From f2abc6bb9edbcb23c7e314873b26ca6303a9c1b7 Mon Sep 17 00:00:00 2001
From: Brandon Potter <brandon.potter@amd.com>
Date: Wed, 18 Apr 2018 14:45:37 -0400
Subject: syscall_emul: implement dir-related syscalls

Add getdents, rmdir, chdir, and mknod to SE mode for x86.

Change-Id: I387ea3066869e8999bc0064f74070f4e47c1e9a1
Reviewed-on: https://gem5-review.googlesource.com/12112
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
---
 src/sim/syscall_emul.cc | 96 ++++++++++++++++++++++++++++++++++++++++++++++++-
 src/sim/syscall_emul.hh | 18 +++++++++-
 2 files changed, 112 insertions(+), 2 deletions(-)

(limited to 'src/sim')

diff --git a/src/sim/syscall_emul.cc b/src/sim/syscall_emul.cc
index dd2323eaa..794b0bc2c 100644
--- a/src/sim/syscall_emul.cc
+++ b/src/sim/syscall_emul.cc
@@ -32,10 +32,12 @@
 #include "sim/syscall_emul.hh"
 
 #include <fcntl.h>
+#include <syscall.h>
 #include <unistd.h>
 
 #include <csignal>
 #include <iostream>
+#include <mutex>
 #include <string>
 
 #include "arch/utility.hh"
@@ -45,6 +47,7 @@
 #include "cpu/thread_context.hh"
 #include "dev/net/dist_iface.hh"
 #include "mem/page_table.hh"
+#include "sim/byteswap.hh"
 #include "sim/process.hh"
 #include "sim/sim_exit.hh"
 #include "sim/syscall_debug_macros.hh"
@@ -512,7 +515,6 @@ unlinkHelper(SyscallDesc *desc, int num, Process *p, ThreadContext *tc,
     if (!tc->getMemProxy().tryReadString(path, p->getSyscallArg(tc, index)))
         return -EFAULT;
 
-    // Adjust path for current working directory
     path = p->fullPath(path);
 
     int result = unlink(path.c_str());
@@ -1105,3 +1107,95 @@ accessFunc(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc)
     return accessFunc(desc, callnum, p, tc, 0);
 }
 
+SyscallReturn
+mknodFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
+{
+    int index = 0;
+    std::string path;
+    if (!tc->getMemProxy().tryReadString(path, p->getSyscallArg(tc, index)))
+        return -EFAULT;
+
+    path = p->fullPath(path);
+    mode_t mode = p->getSyscallArg(tc, index);
+    dev_t dev = p->getSyscallArg(tc, index);
+
+    auto result = mknod(path.c_str(), mode, dev);
+    return (result == -1) ? -errno : result;
+}
+
+SyscallReturn
+chdirFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
+{
+    int index = 0;
+    std::string path;
+    if (!tc->getMemProxy().tryReadString(path, p->getSyscallArg(tc, index)))
+        return -EFAULT;
+
+    path = p->fullPath(path);
+
+    auto result = chdir(path.c_str());
+    return (result == -1) ? -errno : result;
+}
+
+SyscallReturn
+rmdirFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
+{
+    int index = 0;
+    std::string path;
+    if (!tc->getMemProxy().tryReadString(path, p->getSyscallArg(tc, index)))
+        return -EFAULT;
+
+    path = p->fullPath(path);
+
+    auto result = rmdir(path.c_str());
+    return (result == -1) ? -errno : result;
+}
+
+SyscallReturn
+getdentsFunc(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc)
+{
+    int index = 0;
+    int tgt_fd = p->getSyscallArg(tc, index);
+    Addr buf_ptr = p->getSyscallArg(tc, index);
+    unsigned count = p->getSyscallArg(tc, index);
+
+    auto hbfdp = std::dynamic_pointer_cast<HBFDEntry>((*p->fds)[tgt_fd]);
+    if (!hbfdp)
+        return -EBADF;
+    int sim_fd = hbfdp->getSimFD();
+
+    BufferArg buf_arg(buf_ptr, count);
+    auto status = syscall(SYS_getdents, sim_fd, buf_arg.bufferPtr(), count);
+
+    if (status == -1)
+        return -errno;
+
+    typedef struct linux_dirent {
+        unsigned long d_ino;
+        unsigned long d_off;
+        unsigned short d_reclen;
+        char dname[];
+    } LinDent;
+
+    unsigned traversed = 0;
+    while (traversed < status) {
+        LinDent *buffer = (LinDent*)((Addr)buf_arg.bufferPtr() + traversed);
+
+        auto host_reclen = buffer->d_reclen;
+
+        /**
+         * Convert the byte ordering from the host to the target before
+         * passing the data back into the target's address space to preserve
+         * endianness.
+         */
+        buffer->d_ino = htog(buffer->d_ino);
+        buffer->d_off = htog(buffer->d_off);
+        buffer->d_reclen = htog(buffer->d_reclen);
+
+        traversed += host_reclen;
+    }
+
+    buf_arg.copyOut(tc->getMemProxy());
+    return status;
+}
+
diff --git a/src/sim/syscall_emul.hh b/src/sim/syscall_emul.hh
index 1f4233aa8..c7818b6c6 100644
--- a/src/sim/syscall_emul.hh
+++ b/src/sim/syscall_emul.hh
@@ -215,6 +215,18 @@ SyscallReturn symlinkFunc(SyscallDesc *desc, int num, Process *p,
 SyscallReturn mkdirFunc(SyscallDesc *desc, int num,
                         Process *p, ThreadContext *tc);
 
+/// Target mknod() handler.
+SyscallReturn mknodFunc(SyscallDesc *desc, int num,
+                        Process *p, ThreadContext *tc);
+
+/// Target chdir() handler.
+SyscallReturn chdirFunc(SyscallDesc *desc, int num,
+                        Process *p, ThreadContext *tc);
+
+// Target rmdir() handler.
+SyscallReturn rmdirFunc(SyscallDesc *desc, int num,
+                        Process *p, ThreadContext *tc);
+
 /// Target rename() handler.
 SyscallReturn renameFunc(SyscallDesc *desc, int num,
                          Process *p, ThreadContext *tc);
@@ -291,7 +303,11 @@ SyscallReturn pipeImpl(SyscallDesc *desc, int num, Process *p,
 SyscallReturn getpidFunc(SyscallDesc *desc, int num,
                          Process *p, ThreadContext *tc);
 
-/// Target getuid() handler.
+// Target getdents() handler.
+SyscallReturn getdentsFunc(SyscallDesc *desc, int num,
+                           Process *p, ThreadContext *tc);
+
+// Target getuid() handler.
 SyscallReturn getuidFunc(SyscallDesc *desc, int num,
                          Process *p, ThreadContext *tc);
 
-- 
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