kernel: vfs: Add SYS_access syscall

Signed-off-by: Ian Moffett <ian@osmora.org>

4 files changed, 36 insertions, 0 deletions

diff --git a/sys/include/sys/syscall.h b/sys/include/sys/syscall.h
index dad2e00..0376bd2 100644
--- a/sys/include/sys/syscall.h
+++ b/sys/include/sys/syscall.h
@@ -50,6 +50,7 @@
 #define SYS_reboot  9
 #define SYS_mmap    10
 #define SYS_munmap  11
+#define SYS_access  12
 
 #if defined(_KERNEL)
 /* Syscall return value and arg type */
diff --git a/sys/include/sys/vfs.h b/sys/include/sys/vfs.h
index 1ff722a..fcb7391 100644
--- a/sys/include/sys/vfs.h
+++ b/sys/include/sys/vfs.h
@@ -40,6 +40,7 @@ scret_t sys_close(struct syscall_args *args);
 scret_t sys_read(struct syscall_args *scargs);
 scret_t sys_write(struct syscall_args *sargs);
 scret_t sys_stat(struct syscall_args *scargs);
+scret_t sys_access(struct syscall_args *scargs);
 
 #endif  /* _KERNEL */
 #endif  /* !_SYS_VFS_H_ */
diff --git a/sys/kern/kern_syscall.c b/sys/kern/kern_syscall.c
index 8a66f0e..fdcc73f 100644
--- a/sys/kern/kern_syscall.c
+++ b/sys/kern/kern_syscall.c
@@ -48,6 +48,7 @@ scret_t(*g_sctab[])(struct syscall_args *) = {
     sys_reboot, /* SYS_reboot */
     sys_mmap,   /* SYS_mmap */
     sys_munmap, /* SYS_munap */
+    sys_access, /* SYS_access */
 };
 
 const size_t MAX_SYSCALLS = NELEM(g_sctab);
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 8ce1639..0d51331 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -85,6 +85,28 @@ vfs_dostat(const char *path, struct stat *sbuf)
 }
 
 static int
+vfs_doaccess(const char *path)
+{
+    struct nameidata nd;
+    char pathbuf[PATH_MAX];
+    int error;
+
+    if ((copyinstr(path, pathbuf, sizeof(pathbuf))) < 0) {
+        return -EFAULT;
+    }
+
+    nd.path = pathbuf;
+    nd.flags = 0;
+
+    if ((error = namei(&nd)) != 0) {
+        return error;
+    }
+
+    vfs_release_vnode(nd.vp);
+    return 0;
+}
+
+static int
 vfs_doopen(const char *pathname, int flags)
 {
     char pathbuf[PATH_MAX];
@@ -150,3 +172,14 @@ sys_stat(struct syscall_args *scargs)
 {
     return vfs_dostat((const char *)scargs->arg0, (void *)scargs->arg1);
 }
+
+/*
+ * Check if a file can be accessed.
+ *
+ * @arg0: path
+ */
+scret_t
+sys_access(struct syscall_args *scargs)
+{
+    return vfs_doaccess((const char *)scargs->arg0);
+}