X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fenv%2F__libc_start_main.c;h=8fbe526271d812cc467664e9a1c96fb813c528b7;hb=e4dd65305a046019123ab34ebdcbe761a3a719ca;hp=c1b066974d48e57baf4c39165c1cc1346fbaac21;hpb=9b95fd0944e4206949e90633c3fed088202810ec;p=musl

diff --git a/src/env/__libc_start_main.c b/src/env/__libc_start_main.c
index c1b06697..8fbe5262 100644
--- a/src/env/__libc_start_main.c
+++ b/src/env/__libc_start_main.c
@@ -2,12 +2,11 @@
 #include <poll.h>
 #include <fcntl.h>
 #include <signal.h>
+#include <unistd.h>
 #include "syscall.h"
 #include "atomic.h"
 #include "libc.h"
 
-void __init_tls(size_t *);
-
 static void dummy(void) {}
 weak_alias(dummy, _init);
 
@@ -18,6 +17,9 @@ weak_alias(dummy1, __init_ssp);
 
 #define AUX_CNT 38
 
+#ifdef __GNUC__
+__attribute__((__noinline__))
+#endif
 void __init_libc(char **envp, char *pn)
 {
 	size_t i, *auxv, aux[AUX_CNT] = { 0 };
@@ -26,7 +28,7 @@ void __init_libc(char **envp, char *pn)
 	libc.auxv = auxv = (void *)(envp+i+1);
 	for (i=0; auxv[i]; i+=2) if (auxv[i]<AUX_CNT) aux[auxv[i]] = auxv[i+1];
 	__hwcap = aux[AT_HWCAP];
-	__sysinfo = aux[AT_SYSINFO];
+	if (aux[AT_SYSINFO]) __sysinfo = aux[AT_SYSINFO];
 	libc.page_size = aux[AT_PAGESZ];
 
 	if (!pn) pn = (void*)aux[AT_EXECFN];
@@ -64,11 +66,28 @@ static void libc_start_init(void)
 
 weak_alias(libc_start_init, __libc_start_init);
 
+typedef int lsm2_fn(int (*)(int,char **,char **), int, char **);
+static lsm2_fn libc_start_main_stage2;
+
 int __libc_start_main(int (*main)(int,char **,char **), int argc, char **argv)
 {
 	char **envp = argv+argc+1;
 
+	/* External linkage, and explicit noinline attribute if available,
+	 * are used to prevent the stack frame used during init from
+	 * persisting for the entire process lifetime. */
 	__init_libc(envp, argv[0]);
+
+	/* Barrier against hoisting application code or anything using ssp
+	 * or thread pointer prior to its initialization above. */
+	lsm2_fn *stage2 = libc_start_main_stage2;
+	__asm__ ( "" : "+r"(stage2) : : "memory" );
+	return stage2(main, argc, argv);
+}
+
+static int libc_start_main_stage2(int (*main)(int,char **,char **), int argc, char **argv)
+{
+	char **envp = argv+argc+1;
 	__libc_start_init();
 
 	/* Pass control to the application */