/*-*- 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" #include "def.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; 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 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_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; } _pure_ 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; } 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; } 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 (strneq(*i, name, k) && (*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_log(char **e, const char *message) { char **p, **q; int k = 0; STRV_FOREACH(p, e) { size_t n; bool duplicate = false; if (!env_assignment_is_valid(*p)) { if (message) log_error("Ignoring invalid environment '%s': %s", *p, message); 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 **strv_env_clean(char **e) { return strv_env_clean_log(e, NULL); }