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udev: extract same logic of creating device symlink

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This also limits the number of trial.
This commit is contained in:
Yu Watanabe 2021-06-03 01:07:45 +09:00
parent 1ddfb6cf29
commit 5802d4ea03
1 changed files with 41 additions and 26 deletions
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65
src/udev/udev-node.c
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@ -29,10 +29,37 @@
#include "udev-node.h"
#include "user-util.h"
#define CREATE_LINK_MAX_RETRIES 128
#define LINK_UPDATE_MAX_RETRIES 128
#define TOUCH_FILE_MAX_RETRIES 128
#define UDEV_NODE_HASH_KEY SD_ID128_MAKE(b9,6a,f1,ce,40,31,44,1a,9e,19,ec,8b,ae,f3,e3,2f)
static int create_symlink(const char *target, const char *slink) {
int r;
assert(target);
assert(slink);
for (unsigned i = 0; i < CREATE_LINK_MAX_RETRIES; i++) {
r = mkdir_parents_label(slink, 0755);
if (r == -ENOENT)
continue;
if (r < 0)
return r;
mac_selinux_create_file_prepare(slink, S_IFLNK);
if (symlink(target, slink) < 0)
r = -errno;
else
r = 0;
mac_selinux_create_file_clear();
if (r != -ENOENT)
return r;
}
return r;
}
static int node_symlink(sd_device *dev, const char *node, const char *slink) {
_cleanup_free_ char *slink_dirname = NULL, *target = NULL;
const char *id, *slink_tmp;
@ -71,47 +98,35 @@ static int node_symlink(sd_device *dev, const char *node, const char *slink) {
}
} else {
log_device_debug(dev, "Creating symlink '%s' to '%s'", slink, target);
do {
r = mkdir_parents_label(slink, 0755);
if (!IN_SET(r, 0, -ENOENT))
break;
mac_selinux_create_file_prepare(slink, S_IFLNK);
if (symlink(target, slink) < 0)
r = -errno;
mac_selinux_create_file_clear();
} while (r == -ENOENT);
if (r == 0)
r = create_symlink(target, slink);
if (r >= 0)
return 0;
if (r < 0)
log_device_debug_errno(dev, r, "Failed to create symlink '%s' to '%s', trying to replace '%s': %m", slink, target, slink);
}
log_device_debug(dev, "Atomically replace '%s'", slink);
r = device_get_device_id(dev, &id);
if (r < 0)
return log_device_error_errno(dev, r, "Failed to get device id: %m");
slink_tmp = strjoina(slink, ".tmp-", id);
(void) unlink(slink_tmp);
do {
r = mkdir_parents_label(slink_tmp, 0755);
if (!IN_SET(r, 0, -ENOENT))
break;
mac_selinux_create_file_prepare(slink_tmp, S_IFLNK);
if (symlink(target, slink_tmp) < 0)
r = -errno;
mac_selinux_create_file_clear();
} while (r == -ENOENT);
r = create_symlink(target, slink_tmp);
if (r < 0)
return log_device_error_errno(dev, r, "Failed to create symlink '%s' to '%s': %m", slink_tmp, target);
return log_device_debug_errno(dev, r, "Failed to create symlink '%s' to '%s': %m", slink_tmp, target);
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;
}
/* Tell caller that we replaced already existing symlink. */
return 1;
}
static int link_find_prioritized(sd_device *dev, bool add, const char *stackdir, char **ret) {