Author: bdrewery Date: Wed Aug 10 18:19:02 2016 New Revision: 303929 URL: https://svnweb.freebsd.org/changeset/base/303929
Log: Fix -S with -b not atomically updating the destination file. With both of these flags, the backup was created via rename(dest, backup) followed by rename(tmp, dest). This left the destination file missing for a moment which contradicts the point of -S. This fixes a race with installworld where PRECIOUSPROG and PRECIOUSLIB files (which use -S for installation) would briefly be missing. In the case of installing rtld with parallel installworld it could render an error due to not having rtld present to run install/cp in another process. Reported by: jhb Reviewed by: jhb MFC after: 1 week Sponsored by: EMC / Isilon Storage Division Differential Revision: https://reviews.freebsd.org/D7451 Modified: head/usr.bin/xinstall/xinstall.c Modified: head/usr.bin/xinstall/xinstall.c ============================================================================== --- head/usr.bin/xinstall/xinstall.c Wed Aug 10 18:18:51 2016 (r303928) +++ head/usr.bin/xinstall/xinstall.c Wed Aug 10 18:19:02 2016 (r303929) @@ -892,11 +892,17 @@ install(const char *from_name, const cha } if (verbose) (void)printf("install: %s -> %s\n", to_name, backup); - if (rename(to_name, backup) < 0) { + if (unlink(backup) < 0 && errno != ENOENT) { serrno = errno; unlink(tempfile); errno = serrno; - err(EX_OSERR, "rename: %s to %s", to_name, + err(EX_OSERR, "unlink: %s", backup); + } + if (link(to_name, backup) < 0) { + serrno = errno; + unlink(tempfile); + errno = serrno; + err(EX_OSERR, "link: %s to %s", to_name, backup); } } _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "[email protected]"
