ff461576de
This reverts commitb45c068dd8. I think the idea was generally sound, but didn't take into account the limitations of show-environment and how it is used. People expect to be able to eval systemctl show-environment output in bash, and no escaping syntax is defined for environment *names* (we only do escaping for *values*). We could skip such problematic variables in 'systemctl show-environment', and only allow them to be inherited directly. But this would be confusing and ugly. The original motivation for this change was that various import operations would fail.a4ccce22d9changed systemctl to filter invalid variables in import-environment. https://gitlab.gnome.org/GNOME/gnome-session/-/issues/71 does a similar change in GNOME. So those problematic variables should not cause failures, but just be silently ignored. Finally, the environment block is becoming a dumping ground. In my gnome session 'systemctl show-environment --user' includes stuff like PWD, FPATH (from zsh), SHLVL=0 (no idea what that is). This is not directly related to variable names (since all those are allowed under the stricter rules too), but I think we should start pushing people away from running import-environment and towards importing only select variables. https://github.com/systemd/systemd/pull/17188#issuecomment-708676511
750 lines
20 KiB
C
750 lines
20 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <limits.h>
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#include <stdarg.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "alloc-util.h"
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#include "env-util.h"
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#include "escape.h"
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#include "extract-word.h"
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#include "macro.h"
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#include "parse-util.h"
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#include "string-util.h"
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#include "strv.h"
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#include "utf8.h"
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/* We follow bash for the character set. Different shells have different rules. */
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#define VALID_BASH_ENV_NAME_CHARS \
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DIGITS LETTERS \
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"_"
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static bool env_name_is_valid_n(const char *e, size_t n) {
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const char *p;
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if (!e)
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return false;
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if (n <= 0)
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return false;
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if (e[0] >= '0' && e[0] <= '9')
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return false;
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/* POSIX says the overall size of the environment block cannot
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* be > ARG_MAX, an individual assignment hence cannot be
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* either. Discounting the equal sign and trailing NUL this
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* hence leaves ARG_MAX-2 as longest possible variable
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* name. */
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if (n > (size_t) sysconf(_SC_ARG_MAX) - 2)
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return false;
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for (p = e; p < e + n; p++)
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if (!strchr(VALID_BASH_ENV_NAME_CHARS, *p))
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return false;
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return true;
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}
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bool env_name_is_valid(const char *e) {
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return env_name_is_valid_n(e, strlen_ptr(e));
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}
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bool env_value_is_valid(const char *e) {
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if (!e)
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return false;
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if (!utf8_is_valid(e))
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return false;
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/* bash allows tabs and newlines in environment variables, and so
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* should we */
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if (string_has_cc(e, "\t\n"))
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return false;
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/* POSIX says the overall size of the environment block cannot
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* be > ARG_MAX, an individual assignment hence cannot be
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* either. Discounting the shortest possible variable name of
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* length 1, the equal sign and trailing NUL this hence leaves
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* ARG_MAX-3 as longest possible variable value. */
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if (strlen(e) > sc_arg_max() - 3)
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return false;
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return true;
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}
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bool env_assignment_is_valid(const char *e) {
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const char *eq;
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eq = strchr(e, '=');
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if (!eq)
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return false;
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if (!env_name_is_valid_n(e, eq - e))
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return false;
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if (!env_value_is_valid(eq + 1))
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return false;
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/* POSIX says the overall size of the environment block cannot
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* be > ARG_MAX, hence the individual variable assignments
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* cannot be either, but let's leave room for one trailing NUL
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* byte. */
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if (strlen(e) > sc_arg_max() - 1)
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return false;
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return true;
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}
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bool strv_env_is_valid(char **e) {
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char **p, **q;
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STRV_FOREACH(p, e) {
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size_t k;
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if (!env_assignment_is_valid(*p))
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return false;
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/* Check if there are duplicate assignments */
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k = strcspn(*p, "=");
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STRV_FOREACH(q, p + 1)
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if (strneq(*p, *q, k) && (*q)[k] == '=')
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return false;
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}
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return true;
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}
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bool strv_env_name_is_valid(char **l) {
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char **p;
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STRV_FOREACH(p, l) {
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if (!env_name_is_valid(*p))
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return false;
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if (strv_contains(p + 1, *p))
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return false;
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}
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return true;
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}
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bool strv_env_name_or_assignment_is_valid(char **l) {
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char **p;
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STRV_FOREACH(p, l) {
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if (!env_assignment_is_valid(*p) && !env_name_is_valid(*p))
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return false;
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if (strv_contains(p + 1, *p))
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return false;
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}
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return true;
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}
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static int env_append(char **r, char ***k, char **a) {
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assert(r);
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assert(k);
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assert(*k >= r);
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if (!a)
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return 0;
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/* Expects the following arguments: 'r' shall point to the beginning of an strv we are going to append to, 'k'
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* to a pointer pointing to the NULL entry at the end of the same array. 'a' shall point to another strv.
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*
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* This call adds every entry of 'a' to 'r', either overriding an existing matching entry, or appending to it.
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*
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* This call assumes 'r' has enough pre-allocated space to grow by all of 'a''s items. */
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for (; *a; a++) {
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char **j, *c;
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size_t n;
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n = strcspn(*a, "=");
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if ((*a)[n] == '=')
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n++;
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for (j = r; j < *k; j++)
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if (strneq(*j, *a, n))
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break;
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c = strdup(*a);
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if (!c)
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return -ENOMEM;
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if (j >= *k) { /* Append to the end? */
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(*k)[0] = c;
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(*k)[1] = NULL;
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(*k)++;
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} else
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free_and_replace(*j, c); /* Override existing item */
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}
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return 0;
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}
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char **strv_env_merge(size_t n_lists, ...) {
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_cleanup_strv_free_ char **ret = NULL;
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size_t n = 0, i;
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char **l, **k;
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va_list ap;
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/* Merges an arbitrary number of environment sets */
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va_start(ap, n_lists);
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for (i = 0; i < n_lists; i++) {
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l = va_arg(ap, char**);
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n += strv_length(l);
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}
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va_end(ap);
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ret = new(char*, n+1);
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if (!ret)
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return NULL;
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*ret = NULL;
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k = ret;
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va_start(ap, n_lists);
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for (i = 0; i < n_lists; i++) {
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l = va_arg(ap, char**);
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if (env_append(ret, &k, l) < 0) {
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va_end(ap);
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return NULL;
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}
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}
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va_end(ap);
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return TAKE_PTR(ret);
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}
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static bool env_match(const char *t, const char *pattern) {
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assert(t);
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assert(pattern);
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/* pattern a matches string a
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* a matches a=
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* a matches a=b
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* a= matches a=
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* a=b matches a=b
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* a= does not match a
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* a=b does not match a=
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* a=b does not match a
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* a=b does not match a=c */
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if (streq(t, pattern))
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return true;
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if (!strchr(pattern, '=')) {
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size_t l = strlen(pattern);
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return strneq(t, pattern, l) && t[l] == '=';
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}
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return false;
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}
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static bool env_entry_has_name(const char *entry, const char *name) {
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const char *t;
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assert(entry);
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assert(name);
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t = startswith(entry, name);
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if (!t)
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return false;
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return *t == '=';
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}
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char **strv_env_delete(char **x, size_t n_lists, ...) {
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size_t n, i = 0;
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char **k, **r;
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va_list ap;
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/* Deletes every entry from x that is mentioned in the other
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* string lists */
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n = strv_length(x);
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r = new(char*, n+1);
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if (!r)
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return NULL;
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STRV_FOREACH(k, x) {
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size_t v;
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va_start(ap, n_lists);
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for (v = 0; v < n_lists; v++) {
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char **l, **j;
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l = va_arg(ap, char**);
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STRV_FOREACH(j, l)
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if (env_match(*k, *j))
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goto skip;
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}
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va_end(ap);
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r[i] = strdup(*k);
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if (!r[i]) {
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strv_free(r);
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return NULL;
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}
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i++;
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continue;
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skip:
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va_end(ap);
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}
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r[i] = NULL;
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assert(i <= n);
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return r;
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}
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char **strv_env_unset(char **l, const char *p) {
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char **f, **t;
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if (!l)
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return NULL;
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assert(p);
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/* Drops every occurrence of the env var setting p in the
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* string list. Edits in-place. */
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for (f = t = l; *f; f++) {
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if (env_match(*f, p)) {
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free(*f);
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continue;
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}
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*(t++) = *f;
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}
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*t = NULL;
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return l;
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}
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char **strv_env_unset_many(char **l, ...) {
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char **f, **t;
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if (!l)
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return NULL;
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/* Like strv_env_unset() but applies many at once. Edits in-place. */
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for (f = t = l; *f; f++) {
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bool found = false;
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const char *p;
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va_list ap;
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va_start(ap, l);
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while ((p = va_arg(ap, const char*))) {
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if (env_match(*f, p)) {
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found = true;
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break;
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}
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}
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va_end(ap);
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if (found) {
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free(*f);
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continue;
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}
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*(t++) = *f;
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}
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*t = NULL;
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return l;
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}
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int strv_env_replace(char ***l, char *p) {
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const char *t, *name;
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char **f;
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int r;
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assert(p);
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/* Replace first occurrence of the env var or add a new one in the string list. Drop other occurrences. Edits
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* in-place. Does not copy p. p must be a valid key=value assignment.
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*/
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t = strchr(p, '=');
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if (!t)
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return -EINVAL;
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name = strndupa(p, t - p);
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STRV_FOREACH(f, *l)
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if (env_entry_has_name(*f, name)) {
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free_and_replace(*f, p);
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strv_env_unset(f + 1, *f);
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return 0;
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}
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/* We didn't find a match, we need to append p or create a new strv */
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r = strv_push(l, p);
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if (r < 0)
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return r;
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return 1;
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}
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char **strv_env_set(char **x, const char *p) {
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_cleanup_strv_free_ char **ret = NULL;
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size_t n, m;
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char **k;
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/* Overrides the env var setting of p, returns a new copy */
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n = strv_length(x);
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m = n + 2;
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if (m < n) /* overflow? */
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return NULL;
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ret = new(char*, m);
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if (!ret)
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return NULL;
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*ret = NULL;
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k = ret;
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if (env_append(ret, &k, x) < 0)
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return NULL;
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if (env_append(ret, &k, STRV_MAKE(p)) < 0)
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return NULL;
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return TAKE_PTR(ret);
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}
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char *strv_env_get_n(char **l, const char *name, size_t k, unsigned flags) {
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char **i;
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assert(name);
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if (k <= 0)
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return NULL;
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STRV_FOREACH_BACKWARDS(i, l)
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if (strneq(*i, name, k) &&
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(*i)[k] == '=')
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return *i + k + 1;
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if (flags & REPLACE_ENV_USE_ENVIRONMENT) {
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const char *t;
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t = strndupa(name, k);
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return getenv(t);
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};
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return NULL;
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}
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char *strv_env_get(char **l, const char *name) {
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assert(name);
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return strv_env_get_n(l, name, strlen(name), 0);
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}
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char **strv_env_clean_with_callback(char **e, void (*invalid_callback)(const char *p, void *userdata), void *userdata) {
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char **p, **q;
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int k = 0;
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STRV_FOREACH(p, e) {
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size_t n;
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bool duplicate = false;
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if (!env_assignment_is_valid(*p)) {
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if (invalid_callback)
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invalid_callback(*p, userdata);
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free(*p);
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continue;
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}
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n = strcspn(*p, "=");
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STRV_FOREACH(q, p + 1)
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if (strneq(*p, *q, n) && (*q)[n] == '=') {
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duplicate = true;
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break;
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}
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if (duplicate) {
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free(*p);
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continue;
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}
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e[k++] = *p;
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}
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if (e)
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e[k] = NULL;
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return e;
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}
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char *replace_env_n(const char *format, size_t n, char **env, unsigned flags) {
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enum {
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WORD,
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CURLY,
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VARIABLE,
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VARIABLE_RAW,
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TEST,
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DEFAULT_VALUE,
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ALTERNATE_VALUE,
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} state = WORD;
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const char *e, *word = format, *test_value;
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char *k;
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_cleanup_free_ char *r = NULL;
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size_t i, len;
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int nest = 0;
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assert(format);
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for (e = format, i = 0; *e && i < n; e ++, i ++)
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switch (state) {
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case WORD:
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if (*e == '$')
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state = CURLY;
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break;
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case CURLY:
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if (*e == '{') {
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k = strnappend(r, word, e-word-1);
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if (!k)
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return NULL;
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free_and_replace(r, k);
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word = e-1;
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state = VARIABLE;
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nest++;
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} else if (*e == '$') {
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k = strnappend(r, word, e-word);
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if (!k)
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return NULL;
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free_and_replace(r, k);
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word = e+1;
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state = WORD;
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} else if (flags & REPLACE_ENV_ALLOW_BRACELESS && strchr(VALID_BASH_ENV_NAME_CHARS, *e)) {
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k = strnappend(r, word, e-word-1);
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if (!k)
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return NULL;
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free_and_replace(r, k);
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word = e-1;
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state = VARIABLE_RAW;
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} else
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state = WORD;
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break;
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case VARIABLE:
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if (*e == '}') {
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const char *t;
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t = strv_env_get_n(env, word+2, e-word-2, flags);
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k = strjoin(r, t);
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if (!k)
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return NULL;
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free_and_replace(r, k);
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word = e+1;
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state = WORD;
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} else if (*e == ':') {
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if (!(flags & REPLACE_ENV_ALLOW_EXTENDED))
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/* Treat this as unsupported syntax, i.e. do no replacement */
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state = WORD;
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else {
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len = e-word-2;
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state = TEST;
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}
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}
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break;
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case TEST:
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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 = strjoin(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_BASH_ENV_NAME_CHARS, *e)) {
|
|
const char *t;
|
|
|
|
t = strv_env_get_n(env, word+1, e-word-1, flags);
|
|
|
|
k = strjoin(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 strjoin(r, t);
|
|
} else
|
|
return strnappend(r, word, e-word);
|
|
}
|
|
|
|
char **replace_env_argv(char **argv, char **env) {
|
|
char **ret, **i;
|
|
size_t 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;
|
|
size_t q;
|
|
|
|
e = strv_env_get(env, *i+1);
|
|
if (e) {
|
|
int r;
|
|
|
|
r = strv_split_full(&m, e, WHITESPACE, EXTRACT_RELAX|EXTRACT_UNQUOTE);
|
|
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);
|
|
}
|