* [musl] [PATCH v2 0/2] nftw: Implement FTW_CHDIR and FTW_ACTIONRETVAL
@ 2022-01-22 14:51 Ismael Luceno
2022-01-22 14:51 ` [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR Ismael Luceno
2022-01-22 14:51 ` [musl] [PATCH v2 2/2] nftw: implement FTW_ACTIONRETVAL (GNU extension) Ismael Luceno
0 siblings, 2 replies; 5+ messages in thread
From: Ismael Luceno @ 2022-01-22 14:51 UTC (permalink / raw)
To: musl; +Cc: Rich Felker, Ismael Luceno
FTW_CHDIR is specified by POSIX. While the spec doesn't clarify, nftw
restores the starting directory in conformance with other implementations.
FTW_ACTIONRETVAL is a GNU extension added by glibc 2.3.3.
Changes since v1:
- Fixed handling of FTW_STOP when FTW_DEPTH isn't set.
Ismael Luceno (2):
nftw: implement FTW_CHDIR
nftw: implement FTW_ACTIONRETVAL (GNU extension)
include/ftw.h | 7 +++++++
src/misc/nftw.c | 43 +++++++++++++++++++++++++++++++++----------
2 files changed, 40 insertions(+), 10 deletions(-)
--
2.33.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR
2022-01-22 14:51 [musl] [PATCH v2 0/2] nftw: Implement FTW_CHDIR and FTW_ACTIONRETVAL Ismael Luceno
@ 2022-01-22 14:51 ` Ismael Luceno
2022-01-22 15:50 ` Markus Wichmann
2022-01-22 14:51 ` [musl] [PATCH v2 2/2] nftw: implement FTW_ACTIONRETVAL (GNU extension) Ismael Luceno
1 sibling, 1 reply; 5+ messages in thread
From: Ismael Luceno @ 2022-01-22 14:51 UTC (permalink / raw)
To: musl; +Cc: Rich Felker, Ismael Luceno
Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
---
src/misc/nftw.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/src/misc/nftw.c b/src/misc/nftw.c
index 8dcff7fefd2a..0a35686e663d 100644
--- a/src/misc/nftw.c
+++ b/src/misc/nftw.c
@@ -87,6 +87,8 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
DIR *d = fdopendir(dfd);
if (d) {
struct dirent *de;
+ if (flags & FTW_CHDIR)
+ fchdir(dfd);
while ((de = readdir(d))) {
if (de->d_name[0] == '.'
&& (!de->d_name[1]
@@ -123,6 +125,7 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str
int r, cs;
size_t l;
char pathbuf[PATH_MAX+1];
+ int orig_dfd;
if (fd_limit <= 0) return 0;
@@ -133,9 +136,16 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str
}
memcpy(pathbuf, path, l+1);
+ if (flags & FTW_CHDIR)
+ orig_dfd = open(".", O_CLOEXEC | O_PATH);
+
pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
pthread_setcancelstate(cs, 0);
+ if (flags & FTW_CHDIR) {
+ fchdir(orig_dfd);
+ close(orig_dfd);
+ }
return r;
}
--
2.33.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [musl] [PATCH v2 2/2] nftw: implement FTW_ACTIONRETVAL (GNU extension)
2022-01-22 14:51 [musl] [PATCH v2 0/2] nftw: Implement FTW_CHDIR and FTW_ACTIONRETVAL Ismael Luceno
2022-01-22 14:51 ` [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR Ismael Luceno
@ 2022-01-22 14:51 ` Ismael Luceno
1 sibling, 0 replies; 5+ messages in thread
From: Ismael Luceno @ 2022-01-22 14:51 UTC (permalink / raw)
To: musl; +Cc: Rich Felker, Ismael Luceno
Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
---
include/ftw.h | 7 +++++++
src/misc/nftw.c | 33 +++++++++++++++++++++++----------
2 files changed, 30 insertions(+), 10 deletions(-)
diff --git a/include/ftw.h b/include/ftw.h
index b15c062a8389..2e77dc76e11b 100644
--- a/include/ftw.h
+++ b/include/ftw.h
@@ -21,6 +21,13 @@ extern "C" {
#define FTW_CHDIR 4
#define FTW_DEPTH 8
+#define FTW_ACTIONRETVAL 16
+/* return values for callback */
+#define FTW_CONTINUE 0
+#define FTW_STOP 1
+#define FTW_SKIP_SUBTREE 2
+#define FTW_SKIP_SIBLINGS 3
+
struct FTW {
int base;
int level;
diff --git a/src/misc/nftw.c b/src/misc/nftw.c
index 0a35686e663d..17e287c4c091 100644
--- a/src/misc/nftw.c
+++ b/src/misc/nftw.c
@@ -26,7 +26,7 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
struct stat st;
struct history new;
int type;
- int r;
+ int r, r2;
int dfd;
int err;
struct FTW lev;
@@ -72,12 +72,19 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
if (!fd_limit) close(dfd);
}
- if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
- return r;
+ r = 0;
+ if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev))) {
+ if ((flags & FTW_ACTIONRETVAL)) {
+ if (r == FTW_STOP) return FTW_STOP;
+ if (r == FTW_SKIP_SUBTREE) return 0;
+ /* other values are saved for when returning */
+ } else
+ return r;
+ }
for (; h; h = h->chain)
if (h->dev == st.st_dev && h->ino == st.st_ino)
- return 0;
+ return r;
if ((type == FTW_D || type == FTW_DP) && fd_limit) {
if (dfd < 0) {
@@ -101,9 +108,12 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
}
path[j]='/';
strcpy(path+j+1, de->d_name);
- if ((r=do_nftw(path, fn, fd_limit-1, flags, &new))) {
+ if ((r2=do_nftw(path, fn, fd_limit-1, flags, &new))) {
+ if ((flags & FTW_ACTIONRETVAL)
+ && r2 == FTW_SKIP_SIBLINGS)
+ break;
closedir(d);
- return r;
+ return r2;
}
}
closedir(d);
@@ -114,10 +124,13 @@ static int do_nftw(char *path, int (*fn)(const char *, const struct stat *, int,
}
path[l] = 0;
- if ((flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev)))
- return r;
-
- return 0;
+ if (flags & FTW_DEPTH) {
+ r = fn(path, &st, type, &lev);
+ /* ignore FTW_SKIP_SUBTREE (too late), the caller is broken */
+ if ((flags & FTW_ACTIONRETVAL) && r == FTW_SKIP_SUBTREE)
+ return 0;
+ }
+ return r;
}
int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, struct FTW *), int fd_limit, int flags)
--
2.33.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR
2022-01-22 14:51 ` [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR Ismael Luceno
@ 2022-01-22 15:50 ` Markus Wichmann
2022-01-23 15:47 ` Ismael Luceno
0 siblings, 1 reply; 5+ messages in thread
From: Markus Wichmann @ 2022-01-22 15:50 UTC (permalink / raw)
To: musl
On Sat, Jan 22, 2022 at 03:51:58PM +0100, Ismael Luceno wrote:
> @@ -133,9 +136,16 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str
> }
> memcpy(pathbuf, path, l+1);
>
> + if (flags & FTW_CHDIR)
> + orig_dfd = open(".", O_CLOEXEC | O_PATH);
> +
> pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
> r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
> pthread_setcancelstate(cs, 0);
> + if (flags & FTW_CHDIR) {
> + fchdir(orig_dfd);
> + close(orig_dfd);
> + }
> return r;
> }
>
> --
> 2.33.0
>
Erm... maybe a dumb question, but what if either the open() or the
fchdir() fails? Is anything specified for that case? Is effectively
ignoring FTW_CHDIR OK in that case or would you have to signal failure?
I mean, I see that there is not much you can do in either case, but to
just fail silently seems wrong to me.
Ciao,
Markus
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR
2022-01-22 15:50 ` Markus Wichmann
@ 2022-01-23 15:47 ` Ismael Luceno
0 siblings, 0 replies; 5+ messages in thread
From: Ismael Luceno @ 2022-01-23 15:47 UTC (permalink / raw)
To: musl
On 22/Jan/2022 16:50, Markus Wichmann wrote:
> On Sat, Jan 22, 2022 at 03:51:58PM +0100, Ismael Luceno wrote:
> > @@ -133,9 +136,16 @@ int nftw(const char *path, int (*fn)(const char *, const struct stat *, int, str
> > }
> > memcpy(pathbuf, path, l+1);
> >
> > + if (flags & FTW_CHDIR)
> > + orig_dfd = open(".", O_CLOEXEC | O_PATH);
> > +
> > pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
> > r = do_nftw(pathbuf, fn, fd_limit, flags, NULL);
> > pthread_setcancelstate(cs, 0);
> > + if (flags & FTW_CHDIR) {
> > + fchdir(orig_dfd);
> > + close(orig_dfd);
> > + }
> > return r;
> > }
> >
> > --
> > 2.33.0
> >
>
> Erm... maybe a dumb question, but what if either the open() or the
> fchdir() fails? Is anything specified for that case? Is effectively
> ignoring FTW_CHDIR OK in that case or would you have to signal failure?
> I mean, I see that there is not much you can do in either case, but to
> just fail silently seems wrong to me.
Ah, indeed. I'll try to address that.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-01-22 14:51 [musl] [PATCH v2 0/2] nftw: Implement FTW_CHDIR and FTW_ACTIONRETVAL Ismael Luceno
2022-01-22 14:51 ` [musl] [PATCH v2 1/2] nftw: implement FTW_CHDIR Ismael Luceno
2022-01-22 15:50 ` Markus Wichmann
2022-01-23 15:47 ` Ismael Luceno
2022-01-22 14:51 ` [musl] [PATCH v2 2/2] nftw: implement FTW_ACTIONRETVAL (GNU extension) Ismael Luceno
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