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-rw-r--r--src/shared/env-util.c394
1 files changed, 394 insertions, 0 deletions
diff --git a/src/shared/env-util.c b/src/shared/env-util.c
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+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+ This file is part of systemd.
+
+ Copyright 2012 Lennart Poettering
+
+ systemd is free software; you can redistribute it and/or modify it
+ under the terms of the GNU Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 of the License, or
+ (at your option) any later version.
+
+ systemd is distributed in the hope that it will be useful, but
+ WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <limits.h>
+#include <sys/param.h>
+#include <unistd.h>
+
+#include "strv.h"
+#include "utf8.h"
+#include "util.h"
+#include "env-util.h"
+
+#define VALID_CHARS_ENV_NAME \
+ "0123456789" \
+ "abcdefghijklmnopqrstuvwxyz" \
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+ "_"
+
+#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;
+
+ if (string_has_cc(e))
+ 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 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 (strncmp(*p, *q, k) == 0 && (*q)[k] == '=')
+ 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 (strncmp(*j, *a, n) == 0)
+ 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 strncmp(t, pattern, l) == 0 && t[l] == '=';
+ }
+
+ return false;
+}
+
+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_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) {
+ char **i;
+
+ assert(name);
+
+ if (k <= 0)
+ return NULL;
+
+ STRV_FOREACH(i, l)
+ if (strncmp(*i, name, k) == 0 &&
+ (*i)[k] == '=')
+ return *i + k + 1;
+
+ return NULL;
+}
+
+char *strv_env_get(char **l, const char *name) {
+ assert(name);
+
+ return strv_env_get_n(l, name, strlen(name));
+}
+
+char **strv_env_clean(char **e) {
+ char **p, **q;
+ int k = 0;
+
+ STRV_FOREACH(p, e) {
+ size_t n;
+ bool duplicate = false;
+
+ if (!env_assignment_is_valid(*p)) {
+ free(*p);
+ continue;
+ }
+
+ n = strcspn(*p, "=");
+ STRV_FOREACH(q, p + 1)
+ if (strncmp(*p, *q, n) == 0 && (*q)[n] == '=') {
+ duplicate = true;
+ break;
+ }
+
+ if (duplicate) {
+ free(*p);
+ continue;
+ }
+
+ e[k++] = *p;
+ }
+
+ e[k] = NULL;
+ return e;
+}
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