diff options
Diffstat (limited to 'src/udev')
| -rw-r--r-- | src/udev/udev-event.c | 7 | ||||
| -rw-r--r-- | src/udev/udev-node.c | 75 |
2 files changed, 67 insertions, 15 deletions
diff --git a/src/udev/udev-event.c b/src/udev/udev-event.c index fd00a24e99..64ae83c479 100644 --- a/src/udev/udev-event.c +++ b/src/udev/udev-event.c @@ -1041,6 +1041,13 @@ int udev_event_execute_rules(UdevEvent *event, if (r < 0) return log_device_debug_errno(dev, r, "Failed to update database under /run/udev/data/: %m"); + /* Yes, we run update_devnode() twice, because in the first invocation, that is before update of udev database, + * it could happen that two contenders are replacing each other's symlink. Hence we run it again to make sure + * symlinks point to devices that claim them with the highest priority. */ + r = update_devnode(event); + if (r < 0) + return r; + device_set_is_initialized(dev); return 0; diff --git a/src/udev/udev-node.c b/src/udev/udev-node.c index 9d4b7d91e8..bde18f756e 100644 --- a/src/udev/udev-node.c +++ b/src/udev/udev-node.c @@ -20,12 +20,15 @@ #include "path-util.h" #include "selinux-util.h" #include "smack-util.h" +#include "stat-util.h" #include "stdio-util.h" #include "string-util.h" #include "strxcpyx.h" #include "udev-node.h" #include "user-util.h" +#define LINK_UPDATE_MAX_RETRIES 128 + static int node_symlink(sd_device *dev, const char *node, const char *slink) { _cleanup_free_ char *slink_dirname = NULL, *target = NULL; const char *id_filename, *slink_tmp; @@ -99,7 +102,9 @@ static int node_symlink(sd_device *dev, const char *node, const char *slink) { if (rename(slink_tmp, slink) < 0) { r = log_device_error_errno(dev, errno, "Failed to rename '%s' to '%s': %m", slink_tmp, slink); (void) unlink(slink_tmp); - } + } else + /* Tell caller that we replaced already existing symlink. */ + r = 1; return r; } @@ -192,7 +197,7 @@ static int link_update(sd_device *dev, const char *slink, bool add) { _cleanup_free_ char *target = NULL, *filename = NULL, *dirname = NULL; char name_enc[PATH_MAX]; const char *id_filename; - int r; + int i, r, retries; assert(dev); assert(slink); @@ -212,14 +217,6 @@ static int link_update(sd_device *dev, const char *slink, bool add) { if (!add && unlink(filename) == 0) (void) rmdir(dirname); - r = link_find_prioritized(dev, add, dirname, &target); - if (r < 0) { - log_device_debug(dev, "No reference left, removing '%s'", slink); - if (unlink(slink) == 0) - (void) rmdir_parents(slink, "/"); - } else - (void) node_symlink(dev, target, slink); - if (add) do { _cleanup_close_ int fd = -1; @@ -232,7 +229,49 @@ static int link_update(sd_device *dev, const char *slink, bool add) { r = -errno; } while (r == -ENOENT); - return r; + /* If the database entry is not written yet we will just do one iteration and possibly wrong symlink + * will be fixed in the second invocation. */ + retries = sd_device_get_is_initialized(dev) > 0 ? LINK_UPDATE_MAX_RETRIES : 1; + + for (i = 0; i < retries; i++) { + struct stat st1 = {}, st2 = {}; + + r = stat(dirname, &st1); + if (r < 0 && errno != ENOENT) + return -errno; + + r = link_find_prioritized(dev, add, dirname, &target); + if (r == -ENOENT) { + log_device_debug(dev, "No reference left, removing '%s'", slink); + if (unlink(slink) == 0) + (void) rmdir_parents(slink, "/"); + + break; + } else if (r < 0) + return log_device_error_errno(dev, r, "Failed to determine highest priority symlink: %m"); + + r = node_symlink(dev, target, slink); + if (r < 0) { + (void) unlink(filename); + break; + } else if (r == 1) + /* We have replaced already existing symlink, possibly there is some other device trying + * to claim the same symlink. Let's do one more iteration to give us a chance to fix + * the error if other device actually claims the symlink with higher priority. */ + continue; + + /* Skip the second stat() if the first failed, stat_inode_unmodified() would return false regardless. */ + if ((st1.st_mode & S_IFMT) != 0) { + r = stat(dirname, &st2); + if (r < 0 && errno != ENOENT) + return -errno; + + if (stat_inode_unmodified(&st1, &st2)) + break; + } + } + + return i < LINK_UPDATE_MAX_RETRIES ? 0 : -ELOOP; } int udev_node_update_old_links(sd_device *dev, sd_device *dev_old) { @@ -451,8 +490,11 @@ int udev_node_add(sd_device *dev, bool apply, (void) node_symlink(dev, devnode, filename); /* create/update symlinks, add symlinks to name index */ - FOREACH_DEVICE_DEVLINK(dev, devlink) - (void) link_update(dev, devlink, true); + FOREACH_DEVICE_DEVLINK(dev, devlink) { + r = link_update(dev, devlink, true); + if (r < 0) + log_device_info_errno(dev, r, "Failed to update device symlinks: %m"); + } return 0; } @@ -465,8 +507,11 @@ int udev_node_remove(sd_device *dev) { assert(dev); /* remove/update symlinks, remove symlinks from name index */ - FOREACH_DEVICE_DEVLINK(dev, devlink) - (void) link_update(dev, devlink, false); + FOREACH_DEVICE_DEVLINK(dev, devlink) { + r = link_update(dev, devlink, false); + if (r < 0) + log_device_info_errno(dev, r, "Failed to update device symlinks: %m"); + } r = xsprintf_dev_num_path_from_sd_device(dev, &filename); if (r < 0) |