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| void | blkid_free_probe () |
| blkid_probe | blkid_new_probe () |
| blkid_probe | blkid_new_probe_from_filename () |
| dev_t | blkid_probe_get_devno () |
| int | blkid_probe_get_fd () |
| blkid_loff_t | blkid_probe_get_offset () |
| blkid_loff_t | blkid_probe_get_sectors () |
| unsigned int | blkid_probe_get_sectorsize () |
| blkid_loff_t | blkid_probe_get_size () |
| dev_t | blkid_probe_get_wholedisk_devno () |
| int | blkid_probe_is_wholedisk () |
| int | blkid_probe_set_device () |
| int | blkid_probe_step_back () |
| void | blkid_reset_probe () |
The low-level probing routines always and directly read information from
the selected (see blkid_probe_set_device()) device.
The probing routines are grouped together into separate chains. Currently, the library provides superblocks, partitions and topology chains.
The probing routines is possible to filter (enable/disable) by type (e.g.
fstype "vfat" or partype "gpt") or by usage flags (e.g. BLKID_USAGE_RAID).
These filters are per-chain. Note that always when you touch the chain
filter the current probing position is reset and probing starts from
scratch. It means that the chain filter should not be modified during
probing, for example in loop where you call blkid_do_probe().
For more details see the chain specific documentation.
The low-level API provides two ways how access to probing results.
The NAME=value (tag) interface. This interface is older and returns all data as strings. This interface is generic for all chains.
The binary interfaces. These interfaces return data in the native formats. The interface is always specific to the probing chain.
Note that the previous probing result (binary or NAME=value) is always zeroized when a chain probing function is called. For example:
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blkid_probe_enable_partitions(pr, TRUE); blkid_probe_enable_superblocks(pr, FALSE); blkid_do_safeprobe(pr); |
overwrites the previous probing result for the partitions chain, the superblocks result is not modified.
void
blkid_free_probe (blkid_probe pr);
Deallocates the probe struct, buffers and all allocated data that are associated with this probing control struct.
blkid_probe
blkid_new_probe_from_filename (const char *filename);
This function is same as call open(filename), blkid_new_probe() and
blkid_probe_set_device(pr, fd, 0, 0).
The filename
is closed by blkid_free_probe() or by the
blkid_probe_set_device() call.
blkid_loff_t
blkid_probe_get_offset (blkid_probe pr);
This function returns offset of probing area as defined by blkid_probe_set_device().
blkid_loff_t
blkid_probe_get_size (blkid_probe pr);
This function returns size of probing area as defined by blkid_probe_set_device().
If the size of the probing area is unrestricted then this function returns
the real size of device. See also blkid_get_dev_size().
int blkid_probe_set_device (blkid_probe pr,int fd,blkid_loff_t off,blkid_loff_t size);
Assigns the device to probe control struct, resets internal buffers and resets the current probing.
int
blkid_probe_step_back (blkid_probe pr);
This function move pointer to the probing chain one step back -- it means
that the previously used probing function will be called again in the next
blkid_do_probe() call.
This is necessary for example if you erase or modify on-disk superblock according to the current libblkid probing result.
Example 1. wipe all superblock, but use libblkid only for probing
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pr = blkid_new_probe_from_filename(devname); blkid_probe_enable_superblocks(pr, 1); blkid_probe_set_superblocks_flags(pr, BLKID_SUBLKS_MAGIC); blkid_probe_enable_partitions(pr, 1); blkid_probe_set_partitions_flags(pr, BLKID_PARTS_MAGIC); while (blkid_do_probe(pr) == 0) { const char *ostr = NULL; size_t len = 0; // superblocks if (blkid_probe_lookup_value(pr, "SBMAGIC_OFFSET", &ostr, NULL) == 0) blkid_probe_lookup_value(pr, "SBMAGIC", NULL, &len); // partition tables if (len == 0 && blkid_probe_lookup_value(pr, "PTMAGIC_OFFSET", &ostr, NULL) == 0) blkid_probe_lookup_value(pr, "PTMAGIC", NULL, &len); if (!len || !str) continue; // convert ostr to the real offset by off = strtoll(ostr, NULL, 10); // use your stuff to errase @len bytes at the @off .... // retry the last probing to check for backup superblocks ..etc. blkid_probe_step_back(pr); } |
void
blkid_reset_probe (blkid_probe pr);
Zeroize probing results and resets the current probing (this has impact to
blkid_do_probe() only). This function does not touch probing filters and
keeps assigned device.