[PATCH 1/6] lib/cmdline.c: Add backslash support to kernel commandline parsing.

From: Michal Suchanek
Date: Fri Sep 15 2017 - 13:03:02 EST


This allows passing quotes in kernel arguments. It is useful for passing
fadump nested arguemnts in fadump_extra_args and might be useful if
somebody wanted to pass a double quote directly as part of an argument.

It is also useful to have quoting grammar more similar to shells and
bootloaders.

Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
---
lib/cmdline.c | 41 ++++++++++++++++++++---------------------
1 file changed, 20 insertions(+), 21 deletions(-)

diff --git a/lib/cmdline.c b/lib/cmdline.c
index 6d398a8b63fc..d98bdc017545 100644
--- a/lib/cmdline.c
+++ b/lib/cmdline.c
@@ -193,30 +193,36 @@ bool parse_option_str(const char *str, const char *option)

/*
* Parse a string to get a param value pair.
- * You can use " around spaces, but can't escape ".
+ * You can use " around spaces, and you can escape with \
* Hyphens and underscores equivalent in parameter names.
*/
char *next_arg(char *args, char **param, char **val)
{
unsigned int i, equals = 0;
- int in_quote = 0, quoted = 0;
+ int in_quote = 0, backslash = 0;
char *next;

- if (*args == '"') {
- args++;
- in_quote = 1;
- quoted = 1;
- }
-
for (i = 0; args[i]; i++) {
- if (isspace(args[i]) && !in_quote)
+ if (isspace(args[i]) && !in_quote && !backslash)
break;
- if (equals == 0) {
- if (args[i] == '=')
- equals = i;
+
+ if ((equals == 0) && (args[i] == '='))
+ equals = i;
+
+ if (!backslash) {
+ if ((args[i] == '"') || (args[i] == '\\')) {
+ if (args[i] == '"')
+ in_quote = !in_quote;
+ if (args[i] == '\\')
+ backslash = 1;
+
+ memmove(args + 1, args, i);
+ args++;
+ i--;
+ }
+ } else {
+ backslash = 0;
}
- if (args[i] == '"')
- in_quote = !in_quote;
}

*param = args;
@@ -225,13 +231,6 @@ char *next_arg(char *args, char **param, char **val)
else {
args[equals] = '\0';
*val = args + equals + 1;
-
- /* Don't include quotes in value. */
- if ((args[i-1] == '"') && ((quoted) || (**val == '"'))) {
- args[i-1] = '\0';
- if (!quoted)
- (*val)++;
- }
}

if (args[i]) {
--
2.10.2