core: add minimal templating system

1 files changed, 373 insertions, 0 deletions

diff --git a/unit-name.c b/unit-name.c
new file mode 100644
index 0000000000..219997b681
--- /dev/null
+++ b/unit-name.c
@@ -0,0 +1,373 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2010 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <string.h>
+
+#include "unit.h"
+#include "unit-name.h"
+
+#define VALID_CHARS                             \
+        "0123456789"                            \
+        "abcdefghijklmnopqrstuvwxyz"            \
+        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"            \
+        "-_.\\"
+
+UnitType unit_name_to_type(const char *n) {
+        UnitType t;
+
+        assert(n);
+
+        for (t = 0; t < _UNIT_TYPE_MAX; t++)
+                if (endswith(n, unit_vtable[t]->suffix))
+                        return t;
+
+        return _UNIT_TYPE_INVALID;
+}
+
+bool unit_name_is_valid(const char *n) {
+        UnitType t;
+        const char *e, *i, *at;
+
+        /* Valid formats:
+         *
+         *         string@instance.suffix
+         *         string.suffix
+         */
+
+        assert(n);
+
+        if (strlen(n) >= UNIT_NAME_MAX)
+                return false;
+
+        t = unit_name_to_type(n);
+        if (t < 0 || t >= _UNIT_TYPE_MAX)
+                return false;
+
+        assert_se(e = strrchr(n, '.'));
+
+        if (e == n)
+                return false;
+
+        for (i = n, at = NULL; i < e; i++) {
+
+                if (*i == '@' && !at)
+                        at = i;
+
+                if (!strchr("@" VALID_CHARS, *i))
+                        return false;
+        }
+
+        if (at) {
+                if (at == n)
+                        return false;
+
+                if (at[1] == '.')
+                        return false;
+        }
+
+        return true;
+}
+
+bool unit_instance_is_valid(const char *i) {
+        assert(i);
+
+        /* The max length depends on the length of the string, so we
+         * don't really check this here. */
+
+        if (i[0] == 0)
+                return false;
+
+        /* We allow additional @ in the instance string, we do not
+         * allow them in the prefix! */
+
+        for (; *i; i++)
+                if (!strchr("@" VALID_CHARS, *i))
+                        return false;
+
+        return true;
+}
+
+bool unit_prefix_is_valid(const char *p) {
+
+        /* We don't allow additional @ in the instance string */
+
+        if (p[0] == 0)
+                return false;
+
+        for (; *p; p++)
+                if (!strchr(VALID_CHARS, *p))
+                        return false;
+
+        return true;
+}
+
+int unit_name_to_instance(const char *n, char **instance) {
+        const char *p, *d;
+        char *i;
+
+        assert(n);
+        assert(instance);
+
+        /* Everything past the first @ and before the last . is the instance */
+        if (!(p = strchr(n, '@'))) {
+                *instance = NULL;
+                return 0;
+        }
+
+        assert_se(d = strrchr(n, '.'));
+        assert(p < d);
+
+        if (!(i = strndup(p+1, d-p-1)))
+                return -ENOMEM;
+
+        *instance = i;
+        return 0;
+}
+
+char *unit_name_to_prefix_and_instance(const char *n) {
+        const char *d;
+
+        assert(n);
+
+        assert_se(d = strrchr(n, '.'));
+
+        return strndup(n, d - n);
+}
+
+char *unit_name_to_prefix(const char *n) {
+        const char *p;
+
+        if ((p = strchr(n, '@')))
+                return strndup(n, p - n);
+
+        return unit_name_to_prefix_and_instance(n);
+}
+
+char *unit_name_change_suffix(const char *n, const char *suffix) {
+        char *e, *r;
+        size_t a, b;
+
+        assert(n);
+        assert(unit_name_is_valid(n));
+        assert(suffix);
+
+        assert_se(e = strrchr(n, '.'));
+        a = e - n;
+        b = strlen(suffix);
+
+        if (!(r = new(char, a + b + 1)))
+                return NULL;
+
+        memcpy(r, n, a);
+        memcpy(r+a, suffix, b+1);
+
+        return r;
+}
+
+char *unit_name_build(const char *prefix, const char *instance, const char *suffix) {
+        char *r;
+
+        assert(prefix);
+        assert(unit_prefix_is_valid(prefix));
+        assert(!instance || unit_instance_is_valid(instance));
+        assert(suffix);
+        assert(unit_name_to_type(suffix) >= 0);
+
+        if (!instance)
+                return strappend(prefix, suffix);
+
+        if (asprintf(&r, "%s@%s%s", prefix, instance, suffix) < 0)
+                return NULL;
+
+        return r;
+}
+
+static char* do_escape(const char *f, char *t) {
+        assert(f);
+        assert(t);
+
+        for (; *f; f++) {
+                if (*f == '/')
+                        *(t++) = '.';
+                else if (*f == '.' || *f == '\\' || !strchr(VALID_CHARS, *f)) {
+                        *(t++) = '\\';
+                        *(t++) = 'x';
+                        *(t++) = hexchar(*f > 4);
+                        *(t++) = hexchar(*f);
+                } else
+                        *(t++) = *f;
+        }
+
+        return t;
+}
+
+char *unit_name_build_escape(const char *prefix, const char *instance, const char *suffix) {
+        char *r, *t;
+        size_t a, b, c;
+
+        assert(prefix);
+        assert(suffix);
+        assert(unit_name_to_type(suffix) >= 0);
+
+        /* Takes a arbitrary string for prefix and instance plus a
+         * suffix and makes a nice string suitable as unit name of it,
+         * escaping all weird chars on the way.
+         *
+         * / becomes ., and all chars not alloweed in a unit name get
+         * escaped as \xFF, including \ and ., of course. This
+         * escaping is hence reversible.
+         *
+         * This is primarily useful to make nice unit names from
+         * strings, but is actually useful for any kind of string.
+         */
+
+        a = strlen(prefix);
+        c = strlen(suffix);
+
+        if (instance) {
+                b = strlen(instance);
+
+                if (!(r = new(char, a*4 + 1 + b*4 + c + 1)))
+                        return NULL;
+
+                t = do_escape(prefix, r);
+                *(t++) = '@';
+                t = do_escape(instance, t);
+        } else {
+
+                if (!(r = new(char, a*4 + c + 1)))
+                        return NULL;
+
+                t = do_escape(prefix, r);
+        }
+
+        strcpy(t, suffix);
+        return r;
+}
+
+char *unit_name_escape(const char *f) {
+        char *r, *t;
+
+        if (!(r = new(char, strlen(f)*4+1)))
+                return NULL;
+
+        t = do_escape(f, r);
+        *t = 0;
+
+        return r;
+
+}
+
+char *unit_name_unescape(const char *f) {
+        char *r, *t;
+
+        assert(f);
+
+        if (!(r = strdup(f)))
+                return NULL;
+
+        for (t = r; *f; f++) {
+                if (*f == '.')
+                        *(t++) = '/';
+                else if (*f == '\\') {
+                        int a, b;
+
+                        if ((a = unhexchar(f[1])) < 0 ||
+                            (b = unhexchar(f[2])) < 0) {
+                                /* Invalid escape code, let's take it literal then */
+                                *(t++) = '\\';
+                        } else {
+                                *(t++) = (char) ((a << 4) | b);
+                                f += 2;
+                        }
+                } else
+                        *(t++) = *f;
+        }
+
+        *t = 0;
+
+        return r;
+}
+
+bool unit_name_is_template(const char *n) {
+        const char *p;
+
+        assert(n);
+
+        if (!(p = strchr(n, '@')))
+                return false;
+
+        return p[1] == '.';
+}
+
+char *unit_name_replace_instance(const char *f, const char *i) {
+        const char *p, *e;
+        char *r, *k;
+        size_t a;
+
+        assert(f);
+
+        p = strchr(f, '@');
+        assert_se(e = strrchr(f, '.'));
+
+        a = p - f;
+
+        if (p) {
+                size_t b;
+
+                b = strlen(i);
+
+                if (!(r = new(char, a + 1 + b + strlen(e) + 1)))
+                        return NULL;
+
+                k = mempcpy(r, f, a + 1);
+                k = mempcpy(k, i, b);
+        } else {
+
+                if (!(r = new(char, a + strlen(e) + 1)))
+                        return NULL;
+
+                k = mempcpy(r, f, a);
+        }
+
+        strcpy(k, e);
+        return r;
+}
+
+char *unit_name_template(const char *f) {
+        const char *p, *e;
+        char *r;
+        size_t a;
+
+        if (!(p = strchr(f, '@')))
+                return strdup(f);
+
+        assert_se(e = strrchr(f, '.'));
+        a = p - f + 1;
+
+        if (!(r = new(char, a + strlen(e) + 1)))
+                return NULL;
+
+        strcpy(mempcpy(r, f, a), e);
+        return r;
+
+}