Fetch the aux vector for the static libc, and use the entries to

initialize the cache of the system information as it was done for the
dynamic libc. This removes several sysctls from the static binary
startup.

Use the aux vector to fill the single struct dl_phdr_info describing
the static binary itself, to implement dl_iterate_phdr(3) for the
static binaries. [1]

Based on the submission by:	John Marino <draco marino st> [1]
Tested by:   flo (sparc64)
MFC after:	2 weeks

1 files changed, 51 insertions, 2 deletions

diff --git a/lib/libc/gen/dlfcn.c b/lib/libc/gen/dlfcn.c
index 7be9f87..ad24bb4 100644
--- a/lib/libc/gen/dlfcn.c
+++ b/lib/libc/gen/dlfcn.c
@@ -34,6 +34,10 @@ __FBSDID("$FreeBSD$");
 #include <dlfcn.h>
 #include <link.h>
 #include <stddef.h>
+#include "namespace.h"
+#include <pthread.h>
+#include "un-namespace.h"
+#include "libc_private.h"
 
 static char sorry[] = "Service unavailable";
 
@@ -138,13 +142,58 @@ _rtld_thread_init(void * li)
 	_rtld_error(sorry);
 }
 
+static pthread_once_t dl_phdr_info_once = PTHREAD_ONCE_INIT;
+static struct dl_phdr_info phdr_info;
+
+static void
+dl_init_phdr_info(void)
+{
+	Elf_Auxinfo *auxp;
+	size_t phent;
+	unsigned int i;
+
+	phent = 0;
+	for (auxp = __elf_aux_vector; auxp->a_type != AT_NULL; auxp++) {
+		switch (auxp->a_type) {
+		case AT_BASE:
+			phdr_info.dlpi_addr = (Elf_Addr)auxp->a_un.a_ptr;
+			break;
+		case AT_EXECPATH:
+			phdr_info.dlpi_name = (const char *)auxp->a_un.a_ptr;
+			break;
+		case AT_PHDR:
+			phdr_info.dlpi_phdr =
+			    (const Elf_Phdr *)auxp->a_un.a_ptr;
+			break;
+		case AT_PHENT:
+			phent = auxp->a_un.a_val;
+			break;
+		case AT_PHNUM:
+			phdr_info.dlpi_phnum = (Elf_Half)auxp->a_un.a_val;
+			break;
+		}
+	}
+	for (i = 0; i < phdr_info.dlpi_phnum; i++) {
+		if (phdr_info.dlpi_phdr[i].p_type == PT_TLS) {
+			phdr_info.dlpi_tls_modid = 1;
+			phdr_info.dlpi_tls_data =
+			    (void*)phdr_info.dlpi_phdr[i].p_vaddr;
+		}
+	}
+	phdr_info.dlpi_adds = 1;
+}
+
 #pragma weak dl_iterate_phdr
 int
 dl_iterate_phdr(int (*callback)(struct dl_phdr_info *, size_t, void *),
     void *data)
 {
-	_rtld_error(sorry);
-	return 0;
+
+	__init_elf_aux_vector();
+	if (__elf_aux_vector == NULL)
+		return (1);
+	_once(&dl_phdr_info_once, dl_init_phdr_info);
+	return (callback(&phdr_info, sizeof(phdr_info), data));
 }
 
 #pragma weak fdlopen