uxshm.c

Netscape NSPR库源码

    {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0 );
        PR_LOG(_pr_shm_lm, PR_LOG_DEBUG, ( "PR_OpenSharedMemory: New PRSharedMemory out of memory")); 
        return( NULL );
    }

    shm->ipcname = PR_MALLOC( strlen( ipcname ) + 1 );
    if ( NULL == shm->ipcname )
    {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0 );
        PR_LOG(_pr_shm_lm, PR_LOG_DEBUG, ( "PR_OpenSharedMemory: New shm->ipcname out of memory")); 
        return( NULL );
    }

    /* copy args to struct */
    strcpy( shm->ipcname, ipcname );
    shm->size = size; 
    shm->mode = mode;
    shm->flags = flags;
    shm->ident = _PR_SHM_IDENT;

    /*
    ** Create the shared memory
    */
    if ( flags & PR_SHM_CREATE )  {
        int oflag = (O_CREAT | O_RDWR);
        
        if ( flags & PR_SHM_EXCL )
            oflag |= O_EXCL;
        shm->id = shm_open( shm->ipcname, oflag, shm->mode );
    } else {
        shm->id = shm_open( shm->ipcname, O_RDWR, shm->mode );
    }

    if ( -1 == shm->id )  {
        _PR_MD_MAP_DEFAULT_ERROR( errno );
        PR_LOG(_pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_OpenSharedMemory(): shm_open failed: %s, OSError: %d",
                shm->ipcname, PR_GetOSError())); 
        PR_DELETE( shm->ipcname );
        PR_DELETE( shm );
        return(NULL);
    }

    end = ftruncate( shm->id, shm->size );
    if ( -1 == end ) {
        _PR_MD_MAP_DEFAULT_ERROR( errno );
        PR_LOG(_pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_OpenSharedMemory(): ftruncate failed, OSError: %d",
                PR_GetOSError()));
        PR_DELETE( shm->ipcname );
        PR_DELETE( shm );
        return(NULL);
    }

    return(shm);
} /* end _MD_OpenSharedMemory() */

extern void * _MD_AttachSharedMemory( PRSharedMemory *shm, PRIntn flags )
{
    void        *addr;
    PRIntn      prot = (PROT_READ | PROT_WRITE);

    PR_ASSERT( shm->ident == _PR_SHM_IDENT );

    if ( PR_SHM_READONLY == flags)
        prot ^= PROT_WRITE;

    addr = mmap( (void*)0, shm->size, prot, MAP_SHARED, shm->id, 0 );
    if ((void*)-1 == addr )
    {
        _PR_MD_MAP_DEFAULT_ERROR( errno );
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_AttachSharedMemory(): mmap failed: %s, errno: %d",
                shm->ipcname, PR_GetOSError()));
        addr = NULL;
    } else {
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_AttachSharedMemory(): name: %s, attached at: %p", shm->ipcname, addr));
    }
    
    return addr;
}    

extern PRStatus _MD_DetachSharedMemory( PRSharedMemory *shm, void *addr )
{
    PRStatus    rc = PR_SUCCESS;
    PRIntn      urc;

    PR_ASSERT( shm->ident == _PR_SHM_IDENT );

    urc = munmap( addr, shm->size );
    if ( -1 == urc )
    {
        rc = PR_FAILURE;
        _PR_MD_MAP_DEFAULT_ERROR( errno );
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_DetachSharedMemory(): munmap failed: %s, errno: %d", 
                shm->ipcname, PR_GetOSError()));
    }
    return rc;
}    

extern PRStatus _MD_CloseSharedMemory( PRSharedMemory *shm )
{
    int urc;
    
    PR_ASSERT( shm->ident == _PR_SHM_IDENT );

    urc = close( shm->id );
    if ( -1 == urc ) {
        _PR_MD_MAP_CLOSE_ERROR( errno );
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_CloseSharedMemory(): close() failed, error: %d", PR_GetOSError()));
        return(PR_FAILURE);
    }
    PR_DELETE( shm->ipcname );
    PR_DELETE( shm );
    return PR_SUCCESS;
}    

extern PRStatus _MD_DeleteSharedMemory( const char *name )
{
    PRStatus    rc = PR_SUCCESS;
    PRUintn     urc;
    char        ipcname[PR_IPC_NAME_SIZE];

    rc = _PR_MakeNativeIPCName( name, ipcname, PR_IPC_NAME_SIZE, _PRIPCShm );
    if ( PR_FAILURE == rc )
    {
        PR_SetError( PR_UNKNOWN_ERROR , errno );
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_OpenSharedMemory(): _PR_MakeNativeIPCName() failed: %s", name ));
        return rc;
    }

    urc = shm_unlink( ipcname );
    if ( -1 == urc ) {
        rc = PR_FAILURE;
        _PR_MD_MAP_DEFAULT_ERROR( errno );
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_DeleteSharedMemory(): shm_unlink failed: %s, errno: %d", 
                ipcname, PR_GetOSError()));
    } else {
        PR_LOG( _pr_shm_lm, PR_LOG_DEBUG, 
            ("_MD_DeleteSharedMemory(): %s, success", ipcname));
    }

    return rc;
} /* end _MD_DeleteSharedMemory() */
#endif



/*
** Unix implementation for anonymous memory (file) mapping
*/
extern PRLogModuleInfo *_pr_shma_lm;

#include <unistd.h>

extern PRFileMap* _md_OpenAnonFileMap( 
    const char *dirName,
    PRSize      size,
    PRFileMapProtect prot
)
{
    PRFileMap   *fm = NULL;
    PRFileDesc  *fd;
    int         osfd;
    PRIntn      urc;
    PRIntn      mode = 0600;
    char        *genName;
    pid_t       pid = getpid(); /* for generating filename */
    PRThread    *tid = PR_GetCurrentThread(); /* for generating filename */
    int         incr; /* for generating filename */
    const int   maxTries = 20; /* maximum # attempts at a unique filename */
    PRInt64     size64; /* 64-bit version of 'size' */

    /*
    ** generate a filename from input and runtime environment
    ** open the file, unlink the file.
    ** make maxTries number of attempts at uniqueness in the filename
    */
    for ( incr = 0; incr < maxTries ; incr++ ) {
        genName = PR_smprintf( "%s/.NSPR-AFM-%d-%p.%d", 
            dirName, (int) pid, tid, incr );
        if ( NULL == genName ) {
            PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
                ("_md_OpenAnonFileMap(): PR_snprintf(): failed, generating filename"));
            goto Finished;
        }
        
        /* create the file */
        osfd = open( genName, (O_CREAT | O_EXCL | O_RDWR), mode );
        if ( -1 == osfd ) {
            if ( EEXIST == errno )  {
                PR_smprintf_free( genName );
                continue; /* name exists, try again */
            } else {
                _PR_MD_MAP_OPEN_ERROR( errno );
                PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
                    ("_md_OpenAnonFileMap(): open(): failed, filename: %s, errno: %d", 
                        genName, PR_GetOSError()));
                PR_smprintf_free( genName );
                goto Finished;
            }
        }
        break; /* name generation and open successful, break; */
    } /* end for() */

    if ( incr == maxTries ) {
        PR_ASSERT( -1 == osfd );
        PR_ASSERT( EEXIST == errno );
        _PR_MD_MAP_OPEN_ERROR( errno );
        goto Finished;
    }

    urc = unlink( genName );
    if ( -1 == urc ) {
        _PR_MD_MAP_UNLINK_ERROR( errno );
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("_md_OpenAnonFileMap(): failed on unlink(), errno: %d", errno));
        PR_smprintf_free( genName );
        close( osfd );
        goto Finished;        
    }
    PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
        ("_md_OpenAnonFileMap(): unlink(): %s", genName ));

    PR_smprintf_free( genName );

    fd = PR_ImportFile( osfd );
    if ( NULL == fd ) {
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("_md_OpenAnonFileMap(): PR_ImportFile(): failed"));
        goto Finished;        
    }
    PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
        ("_md_OpenAnonFileMap(): fd: %p", fd ));

    urc = ftruncate( fd->secret->md.osfd, size );
    if ( -1 == urc ) {
        _PR_MD_MAP_DEFAULT_ERROR( errno );
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("_md_OpenAnonFileMap(): failed on ftruncate(), errno: %d", errno));
        PR_Close( fd );
        goto Finished;        
    }
    PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
        ("_md_OpenAnonFileMap(): ftruncate(): size: %d", size ));

    LL_UI2L(size64, size);  /* PRSize (size_t) is unsigned */
    fm = PR_CreateFileMap( fd, size64, prot );
    if ( NULL == fm )  {
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("PR_OpenAnonFileMap(): failed"));
        PR_Close( fd );
        goto Finished;        
    }
    fm->md.isAnonFM = PR_TRUE; /* set fd close */

    PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
        ("_md_OpenAnonFileMap(): PR_CreateFileMap(): fm: %p", fm ));

Finished:    
    return(fm);
} /* end md_OpenAnonFileMap() */

/*
** _md_ExportFileMapAsString()
**
**
*/
extern PRStatus _md_ExportFileMapAsString(
    PRFileMap *fm,
    PRSize    bufSize,
    char      *buf
)
{
    PRIntn  written;
    PRIntn  prot = (PRIntn)fm->prot;
    
    written = PR_snprintf( buf, bufSize, "%ld:%d",
        fm->fd->secret->md.osfd, prot );
        
    return((written == -1)? PR_FAILURE : PR_SUCCESS);
} /* end _md_ExportFileMapAsString() */


extern PRFileMap * _md_ImportFileMapFromString(
    const char *fmstring
)
{
    PRStatus    rc;
    PRInt32     osfd;
    PRIntn      prot; /* really: a PRFileMapProtect */
    PRFileDesc  *fd;
    PRFileMap   *fm = NULL; /* default return value */
    PRFileInfo64 info;

    PR_sscanf( fmstring, "%ld:%d", &osfd, &prot );

    /* import the os file descriptor */
    fd = PR_ImportFile( osfd );
    if ( NULL == fd ) {
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("_md_ImportFileMapFromString(): PR_ImportFile() failed"));
        goto Finished;
    }

    rc = PR_GetOpenFileInfo64( fd, &info );
    if ( PR_FAILURE == rc )  {
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("_md_ImportFileMapFromString(): PR_GetOpenFileInfo64() failed"));    
        goto Finished;
    }

    fm = PR_CreateFileMap( fd, info.size, (PRFileMapProtect)prot );
    if ( NULL == fm ) {
        PR_LOG( _pr_shma_lm, PR_LOG_DEBUG,
            ("_md_ImportFileMapFromString(): PR_CreateFileMap() failed"));    
    }

Finished:
    return(fm);
} /* end _md_ImportFileMapFromString() */