Fix #100: Adjust path to COND_RECONF /var/run symlink may be missing

On systems with the new /run hierarchy the compat symlink from /var/run
may be missing, or not yet be set up by bootmisc.so.  This patch adds a
layer of safety to the condition layer, both set and get cond ops now
perform an adjustmed of the condition path if needed.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/cond-w.c

@@ -31,12 +31,16 @@
 #include "pid.h"
 #include "service.h"
 
-static int cond_set_gen(const char *path, unsigned int gen)
+static int cond_set_gen(const char *file, unsigned int gen)
 {
+	char *ptr, path[256];
 	FILE *fp;
 	int ret;
 
-	fp = fopen(path, "w");
+	/* /var/run --> /run symlink may not exist (yet) */
+	ptr = pid_runpath(file, path, sizeof(path));
+
+	fp = fopen(ptr, "w");
 	if (!fp)
 		return -1;
 

src/cond.c

@@ -51,13 +51,17 @@ const char *cond_path(const char *name)
 	return pid_runpath(tmp, file, sizeof(file));
 }
 
-unsigned int cond_get_gen(const char *path)
+unsigned int cond_get_gen(const char *file)
 {
+	char *ptr, path[256];
 	unsigned int gen;
 	FILE *fp;
 	int ret;
 
-	fp = fopen(path, "r");
+	/* /var/run --> /run symlink may not exist (yet) */
+	ptr = pid_runpath(file, path, sizeof(path));
+
+	fp = fopen(ptr, "r");
 	if (!fp)
 		return 0;
 

src/pid.h

@@ -34,7 +34,17 @@ char *pid_file        (svc_t *svc);
 int   pid_file_create (svc_t *svc);
 int   pid_file_parse  (svc_t *svc, char *arg);
 
-static inline char *pid_runpath(char *file, char *path, size_t len)
+/**
+ * pid_runpath - Adjust /var/run --> /run path depending on system
+ * @file: Path to file in /run/path or /var/run/path
+ * @path: Pointer to buffer to write correct path
+ * @len:  Length, in bytes, of @path buffer
+ *
+ * Returns:
+ * Always returns a valid pointer, which can be either @path with a /run
+ * or /var/run prefix to @file, or it may be @file if the prefix is OK.
+ */
+static inline char *pid_runpath(const char *file, char *path, size_t len)
 {
 	static int unknown = 1;
 	static char *prefix = "/var/run";
@@ -45,6 +55,9 @@ static inline char *pid_runpath(char *file, char *path, size_t len)
 		unknown = 0;
 	}
 
+	if (!strncmp(file, prefix, strlen(prefix)))
+		return (char *)file;
+
 	if (!strncmp(file, "/var/run/", 9))
 		file += 9;
 	else if (!strncmp(file, "/run/", 5))