Support glibc 2.20 programs

pk/elf.h

@@ -22,6 +22,7 @@
 #define AT_PAGESZ 6
 #define AT_ENTRY  9
 #define AT_SECURE 23
+#define AT_RANDOM 25
 
 typedef struct {
   uint8_t  e_ident[16];

pk/file.h

@@ -4,7 +4,6 @@
 #define _FILE_H
 
 #include <sys/stat.h>
-#include <machine/syscall.h>
 #include "atomic.h"
 
 typedef struct file

pk/init.c

@@ -98,6 +98,7 @@ static void user_init(struct mainvars* args)
     {AT_PHDR, current.phdr},
     {AT_PAGESZ, RISCV_PGSIZE},
     {AT_SECURE, 0},
+    {AT_RANDOM, stack_top},
     {AT_NULL, 0}
   };
 

pk/syscall.c

@@ -379,12 +379,16 @@ ssize_t sys_writev(int fd, const void* iov, int cnt)
   return ret;
 }
 
-
 int sys_getdents(int fd, void* dirbuf, int count)
 {
   return 0; //stub
 }
 
+int sys_nosys()
+{
+  return -ENOSYS;
+}
+
 long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
 {
   const static void* syscall_table[] = {
@@ -426,6 +430,7 @@ long syscall(long a0, long a1, long a2, long a3, long a4, long a5, long n)
     [SYS_fcntl] = sys_fcntl,
     [SYS_getdents] = sys_getdents,
     [SYS_dup] = sys_dup,
+    [SYS_readlinkat] = sys_nosys,
   };
 
   if(n >= ARRAY_SIZE(syscall_table) || !syscall_table[n])

pk/syscall.h

@@ -45,6 +45,7 @@
 #define SYS_fcntl 25
 #define SYS_getdents 61
 #define SYS_dup 23
+#define SYS_readlinkat 78
 
 #define IS_ERR_VALUE(x) ((unsigned long)(x) >= (unsigned long)-4096)
 #define ERR_PTR(x) ((void*)(long)(x))