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Please see the .\" License for the specific language governing rights and limitations .\" under the License. .\" .\" @(#)getattrlistbulk.2 . .Dd November 15, 2013 .Dt GETATTRLISTBULK 2 .Os Darwin .Sh NAME .Nm getattrlistbulk .Nd get file system attributes for multiple directory entries .Sh SYNOPSIS .Fd #include .Fd #include .Pp .Ft int .Fn getattrlistbulk "int dirfd" "struct attrlist * attrList" "void * attrBuf" "size_t attrBufSize" "uint64_t options" . . .Sh DESCRIPTION The .Fn getattrlistbulk function iterates over the items in a directory and returns information about each directory entry like .Xr getattrlist 2 . Note: when .Fn getattrlistbulk returns information about a symbolic link, the information returned is about the link itself, not the target of the link. The order of the directory entries (and their associated metadata) vended by .Fn getattrlistbulk is not specified. Some file systems may return entries in lexicographic sort order and others may not. .Pp The function reads directory entries from the directory referenced by the file descriptor .Fa dirfd . The .Fa attrList parameter determines what attributes are returned for each entry. Attributes of those directory entries are placed into the buffer specified by .Fa attrBuf and .Fa attrBufSize . The .Fa options parameter allows you to modify the behaviour of the call. .Pp . .Pp . .\" dirfd parameter . The .Fa dirfd parameter must be a file descriptor that references a directory that you have opened for reading. .Pp . .\" attrList parameter . The .Fa attrList parameter is a pointer to an .Vt attrlist structure. All fields of this structure must be filled before calling the function. See the discussion of the .Xr getattrlist 2 function for a detailed description of this structure. To get an attribute, the corresponding bit in the appropriate .Vt attrgroup_t field of the .Vt attrlist structure must be set. Volume attributes cannot be requested but all other supported getattrlist attributes can be used. For this function, .Dv ATTR_CMN_NAME and .Dv ATRR_CMN_RETURNED_ATTRS are required and the absence of these attributes in the attrList parameter results in an error. Note that not all attributes supported by .Fn getattrlist may be vended back by this call, which is why the aforementioned flag must be supplied. In particular .Dv ATTR_CMN_FULLPATH may not be valid on all directory entries whose information is requested by this call. .Pp . .\" attrBuf and attrBufSize parameters . The .Fa attrBuf and .Fa attrBufSize parameters specify a buffer into which the function places attribute values. The attributes for any given directory entry are grouped together and packed in exactly the same way as they are returned from .Xr getattrlist 2 and are subject to exactly the same alignment specifications and restrictions. These groups are then placed into the buffer, one after another. .Xr getattrlist 2 should be consulted on details of the attributes that can be requested for and returned. The name of the entry itself is provided by the .Dv ATTR_CMN_NAME attribute. Each group starts with a leading .Vt uint32_t , which will always be 8-byte aligned that contains the overall length of the group. You can step from one group to the next by simply adding this length to your pointer. The sample code (below) shows how to do this. The initial contents of this buffer are ignored. .Pp . .\" options parameter . The .Fa options parameter is a bit set that controls the behaviour of .Fn getattrlistbulk . The following option bits are defined. . .Bl -tag -width FSOPT_PACK_INVAL_ATTRS . .It FSOPT_PACK_INVAL_ATTRS If this is bit is set, then all requested attributes, even ones that are not supported by the object or file file system, will be returned the attrBuf. The attributes actually returned can be determined by looking at the attribute_set_t structure returned for the .Dv ATTR_CMN_RETURNED_ATTRS attribute. Default values will be returned for invalid attributes and should be ignored. .Pp Please see the discussion of this flag in .Xr getattrlist 2 . .El .Pp If .Dv ATTR_CMN_ERROR has been requested and an error specific to a directory entry occurs, an error will be reported. The .Dv ATTR_CMN_ERROR attribute is a uint32_t which, if non-zero, specifies the error code that was encountered during the processing of that directory entry. The .Dv ATTR_CMN_ERROR attribute will be after .Dv ATTR_CMN_RETURNED_ATTRS attribute in the returned buffer. .Pp It is typical to ask for a combination of common, file, and directory attributes and then use the value of the .Dv ATTR_CMN_OBJTYPE attribute to parse the resulting attribute buffer. .Pp A directory which is a mount point for a file system, will have a value of "DIR_MNTSTATUS_MNTPOINT" set for it's the ATTR_DIR_MOUNTSTATUS attribute entry. However the attributes for the mount point will be those from the (underlying) file system. The only way to get the attributes of mounted root directory is to call getattrlist(2) on the mount point. . .Sh RETURN VALUES Upon successful completion the numbers of entries successfully read is returned. A value of 0 indicates there are no more entries. Once 0 is returned, no further entries are returned even if new entries are added to the directory. Directory iteration should be restarted either by repostioning the offset to 0 by .Fn lseek or by closing the file descriptor and opening the directory again. On error, a value of -1 is returned and .Va errno is set to indicate the error. .Pp When iterating all entries in a directory, .Fn getattrlistbulk is called repeatedly until a 0 is returned. In such a case if .Fn readdir and .Fn getattrlistbulk calls on the same fd are mixed, the behavior is undefined. .Pp .Sh ERRORS .Fn getattrlistbulk will fail if: .Bl -tag -width Er . .It Bq Er EBADF .Fa dirfd is not a valid file descriptor for a directory open for reading. . .It Bq Er ENOTDIR The File descriptor .Fa dirfd is not a directory. . .It Bq Er EACCES Search permission is denied on the directory whose descriptor is given as input. . .It Bq Er EFAULT .Fa attrList or .Em attrBuf points to an invalid address. . .It Bq Er ERANGE The buffer was too small. . .It Bq Er EINVAL The .Fa bitmapcount field of .Fa attrList is not .Dv ATTR_BIT_MAP_COUNT . . .It Bq Er EINVAL An invalid attribute was requested. . .It Bq Er EINVAL Volume attributes were requested. . .It Bq Er EINVAL .Dv ATTR_CMN_NAME or .Dv ATTR_CMN_RETURNED_ATTRS was not requested in the attrList parameter. . .It Bq Er EIO An I/O error occurred while reading from or writing to the file system. .El .Pp . .Sh EXAMPLES . The following code lists the contents of a directory using .Fn getattrlistbulk . The listing includes the file type. . .Bd -literal #include #include #include #include #include #include #include #include #include #include #include typedef struct val_attrs { uint32_t length; attribute_set_t returned; uint32_t error; attrreference_t name_info; char *name; fsobj_type_t obj_type; } val_attrs_t; void demo(const char *dirpath) { int error; int dirfd; struct attrlist attrList; char *entry_start; char attrBuf[256]; memset(&attrList, 0, sizeof(attrList)); attrList.bitmapcount = ATTR_BIT_MAP_COUNT; attrList.commonattr = ATTR_CMN_RETURNED_ATTRS | ATTR_CMN_NAME | ATTR_CMN_ERROR | ATTR_CMN_OBJTYPE; error = 0; dirfd = open(dirpath, O_RDONLY, 0); if (dirfd < 0) { error = errno; printf("Could not open directory %s", dirpath); perror("Error was "); } else { for (;;) { int retcount; retcount = getattrlistbulk(dirfd, &attrList, &attrBuf[0], sizeof(attrBuf), 0); printf("\engetattrlistbulk returned %d", retcount); if (retcount == -1) { error = errno; perror("Error returned : "); printf("\en"); break; } else if (retcount == 0) { /* No more entries in directory */ error = 0; break; } else { int index; uint32_t total_length; char *field; entry_start = &attrBuf[0]; total_length = 0; printf(" -> entries returned"); for (index = 0; index < retcount; index++) { val_attrs_t attrs = {0}; printf("\en Entry %d", index); printf(" -- "); field = entry_start; attrs.length = *(uint32_t *)field; printf(" Length %d ", attrs.length); total_length += attrs.length; printf(" Total Length %d ", total_length); field += sizeof(uint32_t); printf(" -- "); /* set starting point for next entry */ entry_start += attrs.length; attrs.returned = *(attribute_set_t *)field; field += sizeof(attribute_set_t); if (attrs.returned.commonattr & ATTR_CMN_ERROR) { attrs.error = *(uint32_t *)field; field += sizeof(uint32_t); } if (attrs.returned.commonattr & ATTR_CMN_NAME) { attrs.name = field; attrs.name_info = *(attrreference_t *)field; field += sizeof(attrreference_t); printf(" %s ", (attrs.name + attrs.name_info.attr_dataoffset)); } /* Check for error for this entry */ if (attrs.error) { /* * Print error and move on to next * entry */ printf("Error in reading attributes for directory \ entry %d", attrs.error); continue; } printf(" -- "); if (attrs.returned.commonattr & ATTR_CMN_OBJTYPE) { attrs.obj_type = *(fsobj_type_t *)field; field += sizeof(fsobj_type_t); switch (attrs.obj_type) { case VREG: printf("file "); break; case VDIR: printf("directory "); break; default: printf("obj_type = %-2d ", attrs.obj_type); break; } } printf(" -- "); } } } (void)close(dirfd); } } .Ed .Pp . .Sh SEE ALSO . .Xr getattrlist 2 , .Xr lseek 2 . .Sh HISTORY A .Fn getattrlistbulk function call appeared in OS X version 10.10 .