, devpath, devpath_len); - - /* try to handle ENOSPC */ - if (err != 0 && udev_queue_export->queued_count == 0) { - udev_queue_export_cleanup(udev_queue_export); - err = rebuild_queue_file(udev_queue_export); - } - - return err; -} - -static int update(struct udev_queue_export *udev_queue_export, - struct udev_device *udev_device, enum device_state state) -{ - if (update_queue(udev_queue_export, udev_device, state) != 0) - return -1; - - return 0; -} - -int udev_queue_export_device_queued(struct udev_queue_export *udev_queue_export, struct udev_device *udev_device) -{ - return update(udev_queue_export, udev_device, DEVICE_QUEUED); -} - -int udev_queue_export_device_finished(struct udev_queue_export *udev_queue_export, struct udev_device *udev_device) -{ - return update(udev_queue_export, udev_device, DEVICE_FINISHED); -} |