Socket calls could not be restarted after being interrupted by

a signal.  The parameters on the stack were corrupted by the
signal handler.

diff --git a/sysdeps/unix/sysv/linux/arm/socket.S b/sysdeps/unix/sysv/linux/arm/socket.S
index b51d887..92c7e90 100644 (file)
--- a/sysdeps/unix/sysv/linux/arm/socket.S
+++ b/sysdeps/unix/sysv/linux/arm/socket.S
@@ -35,12 +35,19 @@
 #define __socket P(__,socket)
 #endif
 
-#define PUSHARGS_1     stmfd ip!, {a1}
-#define PUSHARGS_2     stmfd ip!, {a1, a2}
-#define PUSHARGS_3     stmfd ip!, {a1, a2, a3}
-#define PUSHARGS_4     stmfd ip!, {a1, a2, a3, a4}
-#define PUSHARGS_5     stmfd ip!, {a1, a2, a3, a4}     /* Caller has already pushed arg 5 */
-#define PUSHARGS_6     stmfd ip!, {a1, a2, a3, a4}
+#define PUSHARGS_1     stmfd sp!, {a1}
+#define PUSHARGS_2     stmfd sp!, {a1, a2}
+#define PUSHARGS_3     stmfd sp!, {a1, a2, a3}
+#define PUSHARGS_4     stmfd sp!, {a1, a2, a3, a4}
+#define PUSHARGS_5     stmfd sp!, {a1, a2, a3, a4}     /* Caller has already pushed arg 5 */
+#define PUSHARGS_6     stmfd sp!, {a1, a2, a3, a4}
+
+#define POPARGS_1      add sp, sp, #4
+#define POPARGS_2      add sp, sp, #8
+#define POPARGS_3      add sp, sp, #12
+#define POPARGS_4      add sp, sp, #16
+#define POPARGS_5      add sp, sp, #16
+#define POPARGS_6      add sp, sp, #16 
 
 #ifndef NARGS
 #define NARGS 3                        /* If we were called with no wrapper, this is really socket() */
@@ -48,15 +55,27 @@
 
 .globl __socket
 ENTRY (__socket)
+       /* This code previously moved sp into ip and stored the args using
+          stmdb ip!, {a1-a4}.  It did not modify sp, so the stack never had 
+          to be restored after the syscall completed.  It saved an 
+          instruction and meant no stack cleanup work was required.
+
+          This will not work in the case of a socket call being interrupted
+          by a signal.  If the signal handler uses any stack the arguments
+          to socket will be trashed.  The results of a restart of any
+          socket call are then unpredictable. */
+
        /* Push args onto the stack.  */
-       mov ip, sp
        P(PUSHARGS_,NARGS)
 
         /* Do the system call trap.  */
        mov a1, $P(SOCKOP_,socket)
-       mov a2, ip
+       mov a2, sp
        swi SYS_ify(socketcall)
 
+       /* Pop args off the stack */
+       P(POPARGS_,NARGS)
+
        /* r0 is < 0 if there was an error.  */
        cmn r0, $124
        bhs PLTJMP(syscall_error)