Messages in this thread | | | Date | Tue, 18 May 2021 16:10:29 +0300 | From | Andy Shevchenko <> | Subject | Re: [PATCH v6 1/4] string_helpers: Escape double quotes in escape_special |
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On Tue, May 18, 2021 at 01:00:32PM +0100, Chris Down wrote: > From an abstract point of view, escape_special's counterpart, > unescape_special, already handles the unescaping of blackslashed double > quote sequences. > > As a more practical example, printk indexing is an example case where > this is already practically useful. Compare an example with > `ESCAPE_SPECIAL | ESCAPE_SPACE`, with quotes not escaped: > > [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux > <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string "%s"\n" > > ...and the same after this patch: > > [root@ktst ~]# grep drivers/pci/pci-stub.c:69 /sys/kernel/debug/printk/index/vmlinux > <4> drivers/pci/pci-stub.c:69 pci_stub_init "pci-stub: invalid ID string \"%s\"\n" > > One can of course, alternatively, use ESCAPE_APPEND with a quote in > @only, but without this patch quotes are coerced into hex or octal which > can hurt readability quite significantly. > > A new ESCAPE_QUOTE/ESCAPE_PRINTK option is also possible, but it seems > reasonable to use the simplest strategy first, since this is already > decoded properly.
We have only one direct user of ESCAPE_SPECIAL and there " is not used.
Indirect ones are %pE, but IIRC most of them are either debug messages or some kind of (non-ABI) messages.
It would be nice if you can confirm this and put a note into commit message.
If the above is confirmed, feel free to add mine Reviewed-by; Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Chris Down <chris@chrisdown.name> > Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> > --- > lib/string_helpers.c | 4 ++++ > lib/test-string_helpers.c | 14 +++++++------- > 2 files changed, 11 insertions(+), 7 deletions(-) > > diff --git a/lib/string_helpers.c b/lib/string_helpers.c > index 5a35c7e16e96..3806a52ce697 100644 > --- a/lib/string_helpers.c > +++ b/lib/string_helpers.c > @@ -361,6 +361,9 @@ static bool escape_special(unsigned char c, char **dst, char *end) > case '\e': > to = 'e'; > break; > + case '"': > + to = '"'; > + break; > default: > return false; > } > @@ -474,6 +477,7 @@ static bool escape_hex(unsigned char c, char **dst, char *end) > * '\t' - horizontal tab > * '\v' - vertical tab > * %ESCAPE_SPECIAL: > + * '\"' - double quote > * '\\' - backslash > * '\a' - alert (BEL) > * '\e' - escape > diff --git a/lib/test-string_helpers.c b/lib/test-string_helpers.c > index 2185d71704f0..437d8e6b7cb1 100644 > --- a/lib/test-string_helpers.c > +++ b/lib/test-string_helpers.c > @@ -140,13 +140,13 @@ static const struct test_string_2 escape0[] __initconst = {{ > },{ > .in = "\\h\\\"\a\e\\", > .s1 = {{ > - .out = "\\\\h\\\\\"\\a\\e\\\\", > + .out = "\\\\h\\\\\\\"\\a\\e\\\\", > .flags = ESCAPE_SPECIAL, > },{ > - .out = "\\\\\\150\\\\\\042\\a\\e\\\\", > + .out = "\\\\\\150\\\\\\\"\\a\\e\\\\", > .flags = ESCAPE_SPECIAL | ESCAPE_OCTAL, > },{ > - .out = "\\\\\\x68\\\\\\x22\\a\\e\\\\", > + .out = "\\\\\\x68\\\\\\\"\\a\\e\\\\", > .flags = ESCAPE_SPECIAL | ESCAPE_HEX, > },{ > /* terminator */ > @@ -157,10 +157,10 @@ static const struct test_string_2 escape0[] __initconst = {{ > .out = "\eb \\C\007\"\x90\\r]", > .flags = ESCAPE_SPACE, > },{ > - .out = "\\eb \\\\C\\a\"\x90\r]", > + .out = "\\eb \\\\C\\a\\\"\x90\r]", > .flags = ESCAPE_SPECIAL, > },{ > - .out = "\\eb \\\\C\\a\"\x90\\r]", > + .out = "\\eb \\\\C\\a\\\"\x90\\r]", > .flags = ESCAPE_SPACE | ESCAPE_SPECIAL, > },{ > .out = "\\033\\142\\040\\134\\103\\007\\042\\220\\015\\135", > @@ -169,10 +169,10 @@ static const struct test_string_2 escape0[] __initconst = {{ > .out = "\\033\\142\\040\\134\\103\\007\\042\\220\\r\\135", > .flags = ESCAPE_SPACE | ESCAPE_OCTAL, > },{ > - .out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\015\\135", > + .out = "\\e\\142\\040\\\\\\103\\a\\\"\\220\\015\\135", > .flags = ESCAPE_SPECIAL | ESCAPE_OCTAL, > },{ > - .out = "\\e\\142\\040\\\\\\103\\a\\042\\220\\r\\135", > + .out = "\\e\\142\\040\\\\\\103\\a\\\"\\220\\r\\135", > .flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_OCTAL, > },{ > .out = "\eb \\C\007\"\x90\r]", > -- > 2.31.1 >
-- With Best Regards, Andy Shevchenko
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