libexplain/acl_to_text.h File Reference

explain acl_to_text(3) errors More...

#include <libexplain/gcc_attributes.h>
#include <libexplain/large_file_support.h>
#include <sys/acl.h>

Go to the source code of this file.

Functions
char *	explain_acl_to_text_or_die (acl_t acl, ssize_t *len_p) LIBEXPLAIN_WARN_UNUSED_RESULT
char *	explain_acl_to_text_on_error (acl_t acl, ssize_t *len_p) LIBEXPLAIN_WARN_UNUSED_RESULT
const char *	explain_acl_to_text (acl_t acl, ssize_t *len_p) LIBEXPLAIN_WARN_UNUSED_RESULT
const char *	explain_errno_acl_to_text (int errnum, acl_t acl, ssize_t *len_p) LIBEXPLAIN_WARN_UNUSED_RESULT
void	explain_message_acl_to_text (char *message, int message_size, acl_t acl, ssize_t *len_p)
void	explain_message_errno_acl_to_text (char *message, int message_size, int errnum, acl_t acl, ssize_t *len_p)

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Detailed Description

explain acl_to_text(3) errors

These functions may be used to obtain explanations for errors returned by the acl_to_text(3) system call.

Definition in file acl_to_text.h.

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Function Documentation

const char* explain_acl_to_text	(	acl_t	acl,
		ssize_t *	len_p
	)

The explain_acl_to_text function is used to obtain an explanation of an error returned by the acl_to_text(3) system call. The least the message will contain is the value of strerror(errno), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

Parameters:

acl	The original acl, exactly as passed to the acl_to_text(3) system call.
len_p	The original len_p, exactly as passed to the acl_to_text(3) system call.

Returns:

The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

Note:

This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Example:

This function is intended to be used in a fashion similar to the following example:

 char *result = acl_to_text(acl, len_p);
 if (!result)
 {
     explain_output_error_and_die("%s\n", explain_acl_to_text(acl, len_p));
 }

The above code example is available pre\-packaged as the explain_acl_to_text_or_die function.

char* explain_acl_to_text_on_error	(	acl_t	acl,
		ssize_t *	len_p
	)

The explain_acl_to_text_on_error function is used to call the acl_to_text(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_acl_to_text(3) function.

Parameters:

acl	The acl, exactly as to be passed to the acl_to_text(3) system call.
len_p	The len_p, exactly as to be passed to the acl_to_text(3) system call.

Returns:

The value returned by the wrapped acl_to_text(3) system call.

Example:

This function is intended to be used in a fashion similar to the following example:

 char *result = explain_acl_to_text_on_error(acl, len_p);
 if (!result)
 {
     ...cope with error
     ...no need to print error message
 }

char* explain_acl_to_text_or_die	(	acl_t	acl,
		ssize_t *	len_p
	)

The explain_acl_to_text_or_die function is used to call the acl_to_text(3) system call. On failure an explanation will be printed to stderr, obtained from the explain_acl_to_text(3) function, and then the process terminates by calling exit(EXIT_FAILURE).

Parameters:

acl	The acl, exactly as to be passed to the acl_to_text(3) system call.
len_p	The len_p, exactly as to be passed to the acl_to_text(3) system call.

Returns:

This function only returns on success, see acl_to_text(3) for more information. On failure, prints an explanation and exits, it does not return.

Example:

This function is intended to be used in a fashion similar to the following example:

 char *result = explain_acl_to_text_or_die(acl, len_p);

const char* explain_errno_acl_to_text	(	int	errnum,
		acl_t	acl,
		ssize_t *	len_p
	)

The explain_errno_acl_to_text function is used to obtain an explanation of an error returned by the acl_to_text(3) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

Parameters:

errnum	The error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.
acl	The original acl, exactly as passed to the acl_to_text(3) system call.
len_p	The original len_p, exactly as passed to the acl_to_text(3) system call.

Returns:

The message explaining the error. This message buffer is shared by all libexplain functions which do not supply a buffer in their argument list. This will be overwritten by the next call to any libexplain function which shares this buffer, including other threads.

Note:

This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

Example:

This function is intended to be used in a fashion similar to the following example:

 char *result = acl_to_text(acl, len_p);
 if (!result)
 {
     int err = errno;
     fprintf(stderr, "%s\n", explain_errno_acl_to_text(err, acl, len_p));
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_acl_to_text_or_die function.

void explain_message_acl_to_text	(	char *	message,
		int	message_size,
		acl_t	acl,
		ssize_t *	len_p
	)

The explain_message_acl_to_text function is used to obtain an explanation of an error returned by the acl_to_text(3) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

Parameters:

message	The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_size	The size in bytes of the location in which to store the returned message.
acl	The original acl, exactly as passed to the acl_to_text(3) system call.
len_p	The original len_p, exactly as passed to the acl_to_text(3) system call.

Example:

This function is intended to be used in a fashion similar to the following example:

 char *result = acl_to_text(acl, len_p);
 if (!result)
 {
     char message[3000];
     explain_message_acl_to_text(message, sizeof(message), acl, len_p);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_acl_to_text_or_die function.

void explain_message_errno_acl_to_text	(	char *	message,
		int	message_size,
		int	errnum,
		acl_t	acl,
		ssize_t *	len_p
	)

The explain_message_errno_acl_to_text function is used to obtain an explanation of an error returned by the acl_to_text(3) system call. The least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail.

Parameters:

message	The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
message_size	The size in bytes of the location in which to store the returned message.
errnum	The error value to be decoded, usually obtained from the errno global variable just before this function is called. This is necessary if you need to call any code between the system call to be explained and this function, because many libc functions will alter the value of errno.
acl	The original acl, exactly as passed to the acl_to_text(3) system call.
len_p	The original len_p, exactly as passed to the acl_to_text(3) system call.

Example:

This function is intended to be used in a fashion similar to the following example:

 char *result = acl_to_text(acl, len_p);
 if (!result)
 {
     int err = errno;
     char message[3000];
     explain_message_errno_acl_to_text(message, sizeof(message), err, acl,
         len_p);
     fprintf(stderr, "%s\n", message);
     exit(EXIT_FAILURE);
 }

The above code example is available pre-packaged as the explain_acl_to_text_or_die function.