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4bd983bf34
work in BeOS port.
293 lines
7.8 KiB
C
293 lines
7.8 KiB
C
/*-------------------------------------------------------------------------
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*
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* support.c
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* BeOS Support functions
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*
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* Copyright (c) 1999-2001, Cyril VELTER
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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/* Support Globals */
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port_id beos_dl_port_in=0;
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port_id beos_dl_port_out=0;
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sem_id beos_shm_sem;
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/* Global var containing the postgres path */
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extern char pg_pathname[];
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/* Shared library loading doesn't work after fork in beos. The solution is to use an exact
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copy of the process and use it to perform the loading, then just map the Text and Data segment
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of the add-on in our address space. Both process must have the exact same memory mapping, so
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we use the postgres executable. When it's lauched with the -beossupportserver parameter, the
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postgres executable just run a loop to wait command on a port. Its only action is to load the addon,
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the beos_dl_open will then remap the good areas in the backend address space. */
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image_id beos_dl_open(char * filename)
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{
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image_id im;
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/* If a port doesn't exist, lauch support server */
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if ((beos_dl_port_in<=0)||(beos_dl_port_out<=0))
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{
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/* Create communication port */
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beos_dl_port_in=create_port(50,"beos_support_in");
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beos_dl_port_out=create_port(50,"beos_support_in");
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if ((beos_dl_port_in<=0)||(beos_dl_port_out<=0))
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{
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elog(NOTICE, "Error loading BeOS support server : can't create communication ports");
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return B_ERROR;
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}
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else
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{
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char Cmd[4000];
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/* Build arg list */
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sprintf(Cmd,"%s -beossupportserver %d %d &",pg_pathname,(int)beos_dl_port_in,(int)beos_dl_port_out);
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/* Lauch process */
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system(Cmd);
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}
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}
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/* Add-on loading */
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/* Send command '1' (load) to the support server */
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write_port(beos_dl_port_in,1,filename,strlen(filename)+1);
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/* Read Object Id */
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read_port(beos_dl_port_out,&im,NULL,0);
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/* Checking integrity */
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if (im<0)
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{
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elog(NOTICE, "Can't load this add-on ");
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return B_ERROR;
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}
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else
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{
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/* Map text and data segment in our address space */
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char datas[4000];
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int32 area;
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int32 resu;
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void* add;
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/* read text segment id and address */
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read_port(beos_dl_port_out,&area,datas,4000);
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read_port(beos_dl_port_out,(void*)&add,datas,4000);
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/* map text segment in our address space */
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resu=clone_area(datas,&add,B_EXACT_ADDRESS,B_READ_AREA|B_WRITE_AREA,area);
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if (resu<0)
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{
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/* If we can't map, we are in reload case */
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/* delete the mapping */
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resu=delete_area(area_for(add));
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/* Remap */
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resu=clone_area(datas,&add,B_EXACT_ADDRESS,B_READ_AREA|B_WRITE_AREA,area);
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if (resu<0)
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{
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elog(NOTICE, "Can't load this add-on : map text error");
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}
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}
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/* read text segment id and address */
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read_port(beos_dl_port_out,&area,datas,4000);
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read_port(beos_dl_port_out,(void*)&add,datas,4000);
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/* map text segment in our address space */
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resu=clone_area(datas,&add,B_EXACT_ADDRESS,B_READ_AREA|B_WRITE_AREA,area);
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if (resu<0)
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{
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/* If we can't map, we are in reload case */
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/* delete the mapping */
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resu=delete_area(area_for(add));
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/* Remap */
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resu=clone_area(datas,&add,B_EXACT_ADDRESS,B_READ_AREA|B_WRITE_AREA,area);
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if (resu<0)
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{
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elog(NOTICE, "Can't load this add-on : map data error");
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}
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}
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return im;
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}
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}
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status_t beos_dl_close(image_id im)
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{
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/* unload add-on */
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int32 resu;
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write_port(beos_dl_port_in,2,&im,4);
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read_port(beos_dl_port_out,&resu,NULL,0);
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return resu;
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}
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/* Main support server loop */
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void beos_startup(int argc,char** argv)
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{
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if (strlen(argv[0]) >= 10 && !strcmp(argv[0] + strlen(argv[0]) - 10, "postmaster"))
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{
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/* We are in the postmaster, create the protection semaphore for shared mem remapping */
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beos_shm_sem=create_sem(1,"beos_shm_sem");
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}
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if (argc > 1 && strcmp(argv[1], "-beossupportserver") == 0)
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{
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/* We are in the support server, run it ... */
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port_id port_in;
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port_id port_out;
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/* Get back port ids from arglist */
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sscanf(argv[2],"%d",(int*)(&port_in));
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sscanf(argv[3],"%d",(int*)(&port_out));
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/* Main server loop */
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for (;;)
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{
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int32 opcode=0;
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char datas[4000];
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/* Wait for a message from the backend :
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1 : load a shared object
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2 : unload a shared object
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any other : exit support server */
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read_port(port_in,&opcode,datas,4000);
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switch(opcode)
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{
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image_id addon;
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image_info info_im;
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area_info info_ar;
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/* Load Add-On */
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case 1 :
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/* Load shared object */
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addon=load_add_on(datas);
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/* send back the shared object Id */
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write_port(port_out,addon,NULL,0);
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/* Get Shared Object infos */
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get_image_info(addon,&info_im);
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/* get text segment info */
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get_area_info(area_for(info_im.text),&info_ar);
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/* Send back area_id of text segment */
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write_port(port_out,info_ar.area,info_ar.name,strlen(info_ar.name)+1);
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/* Send back real address of text segment */
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write_port(port_out,(int)info_ar.address,info_ar.name,strlen(info_ar.name)+1);
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/* get data segment info */
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get_area_info(area_for(info_im.data),&info_ar);
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/* Send back area_id of data segment */
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write_port(port_out,info_ar.area,info_ar.name,strlen(info_ar.name)+1);
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/* Send back real address of data segment */
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write_port(port_out,(int)info_ar.address,info_ar.name,strlen(info_ar.name)+1);
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break;
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/* UnLoad Add-On */
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case 2 :
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/* Unload shared object and send back the result of the operation */
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write_port(port_out,unload_add_on(*((int*)(datas))),NULL,0);
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break;
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/* Cleanup and exit */
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default:
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/* Free system resources */
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delete_port(port_in);
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delete_port(port_out);
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/* Exit */
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exit(0);
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break;
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}
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}
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/* Never be there */
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exit(1);
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}
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}
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/* The behavior of fork is borken on beos regarding shared memory. In fact
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all shared memory areas are clones in copy on write mode in the new process.
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We need to do a remapping of these areas. Just afer the fork we performe the
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following actions :
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* Find all areas with a name begining by SYS_V_IPC_ in our process
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(areas created by the SYSV IPC emulation functions). The name is
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followed by the IPC KEY in decimal format
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* For each area we do :
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* 1 : Get its name
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* 2 : destroy it
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* 3 : find another area with the exact same name
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* 4 : clone it in our address space with a different name
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There is a race condition in 3-4 : if there two fork in a very short
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time, in step 3 we might end up with two areas with the same name, and no
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possibility to find the postmaster one. So the whole process is protected
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by a semaphore which is acquires just before the fork and released in case
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of fork failure or just after the end of the remapping.*/
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void beos_before_backend_startup(void)
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{
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/* Just before forking, acquire the semaphore */
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if(acquire_sem(beos_shm_sem)!=B_OK)
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exit(1); /* Fatal error, exiting with error */
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}
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void beos_backend_startup_failed(void)
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{
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/* The foek failed, just release the semaphore */
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release_sem(beos_shm_sem);
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}
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void beos_backend_startup(void)
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{
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char nom[50];
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char nvnom[50];
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area_info inf;
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int32 cook=0;
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/* Perform the remapping process */
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/* Loop in all our team areas */
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while (get_next_area_info(0, &cook, &inf) == B_OK)
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{
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strcpy(nom,inf.name);
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strcpy(nvnom,inf.name);
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nom[9]=0;
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nvnom[5]='i';
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/* Is it a SYS V area ? */
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if (!strcmp(nom,"SYSV_IPC_"))
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{
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void* area_address;
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area_id area_postmaster;
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/* Get the area address */
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area_address=inf.address;
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/* Destroy the bad area */
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delete_area(inf.area);
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/* Find the postmaster area */
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area_postmaster=find_area(inf.name);
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/* Compute new area name */
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sprintf(nvnom,"SYSV_IPC %d",area_postmaster);
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/* Clone it at the exact same address */
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clone_area(nvnom,&area_address,B_CLONE_ADDRESS,B_READ_AREA|B_WRITE_AREA,area_postmaster);
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}
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}
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/* remapping done release semaphore to allow other backend to startup */
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release_sem(beos_shm_sem);
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}
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