Map safepath errors to strings.

* safepath.[ch]: New function, safepath_strerr.

* testsp.c (main): Use new function to print message,
rather than integer code.

3 files changed, 23 insertions, 1 deletions

diff --git a/safepath.c b/safepath.c
index ba4996c..862b5ed 100644
--- a/safepath.c
+++ b/safepath.c
@@ -337,6 +337,27 @@ out:
   return ret;
 }
 
+const char *safepath_strerr(int err)
+{
+  const char *str[] = {
+    [SAFEPATH_OK]       = "path appears safe",
+    [SAFEPATH_UNSAFE]   = "path contains untrusted component",
+    [SAFEPATH_PERM]     = "path contains inaccessible component",
+    [SAFEPATH_NOENT]    = "path contains nonexistent component",
+    [SAFEPATH_INVAL]    = "path is syntactically invalid",
+    [SAFEPATH_NOMEM]    = "out of memory",
+    [SAFEPATH_LOOP]     = "too many symlink resolutions"
+  };
+  const char *ret = "SAFEPATH_BAD_ERROR_CODE";
+
+  if (err >= 0 && err <= (int) (sizeof str / sizeof str[0]) && str[err] != 0)
+  {
+    ret = str[err];
+  }
+
+  return ret;
+}
+
 int safepath_open(const char *name, int flags)
 {
   int res = safepath_check(name);
diff --git a/safepath.h b/safepath.h
index b6a8a39..db83d4c 100644
--- a/safepath.h
+++ b/safepath.h
@@ -47,6 +47,7 @@ enum {
 };
 
 int safepath_check(const char *name);
+const char *safepath_strerr(int err);
 
 /* Common POSIX API wrappers */
 int safepath_open(const char *name, int flags);
diff --git a/testsp.c b/testsp.c
index 4691d31..1d9f396 100644
--- a/testsp.c
+++ b/testsp.c
@@ -37,7 +37,7 @@ int main(int argc, char **argv)
 
   if (argv[0] && argv[1] && !argv[2]) {
     int res = safepath_check(argv[1]);
-    printf("safepath_check(\"%s\") == %d\n", argv[1], res);
+    printf("safepath_check(\"%s\") == %s\n", argv[1], safepath_strerr(res));
     return res == SAFEPATH_OK ? 0 : EXIT_FAILURE;
   } else if (argv[0]) {
     printf("%s: requires exactly one argument\n", argv[0]);