strerror.c

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#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <ipxe/errortab.h>
#include <config/branding.h>

/** @file
 *
 * Error descriptions.
 *
 * The error numbers used by Etherboot are a superset of those defined
 * by the PXE specification version 2.1.  See errno.h for a listing of
 * the error values.
 *
 * To save space in ROM images, error string tables are optional.  Use
 * the ERRORMSG_XXX options in config.h to select which error string
 * tables you want to include.  If an error string table is omitted,
 * strerror() will simply return the text "Error 0x<errno>".
 *
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
FILE_SECBOOT ( PERMITTED );

/**
 * Find error description
 *
 * @v errno             Error number
 * @ret errortab        Error description, or NULL
 */
static struct errortab * find_error ( int errno ) {
        struct errortab *errortab;

        for_each_table_entry ( errortab, ERRORTAB ) {
                if ( errortab->errno == errno )
                        return errortab;
        }

        return NULL;
}

/**
 * Find closest error description
 *
 * @v errno             Error number
 * @ret errortab        Error description, or NULL
 *
 * 
 */
static struct errortab * find_closest_error ( int errno ) {
        struct errortab *errortab;

        /* First, look for an exact match */
        if ( ( errortab = find_error ( errno ) ) != NULL )
                return errortab;

        /* Second, try masking off the iPXE-specific bit and seeing if
         * we have an entry for the generic POSIX error message.
         */
        if ( ( errortab = find_error ( errno & 0x7f0000ff ) ) != NULL )
                return errortab;

        return NULL;
}

/**
 * Retrieve string representation of error number.
 *
 * @v errno/rc          Error number or return status code
 * @ret strerror        Pointer to error text
 *
 * If the error is not found in the linked-in error tables, generates
 * a generic "Error 0x<errno>" message.
 *
 * The pointer returned by strerror() is valid only until the next
 * call to strerror().
 *
 */
char * strerror ( int errno ) {
        static char errbuf[64];
        struct errortab *errortab;

        /* Allow for strerror(rc) as well as strerror(errno) */
        if ( errno < 0 )
                errno = -errno;

        /* Find the error description, if one exists */
        errortab = find_closest_error ( errno );

        /* Construct the error message */
        if ( errortab ) {
                snprintf ( errbuf, sizeof ( errbuf ),
                           "%s (" PRODUCT_ERROR_URI ")",
                           errortab->text, errno );
        } else {
                snprintf ( errbuf, sizeof ( errbuf ),
                           "Error %#08x (" PRODUCT_ERROR_URI ")",
                           errno, errno );
        }

        return errbuf;
}

/* Do not include ERRFILE portion in the numbers in the error table */
#undef ERRFILE
#define ERRFILE 0

/** The most common errors */
struct errortab common_errors[] __errortab = {
        __einfo_errortab ( EINFO_ENOERR ),
        __einfo_errortab ( EINFO_EACCES ),
        __einfo_errortab ( EINFO_ECANCELED ),
        __einfo_errortab ( EINFO_ECONNRESET ),
        __einfo_errortab ( EINFO_EINVAL ),
        __einfo_errortab ( EINFO_EIO ),
        __einfo_errortab ( EINFO_ENETUNREACH ),
        __einfo_errortab ( EINFO_ENODEV ),
        __einfo_errortab ( EINFO_ENOENT ),
        __einfo_errortab ( EINFO_ENOEXEC ),
        __einfo_errortab ( EINFO_ENOMEM ),
        __einfo_errortab ( EINFO_ENOSPC ),
        __einfo_errortab ( EINFO_ENOTCONN ),
        __einfo_errortab ( EINFO_ENOTSUP ),
        __einfo_errortab ( EINFO_EPERM ),
        __einfo_errortab ( EINFO_ERANGE ),
        __einfo_errortab ( EINFO_ETIMEDOUT ),
};