Systemd/src/basic/env-util.c
Zbigniew Jędrzejewski-Szmek 11a1589223 tree-wide: drop license boilerplate
Files which are installed as-is (any .service and other unit files, .conf
files, .policy files, etc), are left as is. My assumption is that SPDX
identifiers are not yet that well known, so it's better to retain the
extended header to avoid any doubt.

I also kept any copyright lines. We can probably remove them, but it'd nice to
obtain explicit acks from all involved authors before doing that.
2018-04-06 18:58:55 +02:00

794 lines
21 KiB
C

/* SPDX-License-Identifier: LGPL-2.1+ */
/***
This file is part of systemd.
Copyright 2012 Lennart Poettering
***/
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "alloc-util.h"
#include "env-util.h"
#include "escape.h"
#include "extract-word.h"
#include "macro.h"
#include "parse-util.h"
#include "string-util.h"
#include "strv.h"
#include "utf8.h"
#define VALID_CHARS_ENV_NAME \
DIGITS LETTERS \
"_"
#ifndef ARG_MAX
#define ARG_MAX ((size_t) sysconf(_SC_ARG_MAX))
#endif
static bool env_name_is_valid_n(const char *e, size_t n) {
const char *p;
if (!e)
return false;
if (n <= 0)
return false;
if (e[0] >= '0' && e[0] <= '9')
return false;
/* POSIX says the overall size of the environment block cannot
* be > ARG_MAX, an individual assignment hence cannot be
* either. Discounting the equal sign and trailing NUL this
* hence leaves ARG_MAX-2 as longest possible variable
* name. */
if (n > ARG_MAX - 2)
return false;
for (p = e; p < e + n; p++)
if (!strchr(VALID_CHARS_ENV_NAME, *p))
return false;
return true;
}
bool env_name_is_valid(const char *e) {
if (!e)
return false;
return env_name_is_valid_n(e, strlen(e));
}
bool env_value_is_valid(const char *e) {
if (!e)
return false;
if (!utf8_is_valid(e))
return false;
/* bash allows tabs and newlines in environment variables, and so
* should we */
if (string_has_cc(e, "\t\n"))
return false;
/* POSIX says the overall size of the environment block cannot
* be > ARG_MAX, an individual assignment hence cannot be
* either. Discounting the shortest possible variable name of
* length 1, the equal sign and trailing NUL this hence leaves
* ARG_MAX-3 as longest possible variable value. */
if (strlen(e) > ARG_MAX - 3)
return false;
return true;
}
bool env_assignment_is_valid(const char *e) {
const char *eq;
eq = strchr(e, '=');
if (!eq)
return false;
if (!env_name_is_valid_n(e, eq - e))
return false;
if (!env_value_is_valid(eq + 1))
return false;
/* POSIX says the overall size of the environment block cannot
* be > ARG_MAX, hence the individual variable assignments
* cannot be either, but let's leave room for one trailing NUL
* byte. */
if (strlen(e) > ARG_MAX - 1)
return false;
return true;
}
bool strv_env_is_valid(char **e) {
char **p, **q;
STRV_FOREACH(p, e) {
size_t k;
if (!env_assignment_is_valid(*p))
return false;
/* Check if there are duplicate assginments */
k = strcspn(*p, "=");
STRV_FOREACH(q, p + 1)
if (strneq(*p, *q, k) && (*q)[k] == '=')
return false;
}
return true;
}
bool strv_env_name_is_valid(char **l) {
char **p, **q;
STRV_FOREACH(p, l) {
if (!env_name_is_valid(*p))
return false;
STRV_FOREACH(q, p + 1)
if (streq(*p, *q))
return false;
}
return true;
}
bool strv_env_name_or_assignment_is_valid(char **l) {
char **p, **q;
STRV_FOREACH(p, l) {
if (!env_assignment_is_valid(*p) && !env_name_is_valid(*p))
return false;
STRV_FOREACH(q, p + 1)
if (streq(*p, *q))
return false;
}
return true;
}
static int env_append(char **r, char ***k, char **a) {
assert(r);
assert(k);
if (!a)
return 0;
/* Add the entries of a to *k unless they already exist in *r
* in which case they are overridden instead. This assumes
* there is enough space in the r array. */
for (; *a; a++) {
char **j;
size_t n;
n = strcspn(*a, "=");
if ((*a)[n] == '=')
n++;
for (j = r; j < *k; j++)
if (strneq(*j, *a, n))
break;
if (j >= *k)
(*k)++;
else
free(*j);
*j = strdup(*a);
if (!*j)
return -ENOMEM;
}
return 0;
}
char **strv_env_merge(unsigned n_lists, ...) {
size_t n = 0;
char **l, **k, **r;
va_list ap;
unsigned i;
/* Merges an arbitrary number of environment sets */
va_start(ap, n_lists);
for (i = 0; i < n_lists; i++) {
l = va_arg(ap, char**);
n += strv_length(l);
}
va_end(ap);
r = new(char*, n+1);
if (!r)
return NULL;
k = r;
va_start(ap, n_lists);
for (i = 0; i < n_lists; i++) {
l = va_arg(ap, char**);
if (env_append(r, &k, l) < 0)
goto fail;
}
va_end(ap);
*k = NULL;
return r;
fail:
va_end(ap);
strv_free(r);
return NULL;
}
static bool env_match(const char *t, const char *pattern) {
assert(t);
assert(pattern);
/* pattern a matches string a
* a matches a=
* a matches a=b
* a= matches a=
* a=b matches a=b
* a= does not match a
* a=b does not match a=
* a=b does not match a
* a=b does not match a=c */
if (streq(t, pattern))
return true;
if (!strchr(pattern, '=')) {
size_t l = strlen(pattern);
return strneq(t, pattern, l) && t[l] == '=';
}
return false;
}
static bool env_entry_has_name(const char *entry, const char *name) {
const char *t;
assert(entry);
assert(name);
t = startswith(entry, name);
if (!t)
return false;
return *t == '=';
}
char **strv_env_delete(char **x, unsigned n_lists, ...) {
size_t n, i = 0;
char **k, **r;
va_list ap;
/* Deletes every entry from x that is mentioned in the other
* string lists */
n = strv_length(x);
r = new(char*, n+1);
if (!r)
return NULL;
STRV_FOREACH(k, x) {
unsigned v;
va_start(ap, n_lists);
for (v = 0; v < n_lists; v++) {
char **l, **j;
l = va_arg(ap, char**);
STRV_FOREACH(j, l)
if (env_match(*k, *j))
goto skip;
}
va_end(ap);
r[i] = strdup(*k);
if (!r[i]) {
strv_free(r);
return NULL;
}
i++;
continue;
skip:
va_end(ap);
}
r[i] = NULL;
assert(i <= n);
return r;
}
char **strv_env_unset(char **l, const char *p) {
char **f, **t;
if (!l)
return NULL;
assert(p);
/* Drops every occurrence of the env var setting p in the
* string list. Edits in-place. */
for (f = t = l; *f; f++) {
if (env_match(*f, p)) {
free(*f);
continue;
}
*(t++) = *f;
}
*t = NULL;
return l;
}
char **strv_env_unset_many(char **l, ...) {
char **f, **t;
if (!l)
return NULL;
/* Like strv_env_unset() but applies many at once. Edits in-place. */
for (f = t = l; *f; f++) {
bool found = false;
const char *p;
va_list ap;
va_start(ap, l);
while ((p = va_arg(ap, const char*))) {
if (env_match(*f, p)) {
found = true;
break;
}
}
va_end(ap);
if (found) {
free(*f);
continue;
}
*(t++) = *f;
}
*t = NULL;
return l;
}
int strv_env_replace(char ***l, char *p) {
char **f;
const char *t, *name;
assert(p);
/* Replace first occurrence of the env var or add a new one in the
* string list. Drop other occurences. Edits in-place. Does not copy p.
* p must be a valid key=value assignment.
*/
t = strchr(p, '=');
assert(t);
name = strndupa(p, t - p);
for (f = *l; f && *f; f++)
if (env_entry_has_name(*f, name)) {
free_and_replace(*f, p);
strv_env_unset(f + 1, *f);
return 0;
}
/* We didn't find a match, we need to append p or create a new strv */
if (strv_push(l, p) < 0)
return -ENOMEM;
return 1;
}
char **strv_env_set(char **x, const char *p) {
char **k, **r;
char* m[2] = { (char*) p, NULL };
/* Overrides the env var setting of p, returns a new copy */
r = new(char*, strv_length(x)+2);
if (!r)
return NULL;
k = r;
if (env_append(r, &k, x) < 0)
goto fail;
if (env_append(r, &k, m) < 0)
goto fail;
*k = NULL;
return r;
fail:
strv_free(r);
return NULL;
}
char *strv_env_get_n(char **l, const char *name, size_t k, unsigned flags) {
char **i;
assert(name);
if (k <= 0)
return NULL;
STRV_FOREACH_BACKWARDS(i, l)
if (strneq(*i, name, k) &&
(*i)[k] == '=')
return *i + k + 1;
if (flags & REPLACE_ENV_USE_ENVIRONMENT) {
const char *t;
t = strndupa(name, k);
return getenv(t);
};
return NULL;
}
char *strv_env_get(char **l, const char *name) {
assert(name);
return strv_env_get_n(l, name, strlen(name), 0);
}
char **strv_env_clean_with_callback(char **e, void (*invalid_callback)(const char *p, void *userdata), void *userdata) {
char **p, **q;
int k = 0;
STRV_FOREACH(p, e) {
size_t n;
bool duplicate = false;
if (!env_assignment_is_valid(*p)) {
if (invalid_callback)
invalid_callback(*p, userdata);
free(*p);
continue;
}
n = strcspn(*p, "=");
STRV_FOREACH(q, p + 1)
if (strneq(*p, *q, n) && (*q)[n] == '=') {
duplicate = true;
break;
}
if (duplicate) {
free(*p);
continue;
}
e[k++] = *p;
}
if (e)
e[k] = NULL;
return e;
}
char *replace_env_n(const char *format, size_t n, char **env, unsigned flags) {
enum {
WORD,
CURLY,
VARIABLE,
VARIABLE_RAW,
TEST,
DEFAULT_VALUE,
ALTERNATE_VALUE,
} state = WORD;
const char *e, *word = format, *test_value;
char *k;
_cleanup_free_ char *r = NULL;
size_t i, len;
int nest = 0;
assert(format);
for (e = format, i = 0; *e && i < n; e ++, i ++)
switch (state) {
case WORD:
if (*e == '$')
state = CURLY;
break;
case CURLY:
if (*e == '{') {
k = strnappend(r, word, e-word-1);
if (!k)
return NULL;
free_and_replace(r, k);
word = e-1;
state = VARIABLE;
nest++;
} else if (*e == '$') {
k = strnappend(r, word, e-word);
if (!k)
return NULL;
free_and_replace(r, k);
word = e+1;
state = WORD;
} else if (flags & REPLACE_ENV_ALLOW_BRACELESS && strchr(VALID_CHARS_ENV_NAME, *e)) {
k = strnappend(r, word, e-word-1);
if (!k)
return NULL;
free_and_replace(r, k);
word = e-1;
state = VARIABLE_RAW;
} else
state = WORD;
break;
case VARIABLE:
if (*e == '}') {
const char *t;
t = strv_env_get_n(env, word+2, e-word-2, flags);
k = strappend(r, t);
if (!k)
return NULL;
free_and_replace(r, k);
word = e+1;
state = WORD;
} else if (*e == ':') {
if (!(flags & REPLACE_ENV_ALLOW_EXTENDED))
/* Treat this as unsupported syntax, i.e. do no replacement */
state = WORD;
else {
len = e-word-2;
state = TEST;
}
}
break;
case TEST:
if (*e == '-')
state = DEFAULT_VALUE;
else if (*e == '+')
state = ALTERNATE_VALUE;
else {
state = WORD;
break;
}
test_value = e+1;
break;
case DEFAULT_VALUE: /* fall through */
case ALTERNATE_VALUE:
assert(flags & REPLACE_ENV_ALLOW_EXTENDED);
if (*e == '{') {
nest++;
break;
}
if (*e != '}')
break;
nest--;
if (nest == 0) {
const char *t;
_cleanup_free_ char *v = NULL;
t = strv_env_get_n(env, word+2, len, flags);
if (t && state == ALTERNATE_VALUE)
t = v = replace_env_n(test_value, e-test_value, env, flags);
else if (!t && state == DEFAULT_VALUE)
t = v = replace_env_n(test_value, e-test_value, env, flags);
k = strappend(r, t);
if (!k)
return NULL;
free_and_replace(r, k);
word = e+1;
state = WORD;
}
break;
case VARIABLE_RAW:
assert(flags & REPLACE_ENV_ALLOW_BRACELESS);
if (!strchr(VALID_CHARS_ENV_NAME, *e)) {
const char *t;
t = strv_env_get_n(env, word+1, e-word-1, flags);
k = strappend(r, t);
if (!k)
return NULL;
free_and_replace(r, k);
word = e--;
i--;
state = WORD;
}
break;
}
if (state == VARIABLE_RAW) {
const char *t;
assert(flags & REPLACE_ENV_ALLOW_BRACELESS);
t = strv_env_get_n(env, word+1, e-word-1, flags);
return strappend(r, t);
} else
return strnappend(r, word, e-word);
}
char **replace_env_argv(char **argv, char **env) {
char **ret, **i;
unsigned k = 0, l = 0;
l = strv_length(argv);
ret = new(char*, l+1);
if (!ret)
return NULL;
STRV_FOREACH(i, argv) {
/* If $FOO appears as single word, replace it by the split up variable */
if ((*i)[0] == '$' && !IN_SET((*i)[1], '{', '$')) {
char *e;
char **w, **m = NULL;
unsigned q;
e = strv_env_get(env, *i+1);
if (e) {
int r;
r = strv_split_extract(&m, e, WHITESPACE, EXTRACT_RELAX|EXTRACT_QUOTES);
if (r < 0) {
ret[k] = NULL;
strv_free(ret);
return NULL;
}
} else
m = NULL;
q = strv_length(m);
l = l + q - 1;
w = reallocarray(ret, l + 1, sizeof(char *));
if (!w) {
ret[k] = NULL;
strv_free(ret);
strv_free(m);
return NULL;
}
ret = w;
if (m) {
memcpy(ret + k, m, q * sizeof(char*));
free(m);
}
k += q;
continue;
}
/* If ${FOO} appears as part of a word, replace it by the variable as-is */
ret[k] = replace_env(*i, env, 0);
if (!ret[k]) {
strv_free(ret);
return NULL;
}
k++;
}
ret[k] = NULL;
return ret;
}
int getenv_bool(const char *p) {
const char *e;
e = getenv(p);
if (!e)
return -ENXIO;
return parse_boolean(e);
}
int getenv_bool_secure(const char *p) {
const char *e;
e = secure_getenv(p);
if (!e)
return -ENXIO;
return parse_boolean(e);
}
int serialize_environment(FILE *f, char **environment) {
char **e;
STRV_FOREACH(e, environment) {
_cleanup_free_ char *ce;
ce = cescape(*e);
if (!ce)
return -ENOMEM;
fprintf(f, "env=%s\n", ce);
}
/* caller should call ferror() */
return 0;
}
int deserialize_environment(char ***environment, const char *line) {
char *uce;
int r;
assert(line);
assert(environment);
assert(startswith(line, "env="));
r = cunescape(line + 4, 0, &uce);
if (r < 0)
return r;
return strv_env_replace(environment, uce);
}