nfsd: escape high characters in binary data

I'm exposing some information about NFS clients in pseudofiles. I expect to eventually have simple tools to help read those pseudofiles. But it's also helpful if the raw files are human-readable to the extent possible. It aids debugging and makes them usable on systems that don't have the latest nfs-utils. A minor challenge there is opaque client-generated protocol objects like state owners and client identifiers. Some clients generate those to include handy information in plain ascii. But they may also include arbitrary byte sequences. I think the simplest approach is to limit to isprint(c) && isascii(c) and escape everything else. That means you can just cat the file and get something that looks OK. Also, I'm trying to keep these files legal YAML, which requires them to UTF-8, and this is a simple way to guarantee that.

J. Bruce Fields committed 7 years ago

Commit ea053e11 parent 3bade244 files · +34 −0Browse files

Showing the changes to include/linux (2 of 4 files). Show all

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2 files

include/linux/seq_file.h +1 −0
include/linux/string_helpers.h +3 −0

include/linux/seq_file.h+1−0

@@ -127,6 +127,7 @@ void seq_put_hex_ll(struct seq_file m, const char delimiter, · 126 unmodified lines
127	unsigned long long v, unsigned int width);	127	unsigned long long v, unsigned int width);
128		128
129	void seq_escape(struct seq_file m, const char s, const char *esc);	129	void seq_escape(struct seq_file m, const char s, const char *esc);
		130	void seq_escape_mem_ascii(struct seq_file m, const char src, size_t isz);
130		131
131	void seq_hex_dump(struct seq_file m, const char prefix_str, int prefix_type,	132	void seq_hex_dump(struct seq_file m, const char prefix_str, int prefix_type,
132	int rowsize, int groupsize, const void *buf, size_t len,	133	int rowsize, int groupsize, const void *buf, size_t len,

include/linux/string_helpers.h+3−0

@@ -54,6 +54,9 @@ static inline int string_unescape_any_inplace(char *buf) · 53 unmodified lines
54	int string_escape_mem(const char src, size_t isz, char dst, size_t osz,	54	int string_escape_mem(const char src, size_t isz, char dst, size_t osz,
55	unsigned int flags, const char *only);	55	unsigned int flags, const char *only);
56		56
		57	int string_escape_mem_ascii(const char src, size_t isz, char dst,
		58	size_t osz);
		59
57	static inline int string_escape_mem_any_np(const char *src, size_t isz,	60	static inline int string_escape_mem_any_np(const char *src, size_t isz,
58	char dst, size_t osz, const char only)	61	char dst, size_t osz, const char only)
59	{	62	{

nfsd: escape high characters in binary data

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