NAME
sseeaarrcchhffss - search a volume quickly
SYNOPSIS
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int sseeaarrcchhffss(const char * path, struct fssearchblock * searchBlock, unsigned long * numMatches, unsigned long scriptCode, unsigned long options, struct searchstate * state);> DESCRIPTION
The sseeaarrcchhffss() function searches the volume (that is, mounted file sys-
tem) specified by path for file system objects matching the criteriaspecified by searchBlock, scriptCode, and options. The numMatches param-
eter returns the number of matching file system objects found. The func-
tion also returns attributes of those file system objects in a buffer specified by searchBlock. The searchState parameter allows you search the volume using multiple calls to sseeaarrcchhffss(), resuming the search where it left off. The routine will only return objects to which you have access (that is, you have execute permissions on the directories leading to this object from the root).The path parameter must reference a valid file system object on the vol-
ume to be searched. Typically the path is to the volume's root direc-
tory. The entire volume is always searched. All directories listed in the path name leading to this object must be searchable. The searchBlock parameter is a pointer to an fssearchblock structure, as defined by(shown below). You are responsible for filling out all fields of this structure before calling the function. struct fssearchblock { struct attrlist * returnattrs; void * returnbuffer; sizet returnbuffersize; unsigned long maxmatches; struct timeval timelimit; void * searchparams1; sizet sizeofsearchparams1; void * searchparams2; sizet sizeofsearchparams2; struct attrlist searchattrs; }; For information about the attrlist structure, see the discussion of getattrlist(2). The fields of the fssearchblock structure are defined as follows. returnattrs sseeaarrcchhffss() can return arbitrary attributes of the file system objects that it finds. This field must point to an attrlist structure that specifies the attributes that you want returned. To request an attribute you must set the corresponding bit in the appropriate attrgroupt field of the attrlist struc-
ture. You are responsible for filling out allfields of this structure before calling the func-
tion. You must not request volume attributes. returnbuffer sseeaarrcchhffss() places attributes of the matching file system objects into this returned attributes buffer. The attributes for any given object are grouped together and packed in exactly the same way as they would be returned from getdirentriesattr(2). The initial contents of this buffer are ignored. returnbuffersize Set this field to the size, in bytes, of the buffer pointed to by returnbuffer. maxmatches Specifies the maximum number of matches that you want this call to sseeaarrcchhffss() to return. timelimit Specifies the maximum time that you want this call to sseeaarrcchhffss() to run. If you're implementing a volume format, you should impose your own internal limit on the duration of this call to prevent a malicious user program from monopolising kernel resources. searchparams1 Specifies the lower bound of the search criteria. This is discussed in detail below. You must place attribute values into the buffer in the same way as they would be returned by getattrlist(2), where the searchattrs field determines the exact layout of the attribute values. sizeofsearchparams1 Set this field to the size, in bytes, of the buffer pointed to by searchparams1. searchparams2 Specifies the upper bound of the search criteria. This is discussed in detail below. You must place attribute values into the buffer in the same way as they would be returned by getattrlist(2), where the searchattrs field determines the exact layout of the attribute values. sizeofsearchparams2 Set this field to the size, in bytes, of the buffer pointed to by searchparams2. searchattrs Specifies the attributes that you want you use foryour search criteria. You are responsible for fill-
ing out all fields of this structure before calling the function. To search for an attribute you must set the corresponding bit in the appropriate attrgroupt field of the attrlist structure, and place the appropriate values into the searchparam1 and searchparam2 buffers. The attributes specified here determine the format of those buffers. This is discussed in detail below.The numMatches parameter points to an unsigned long variable. The ini-
tial value of this variable is ignored. On return, this variable con-
tains the number of matching file system objects found. The is always less than or equal to the maxmatches field of the searchBlock parameter. The attributes for the matching objects have been placed into the returned attributes buffer. The scriptCode parameter is currently ignored. You should always pass inthe value 0x08000103, which corresponds to the UTF-8 text encoding value
defined by. The options parameter is a bit set that controls the behaviour of sseeaarrcchhffss(). The following option bits are defined. SRCHFSSTART If this bit is set, sseeaarrcchhffss() will ignore the state parameter and start a new search. Other-
wise sseeaarrcchhffss() assumes that searchstate is valid and attempts to resume a previous search based on that state.SRCHFSMATCHPARTIALNAMES If this bit is set, sseeaarrcchhffss() will consider
substrings to be successful matches when evalu-
ating the ATTRCMNNAME attribute.
SRCHFSMATCHDIRS If this bit is set, sseeaarrcchhffss() will search for directories that match the search criteria. To get meaningful results you must specify either this bit or SRCHFSMATCHFILES, or both. SRCHFSMATCHFILES If this bit is set, sseeaarrcchhffss() will search for files that match the search criteria. To get meaningful results you must specify either this bit or SRCHFSMATCHDIRS, or both. SRCHFSSKIPLINKS If this bit is set, sseeaarrcchhffss() will only return one reference for a hard linked file, rather that a reference for each hard link to the file. This option is not recommended for general development. Its primary client is the quotacheck(2) utility.This option is privileged (the caller's effec-
tive UID must be 0) and cannot be used if yourequest the ATTRCMNNAME or ATTRCMNPAROBJID
attributes. Introduced with Darwin 7.0 (Mac OS X version 10.3). SRCHFSSKIPINVISIBLE If this bit is set, sseeaarrcchhffss() will not match any invisible file system objects (that is, objects whose ATTRCMNFNDRINFO attribute has bit 6 set in the ninth byte) or any objects within invisible directories. Introduced with Darwin 7.0 (Mac OS X version 10.3). SRCHFSSKIPPACKAGES If this bit is set, sseeaarrcchhffss() will not matchany file system objects that are inside a pack-
age. A package is defined as a directory whose extension matches one of the extensions thatare configured into the kernel by Launch Ser-
vices. Introduced with Darwin 7.0 (Mac OS X version 10.3). SRCHFSSKIPINAPPROPRIATE If this bit is set, sseeaarrcchhffss() will not match any file system objects that are within an inappropriate directory. The current list of inappropriate directories contains one item: /System. Introduced with Darwin 7.0 (Mac OS X version 10.3). SRCHFSNEGATEPARAMS If this bit is set, sseeaarrcchhffss() will return all the file system objects that do not match the search criteria. Introduced with Darwin 7.0 (Mac OS X version 10.3). The state parameter is a pointer to an opaque data structure that sseeaarrcchhffss() uses to maintain the state of a search between successive calls. In your first call to sseeaarrcchhffss(), you specify the SRCHFSSTART flag in the options parameter. This tells sseeaarrcchhffss() that the search state is invalid and that it should start a new search. When this call completes, it may have only returned partial results; in that case, it will have updated the structure pointed to by state. If you call sseeaarrcchhffss() again, this time without specifying the SRCHFSSTART flag in the options parameter, it will resume the search where it left off, using the search state that it previously stored in the state structure. You do not need to explicitly dispose of this state. The sseeaarrcchhffss() function returns significant errors in the followings cases. ++oo If it has found as many objects as you requested in the maxmatches field of the searchBlock parameter, it will return EAGAIN. ++oo If there is not enough space in the returned attributes buffer for the first match, it will return ENOBUFS. You should allocate a larger returned attributes buffer and try again. numMatches will be zero in this case. ++oo If the timeout expires it will return EAGAIN.++oo If you attempt to resume a search (that is, SRCHFSSTART is not spec-
ified in the options parameter) and the catalog has changed since the last search, the function will return EBUSY. You must start your search again from the beginning. If sseeaarrcchhffss() returns EAGAIN, the value in numMatches may be greater than zero. This is known as a partial result. You should be sure to process these matches before calling sseeaarrcchhffss() again. SSEEAARRCCHH CCRRIITTEERRIIAA You specify the search criteria using a combination of the searchattrs, searchparams1, sizeofsearchparams1, searchparams2, and sizeofsearchparams2 fields of the searchBlock parameter, and various flags in the options parameter. The searchattrs field determines the attributes considered when comparing a file system object to the searchcriteria. You can specify that an attribute should be considered by set-
ting the corresponding bit in the appropriate attrgroupt field of the attrlist structure. See the discussion of getattrlist(2) for a detailed description of this structure. The searchparams1, sizeofsearchparams1, searchparams2, and sizeofsearchparams2 fields specify the attribute values that must be matched. The format of each of these buffers is determined by the attributes that you're searching for. The values are packed in exactly the same way as they would be returned from getattrlist(2), including the leading unsigned long length value. The attribute values in the first and second search buffers form a lowerand upper bound for the search, respectively. These have different mean-
ings depending on the type of attribute.++oo For string attributes (specifically ATTRCMNNAME, the object name),
the value in the first search buffer is significant and the value in the second search buffer is ignored. The string comparison is either an exact match or a substring match depending on theSRCHFSMATCHPARTIALNAMES flag in the options parameter.
++oo For structured attributes (specifically ATTRCMNFNDRINFO, the Finderinformation), the value from the file system object is masked (logi-
cal AND) with the value in the second search buffer and then com-
pared, byte for byte, against the value in the first search buffer. If it is equal, the object is a match. ++oo For scalar attributes (all other attributes, for example, ATTRCMNMODTIME, the modification date), the values in the first and second search buffers are literally a lower and upper bound. An object matches the criteria if its value is greater than or equal to the value in the first buffer and less than or equal to the value in the second.RETURN VALUES
Upon successful completion, a value of 0 is returned. This means that the entire volume has been searched and all matches returned. Otherwise,a value of -1 is returned and errno is set to indicate the error.
See the discussion of the EAGAIN, ENOBUFS, and EBUSY error codes above. CCOOMMPPAATTIIBBIILLIITTYYNot all volumes support sseeaarrcchhffss(). You can test whether a volume sup-
ports sseeaarrcchhffss() by using getattrlist(2) to get the volume capabilities attribute ATTRVOLCAPABILITIES, and then testing the VOLCAPINTSEARCHFS flag. The sseeaarrcchhffss() function has been undocumented for more than two years. In that time a number of volume format implementations have been created without a proper specification for the behaviour of this routine. Youmay encounter volume format implementations with slightly different be-
haviour than what is described here. Your program is expected to be tol-
erant of this variant behaviour. If you're implementing a volume format that supports sseeaarrcchhffss(), you should be careful to support the behaviour specified by this document. A bug in systems prior to Darwin 7.0 (Mac OS X version 10.3) makes searching for the ATTRCMNBKUPTIME attribute tricky. The bug causes the attribute to consume two items in the search attribute buffers, the first in the proper place and the second between ATTRCMNFNDRINFO and ATTRCMNOWNERID. EERRRROORRSS sseeaarrcchhffss() will fail if: [ENOTSUP] The volume does not support sseeaarrcchhffss(). [ENOTDIR] A component of the path prefix is not a directory.[ENAMETOOLONG] A component of a path name exceeded NAMEMAX charac-
ters, or an entire path name exceeded PATHMAX charac-
ters. [ENOENT] The file system object does not exist. [EACCES] Search permission is denied for a component of the path prefix.[ELOOP] Too many symbolic links were encountered in translat-
ing the pathname. [EFAULT] One of the pointer parameters points to an invalid address. [EINVAL] The options parameter contains an invalid flag or sizeofsearchparams1/2 is greater than SEARCHFSMAXSEARCHPARMS (see attr.h). [EAGAIN] The search terminated with partial results, either because numMatches has hit the limit specified by maxmatches or because the timeout expired. Process the matches returned so far and then call sseeaarrcchhffss() again to look for more. [ENOBUFS] The returned attributes buffer is too small for the first match. You should allocate a larger returned attributes buffer and try again. numMatches will be zero in this case. [EBUSY] The search could not be resumed because the volume has changed. [EIO] An I/O error occurred while reading from or writing to the file system. CCAAVVEEAATTSSNot all attributes can be searched for using sseeaarrcchhffss(). The list cur-
rently includes:ATTRCMNNAME
ATTRCMNOBJID ATTRCMNPAROBJID ATTRCMNCRTIME ATTRCMNMODTIME ATTRCMNCHGTIME ATTRCMNACCTIME ATTRCMNBKUPTIME ATTRCMNFNDRINFO ATTRCMNBKUPTIME ATTRCMNOWNERID ATTRCMNGRPID ATTRCMNACCESSMASK ATTRDIRENTRYCOUNT ATTRFILEDATALENGTH ATTRFILEDATAALLOCSIZE ATTRFILERSRCLENGTH ATTRFILERSRCALLOCSIZE EEXXAAMMPPLLEESS The following code searches a volume for files of the specified type and creator.#include
#include
#include
#include
#include
#include
#include
typedef struct attrlist attrlistt; typedef struct fssearchblock fssearchblockt; typedef struct searchstate searchstatet; struct SearchAttrBuf { unsigned long length; char finderInfo[32]; }; typedef struct SearchAttrBuf SearchAttrBuf; struct ResultAttrBuf { unsigned long length; attrreferencet name; fsobjidt parObjID; }; typedef struct ResultAttrBuf ResultAttrBuf; enum { kMatchesPerCall = 16 }; static int SearchFSDemo( const char *volPath, const char *type, const char *creator ) { int err; fssearchblockt searchBlock; SearchAttrBuf lower; SearchAttrBuf upper; static const unsigned char kAllOnes[4] = { 0xFF, 0xFF, 0xFF, 0xFF }; unsigned long matchCount; unsigned long matchIndex; unsigned long options; searchstatet state; ResultAttrBuf * thisEntry; attrlistt returnAttrList; char resultAttrBuf[ kMatchesPerCall * (sizeof(ResultAttrBuf) + 64)]; // resultAttrBuf is big enough for kMatchesPerCall entries, // assuming that the average name length is less than 64. assert(strlen(type) == 4); assert(strlen(creator) == 4); memset(&searchBlock, 0, sizeof(searchBlock)); searchBlock.searchattrs.bitmapcount = ATTRBITMAPCOUNT; searchBlock.searchattrs.commonattr = ATTRCMNFNDRINFO; memset(&lower, 0, sizeof(lower)); memset(&upper, 0, sizeof(upper)); lower.length = sizeof(lower); upper.length = sizeof(upper); memcpy(&lower.finderInfo[0], type, 4); memcpy(&lower.finderInfo[4], creator, 4); memcpy(&upper.finderInfo[0], kAllOnes, 4); memcpy(&upper.finderInfo[4], kAllOnes, 4); searchBlock.searchparams1 = &lower; searchBlock.sizeofsearchparams1 = sizeof(lower); searchBlock.searchparams2 = &upper; searchBlock.sizeofsearchparams2 = sizeof(lower); searchBlock.timelimit.tvsec = 0; searchBlock.timelimit.tvusec = 100 * 1000; searchBlock.maxmatches = kMatchesPerCall; memset(&returnAttrList, 0, sizeof(returnAttrList)); returnAttrList.bitmapcount = ATTRBITMAPCOUNT;returnAttrList.commonattr = ATTRCMNNAME | ATTRCMNPAROBJID;
searchBlock.returnattrs = &returnAttrList; searchBlock.returnbuffer = resultAttrBuf; searchBlock.returnbuffersize = sizeof(resultAttrBuf); options = SRCHFSSTART | SRCHFSMATCHFILES; do {err = searchfs(
volPath, &searchBlock, &matchCount, 0x08000103, options, &state ); if (err != 0) { err = errno; } if ( (err == 0) || (err == EAGAIN) ) { thisEntry = (ResultAttrBuf *) resultAttrBuf; for (matchIndex = 0; matchIndex < matchCount; matchIndex++) {printf("%08x ", thisEntry->parObjID.fidobjno);
printf("%s\n",
((char *) &thisEntry->name)
+ thisEntry->name.attrdataoffset
); // Advance to the next entry.((char *) thisEntry) += thisEntry->length;
} } options &= ~SRCHFSSTART; } while (err == EAGAIN); return err; }SEE ALSO
getattrlist(2) HISTORY A sseeaarrcchhffss() function call appeared in Darwin 1.3.1 (Mac OS X version 10.0). Darwin December 15, 2003 Darwin