/*-*- 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 <errno.h> #include <stddef.h> #include <stdlib.h> #include <string.h> #include "alloc-util.h" #include "macro.h" #include "replace-var.h" #include "string-util.h" /* * Generic infrastructure for replacing @FOO@ style variables in * strings. Will call a callback for each replacement. */ static int get_variable(const char *b, char **r) { size_t k; char *t; assert(b); assert(r); if (*b != '@') return 0; k = strspn(b + 1, UPPERCASE_LETTERS "_"); if (k <= 0 || b[k+1] != '@') return 0; t = strndup(b + 1, k); if (!t) return -ENOMEM; *r = t; return 1; } char *replace_var(const char *text, char *(*lookup)(const char *variable, void*userdata), void *userdata) { char *r, *t; const char *f; size_t l; assert(text); assert(lookup); l = strlen(text); r = new(char, l+1); if (!r) return NULL; f = text; t = r; while (*f) { _cleanup_free_ char *v = NULL, *n = NULL; char *a; int k; size_t skip, d, nl; k = get_variable(f, &v); if (k < 0) goto oom; if (k == 0) { *(t++) = *(f++); continue; } n = lookup(v, userdata); if (!n) goto oom; skip = strlen(v) + 2; d = t - r; nl = l - skip + strlen(n); a = realloc(r, nl + 1); if (!a) goto oom; l = nl; r = a; t = r + d; t = stpcpy(t, n); f += skip; } *t = 0; return r; oom: free(r); return NULL; }