[musl] [PATCH 0/2] nftw: Implement FTW_CHDIR and FTW_ACTIONRETVAL

[musl] [PATCH 0/2] nftw: Implement FTW_CHDIR and FTW_ACTIONRETVAL

[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.

Ismael Luceno (2):
  nftw: implement FTW_CHDIR
  nftw: implement FTW_ACTIONRETVAL (GNU extension)

 include/ftw.h   |  7 +++++++
 src/misc/nftw.c | 42 ++++++++++++++++++++++++++++++++----------
 2 files changed, 39 insertions(+), 10 deletions(-)

-- 
2.33.0

[musl] [PATCH 1/2] nftw: implement FTW_CHDIR

[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

[musl] [PATCH 2/2] nftw: implement FTW_ACTIONRETVAL (GNU extension)

[Ismael Luceno]

Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
---
 include/ftw.h   |  7 +++++++
 src/misc/nftw.c | 32 ++++++++++++++++++++++----------
 2 files changed, 29 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..4b934adcfb0c 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 +72,18 @@ 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;
+	if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev))) {
+		if ((flags & FTW_ACTIONRETVAL)) {
+			if (r == FTW_SKIP_SUBTREE)
+				return 0;
+			/* FTW_SKIP_SIBLINGS is saved for 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 +107,12 @@ 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 +123,13 @@ 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, the caller is broken */
+		if ((flags & FTW_ACTIONRETVAL) && r == FTW_SKIP_SUBTREE)
+			r = 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

Re: [musl] [PATCH 2/2] nftw: implement FTW_ACTIONRETVAL (GNU extension)

[Ismael Luceno]

I noticed a small bug, I'll submit a v2.

On 22/Jan/2022 14:26, Ismael Luceno wrote:
> Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
> ---
>  include/ftw.h   |  7 +++++++
>  src/misc/nftw.c | 32 ++++++++++++++++++++++----------
>  2 files changed, 29 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..4b934adcfb0c 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 +72,18 @@ 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;
> +	if (!(flags & FTW_DEPTH) && (r=fn(path, &st, type, &lev))) {
> +		if ((flags & FTW_ACTIONRETVAL)) {
> +			if (r == FTW_SKIP_SUBTREE)
> +				return 0;
> +			/* FTW_SKIP_SIBLINGS is saved for 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 +107,12 @@ 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 +123,13 @@ 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, the caller is broken */
> +		if ((flags & FTW_ACTIONRETVAL) && r == FTW_SKIP_SUBTREE)
> +			r = 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
> 

-- 
Ismael Luceno
http://iodev.co.uk/