Fix struct stat size mismatch for RV32

pk/file.c

@@ -141,8 +141,10 @@ ssize_t file_pwrite(file_t* f, const void* buf, size_t size, off_t offset)
 
 int file_stat(file_t* f, struct stat* s)
 {
-  populate_mapping(s, sizeof(*s), PROT_WRITE);
-  return frontend_syscall(SYS_fstat, f->kfd, (uintptr_t)s, 0, 0, 0, 0, 0);
+  struct frontend_stat buf;
+  long ret = frontend_syscall(SYS_fstat, f->kfd, (uintptr_t)&buf, 0, 0, 0, 0, 0);
+  copy_stat(s, &buf);
+  return ret;
 }
 
 int file_truncate(file_t* f, off_t len)

pk/frontend.c

@@ -51,3 +51,20 @@ void die(int code)
   frontend_syscall(SYS_exit, code, 0, 0, 0, 0, 0, 0);
   while (1);
 }
+
+void copy_stat(struct stat* dest, struct frontend_stat* src)
+{
+  dest->st_dev = src->dev;
+  dest->st_ino = src->ino;
+  dest->st_mode = src->mode;
+  dest->st_nlink = src->nlink;
+  dest->st_uid = src->uid;
+  dest->st_gid = src->gid;
+  dest->st_rdev = src->rdev;
+  dest->st_size = src->size;
+  dest->st_blksize = src->blksize;
+  dest->st_blocks = src->blocks;
+  dest->st_atime = src->atime;
+  dest->st_mtime = src->mtime;
+  dest->st_ctime = src->ctime;
+}

pk/frontend.h

@@ -4,6 +4,7 @@
 #define _RISCV_FRONTEND_H
 
 #include <stdint.h>
+#include <sys/stat.h>
 
 #ifdef __riscv64
 # define TOHOST_CMD(dev, cmd, payload) \
@@ -21,4 +22,29 @@ void die(int) __attribute__((noreturn));
 long frontend_syscall(long n, long a0, long a1, long a2, long a3, long a4, long a5, long a6);
 uint64_t tohost_sync(unsigned dev, unsigned cmd, uint64_t payload);
 
+struct frontend_stat {
+  uint64_t dev;
+  uint64_t ino;
+  uint32_t mode;
+  uint32_t nlink;
+  uint32_t uid;
+  uint32_t gid;
+  uint64_t rdev;
+  uint64_t __pad1;
+  uint64_t size;
+  uint32_t blksize;
+  uint32_t __pad2;
+  uint64_t blocks;
+  uint64_t atime;
+  uint64_t __pad3;
+  uint64_t mtime;
+  uint64_t __pad4;
+  uint64_t ctime;
+  uint64_t __pad5;
+  uint32_t __unused4;
+  uint32_t __unused5;
+};
+
+void copy_stat(struct stat* dest, struct frontend_stat* src);
+
 #endif

pk/syscall.c

@@ -212,18 +212,22 @@ ssize_t sys_lseek(int fd, size_t ptr, int dir)
 
 long sys_lstat(const char* name, void* st)
 {
+  struct frontend_stat buf;
   size_t name_size = strlen(name)+1;
-  populate_mapping(st, sizeof(struct stat), PROT_WRITE);
-  return frontend_syscall(SYS_lstat, (uintptr_t)name, name_size, (uintptr_t)st, 0, 0, 0, 0);
+  long ret = frontend_syscall(SYS_lstat, (uintptr_t)name, name_size, (uintptr_t)&buf, 0, 0, 0, 0);
+  copy_stat(st, &buf);
+  return ret;
 }
 
 long sys_fstatat(int dirfd, const char* name, void* st, int flags)
 {
   int kfd = at_kfd(dirfd);
   if (kfd != -1) {
+    struct frontend_stat buf;
     size_t name_size = strlen(name)+1;
-    populate_mapping(st, sizeof(struct stat), PROT_WRITE);
-    return frontend_syscall(SYS_fstatat, kfd, (uintptr_t)name, name_size, (uintptr_t)st, flags, 0, 0);
+    long ret = frontend_syscall(SYS_fstatat, kfd, (uintptr_t)name, name_size, (uintptr_t)&buf, flags, 0, 0);
+    copy_stat(st, &buf);
+    return ret;
   }
   return -EBADF;
 }