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ucm: allow to escape the trailing variable substitution character

Browse source 
Example:

  ${find-device:ctl='hw:0',type=pcm,field=id,regex='USB A{1\\}'}

Unescaped find-device arguments:

  ctl='hw:0',type=pcm,field=id,regex='USB A{1}'

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2021-04-16 12:34:29 +02:00
parent ddb0871ec6
commit 652ddf866f
1 changed files with 42 additions and 4 deletions
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46
src/ucm/ucm_subs.c
View file

@ -594,13 +594,52 @@ static char *rval_var(snd_use_case_mgr_t *uc_mgr, const char *id)
goto __match2; \
}
/*
* skip escaped } character (simple version)
*/
static inline const char *strchr_with_escape(const char *str, char c)
{
char *s;
while (1) {
s = strchr(str, c);
if (s && s != str) {
if (*(s - 1) == '\\') {
str = s + 1;
continue;
}
}
return s;
}
}
/*
* remove escaped } character (simple version)
*/
static inline void strncpy_with_escape(char *dst, const char *src, size_t len)
{
char c;
c = *src++;
while (c != '\0' && len > 0) {
if (c == '\\' && *src == '}') {
c = *src++;
len--;
}
*dst++ = c;
len--;
c = *src++;
}
*dst = '\0';
}
int uc_mgr_get_substituted_value(snd_use_case_mgr_t *uc_mgr,
char **_rvalue,
const char *value)
{
size_t size, nsize, idsize, rvalsize, dpos = 0;
const char *tmp;
char *r, *nr, *rval, v2[48];
char *r, *nr, *rval, v2[128];
bool ignore_error, allow_empty;
char *(*fcn2)(snd_use_case_mgr_t *, const char *id);
int err;
@ -658,15 +697,14 @@ __merr:
}
goto __error;
__match2:
tmp = strchr(value + idsize, '}');
tmp = strchr_with_escape(value + idsize, '}');
if (tmp) {
rvalsize = tmp - (value + idsize);
if (rvalsize >= sizeof(v2)) {
err = -ENOMEM;
goto __error;
}
strncpy(v2, value + idsize, rvalsize);
v2[rvalsize] = '\0';
strncpy_with_escape(v2, value + idsize, rvalsize);
idsize += rvalsize + 1;
if (*v2 == '$' && uc_mgr->conf_format >= 3) {
tmp = uc_mgr_get_variable(uc_mgr, v2 + 1);