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* 
* load<i class="textVariable">Omf</i>FmtInit - initialize the OMF loader 
* 
* This routine initializes the correct relocator unit for the current target 
* CPU. 
* 
* RETURNS: OK or ERROR. 
*/ 
 
STATUS load<i class="textVariable">Omf</i>FmtInit (void) 
    { 
     /* OMF relocs routines ( + 1 for the optionnal SegInit routine) */ 
 
    DYNLK_FUNC  relocDllFv[NB_MANDATORY_RELOC_RTNS + 1]; 
 
    relocDllFv[0].name = (char *)tgtSegRelocatorRtnNameGet(); 
    relocDllFv[1].name = (char *)tgtModuleVerifyRtnNameGet(); 
    relocDllFv[2].name = (char *)tgtRelocInitRtnNameGet(); 
 
    /* Link the relocator */ 
 
    if (loadRelocLink( relocDllFv, NB_MANDATORY_RELOC_RTNS+1) != OK) 
        { 
        return ERROR; 
        } 
 
        /* relocation routine pointer */ 
    <i class="textVariable">omf</i>RelSegRtn = (FUNCPTR) relocDllFv[0].func;  
 
        /* module verification routine */ 
    <i class="textVariable">omf</i>ModuleVerify = (FUNCPTR) relocDllFv[1].func;  
 
    /* if an Init routine exists for this relocator, run it */ 
 
    if (relocDllFv[2].func != NULL) 
    (*relocDllFv[2].func)(); 
 
    return (OK); 
    }</a></b></pre>
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<h5 class="HU"><i><a name="85408"><b class="routine"><i class="routine">load</i></b><i class="term">Omf</i><b class="routine"><i class="routine">FmtCheck</i></b><b>(&nbsp;)</b></a></i></h5>
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<dd><p class="Body"><a name="85409"> </a>This routine is the second entry point; it checks the file format.</p>
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<dd><pre class="Code2"><b><a name="85410">STATUS load<i class="term">Omf</i>FmtCheck (int moduleFd, BOOL * pFormatIsKnown);</a></b></pre>
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<dd><p class="Body"><a name="85411"> </a>The input parameter is:</p>
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<dd><div class="Item"><a name="85412"> </a><b class="symbol_lc">int moduleFd</b></div>
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<dd><div class="Indent"><a name="85418"> </a>The file descriptor of the module object.</div>
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<dd><p class="Body"><a name="85419"> </a>The output parameter is:</p>
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<dd><div class="Item"><a name="85420"> </a><b class="symbol_UC">BOOL </b><b class="symbol_lc">* pFormatIsKnown</b></div>
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<dd><div class="Indent"><a name="85421"> </a>A pointer to a boolean that holds the answer.</div>
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<dd><p class="Body"><a name="85422"> </a>The return value is:</p>
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<dd><div class="Item"><a name="85423"> </a><b class="symbol_UC">STATUS</b> </div>
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<dd><div class="Indent"><a name="85424"> </a><b class="symbol_UC">OK </b>or <b class="symbol_UC">ERROR</b>. </div>
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<dd><p class="Body"><a name="85425"> </a>The target server calls <b class="routine"><i class="routine">load</i></b><i class="term">Omf</i><b class="routine"><i class="routine">FmtCheck</i></b><b>(&nbsp;)</b> during initialization to determine if a file is in the appropriate format for the loader. Files submitted to this routine should be core files only. (See <a href="c-loader9.html#85089"><i class="title">3.9.2&nbsp;Installing a Shared-Library Manager</i></a>.) Note that in this example, the first four bytes in the object module are arbitrarily considered a magic number.</p>
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<h4 class="EntityTitle"><a name="85429"><font face="Helvetica, sans-serif" size="-1" class="sans">Example 3-3:&nbsp;&nbsp;<b class="routine"><i class="routine">load</i></b><i class="term">Omf</i><b class="routine"><i class="routine">FmtCheck</i></b><b>(&nbsp;)</b> </font></a></h4>
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<dd><pre class="Code"><b><a name="86688">/************************************************************************ 
* 
* load<i class="term">Omf</i>FmtCheck - see if the object file is in a known format 
* 
* This routine contains the heuristic required to determine if the object 
* file belongs to the OMF handled by this OMF reader, and is intended for 
* the appropriate target architecture. 
* 
* RETURNS: OK or ERROR if file cannot be read. 
*/ 
 
STATUS load<i class="term">Omf</i>FmtCheck 
    ( 
    int         moduleFd,       /* module object descriptor */ 
    BOOL *      pFormatIsKnown  /* hold the answer */ 
    ) 
    { 
    UINT32      magicNumber;    /* OMF magic number */ 
    BOOL        swap;           /* not used here */ 
 
    /* Get the magic number */ 
 
    if (read (moduleFd, (char *)&amp;magicNumber, 4) != 4) 
        return (ERROR); 
 
    /* Check the module format */ 
 
    if (load<i class="term">Omf</i>ModuleIsOk (magicNumber, &amp;swap))            *pFormatIsKnown = TRUE; 
    else            *pFormatIsKnown = FALSE; 
 
    return (OK); 
    }</a></b></pre>
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<h5 class="HU"><i><a name="85441"><b class="routine"><i class="routine">load</i></b><i class="term">Omf</i><b class="routine"><i class="routine">FmtManage</i></b><b>(&nbsp;)</b> </a></i></h5>
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<dd><p class="Body"><a name="85442"> </a>This routine is the third and main entry point; it carries out the load process.</p>
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<dd><pre class="Code2"><b><a name="85443">STATUS load<i class="term">Omf</i>FmtManage (char * pObjMod, int loadFlag, void ** ppText, 
                        void ** ppData, void ** ppBss, SYMTAB_ID symTbl, 
                        MODULE_ID moduleId, SEG_INFO *pSeg);</a></b></pre>
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<dd><p class="Body"><a name="85446"> </a>The input parameters are:</p>
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<dd><div class="Item"><a name="85447"> </a><b class="symbol_lc">char * pObjMode</b> </div>
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<dd><div class="Indent"><a name="85448"> </a>A pointer to the beginning of the object-module copy in memory.</div>
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<dd><div class="Item"><a name="85449"> </a><b class="symbol_lc">int loadFlag</b> </div>
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<dd><div class="Indent"><a name="85450"> </a>The loader option(s). See <b class="file">loadlib.h</b> for the definition of all macros associated with the options.</div>
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<dd><div class="Item"><a name="85451"> </a><b class="symbol_UC">SYMTAB_ID</b><b class="symbol_lc"> symTbl</b> </div>
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<dd><div class="Indent"><a name="85452"> </a>The target symbol table. This is actually a pointer to a <b class="symbol_UC">SYMTAB</b> structure. See <b class="file">symlib.h</b> for a description of this structure.</div>
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<dd><div class="Item"><a name="85453"> </a><b class="symbol_UC">MODULE_ID</b><b class="symbol_lc"> moduleId</b> </div>
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<dd><div class="Indent"><a name="85454"> </a>A pointer to the object-module descriptor (<b class="symbol_UC">MODULE</b> structure). See <b class="file">module.h</b> for a description of this structure.</div>
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<dd><p class="Body"><a name="85455"> </a>The input-output parameters are:</p>
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<dd><div class="Item"><a name="85456"> </a><b class="symbol_lc">void ** ppText</b> </div>
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<dd><div class="Indent"><a name="85457"> </a>Holds the required address where the text segment must be stored, or <b class="symbol_UC">NULL</b> if no special address is required. When the routine returns, it is set with the final address of the text segment (which may or may not have changed).</div>
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<dd><div class="Item"><a name="85458"> </a><b class="symbol_lc">void ** ppData</b> </div>
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<dd><div class="Indent"><a name="85459"> </a>Holds the required address for the data segment, or <b class="symbol_UC">NULL</b>. It returns the final address of the data segment.</div>
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<dd><div class="Item"><a name="85460"> </a><b class="symbol_lc">void ** ppBss</b> </div>
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<dd><div class="Indent"><a name="85461"> </a>Holds the required address for the <i class="term">bss </i>segment, or <b class="symbol_UC">NULL</b>. It returns the final address of the <i class="term">bss </i>segment.</div>
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<dd><div class="Item"><a name="85462"> </a><b class="symbol_UC">SEG_INFO </b><b>* </b><b class="symbol_lc">pSeg</b> </div>
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<dd><div class="Indent"><a name="85463"> </a>A pointer to a structure that holds all information about segments required to process the object file. See <b class="file">loadLib.h </b>for a description of the <b class="symbol_UC">SEG_INFO</b> structure.</div>
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<dd><p class="Body"><a name="85464"> </a>The return value is:</p>
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<dd><div class="Item"><a name="85465"> </a><b class="symbol_UC">STATUS</b> <b class="symbol_UC"></b></div>
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<dd><div class="Indent"><a name="85466"> </a><b class="symbol_UC">OK </b>or <b class="symbol_UC">ERROR</b>. </div>
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<hr><div class="CalloutCell"><a name="88651"><b class="symbol_UC"><font face="Helvetica, sans-serif" size="-1" class="sans">NOTE:  </font></b></a>When no address is required (<b class="symbol_UC">NULL</b> pointers are given), the value <b class="symbol_UC">LOAD_NO_ADDRESS </b>is assigned to the fields pAddrText, pAddrData, and pAddrBss of the <b class="symbol_UC">SEG_INFO</b> structure.</div>
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<dd><p class="Body"><a name="85476"> </a>The steps taken by <b class="routine"><i class="routine">load</i></b><i class="term">Omf</i><b class="routine"><i class="routine">FmtManage</i></b><b>(&nbsp;)</b> are summarized below and in <a href="c-loader9.html#85514">Example&nbsp;3-4</a>. The steps flagged with (*) are described in more detail in later code examples.</p>
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<p><ol class="List"><li value="1."><a name="85480"> </a>Check the loader options for consistency.</li></ol></p>
<p><ol class="List"><li value="2."><a name="85481"> </a>Check whether the host and target byte orders are identical. (*)</li></ol></p>
<p><ol class="List"><li value="3."><a name="85482"> </a>Read in the module headers. (*)</li></ol></p>
<p><ol class="List"><li value="4."><a name="85483"> </a>Determine the final size of the three segments: text, data, <i class="term">bss. </i>(*)</li></ol></p>
<p><ol class="List"><li value="5."><a name="85484"> </a>Read in the module symbol table and string table. (*)</li></ol></p>
<p><ol class="List"><li value="6."><a name="85485"> </a>Determine the compiler signature and publish the builder. (*)</li></ol></p>
<p><ol class="List"><li value="7."><a name="85486"> </a>Allocate memory for the segments, if required.</li></ol></p>
<p><ol class="List"><li value="8."><a name="85487"> </a>Read in the various module sections. (*)</li></ol></p>
<p><ol class="List"><li value="9."><a name="85488"> </a>Check that the core-file checksum and the target-text-section checksum match.</li></ol></p>
<p><ol class="List"><li value="10."><a name="85489"> </a>Process the module symbol table. (*)</li></ol></p>
<p><ol class="List"><li value="11."><a name="85490"> </a>Relocate the text and data segments, if required. (*)</li></ol></p>
<p><ol class="List"><li value="12."><a name="85491"> </a>Download text and data segments, if required. (*)</li></ol></p>
<p><ol class="List"><li value="13."><a name="85492"> </a>Apply virtual memory protection and cache update, if required.</li></ol></p>
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<dd>&nbsp;&nbsp;&nbsp;
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<hr><div class="CalloutCell"><a name="88686"><b class="symbol_UC"><font face="Helvetica, sans-serif" size="-1" class="sans">NOTE:  </font></b></a>If the loader calls <b class="routine"><i class="routine">loadOutputToFile</i></b><b>(&nbsp;)</b>, it does not download the module to the target memory. It returns with a <b class="routine"><i class="routine">loadOutputToFile</i></b><b>(&nbsp;)</b><b class="routine"><i class="routine"> </i></b>status code instead. This facility allows automated testing without live hardware.</div>
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<hr><div class="CalloutCell"><a name="86541"><b class="symbol_UC"><font face="Helvetica, sans-serif" size="-1" class="sans">NOTE:  </font></b></a>Even for a fully linked file, the <b class="symbol_UC">SEG_INFO</b> structure must be filled in because it is used for module management, core file verification, and cache and virtual memory management. If a fully linked file holds several text, data, and <i class="term">bss </i>sections, for instance, one of each type should be chosen as representative and the information loaded into the <b class="symbol_UC">SEG_INFO</b> structure.</div>
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