The SSH helper functions.

Different helper functions used in the SSH Library. More...

Functions
char *	ssh_basename (const char *path)
	basename - parse filename component. More...
char *	ssh_dirname (const char *path)
	Parse directory component. More...
int	ssh_getpass (const char *prompt, char *buf, size_t len, int echo, int verify)
	Get a password from the console. More...
int	ssh_mkdir (const char *pathname, mode_t mode)
	Attempts to create a directory with the given pathname. More...
char *	ssh_path_expand_tilde (const char *d)
	Expand a directory starting with a tilde '~'. More...
int	ssh_timeout_update (struct ssh_timestamp *ts, int timeout)
	updates a timeout value so it reflects the remaining time More...
const char *	ssh_version (int req_version)
	Check if libssh is the required version or get the version string. More...

Detailed Description

Different helper functions used in the SSH Library.

Function Documentation

char* ssh_basename

(

const char *

path

)

basename - parse filename component.

basename breaks a null-terminated pathname string into a filename component. ssh_basename() returns the component following the final '/'. Trailing '/' characters are not counted as part of the pathname.

Parameters

[in]

path

The path to parse.

Returns

The filename of path or NULL if we can't allocate memory. If path is a the string "/", basename returns the string "/". If path is NULL or an empty string, "." is returned.

Referenced by ssh_scp_push_directory(), and ssh_scp_push_file64().

char* ssh_dirname

(

const char *

path

)

Parse directory component.

dirname breaks a null-terminated pathname string into a directory component. In the usual case, ssh_dirname() returns the string up to, but not including, the final '/'. Trailing '/' characters are not counted as part of the pathname. The caller must free the memory.

Parameters

[in]

path

The path to parse.

Returns

The dirname of path or NULL if we can't allocate memory. If path does not contain a slash, c_dirname() returns the string ".". If path is the string "/", it returns the string "/". If path is NULL or an empty string, "." is returned.

Referenced by ssh_write_knownhost().

int ssh_getpass	(	const char *	prompt,
		char *	buf,
		size_t	len,
		int	echo,
		int	verify
	)

Get a password from the console.

You should make sure that the buffer is an empty string!

You can also use this function to ask for a username. Then you can fill the buffer with the username and it is shows to the users. If the users just presses enter the buffer will be untouched.

char username[128];

snprintf(username, sizeof(username), "john");

ssh_getpass("Username:", username, sizeof(username), 1, 0);

The prompt will look like this:

Username: [john]

If you press enter then john is used as the username, or you can type it in to change it.

Parameters

[in]	prompt	The prompt to show to ask for the password.
[out]	buf	The buffer the password should be stored. It NEEDS to be empty or filled out.
[in]	len	The length of the buffer.
[in]	echo	Should we echo what you type.
[in]	verify	Should we ask for the password twice.

Returns

0 on success, -1 on error.

int ssh_mkdir	(	const char *	pathname,
		mode_t	mode
	)

Attempts to create a directory with the given pathname.

This is the portable version of mkdir, mode is ignored on Windows systems.

Parameters

[in]	pathname	The path name to create the directory.
[in]	mode	The permissions to use.

Returns

0 on success, < 0 on error with errno set.

Referenced by ssh_write_knownhost().

char* ssh_path_expand_tilde

(

const char *

d

)

Expand a directory starting with a tilde '~'.

Parameters

[in]

d

The directory to expand.

Returns

The expanded directory, NULL on error.

Referenced by ssh_options_set().

int ssh_timeout_update	(	struct ssh_timestamp *	ts,
		int	timeout
	)

updates a timeout value so it reflects the remaining time

Parameters

[in]	ts	pointer to an existing timestamp
[in]	timeout	timeout in milliseconds. Negative values mean infinite timeout

Returns

remaining time in milliseconds, 0 if elapsed, -1 if never.

Referenced by ssh_channel_select(), ssh_poll_ctx_dopoll(), and ssh_select().

const char* ssh_version

(

int

req_version

)

Check if libssh is the required version or get the version string.

Parameters

[in]

req_version

The version required.

Returns

If the version of libssh is newer than the version required it will return a version string. NULL if the version is older.

Example:

if (ssh_version(SSH_VERSION_INT(0,2,1)) == NULL) {
  fprintf(stderr, "libssh version is too old!\n");
  exit(1);
}

if (debug) {
  printf("libssh %s\n", ssh_version(0));
}