explain_acl_to_text(3)

NAME
explain_acl_to_text - explain acl_to_text(3) errors

SYNOPSIS
#include <libexplain/acl_to_text.h>

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

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

  explain_acl_to_text
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.

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)
    {
    fprintf(stderr, "%s\n", explain_acl_to_text(acl, len_p));
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_acl_to_text_or_die(3) function.

  explain_errno_acl_to_text
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(errno), but usually it will do much better, and indicate the underlying cause in more detail.

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(3) function.

  explain_message_acl_to_text
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(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.

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(3) function.

  explain_message_errno_acl_to_text
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(errno), but usually it will do much better, and indicate the underlying cause in more detail.

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(3) function.

SEE ALSO

acl_to_text(3)
    convert an ACL to text

explain_acl_to_text_or_die(3)
    convert an ACL to text and report errors

COPYRIGHT
libexplain version
Copyright (C) 2013 Peter Miller