[PATCH 1/2] Add helper function to read file link targets

[Andrew Beltrano]

Signed-off-by: Andrew Beltrano <anbeltra at microsoft.com>
---
 src/utils/common.c | 29 +++++++++++++++++++++++++++++
 src/utils/common.h |  2 ++
 2 files changed, 31 insertions(+)

diff --git a/src/utils/common.c b/src/utils/common.c
index 2c1275193..999e4ebe3 100644
--- a/src/utils/common.c
+++ b/src/utils/common.c
@@ -8,6 +8,7 @@
 
 #include "includes.h"
 #include <limits.h>
+#include <sys/stat.h>
 
 #include "common/ieee802_11_defs.h"
 #include "common.h"
@@ -1302,3 +1303,31 @@ void forced_memzero(void *ptr, size_t len)
    if (len)
        forced_memzero_val = ((u8 *) ptr)[0];
 }
+
+int read_link_target(const char *name, char **target)
+{
+   ssize_t len;
+   char *path;
+   struct stat statbuf;
+
+   if (lstat(name, &statbuf) < 0)
+       return -1;
+   if (!S_ISLNK(statbuf.st_mode)) {
+       *target = NULL;
+       return 0;
+   }
+
+   path = os_malloc(statbuf.st_size+1);
+   if (!path) 
+       return -1;
+
+   len = readlink(name, path, statbuf.st_size+1);
+   if (len < 0 || len > statbuf.st_size) {
+       os_free(path);
+       return -1;
+   }
+
+   path[len] = '\0';
+   *target = path;
+   return 0;
+}
diff --git a/src/utils/common.h b/src/utils/common.h
index 45f72bb30..51e88df98 100644
--- a/src/utils/common.h
+++ b/src/utils/common.h
@@ -595,4 +595,6 @@ void * __hide_aliasing_typecast(void *foo);
 #define WPA_MEM_DEFINED(ptr, len) do { } while (0)
 #endif /* CONFIG_VALGRIND */
 
+int read_link_target(const char *name, char **target);
+
 #endif /* COMMON_H */
-- 
2.20.1