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util: rework word parsing and c unescaping code

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When parsing words from input files, optionally automatically unescape
the passed strings, controllable via a new flags parameter.

Make use of this in tmpfiles, and port everything else over, too.

This improves parsing quite a bit, since we no longer have to process the
same string multiple times with different calls, where an earlier call
might corrupt the input for a later call.
This commit is contained in:
Lennart Poettering
2015-03-26 11:56:22 +01:00
parent be3ce3014e
commit 4034a06ddb
11 changed files with 250 additions and 175 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/shared/condition.c
+1 -1
View File
@@ -100,7 +100,7 @@ static int condition_test_kernel_command_line(Condition *c) {
_cleanup_free_ char *word = NULL;
bool found;
r = unquote_first_word(&p, &word, true);
r = unquote_first_word(&p, &word, UNQUOTE_RELAX);
if (r < 0)
return r;
if (r == 0)
src/shared/strv.c
+2 -2
View File
@@ -278,7 +278,7 @@ char **strv_split_newlines(const char *s) {
return l;
}
int strv_split_quoted(char ***t, const char *s, bool relax) {
int strv_split_quoted(char ***t, const char *s, UnquoteFlags flags) {
size_t n = 0, allocated = 0;
_cleanup_strv_free_ char **l = NULL;
int r;
@@ -289,7 +289,7 @@ int strv_split_quoted(char ***t, const char *s, bool relax) {
for (;;) {
_cleanup_free_ char *word = NULL;
r = unquote_first_word(&s, &word, relax);
r = unquote_first_word(&s, &word, flags);
if (r < 0)
return r;
if (r == 0)
src/shared/strv.h
+1 -1
View File
@@ -73,7 +73,7 @@ static inline bool strv_isempty(char * const *l) {
char **strv_split(const char *s, const char *separator);
char **strv_split_newlines(const char *s);
int strv_split_quoted(char ***t, const char *s, bool relax);
int strv_split_quoted(char ***t, const char *s, UnquoteFlags flags);
char *strv_join(char **l, const char *separator);
char *strv_join_quoted(char **l);
src/shared/util.c
+168 -112
View File
@@ -1347,6 +1347,125 @@ char *cescape(const char *s) {
return r;
}
static int cunescape_one(const char *p, size_t length, char *ret) {
int r = 1;
assert(p);
assert(*p);
assert(ret);
if (length != (size_t) -1 && length < 1)
return -EINVAL;
switch (p[0]) {
case 'a':
*ret = '\a';
break;
case 'b':
*ret = '\b';
break;
case 'f':
*ret = '\f';
break;
case 'n':
*ret = '\n';
break;
case 'r':
*ret = '\r';
break;
case 't':
*ret = '\t';
break;
case 'v':
*ret = '\v';
break;
case '\\':
*ret = '\\';
break;
case '"':
*ret = '"';
break;
case '\'':
*ret = '\'';
break;
case 's':
/* This is an extension of the XDG syntax files */
*ret = ' ';
break;
case 'x': {
/* hexadecimal encoding */
int a, b;
if (length != (size_t) -1 && length < 3)
return -EINVAL;
a = unhexchar(p[1]);
if (a < 0)
return -EINVAL;
b = unhexchar(p[2]);
if (b < 0)
return -EINVAL;
/* don't allow NUL bytes */
if (a == 0 && b == 0)
return -EINVAL;
*ret = (char) ((a << 4) | b);
r = 3;
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7': {
/* octal encoding */
int a, b, c, m;
if (length != (size_t) -1 && length < 4)
return -EINVAL;
a = unoctchar(p[0]);
if (a < 0)
return -EINVAL;
b = unoctchar(p[1]);
if (b < 0)
return -EINVAL;
c = unoctchar(p[2]);
if (c < 0)
return -EINVAL;
/* don't allow NUL bytes */
if (a == 0 && b == 0 && c == 0)
return -EINVAL;
/* Don't allow bytes above 255 */
m = (a << 6) | (b << 3) | c;
if (m > 255)
return -EINVAL;
*ret = (char) m;
r = 3;
break;
}
default:
return -EINVAL;
}
return r;
}
char *cunescape_length_with_prefix(const char *s, size_t length, const char *prefix) {
char *r, *t;
const char *f;
@@ -1366,115 +1485,27 @@ char *cunescape_length_with_prefix(const char *s, size_t length, const char *pre
memcpy(r, prefix, pl);
for (f = s, t = r + pl; f < s + length; f++) {
size_t remaining = s + length - f;
size_t remaining;
int k;
remaining = s + length - f;
assert(remaining > 0);
if (*f != '\\') { /* a literal literal */
if (*f != '\\' || remaining == 1) {
/* a literal literal, or a trailing backslash, copy verbatim */
*(t++) = *f;
continue;
}
if (--remaining == 0) { /* copy trailing backslash verbatim */
*(t++) = *f;
break;
}
f++;
switch (*f) {
case 'a':
*(t++) = '\a';
break;
case 'b':
*(t++) = '\b';
break;
case 'f':
*(t++) = '\f';
break;
case 'n':
*(t++) = '\n';
break;
case 'r':
*(t++) = '\r';
break;
case 't':
*(t++) = '\t';
break;
case 'v':
*(t++) = '\v';
break;
case '\\':
*(t++) = '\\';
break;
case '"':
*(t++) = '"';
break;
case '\'':
*(t++) = '\'';
break;
case 's':
/* This is an extension of the XDG syntax files */
*(t++) = ' ';
break;
case 'x': {
/* hexadecimal encoding */
int a = -1, b = -1;
if (remaining >= 2) {
a = unhexchar(f[1]);
b = unhexchar(f[2]);
}
if (a < 0 || b < 0 || (a == 0 && b == 0)) {
/* Invalid escape code, let's take it literal then */
*(t++) = '\\';
*(t++) = 'x';
} else {
*(t++) = (char) ((a << 4) | b);
f += 2;
}
break;
}
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7': {
/* octal encoding */
int a = -1, b = -1, c = -1;
if (remaining >= 3) {
a = unoctchar(f[0]);
b = unoctchar(f[1]);
c = unoctchar(f[2]);
}
if (a < 0 || b < 0 || c < 0 || (a == 0 && b == 0 && c == 0)) {
/* Invalid escape code, let's take it literal then */
*(t++) = '\\';
*(t++) = f[0];
} else {
*(t++) = (char) ((a << 6) | (b << 3) | c);
f += 2;
}
break;
}
default:
k = cunescape_one(f + 1, remaining - 1, t);
if (k < 0) {
/* Invalid escape code, let's take it literal then */
*(t++) = '\\';
*(t++) = *f;
break;
continue;
}
f += k;
t++;
}
*t = 0;
@@ -3411,7 +3442,7 @@ char **replace_env_argv(char **argv, char **env) {
if (e) {
int r;
r = strv_split_quoted(&m, e, true);
r = strv_split_quoted(&m, e, UNQUOTE_RELAX);
if (r < 0) {
ret[k] = NULL;
strv_free(ret);
@@ -6382,7 +6413,7 @@ int parse_proc_cmdline(int (*parse_item)(const char *key, const char *value)) {
_cleanup_free_ char *word = NULL;
char *value = NULL;
r = unquote_first_word(&p, &word, true);
r = unquote_first_word(&p, &word, UNQUOTE_RELAX);
if (r < 0)
return r;
if (r == 0)
@@ -6422,7 +6453,7 @@ int get_proc_cmdline_key(const char *key, char **value) {
_cleanup_free_ char *word = NULL;
const char *e;
r = unquote_first_word(&p, &word, true);
r = unquote_first_word(&p, &word, UNQUOTE_RELAX);
if (r < 0)
return r;
if (r == 0)
@@ -7275,9 +7306,10 @@ int is_dir(const char* path, bool follow) {
return !!S_ISDIR(st.st_mode);
}
int unquote_first_word(const char **p, char **ret, bool relax) {
int unquote_first_word(const char **p, char **ret, UnquoteFlags flags) {
_cleanup_free_ char *s = NULL;
size_t allocated = 0, sz = 0;
int r;
enum {
START,
@@ -7335,7 +7367,7 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
case VALUE_ESCAPE:
if (c == 0) {
if (relax)
if (flags & UNQUOTE_RELAX)
goto finish;
return -EINVAL;
}
@@ -7343,6 +7375,14 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
if (!GREEDY_REALLOC(s, allocated, sz+2))
return -ENOMEM;
if (flags & UNQUOTE_CUNESCAPE) {
r = cunescape_one(*p, (size_t) -1, &c);
if (r < 0)
return -EINVAL;
(*p) += r - 1;
}
s[sz++] = c;
state = VALUE;
@@ -7350,7 +7390,7 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
case SINGLE_QUOTE:
if (c == 0) {
if (relax)
if (flags & UNQUOTE_RELAX)
goto finish;
return -EINVAL;
} else if (c == '\'')
@@ -7368,7 +7408,7 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
case SINGLE_QUOTE_ESCAPE:
if (c == 0) {
if (relax)
if (flags & UNQUOTE_RELAX)
goto finish;
return -EINVAL;
}
@@ -7376,6 +7416,14 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
if (!GREEDY_REALLOC(s, allocated, sz+2))
return -ENOMEM;
if (flags & UNQUOTE_CUNESCAPE) {
r = cunescape_one(*p, (size_t) -1, &c);
if (r < 0)
return -EINVAL;
(*p) += r - 1;
}
s[sz++] = c;
state = SINGLE_QUOTE;
break;
@@ -7398,7 +7446,7 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
case DOUBLE_QUOTE_ESCAPE:
if (c == 0) {
if (relax)
if (flags & UNQUOTE_RELAX)
goto finish;
return -EINVAL;
}
@@ -7406,6 +7454,14 @@ int unquote_first_word(const char **p, char **ret, bool relax) {
if (!GREEDY_REALLOC(s, allocated, sz+2))
return -ENOMEM;
if (flags & UNQUOTE_CUNESCAPE) {
r = cunescape_one(*p, (size_t) -1, &c);
if (r < 0)
return -EINVAL;
(*p) += r - 1;
}
s[sz++] = c;
state = DOUBLE_QUOTE;
break;
@@ -7435,7 +7491,7 @@ finish:
return 1;
}
int unquote_many_words(const char **p, ...) {
int unquote_many_words(const char **p, UnquoteFlags flags, ...) {
va_list ap;
char **l;
int n = 0, i, c, r;
@@ -7446,7 +7502,7 @@ int unquote_many_words(const char **p, ...) {
assert(p);
/* Count how many words are expected */
va_start(ap, p);
va_start(ap, flags);
for (;;) {
if (!va_arg(ap, char **))
break;
@@ -7461,7 +7517,7 @@ int unquote_many_words(const char **p, ...) {
l = newa0(char*, n);
for (c = 0; c < n; c++) {
r = unquote_first_word(p, &l[c], false);
r = unquote_first_word(p, &l[c], flags);
if (r < 0) {
int j;
@@ -7477,7 +7533,7 @@ int unquote_many_words(const char **p, ...) {
/* If we managed to parse all words, return them in the passed
* in parameters */
va_start(ap, p);
va_start(ap, flags);
for (i = 0; i < n; i++) {
char **v;
src/shared/util.h
+7 -2
View File
@@ -1017,8 +1017,13 @@ int take_password_lock(const char *root);
int is_symlink(const char *path);
int is_dir(const char *path, bool follow);
int unquote_first_word(const char **p, char **ret, bool relax);
int unquote_many_words(const char **p, ...) _sentinel_;
typedef enum UnquoteFlags{
UNQUOTE_RELAX = 1,
UNQUOTE_CUNESCAPE = 2,
} UnquoteFlags;
int unquote_first_word(const char **p, char **ret, UnquoteFlags flags);
int unquote_many_words(const char **p, UnquoteFlags flags, ...) _sentinel_;
int free_and_strdup(char **p, const char *s);