specifier: rework specifier calls to return proper error message

Previously the specifier calls could only indicate OOM by returning
NULL. With this change they will return negative errno-style error codes
like everything else.

1 files changed, 38 insertions, 16 deletions

diff --git a/src/shared/install-printf.c b/src/shared/install-printf.c
index 1157ea989b..1ee1243f4d 100644
--- a/src/shared/install-printf.c
+++ b/src/shared/install-printf.c
@@ -27,21 +27,35 @@
 #include "util.h"
 #include "install-printf.h"
 
-static char *specifier_prefix_and_instance(char specifier, void *data, void *userdata) {
+static int specifier_prefix_and_instance(char specifier, void *data, void *userdata, char **ret) {
         InstallInfo *i = userdata;
+        char *n;
+
         assert(i);
 
-        return unit_name_to_prefix_and_instance(i->name);
+        n = unit_name_to_prefix_and_instance(i->name);
+        if (!n)
+                return -ENOMEM;
+
+        *ret = n;
+        return 0;
 }
 
-static char *specifier_prefix(char specifier, void *data, void *userdata) {
+static int specifier_prefix(char specifier, void *data, void *userdata, char **ret) {
         InstallInfo *i = userdata;
+        char *n;
+
         assert(i);
 
-        return unit_name_to_prefix(i->name);
+        n = unit_name_to_prefix(i->name);
+        if (!n)
+                return -ENOMEM;
+
+        *ret = n;
+        return 0;
 }
 
-static char *specifier_instance(char specifier, void *data, void *userdata) {
+static int specifier_instance(char specifier, void *data, void *userdata, char **ret) {
         InstallInfo *i = userdata;
         char *instance;
         int r;
@@ -50,14 +64,19 @@ static char *specifier_instance(char specifier, void *data, void *userdata) {
 
         r = unit_name_to_instance(i->name, &instance);
         if (r < 0)
-                return NULL;
-        if (instance != NULL)
-                return instance;
-        else
-                return strdup("");
+                return r;
+
+        if (!instance) {
+                instance = strdup("");
+                if (!instance)
+                        return -ENOMEM;
+        }
+
+        *ret = instance;
+        return 0;
 }
 
-static char *specifier_user_name(char specifier, void *data, void *userdata) {
+static int specifier_user_name(char specifier, void *data, void *userdata, char **ret) {
         InstallInfo *i = userdata;
         const char *username;
         _cleanup_free_ char *tmp = NULL;
@@ -82,18 +101,20 @@ static char *specifier_user_name(char specifier, void *data, void *userdata) {
 
                 r = get_user_creds(&username, &uid, NULL, NULL, NULL);
                 if (r < 0)
-                        return NULL;
+                        return r;
 
                 if (asprintf(&printed, "%d", uid) < 0)
-                        return NULL;
+                        return -ENOMEM;
                 break;
         }}
 
-        return printed;
+
+        *ret = printed;
+        return 0;
 }
 
 
-char *install_full_printf(InstallInfo *i, const char *format) {
+int install_full_printf(InstallInfo *i, const char *format, char **ret) {
 
         /* This is similar to unit_full_printf() but does not support
          * anything path-related.
@@ -129,6 +150,7 @@ char *install_full_printf(InstallInfo *i, const char *format) {
 
         assert(i);
         assert(format);
+        assert(ret);
 
-        return specifier_printf(format, table, i);
+        return specifier_printf(format, table, i, ret);
 }