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https://github.com/systemd/systemd-stable.git
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udev-node: save information about device node and priority in symlink
Previously, we only store device IDs in /run/udev/links, and when creating/removing device node symlink, we create sd_device object corresponds to the IDs and read device node and priority from the object. That requires parsing uevent and udev database files. This makes link_find_prioritized() get the most prioritzed device node without parsing the files.
This commit is contained in:
Yu Watanabe
parent
46070dbf26
commit
377a83f0d8
@ -18,6 +18,7 @@
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#include "fs-util.h"
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#include "hexdecoct.h"
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#include "mkdir.h"
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#include "parse-util.h"
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#include "path-util.h"
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#include "selinux-util.h"
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#include "smack-util.h"
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@ -30,7 +31,7 @@
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#define CREATE_LINK_MAX_RETRIES 128
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#define LINK_UPDATE_MAX_RETRIES 128
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#define TOUCH_FILE_MAX_RETRIES 128
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#define CREATE_STACK_LINK_MAX_RETRIES 128
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#define UDEV_NODE_HASH_KEY SD_ID128_MAKE(b9,6a,f1,ce,40,31,44,1a,9e,19,ec,8b,ae,f3,e3,2f)
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static int create_symlink(const char *target, const char *slink) {
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@ -175,39 +176,67 @@ static int link_find_prioritized(sd_device *dev, bool add, const char *stackdir,
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return r;
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FOREACH_DIRENT_ALL(dent, dir, break) {
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_cleanup_(sd_device_unrefp) sd_device *dev_db = NULL;
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const char *devnode;
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int db_prio = 0;
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_cleanup_free_ char *path = NULL, *buf = NULL;
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int tmp_prio;
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if (dent->d_name[0] == '\0')
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break;
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if (dent->d_name[0] == '.')
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continue;
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log_device_debug(dev, "Found '%s' claiming '%s'", dent->d_name, stackdir);
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/* did we find ourself? */
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/* skip ourself */
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if (streq(dent->d_name, id))
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continue;
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if (sd_device_new_from_device_id(&dev_db, dent->d_name) < 0)
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path = path_join(stackdir, dent->d_name);
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if (!path)
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return -ENOMEM;
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if (readlink_malloc(path, &buf) >= 0) {
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char *devnode;
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/* New format. The devnode and priority can be obtained from symlink. */
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devnode = strchr(buf, ':');
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if (!devnode || devnode == buf)
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continue;
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if (sd_device_get_devname(dev_db, &devnode) < 0)
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*(devnode++) = '\0';
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if (!path_startswith(devnode, "/dev"))
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continue;
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if (device_get_devlink_priority(dev_db, &db_prio) < 0)
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if (safe_atoi(buf, &tmp_prio) < 0)
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continue;
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if (target && db_prio <= priority)
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if (target && tmp_prio <= priority)
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continue;
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log_device_debug(dev_db, "Device claims priority %i for '%s'", db_prio, stackdir);
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r = free_and_strdup(&target, devnode);
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if (r < 0)
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return r;
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priority = db_prio;
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} else {
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_cleanup_(sd_device_unrefp) sd_device *tmp_dev = NULL;
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const char *devnode;
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/* Old format. The devnode and priority must be obtained from uevent and
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* udev database files. */
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if (sd_device_new_from_device_id(&tmp_dev, dent->d_name) < 0)
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continue;
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if (device_get_devlink_priority(tmp_dev, &tmp_prio) < 0)
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continue;
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if (target && tmp_prio <= priority)
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continue;
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if (sd_device_get_devname(tmp_dev, &devnode) < 0)
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continue;
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r = free_and_strdup(&target, devnode);
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if (r < 0)
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return r;
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}
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priority = tmp_prio;
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}
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*ret = TAKE_PTR(target);
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@ -256,10 +285,72 @@ toolong:
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return size - 1;
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}
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static int update_stack_directory(sd_device *dev, const char *dirname, bool add) {
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_cleanup_free_ char *filename = NULL, *data = NULL, *buf = NULL;
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const char *devname, *id;
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int priority, r;
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assert(dev);
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assert(dirname);
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r = device_get_device_id(dev, &id);
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if (r < 0)
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return log_device_debug_errno(dev, r, "Failed to get device id: %m");
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filename = path_join(dirname, id);
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if (!filename)
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return log_oom_debug();
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if (!add) {
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if (unlink(filename) < 0 && errno != ENOENT)
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log_device_debug_errno(dev, errno, "Failed to remove %s, ignoring: %m", filename);
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(void) rmdir(dirname);
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return 0;
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}
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r = sd_device_get_devname(dev, &devname);
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if (r < 0)
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return log_device_debug_errno(dev, r, "Failed to get device node: %m");
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r = device_get_devlink_priority(dev, &priority);
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if (r < 0)
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return log_device_debug_errno(dev, r, "Failed to get priority of device node symlink: %m");
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if (asprintf(&data, "%i:%s", priority, devname) < 0)
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return log_oom_debug();
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if (readlink_malloc(filename, &buf) >= 0 && streq(buf, data))
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return 0;
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if (unlink(filename) < 0 && errno != ENOENT)
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log_device_debug_errno(dev, errno, "Failed to remove %s, ignoring: %m", filename);
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for (unsigned j = 0; j < CREATE_STACK_LINK_MAX_RETRIES; j++) {
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/* This may fail with -ENOENT when the parent directory is removed during
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* creating the file by another udevd worker. */
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r = mkdir_p(dirname, 0755);
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if (r == -ENOENT)
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continue;
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if (r < 0)
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return log_device_debug_errno(dev, r, "Failed to create directory %s: %m", dirname);
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if (symlink(data, filename) < 0) {
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if (errno == ENOENT)
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continue;
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return log_device_debug_errno(dev, errno, "Failed to create symbolic link %s: %m", filename);
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}
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return 0;
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}
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return log_device_debug_errno(dev, SYNTHETIC_ERRNO(ELOOP), "Failed to create symbolic link %s: %m", filename);
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}
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/* manage "stack of names" with possibly specified device priorities */
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static int link_update(sd_device *dev, const char *slink_in, bool add) {
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_cleanup_free_ char *slink = NULL, *filename = NULL, *dirname = NULL;
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const char *slink_name, *id;
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_cleanup_free_ char *slink = NULL, *dirname = NULL;
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const char *slink_name;
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char name_enc[NAME_MAX+1];
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int i, r, retries;
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@ -279,35 +370,14 @@ static int link_update(sd_device *dev, const char *slink_in, bool add) {
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return log_device_debug_errno(dev, SYNTHETIC_ERRNO(EINVAL),
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"Invalid symbolic link of device node: %s", slink);
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r = device_get_device_id(dev, &id);
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if (r < 0)
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return log_device_debug_errno(dev, r, "Failed to get device id: %m");
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(void) udev_node_escape_path(slink_name, name_enc, sizeof(name_enc));
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dirname = path_join("/run/udev/links/", name_enc);
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dirname = path_join("/run/udev/links", name_enc);
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if (!dirname)
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return log_oom_debug();
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filename = path_join(dirname, id);
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if (!filename)
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return log_oom_debug();
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if (!add) {
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if (unlink(filename) < 0 && errno != ENOENT)
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log_device_debug_errno(dev, errno, "Failed to remove %s, ignoring: %m", filename);
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(void) rmdir(dirname);
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} else {
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for (unsigned j = 0; j < TOUCH_FILE_MAX_RETRIES; j++) {
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/* This may fail with -ENOENT when the parent directory is removed during
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* creating the file by another udevd worker. */
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r = touch_file(filename, /* parents= */ true, USEC_INFINITY, UID_INVALID, GID_INVALID, 0444);
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if (r != -ENOENT)
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break;
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}
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r = update_stack_directory(dev, dirname, add);
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if (r < 0)
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return log_device_debug_errno(dev, r, "Failed to create %s: %m", filename);
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}
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return r;
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/* If the database entry is not written yet we will just do one iteration and possibly wrong symlink
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* will be fixed in the second invocation. */
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