basic/proc-cmdline: allow parsing of cmdline from a string

Comes with tests.

Also add direct test for $SYSTEMD_PROC_CMDLINE.

In test-proc-cmdline, "true" was masquerading as PROC_CMDLINE_STRIP_RD_PREFIX,
fix that. Also, reorder functions to match call order.

(cherry picked from commit 9a135c084ae6d06734ec3380f0eafdecd7c216f8)

2 files changed, 15 insertions, 7 deletions

diff --git a/src/basic/proc-cmdline.c b/src/basic/proc-cmdline.c
index ae3323379..ab8cab7e3 100644
--- a/src/basic/proc-cmdline.c
+++ b/src/basic/proc-cmdline.c
@@ -39,18 +39,12 @@ int proc_cmdline(char **ret) {
                 return read_one_line_file("/proc/cmdline", ret);
 }
 
-int proc_cmdline_parse(proc_cmdline_parse_t parse_item, void *data, unsigned flags) {
-
-        _cleanup_free_ char *line = NULL;
+int proc_cmdline_parse_given(const char *line, proc_cmdline_parse_t parse_item, void *data, unsigned flags) {
         const char *p;
         int r;
 
         assert(parse_item);
 
-        r = proc_cmdline(&line);
-        if (r < 0)
-                return r;
-
         p = line;
         for (;;) {
                 _cleanup_free_ char *word = NULL;
@@ -86,6 +80,19 @@ int proc_cmdline_parse(proc_cmdline_parse_t parse_item, void *data, unsigned fla
         return 0;
 }
 
+int proc_cmdline_parse(proc_cmdline_parse_t parse_item, void *data, unsigned flags) {
+        _cleanup_free_ char *line = NULL;
+        int r;
+
+        assert(parse_item);
+
+        r = proc_cmdline(&line);
+        if (r < 0)
+                return r;
+
+        return proc_cmdline_parse_given(line, parse_item, data, flags);
+}
+
 static bool relaxed_equal_char(char a, char b) {
 
         return a == b ||
diff --git a/src/basic/proc-cmdline.h b/src/basic/proc-cmdline.h
index 5cb323f79..de4978f2d 100644
--- a/src/basic/proc-cmdline.h
+++ b/src/basic/proc-cmdline.h
@@ -14,6 +14,7 @@ typedef int (*proc_cmdline_parse_t)(const char *key, const char *value, void *da
 
 int proc_cmdline(char **ret);
 
+int proc_cmdline_parse_given(const char *line, proc_cmdline_parse_t parse_item, void *data, unsigned flags);
 int proc_cmdline_parse(const proc_cmdline_parse_t parse, void *userdata, unsigned flags);
 
 #if 0 /// UNNEEDED by elogind