Change setgroups() management, in particular add skalibs_setgroups()

1 files changed, 45 insertions, 0 deletions

diff --git a/src/libstddjb/setgroups.c b/src/libstddjb/setgroups.c
new file mode 100644
index 0000000..0bcda12
--- /dev/null
+++ b/src/libstddjb/setgroups.c
@@ -0,0 +1,45 @@
+/* ISC license. */
+
+#include <skalibs/sysdeps.h>
+
+#ifdef SKALIBS_HASSETGROUPS
+
+#include <skalibs/nonposix.h>
+#include <string.h>
+#include <unistd.h>
+#include <skalibs/setgroups.h>
+
+int setgroups_with_egid (size_t n, gid_t const *tab)
+{
+  size_t i = 1 ;
+  gid_t g = getegid() ;
+  if (!n) return setgroups(1, &g) ;
+  if (tab[0] == g) return setgroups(n, tab) ;
+  for (; i < n ; i++) if (tab[i] == g) break ;
+  if (i < n)
+  {
+    gid_t newtab[n] ;
+    newtab[0] = g ;
+    memcpy(newtab + 1, tab, i * sizeof(gid_t)) ;
+    memcpy(newtab + i + 1, tab + i + 1, (n - i - 1) * sizeof(gid_t)) ;
+    return setgroups(n, newtab) ;
+  }
+  else
+  {
+    gid_t newtab[n+1] ;
+    newtab[0] = g ;
+    memcpy(newtab + 1, tab, n * sizeof(gid_t)) ;
+    return setgroups(n+1, newtab) ;
+  }
+}
+
+int skalibs_setgroups (size_t n, gid_t const *tab)
+{
+#ifdef SKALIBS_BSD_SUCKS
+  return setgroups_with_egid(n, tab) ;
+#else
+  return setgroups(n, tab) ;
+#endif
+}
+
+#endif