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libnvme/doc/rst/util.rst
Daniel Baumann bd2208f611
Merging upstream version 1.11.1.
Signed-off-by: Daniel Baumann <daniel@debian.org>
2025-02-16 10:51:37 +01:00

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.. _util.h:
**util.h**
libnvme utility functions
.. c:type:: enum nvme_connect_err
nvme connect error codes
**Constants**
``ENVME_CONNECT_RESOLVE``
failed to resolve host
``ENVME_CONNECT_ADDRFAM``
unrecognized address family
``ENVME_CONNECT_TRADDR``
failed to get traddr
``ENVME_CONNECT_TARG``
need a transport (-t) argument
``ENVME_CONNECT_AARG``
need a address (-a) argument
``ENVME_CONNECT_OPEN``
failed to open nvme-fabrics device
``ENVME_CONNECT_WRITE``
failed to write to nvme-fabrics device
``ENVME_CONNECT_READ``
failed to read from nvme-fabrics device
``ENVME_CONNECT_PARSE``
failed to parse ctrl info
``ENVME_CONNECT_INVAL_TR``
invalid transport type
``ENVME_CONNECT_LOOKUP_SUBSYS_NAME``
failed to lookup subsystem name
``ENVME_CONNECT_LOOKUP_SUBSYS``
failed to lookup subsystem
``ENVME_CONNECT_ALREADY``
the connect attempt failed, already connected
``ENVME_CONNECT_INVAL``
invalid arguments/configuration
``ENVME_CONNECT_ADDRINUSE``
hostnqn already in use
``ENVME_CONNECT_NODEV``
invalid interface
``ENVME_CONNECT_OPNOTSUPP``
not supported
``ENVME_CONNECT_CONNREFUSED``
connection refused
``ENVME_CONNECT_ADDRNOTAVAIL``
cannot assign requested address
``ENVME_CONNECT_IGNORED``
connect attempt is ignored due to configuration
``ENVME_CONNECT_NOKEY``
the TLS key is missing
.. c:function:: __u8 nvme_status_to_errno (int status, bool fabrics)
Converts nvme return status to errno
**Parameters**
``int status``
Return status from an nvme passthrough command
``bool fabrics``
Set to true if :c:type:`status` is to a fabrics target.
**Return**
An errno representing the nvme status if it is an nvme status field,
or unchanged status is < 0 since errno is already set.
.. c:function:: const char * nvme_status_to_string (int status, bool fabrics)
Returns string describing nvme return status.
**Parameters**
``int status``
Return status from an nvme passthrough command
``bool fabrics``
Set to true if :c:type:`status` is to a fabrics target.
**Return**
String representation of the nvme status if it is an nvme status field,
or a standard errno string if status is < 0.
.. c:function:: const char * nvme_errno_to_string (int err)
Returns string describing nvme connect failures
**Parameters**
``int err``
Returned error code from nvme_add_ctrl()
**Return**
String representation of the nvme connect error codes
.. c:function:: void nvme_init_ctrl_list (struct nvme_ctrl_list *cntlist, __u16 num_ctrls, __u16 *ctrlist)
Initialize an nvme_ctrl_list structure from an array.
**Parameters**
``struct nvme_ctrl_list *cntlist``
The controller list structure to initialize
``__u16 num_ctrls``
The number of controllers in the array, :c:type:`ctrlist`.
``__u16 *ctrlist``
An array of controller identifiers in CPU native endian.
**Description**
This is intended to be used with any command that takes a controller list
argument. See nvme_ns_attach_ctrls() and nvme_ns_detach().
.. c:function:: void nvme_init_dsm_range (struct nvme_dsm_range *dsm, __u32 *ctx_attrs, __u32 *llbas, __u64 *slbas, __u16 nr_ranges)
Constructs a data set range structure
**Parameters**
``struct nvme_dsm_range *dsm``
DSM range array
``__u32 *ctx_attrs``
Array of context attributes
``__u32 *llbas``
Array of length in logical blocks
``__u64 *slbas``
Array of starting logical blocks
``__u16 nr_ranges``
The size of the dsm arrays
**Description**
Each array must be the same size of size 'nr_ranges'. This is intended to be
used with constructing a payload for nvme_dsm().
**Return**
The nvme command status if a response was received or -errno
otherwise.
.. c:function:: void nvme_init_copy_range (struct nvme_copy_range *copy, __u16 *nlbs, __u64 *slbas, __u32 *eilbrts, __u32 *elbatms, __u32 *elbats, __u16 nr)
Constructs a copy range structure
**Parameters**
``struct nvme_copy_range *copy``
Copy range array
``__u16 *nlbs``
Number of logical blocks
``__u64 *slbas``
Starting LBA
``__u32 *eilbrts``
Expected initial logical block reference tag
``__u32 *elbatms``
Expected logical block application tag mask
``__u32 *elbats``
Expected logical block application tag
``__u16 nr``
Number of descriptors to construct
.. c:function:: void nvme_init_copy_range_f1 (struct nvme_copy_range_f1 *copy, __u16 *nlbs, __u64 *slbas, __u64 *eilbrts, __u32 *elbatms, __u32 *elbats, __u16 nr)
Constructs a copy range f1 structure
**Parameters**
``struct nvme_copy_range_f1 *copy``
Copy range array
``__u16 *nlbs``
Number of logical blocks
``__u64 *slbas``
Starting LBA
``__u64 *eilbrts``
Expected initial logical block reference tag
``__u32 *elbatms``
Expected logical block application tag mask
``__u32 *elbats``
Expected logical block application tag
``__u16 nr``
Number of descriptors to construct
.. c:function:: void nvme_init_copy_range_f2 (struct nvme_copy_range_f2 *copy, __u32 *snsids, __u16 *nlbs, __u64 *slbas, __u16 *sopts, __u32 *eilbrts, __u32 *elbatms, __u32 *elbats, __u16 nr)
Constructs a copy range f2 structure
**Parameters**
``struct nvme_copy_range_f2 *copy``
Copy range array
``__u32 *snsids``
Source namespace identifier
``__u16 *nlbs``
Number of logical blocks
``__u64 *slbas``
Starting LBA
``__u16 *sopts``
Source options
``__u32 *eilbrts``
Expected initial logical block reference tag
``__u32 *elbatms``
Expected logical block application tag mask
``__u32 *elbats``
Expected logical block application tag
``__u16 nr``
Number of descriptors to construct
.. c:function:: void nvme_init_copy_range_f3 (struct nvme_copy_range_f3 *copy, __u32 *snsids, __u16 *nlbs, __u64 *slbas, __u16 *sopts, __u64 *eilbrts, __u32 *elbatms, __u32 *elbats, __u16 nr)
Constructs a copy range f3 structure
**Parameters**
``struct nvme_copy_range_f3 *copy``
Copy range array
``__u32 *snsids``
Source namespace identifier
``__u16 *nlbs``
Number of logical blocks
``__u64 *slbas``
Starting LBA
``__u16 *sopts``
Source options
``__u64 *eilbrts``
Expected initial logical block reference tag
``__u32 *elbatms``
Expected logical block application tag mask
``__u32 *elbats``
Expected logical block application tag
``__u16 nr``
Number of descriptors to construct
.. c:function:: int nvme_get_feature_length (int fid, __u32 cdw11, __u32 *len)
Retreive the command payload length for a specific feature identifier
**Parameters**
``int fid``
Feature identifier, see :c:type:`enum nvme_features_id <nvme_features_id>`.
``__u32 cdw11``
The cdw11 value may affect the transfer (only known fid is
``NVME_FEAT_FID_HOST_ID``)
``__u32 *len``
On success, set to this features payload length in bytes.
**Return**
0 on success, -1 with errno set to EINVAL if the function did not
recognize :c:type:`fid`.
.. c:function:: int nvme_get_feature_length2 (int fid, __u32 cdw11, enum nvme_data_tfr dir, __u32 *len)
Retreive the command payload length for a specific feature identifier
**Parameters**
``int fid``
Feature identifier, see :c:type:`enum nvme_features_id <nvme_features_id>`.
``__u32 cdw11``
The cdw11 value may affect the transfer (only known fid is
``NVME_FEAT_FID_HOST_ID``)
``enum nvme_data_tfr dir``
Data transfer direction: false - host to controller, true -
controller to host may affect the transfer (only known fid is
``NVME_FEAT_FID_HOST_MEM_BUF``).
``__u32 *len``
On success, set to this features payload length in bytes.
**Return**
0 on success, -1 with errno set to EINVAL if the function did not
recognize :c:type:`fid`.
.. c:function:: int nvme_get_directive_receive_length (enum nvme_directive_dtype dtype, enum nvme_directive_receive_doper doper, __u32 *len)
Get directive receive length
**Parameters**
``enum nvme_directive_dtype dtype``
Directive type, see :c:type:`enum nvme_directive_dtype <nvme_directive_dtype>`
``enum nvme_directive_receive_doper doper``
Directive receive operation, see :c:type:`enum nvme_directive_receive_doper <nvme_directive_receive_doper>`
``__u32 *len``
On success, set to this directives payload length in bytes.
**Return**
0 on success, -1 with errno set to EINVAL if the function did not
recognize :c:type:`dtype` or :c:type:`doper`.
.. c:function:: size_t get_entity_name (char *buffer, size_t bufsz)
Get Entity Name (ENAME).
**Parameters**
``char *buffer``
The buffer where the ENAME will be saved as an ASCII string.
``size_t bufsz``
The size of **buffer**.
**Description**
Per TP8010, ENAME is defined as the name associated with the host (i.e.
hostname).
**Return**
Number of characters copied to **buffer**.
.. c:function:: size_t get_entity_version (char *buffer, size_t bufsz)
Get Entity Version (EVER).
**Parameters**
``char *buffer``
The buffer where the EVER will be saved as an ASCII string.
``size_t bufsz``
The size of **buffer**.
**Description**
EVER is defined as the operating system name and version as an ASCII
string. This function reads different files from the file system and
builds a string as follows: [os type] [os release] [distro release]
E.g. "Linux 5.17.0-rc1 SLES 15.4"
**Return**
Number of characters copied to **buffer**.
.. c:function:: char * kv_strip (char *kv)
Strip blanks from key value string
**Parameters**
``char *kv``
The key-value string to strip
**Description**
Strip leading/trailing blanks as well as trailing comments from the
Key=Value string pointed to by **kv**.
**Return**
A pointer to the stripped string. Note that the original string,
**kv**, gets modified.
.. c:function:: char * kv_keymatch (const char *kv, const char *key)
Look for key in key value string
**Parameters**
``const char *kv``
The key=value string to search for the presence of **key**
``const char *key``
The key to look for
**Description**
Look for **key** in the Key=Value pair pointed to by **k** and return a
pointer to the Value if **key** is found.
Check if **kv** starts with **key**. If it does then make sure that we
have a whole-word match on the **key**, and if we do, return a pointer
to the first character of value (i.e. skip leading spaces, tabs,
and equal sign)
**Return**
A pointer to the first character of "value" if a match is found.
NULL otherwise.
.. c:function:: char * startswith (const char *s, const char *prefix)
Checks that a string starts with a given prefix.
**Parameters**
``const char *s``
The string to check
``const char *prefix``
A string that **s** could be starting with
**Return**
If **s** starts with **prefix**, then return a pointer within **s** at
the first character after the matched **prefix**. NULL otherwise.
.. c:function:: round_up (val, mult)
Round a value **val** to the next multiple specified by **mult**.
**Parameters**
``val``
Value to round
``mult``
Multiple to round to.
**Description**
usage: int x = round_up(13, sizeof(__u32)); // 13 -> 16
.. c:function:: __u16 nvmf_exat_len (size_t val_len)
Return length rounded up by 4
**Parameters**
``size_t val_len``
Value length
**Description**
Return the size in bytes, rounded to a multiple of 4 (e.g., size of
__u32), of the buffer needed to hold the exat value of size
**val_len**.
**Return**
Length rounded up by 4
.. c:function:: __u16 nvmf_exat_size (size_t val_len)
Return min aligned size to hold value
**Parameters**
``size_t val_len``
This is the length of the data to be copied to the "exatval"
field of a "struct nvmf_ext_attr".
**Description**
Return the size of the "struct nvmf_ext_attr" needed to hold
a value of size **val_len**.
**Return**
The size in bytes, rounded to a multiple of 4 (i.e. size of
__u32), of the "struct nvmf_ext_attr" required to hold a string of
length **val_len**.
.. c:function:: struct nvmf_ext_attr * nvmf_exat_ptr_next (struct nvmf_ext_attr *p)
Increment **p** to the next element in the array.
**Parameters**
``struct nvmf_ext_attr *p``
Pointer to an element of an array of "struct nvmf_ext_attr".
**Description**
Extended attributes are saved to an array of "struct nvmf_ext_attr"
where each element of the array is of variable size. In order to
move to the next element in the array one must increment the
pointer to the current element (**p**) by the size of the current
element.
**Return**
Pointer to the next element in the array.
.. c:type:: enum nvme_version
Selector for version to be returned by **nvme_get_version**
**Constants**
``NVME_VERSION_PROJECT``
Project release version
``NVME_VERSION_GIT``
Git reference
.. c:function:: const char * nvme_get_version (enum nvme_version type)
Return version libnvme string
**Parameters**
``enum nvme_version type``
Selects which version type (see **struct** nvme_version)
**Return**
Returns version string for known types or else "n/a"
.. c:function:: int nvme_uuid_to_string (unsigned char uuid[NVME_UUID_LEN], char *str)
Return string represenation of encoded UUID
**Parameters**
``unsigned char uuid[NVME_UUID_LEN]``
Binary encoded input UUID
``char *str``
Output string represenation of UUID
**Return**
Returns error code if type conversion fails.
.. c:function:: int nvme_uuid_from_string (const char *str, unsigned char uuid[NVME_UUID_LEN])
Return encoded UUID represenation of string UUID
**Parameters**
``const char *str``
Output string represenation of UUID
``unsigned char uuid[NVME_UUID_LEN]``
Binary encoded input UUID
**Return**
Returns error code if type conversion fails.
.. c:function:: int nvme_uuid_random (unsigned char uuid[NVME_UUID_LEN])
Generate random UUID
**Parameters**
``unsigned char uuid[NVME_UUID_LEN]``
Generated random UUID
**Description**
Generate random number according
https://www.rfc-editor.org/rfc/rfc4122#section-4.4
**Return**
Returns error code if generating of random number fails.
.. c:function:: int nvme_uuid_find (struct nvme_id_uuid_list *uuid_list, const unsigned char uuid[NVME_UUID_LEN])
Find UUID position on UUID list
**Parameters**
``struct nvme_id_uuid_list *uuid_list``
UUID list returned by identify UUID
``const unsigned char uuid[NVME_UUID_LEN]``
Binary encoded input UUID
**Return**
The array position where given UUID is present, or -1 on failure with errno set.
.. c:function:: bool nvme_ipaddrs_eq (const char *addr1, const char *addr2)
Check if 2 IP addresses are equal.
**Parameters**
``const char *addr1``
IP address (can be IPv4 or IPv6)
``const char *addr2``
IP address (can be IPv4 or IPv6)
**Return**
true if addr1 == addr2. false otherwise.
.. c:function:: const char * nvme_iface_matching_addr (const struct ifaddrs *iface_list, const char *addr)
Get interface matching **addr**
**Parameters**
``const struct ifaddrs *iface_list``
Interface list returned by getifaddrs()
``const char *addr``
Address to match
**Description**
Parse the interface list pointed to by **iface_list** looking
for the interface that has **addr** as one of its assigned
addresses.
**Return**
The name of the interface that owns **addr** or NULL.
.. c:function:: bool nvme_iface_primary_addr_matches (const struct ifaddrs *iface_list, const char *iface, const char *addr)
Check that interface's primary address matches
**Parameters**
``const struct ifaddrs *iface_list``
Interface list returned by getifaddrs()
``const char *iface``
Interface to match
``const char *addr``
Address to match
**Description**
Parse the interface list pointed to by **iface_list** and looking for
interface **iface**. The get its primary address and check if it matches
**addr**.
**Return**
true if a match is found, false otherwise.