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authorChris Down <chris@chrisdown.name>2021-06-15 17:52:45 +0100
committerPetr Mladek <pmladek@suse.com>2021-07-19 11:39:28 +0200
commit91027d0a7a0e309b94674923dc1b245b709b5c1e (patch)
tree237323e76bbba832797eb067315c7b9e1d232c0c /lib/string_helpers.c
parente73f0f0ee7541171d89f2e2491130c7771ba58d3 (diff)
downloadlinux-91027d0a7a0e309b94674923dc1b245b709b5c1e.tar.bz2
string_helpers: Escape double quotes in escape_special
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. I've checked uses of ESCAPE_SPECIAL and %pE across the codebase, and I'm pretty confident that this shouldn't affect any stable interfaces. Signed-off-by: Chris Down <chris@chrisdown.name> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com> Link: https://lore.kernel.org/r/af144c5b75e41ce417386253ba2694456bc04118.1623775748.git.chris@chrisdown.name
Diffstat (limited to 'lib/string_helpers.c')
-rw-r--r--lib/string_helpers.c4
1 files changed, 4 insertions, 0 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