1 files changed, 62 insertions, 0 deletions
diff --git a/src/libstddjb/absolutepath_tmp.c b/src/libstddjb/absolutepath_tmp.c
new file mode 100644
index 0000000..79a613a
--- /dev/null
+++ b/src/libstddjb/absolutepath_tmp.c
@@ -0,0 +1,62 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <skalibs/bytestr.h>
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+int sarealpath_tmp (stralloc *sa, char const *path, stralloc *tmp)
+{
+  unsigned int tmpbase = tmp->len ;
+  unsigned int base = sa->len ;
+  unsigned int loop = 48 ;
+  int fdhere ;
+  int wasnull = !sa->s ;
+
+  if (!path) return (errno = EINVAL, -1) ;
+  if (!stralloc_cats(sa, path)) return -1 ;
+  fdhere = open_read(".") ;
+  if (fdhere == -1)
+  {
+    if (wasnull) stralloc_free(sa) ; else sa->len = base ;
+    return -1 ;
+  }
+
+  do
+  {
+    tmp->len = tmpbase ;
+    if (!loop--) { errno = ELOOP ; goto err ; }
+    if (!sadirname(tmp, sa->s + base, sa->len - base)
+     || !stralloc_0(tmp)
+     || (chdir(tmp->s + tmpbase) == -1))
+      goto err ;
+    tmp->len = tmpbase ;
+    if (!sabasename(tmp, sa->s + base, sa->len - base)
+     || !stralloc_0(tmp)) goto err ;
+    sa->len = base ;
+  }
+  while (sareadlink(sa, tmp->s + tmpbase) >= 0) ;
+
+  if ((errno != EINVAL)
+   || (sagetcwd(sa) == -1)
+   || ((sa->len > base + 1) && !stralloc_catb(sa, "/", 1))
+   || ((--tmp->len > tmpbase) && (tmp->s[tmpbase] != '/') && !stralloc_catb(sa, tmp->s + tmpbase, tmp->len - tmpbase)))
+    goto err ;
+
+  tmp->len = tmpbase ;
+  fd_chdir(fdhere) ;
+  fd_close(fdhere) ;
+  return 0 ;
+
+err:
+  {
+    register int e = errno ;
+    tmp->len = tmpbase ;
+    fd_chdir(fdhere) ;
+    fd_close(fdhere) ;
+    if (wasnull) stralloc_free(sa) ; else sa->len = base ;
+    errno = e ;
+  }
+  return -1 ;
+}