1 files changed, 90 insertions, 13 deletions

diff --git a/src/shared/specifier.c b/src/shared/specifier.c
index 81379041cc..23aaa88c4b 100644
--- a/src/shared/specifier.c
+++ b/src/shared/specifier.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 /***
   This file is part of systemd.
 
@@ -31,6 +32,8 @@
 #include "macro.h"
 #include "specifier.h"
 #include "string-util.h"
+#include "strv.h"
+#include "user-util.h"
 
 /*
  * Generic infrastructure for replacing %x style specifiers in
@@ -38,11 +41,16 @@
  *
  */
 
+/* Any ASCII character or digit: our pool of potential specifiers,
+ * and "%" used for escaping. */
+#define POSSIBLE_SPECIFIERS ALPHANUMERICAL "%"
+
 int specifier_printf(const char *text, const Specifier table[], void *userdata, char **_ret) {
-        char *ret, *t;
+        size_t l;
+        _cleanup_free_ char *ret = NULL;
+        char *t;
         const char *f;
         bool percent = false;
-        size_t l;
         int r;
 
         assert(text);
@@ -73,28 +81,25 @@ int specifier_printf(const char *text, const Specifier table[], void *userdata,
                                         size_t k, j;
 
                                         r = i->lookup(i->specifier, i->data, userdata, &w);
-                                        if (r < 0) {
-                                                free(ret);
+                                        if (r < 0)
                                                 return r;
-                                        }
 
                                         j = t - ret;
                                         k = strlen(w);
 
                                         n = new(char, j + k + l + 1);
-                                        if (!n) {
-                                                free(ret);
+                                        if (!n)
                                                 return -ENOMEM;
-                                        }
 
                                         memcpy(n, ret, j);
                                         memcpy(n + j, w, k);
 
-                                        free(ret);
-
-                                        ret = n;
-                                        t = n + j + k;
-                                } else {
+                                        free_and_replace(ret, n);
+                                        t = ret + j + k;
+                                } else if (strchr(POSSIBLE_SPECIFIERS, *f))
+                                        /* Oops, an unknown specifier. */
+                                        return -EBADSLT;
+                                else {
                                         *(t++) = '%';
                                         *(t++) = *f;
                                 }
@@ -113,6 +118,7 @@ int specifier_printf(const char *text, const Specifier table[], void *userdata,
 
         *t = 0;
         *_ret = ret;
+        ret = NULL;
         return 0;
 }
 
@@ -190,3 +196,74 @@ int specifier_kernel_release(char specifier, void *data, void *userdata, char **
         *ret = n;
         return 0;
 }
+
+int specifier_user_name(char specifier, void *data, void *userdata, char **ret) {
+        char *t;
+
+        /* If we are UID 0 (root), this will not result in NSS, otherwise it might. This is good, as we want to be able
+         * to run this in PID 1, where our user ID is 0, but where NSS lookups are not allowed.
+
+         * We don't use getusername_malloc() here, because we don't want to look at $USER, to remain consistent with
+         * specifer_user_id() below.
+         */
+
+        t = uid_to_name(getuid());
+        if (!t)
+                return -ENOMEM;
+
+        *ret = t;
+        return 0;
+}
+
+int specifier_user_id(char specifier, void *data, void *userdata, char **ret) {
+
+        if (asprintf(ret, UID_FMT, getuid()) < 0)
+                return -ENOMEM;
+
+        return 0;
+}
+
+int specifier_user_home(char specifier, void *data, void *userdata, char **ret) {
+
+        /* On PID 1 (which runs as root) this will not result in NSS,
+         * which is good. See above */
+
+        return get_home_dir(ret);
+}
+
+int specifier_user_shell(char specifier, void *data, void *userdata, char **ret) {
+
+        /* On PID 1 (which runs as root) this will not result in NSS,
+         * which is good. See above */
+
+        return get_shell(ret);
+}
+
+int specifier_escape_strv(char **l, char ***ret) {
+        char **z, **p, **q;
+
+        assert(ret);
+
+        if (strv_isempty(l)) {
+                *ret = NULL;
+                return 0;
+        }
+
+        z = new(char*, strv_length(l)+1);
+        if (!z)
+                return -ENOMEM;
+
+        for (p = l, q = z; *p; p++, q++) {
+
+                *q = specifier_escape(*p);
+                if (!*q) {
+                        strv_free(z);
+                        return -ENOMEM;
+                }
+        }
+
+        *q = NULL;
+        *ret = z;
+
+        return 0;
+}