platform_bionic/libc/bionic/ftw.cpp
Elliott Hughes 70a8f2272e Fix various ftw/nftw "shall fail"s from POSIX.
POSIX says ftw/nftw "shall fail" in various cases where BSD's fts_open
doesn't. Since our ftw/nftw are written in terms of fts_open, add a back
door so we can hint to ourselves when we should have the POSIX semantics.

Also pull several O_CLOEXEC and don't-null-check-before-free cleanups
from upstream, and add a couple of tests.

Bug: http://b/31152735
Test: ran bionic tests and LTP "nftw01" test
Change-Id: Ib05facacc1da4c8b2ab48e9ecce88f11a5406630
2018-05-08 15:20:07 -07:00

125 lines
4 KiB
C++

/*
* Copyright (c) 2003, 2004 Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include <errno.h>
#include <fts.h>
#include <ftw.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
extern "C" FTS* __fts_open(char* const*, int, int (*)(const FTSENT**, const FTSENT**));
static int do_nftw(const char* path,
int (*ftw_fn)(const char*, const struct stat*, int),
int (*nftw_fn)(const char*, const struct stat*, int, FTW*),
int nfds,
int nftw_flags) {
// TODO: nfds is currently unused.
if (nfds < 1) {
errno = EINVAL;
return -1;
}
// Translate to fts_open options.
int fts_options = FTS_LOGICAL | FTS_COMFOLLOW | FTS_NOCHDIR;
if (nftw_fn) {
fts_options = FTS_COMFOLLOW | ((nftw_flags & FTW_PHYS) ? FTS_PHYSICAL : FTS_LOGICAL);
if (!(nftw_flags & FTW_CHDIR)) fts_options |= FTS_NOCHDIR;
if (nftw_flags & FTW_MOUNT) fts_options |= FTS_XDEV;
}
bool postorder = (nftw_flags & FTW_DEPTH) != 0;
// Call fts_open.
char* const paths[2] = { const_cast<char*>(path), nullptr };
FTS* fts = __fts_open(paths, fts_options | FTS_FOR_FTW, nullptr);
if (fts == nullptr) {
return -1;
}
// Translate fts_read results into ftw/nftw callbacks.
int error = 0;
FTSENT* cur;
while (error == 0 && (cur = fts_read(fts)) != nullptr) {
int fn_flag;
switch (cur->fts_info) {
case FTS_D:
// In the postorder case, we'll translate FTS_DP to FTW_DP later.
// In the can't-access case, we'll translate FTS_DNR to FTW_DNR later.
if (postorder || access(cur->fts_path, R_OK) == -1) continue;
fn_flag = FTW_D;
break;
case FTS_DC:
// POSIX says nftw "shall not report" directories causing loops (http://b/31152735).
continue;
case FTS_DNR:
fn_flag = FTW_DNR;
break;
case FTS_DP:
if (!postorder) continue;
fn_flag = FTW_DP;
break;
case FTS_F:
case FTS_DEFAULT:
fn_flag = FTW_F;
break;
case FTS_NS:
case FTS_NSOK:
fn_flag = FTW_NS;
break;
case FTS_SL:
fn_flag = FTW_SL;
break;
case FTS_SLNONE:
fn_flag = (nftw_fn != nullptr) ? FTW_SLN : FTW_NS;
break;
default:
error = -1;
continue;
}
// Call the appropriate function.
if (nftw_fn != nullptr) {
FTW ftw;
ftw.base = cur->fts_pathlen - cur->fts_namelen;
ftw.level = cur->fts_level;
error = nftw_fn(cur->fts_path, cur->fts_statp, fn_flag, &ftw);
} else {
error = ftw_fn(cur->fts_path, cur->fts_statp, fn_flag);
}
}
int saved_errno = errno;
if (fts_close(fts) != 0 && error == 0) {
error = -1;
} else {
errno = saved_errno;
}
return error;
}
int ftw(const char* path, int (*ftw_fn)(const char*, const struct stat*, int), int nfds) {
return do_nftw(path, ftw_fn, nullptr, nfds, 0);
}
int nftw(const char* path, int (*nftw_fn)(const char*, const struct stat*, int, FTW*),
int nfds, int nftw_flags) {
return do_nftw(path, nullptr, nftw_fn, nfds, nftw_flags);
}