make sigaltstack work (missing macros in signal.h, error conditions)

diff --git a/arch/i386/bits/signal.h b/arch/i386/bits/signal.h
index 4956a0d..74d9d02 100644 (file)
--- a/arch/i386/bits/signal.h
+++ b/arch/i386/bits/signal.h
@@ -131,6 +131,8 @@ struct __siginfo
 #define POLL_HUP 6
 #define SS_ONSTACK    1
 #define SS_DISABLE    2
+#define MINSIGSTKSZ 2048
+#define SIGSTKSZ 8192
 #endif
 
 #define SA_NOCLDSTOP  1

diff --git a/arch/x86_64/bits/signal.h b/arch/x86_64/bits/signal.h
index f2c92d0..ddebe90 100644 (file)
--- a/arch/x86_64/bits/signal.h
+++ b/arch/x86_64/bits/signal.h
@@ -137,6 +137,8 @@ struct __siginfo
 #define POLL_HUP 6
 #define SS_ONSTACK    1
 #define SS_DISABLE    2
+#define MINSIGSTKSZ 2048
+#define SIGSTKSZ 8192
 #endif
 
 #define SA_NOCLDSTOP  1

diff --git a/src/signal/sigaltstack.c b/src/signal/sigaltstack.c
index 3cc2d45..6e46d09 100644 (file)
--- a/src/signal/sigaltstack.c
+++ b/src/signal/sigaltstack.c
@@ -1,8 +1,18 @@
 #include <signal.h>
+#include <errno.h>
 #include "syscall.h"
 
 int sigaltstack(const stack_t *ss, stack_t *old)
 {
-       /* depends on kernel struct matching */
+       if (ss) {
+               if (ss->ss_size < MINSIGSTKSZ) {
+                       errno = ENOMEM;
+                       return -1;
+               }
+               if (ss->ss_flags & ~SS_DISABLE) {
+                       errno = EINVAL;
+                       return -1;
+               }
+       }
        return syscall2(__NR_sigaltstack, (long)ss, (long)old);
 }