From 334447308fed2eb0a44e67adb95009bb15aa7efe Mon Sep 17 00:00:00 2001
From: Phil Sutter <phil@nwl.cc>
Date: Sun, 14 Dec 2008 17:53:31 +0100
Subject: [PATCH] enable DEV_NAME to handle symlinks

Using a macro is not possible anymore, so have a function dev_name() do
the job. Functionality is the same as the old DEV_NAME, unless the
specified path is a symlink in which case it's being dereferenced first.

To save callers from having to free the returned string, a static local
buffer is used (effectively rendering the function non-reentrant).
---
 src/conky.c | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/src/conky.c b/src/conky.c
index e6591970..dbd58160 100644
--- a/src/conky.c
+++ b/src/conky.c
@@ -1951,9 +1951,25 @@ void scan_mixer_bar(const char *arg, int *a, int *w, int *h)
 	}
 }
 
-/* strip a leading /dev/ if any */
-#define DEV_NAME(x) x != NULL && strlen(x) > 5 && strncmp(x, "/dev/", 5) == 0 \
-	? x + 5 : x
+/* strip a leading /dev/ if any, following symlinks first
+ *
+ * BEWARE: this function returns a pointer to static content
+ *         which gets overwritten in consecutive calls. I.e.:
+ *         this function is NOT reentrant.
+ */
+const char *dev_name(const char *path)
+{
+	static char buf[255];	/* should be enough for pathnames */
+	ssize_t buflen;
+
+#define DEV_NAME(x) \
+  x != NULL && strlen(x) > 5 && strncmp(x, "/dev/", 5) == 0 ? x + 5 : x
+	if ((buflen = readlink(path, buf, 254)) == -1)
+		return DEV_NAME(path);
+	buf[buflen] = '\0';
+	return DEV_NAME(buf);
+#undef DEV_NAME
+}
 
 /* construct_text_object() creates a new text_object */
 static struct text_object *construct_text_object(const char *s,
@@ -2128,7 +2144,7 @@ static struct text_object *construct_text_object(const char *s,
 #if defined(__linux__)
 	END OBJ(disk_protect, 0)
 		if (arg)
-			obj->data.s = strndup(DEV_NAME(arg), text_buffer_size);
+			obj->data.s = strndup(dev_name(arg), text_buffer_size);
 		else
 			CRIT_ERR("disk_protect needs an argument");
 	END OBJ(i8k_version, INFO_I8K)
@@ -2178,7 +2194,7 @@ static struct text_object *construct_text_object(const char *s,
 			CRIT_ERR("get_ioscheduler needs an argument (e.g. hda)");
 			obj->data.s = 0;
 		} else
-			obj->data.s = strndup(DEV_NAME(arg), text_buffer_size);
+			obj->data.s = strndup(dev_name(arg), text_buffer_size);
 	END OBJ(laptop_mode, 0)
 	END OBJ(pb_battery, 0)
 		if (arg && strcmp(arg, "status") == EQUAL) {
@@ -2285,24 +2301,24 @@ static struct text_object *construct_text_object(const char *s,
 #if defined(__linux__)
 	END OBJ(diskio, INFO_DISKIO)
 		if (arg) {
-			obj->data.diskio = prepare_diskio_stat(DEV_NAME(arg));
+			obj->data.diskio = prepare_diskio_stat(dev_name(arg));
 		} else {
 			obj->data.diskio = NULL;
 		}
 	END OBJ(diskio_read, INFO_DISKIO)
 		if (arg) {
-			obj->data.diskio = prepare_diskio_stat(DEV_NAME(arg));
+			obj->data.diskio = prepare_diskio_stat(dev_name(arg));
 		} else {
 			obj->data.diskio = NULL;
 		}
 	END OBJ(diskio_write, INFO_DISKIO)
 		if (arg) {
-			obj->data.diskio = prepare_diskio_stat(DEV_NAME(arg));
+			obj->data.diskio = prepare_diskio_stat(dev_name(arg));
 		} else {
 			obj->data.diskio = NULL;
 		}
 	END OBJ(diskiograph, INFO_DISKIO)
-		char *buf = scan_graph(DEV_NAME(arg), &obj->a, &obj->b, &obj->c, &obj->d,
+		char *buf = scan_graph(dev_name(arg), &obj->a, &obj->b, &obj->c, &obj->d,
 			&obj->e, &obj->showaslog);
 
 		if (buf) {
@@ -2312,7 +2328,7 @@ static struct text_object *construct_text_object(const char *s,
 			obj->data.diskio = NULL;
 		}
 	END OBJ(diskiograph_read, INFO_DISKIO)
-		char *buf = scan_graph(DEV_NAME(arg), &obj->a, &obj->b, &obj->c, &obj->d,
+		char *buf = scan_graph(dev_name(arg), &obj->a, &obj->b, &obj->c, &obj->d,
 			&obj->e, &obj->showaslog);
 
 		if (buf) {
@@ -2322,7 +2338,7 @@ static struct text_object *construct_text_object(const char *s,
 			obj->data.diskio = NULL;
 		}
 	END OBJ(diskiograph_write, INFO_DISKIO)
-		char *buf = scan_graph(DEV_NAME(arg), &obj->a, &obj->b, &obj->c, &obj->d,
+		char *buf = scan_graph(dev_name(arg), &obj->a, &obj->b, &obj->c, &obj->d,
 			&obj->e, &obj->showaslog);
 
 		if (buf) {