Bug 50878 - redundant operation when calling apr_stat
Summary: redundant operation when calling apr_stat
Alias: None
Product: Apache httpd-2
Classification: Unclassified
Component: mod_dav (show other bugs)
Version: 2.2.17
Hardware: PC All
: P2 normal (vote)
Target Milestone: ---
Assignee: Apache HTTPD Bugs Mailing List
Keywords: MassUpdate
Depends on:
Reported: 2011-03-05 22:21 UTC by Linhai Song
Modified: 2018-11-07 21:08 UTC (History)
0 users


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Description Linhai Song 2011-03-05 22:21:35 UTC
apr_stat() function is used to get information for a given file. It has four parameters: the first parameter is a apr_finfo_t struct, which is used to hold the return value, and the third parameter is used to tell apr_stat which information is required by the caller. If caller uses some specific value as the third parameter, like APR_FINFO_DEV and APR_FINFO_TYPE, only some fields of apr_finfo_t struct are filled, but not all. If caller uses APR_FINFO_NORM as the third paramter, all fields of apr_finfo_t will be filled. 

In the bug report https://issues.apache.org/bugzilla/show_bug.cgi?id=45464, the reporter says that misusing of APR_FIFO_NORM as the third parameter causes apr_stat() to return redundant values, which are not used in the calling context, and this brings obvious delay in the reporter's using context. 

I check all apr_stat function call with APR_FINFO_NORM as the third parameter in the latest 2.2.17 httpd version, and find that in some places, only part of return value are used, not all, so they should not use APR_FINFO_NORM as the third parameter. I list places I find, and give out my fixing suggestions. I think that my fixing suggestion will keep the function of codes, and bring a better performance. 

./modules/dav/fs/repos.c:462:    rv = apr_stat(&src_finfo, src, APR_FINFO_NORM, p);

fixing suggestion:

rv = apr_stat(&src_finfo, src, APR_FINFO_DEV, p);


./modules/dav/fs/repos.c:483:    rv = apr_stat(&dst_state_finfo, dst, APR_FINFO_NORM, p);

fixing suggestion:
rv = apr_stat(&dst_state_finfo, dst, APR_FINFO_TYPE | APR_FINFO_DEV, p);


./srclib/apr/test/sendfile.c:149:    rv = apr_stat(&finfo, fname, APR_FINFO_NORM, p);

fixing suggestion:

rv = apr_stat(&finfo, fname, APR_FINFO_SIZE, p);

./srclib/apr/test/testlfs.c:136:                       apr_stat(&finfo, TESTFN, APR_FINFO_NORM, p));

fixing suggestion:

 apr_stat(&finfo, TESTFN, APR_FINFO_SIZE , p));
Comment 1 William A. Rowe Jr. 2018-11-07 21:08:10 UTC
Please help us to refine our list of open and current defects; this is a mass update of old and inactive Bugzilla reports which reflect user error, already resolved defects, and still-existing defects in httpd.

As repeatedly announced, the Apache HTTP Server Project has discontinued all development and patch review of the 2.2.x series of releases. The final release 2.2.34 was published in July 2017, and no further evaluation of bug reports or security risks will be considered or published for 2.2.x releases. All reports older than 2.4.x have been updated to status RESOLVED/LATER; no further action is expected unless the report still applies to a current version of httpd.

If your report represented a question or confusion about how to use an httpd feature, an unexpected server behavior, problems building or installing httpd, or working with an external component (a third party module, browser etc.) we ask you to start by bringing your question to the User Support and Discussion mailing list, see [https://httpd.apache.org/lists.html#http-users] for details. Include a link to this Bugzilla report for completeness with your question.

If your report was clearly a defect in httpd or a feature request, we ask that you retest using a modern httpd release (2.4.33 or later) released in the past year. If it can be reproduced, please reopen this bug and change the Version field above to the httpd version you have reconfirmed with.

Your help in identifying defects or enhancements still applicable to the current httpd server software release is greatly appreciated.