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sim-se: Implement at suffixed syscalls

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All syscalls with the "at" suffix rely on a directory file descriptor
(dirfd) and a pathname, provided as arguments to the syscall

If the pathname is relative, then it is interpreted relative to the
directory referred to by the file descriptor dirfd (rather than relative
to the current working directory of the calling process)

Prior to this patch, only the openat syscall was properly implemented.
Other syscalls were discarding the dirfd argument and producing
a warning instead

JIRA: https://gem5.atlassian.net/browse/GEM5-1098

Change-Id: I0cc20c6ef79fca8c8d1c2c9a52eb54ede3d51312
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/51048
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
This commit is contained in:
Giacomo Travaglini
2021-09-27 14:32:10 +01:00
parent 8f1f50f410
commit 528fae6464
1 changed files with 56 additions and 49 deletions
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105
src/sim/syscall_emul.hh
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 2012-2013, 2015, 2019-2020 ARM Limited
* Copyright (c) 2012-2013, 2015, 2019-2021 Arm Limited
* Copyright (c) 2015 Advanced Micro Devices, Inc.
* All rights reserved
*
@@ -380,6 +380,25 @@ SyscallReturn getcpuFunc(SyscallDesc *desc, ThreadContext *tc,
SyscallReturn getsocknameFunc(SyscallDesc *desc, ThreadContext *tc,
int tgt_fd, VPtr<> addrPtr, VPtr<> lenPtr);
template <class OS>
SyscallReturn
atSyscallPath(ThreadContext *tc, int dirfd, std::string &path)
{
// If pathname is absolute, then dirfd is ignored.
if (dirfd != OS::TGT_AT_FDCWD && !startswith(path, "/")) {
auto process = tc->getProcessPtr();
std::shared_ptr<FDEntry> fdep = ((*process->fds)[dirfd]);
auto ffdp = std::dynamic_pointer_cast<FileFDEntry>(fdep);
if (!ffdp)
return -EBADF;
path = ffdp->getFileName() + "/" + path;
}
return 0;
}
/// Futex system call
/// Implemented by Daniel Sanchez
/// Used by printf's in multi-threaded apps
@@ -928,8 +947,10 @@ unlinkatFunc(SyscallDesc *desc, ThreadContext *tc, int dirfd, VPtr<> pathname)
if (!SETranslatingPortProxy(tc).tryReadString(path, pathname))
return -EFAULT;
if (dirfd != OS::TGT_AT_FDCWD)
warn("unlinkat: first argument not AT_FDCWD; unlikely to work");
// Modifying path from the directory descriptor
if (auto res = atSyscallPath<OS>(tc, dirfd, path); !res.successful()) {
return res;
}
return unlinkImpl(desc, tc, path);
}
@@ -944,8 +965,10 @@ faccessatFunc(SyscallDesc *desc, ThreadContext *tc,
if (!SETranslatingPortProxy(tc).tryReadString(path, pathname))
return -EFAULT;
if (dirfd != OS::TGT_AT_FDCWD)
warn("faccessat: first argument not AT_FDCWD; unlikely to work");
// Modifying path from the directory descriptor
if (auto res = atSyscallPath<OS>(tc, dirfd, path); !res.successful()) {
return res;
}
return accessImpl(desc, tc, path, mode);
}
@@ -960,8 +983,10 @@ readlinkatFunc(SyscallDesc *desc, ThreadContext *tc,
if (!SETranslatingPortProxy(tc).tryReadString(path, pathname))
return -EFAULT;
if (dirfd != OS::TGT_AT_FDCWD)
warn("openat: first argument not AT_FDCWD; unlikely to work");
// Modifying path from the directory descriptor
if (auto res = atSyscallPath<OS>(tc, dirfd, path); !res.successful()) {
return res;
}
return readlinkImpl(desc, tc, path, buf, bufsiz);
}
@@ -981,11 +1006,15 @@ renameatFunc(SyscallDesc *desc, ThreadContext *tc,
if (!proxy.tryReadString(new_name, newpath))
return -EFAULT;
if (olddirfd != OS::TGT_AT_FDCWD)
warn("renameat: first argument not AT_FDCWD; unlikely to work");
// Modifying old_name from the directory descriptor
if (auto res = atSyscallPath<OS>(tc, olddirfd, old_name); !res.successful()) {
return res;
}
if (newdirfd != OS::TGT_AT_FDCWD)
warn("renameat: third argument not AT_FDCWD; unlikely to work");
// Modifying new_name from the directory descriptor
if (auto res = atSyscallPath<OS>(tc, newdirfd, new_name); !res.successful()) {
return res;
}
return renameImpl(desc, tc, old_name, new_name);
}
@@ -1233,39 +1262,6 @@ statFunc(SyscallDesc *desc, ThreadContext *tc,
return 0;
}
/// Target stat64() handler.
template <class OS>
SyscallReturn
stat64Func(SyscallDesc *desc, ThreadContext *tc,
VPtr<> pathname, VPtr<typename OS::tgt_stat64> tgt_stat)
{
std::string path;
auto process = tc->getProcessPtr();
if (!SETranslatingPortProxy(tc).tryReadString(path, pathname))
return -EFAULT;
// Adjust path for cwd and redirection
path = process->checkPathRedirect(path);
#if NO_STAT64
struct stat hostBuf;
int result = stat(path.c_str(), &hostBuf);
#else
struct stat64 hostBuf;
int result = stat64(path.c_str(), &hostBuf);
#endif
if (result < 0)
return -errno;
copyOutStat64Buf<OS>(tgt_stat, &hostBuf);
return 0;
}
/// Target fstatat64() handler.
template <class OS>
SyscallReturn
@@ -1273,16 +1269,19 @@ fstatat64Func(SyscallDesc *desc, ThreadContext *tc,
int dirfd, VPtr<> pathname,
VPtr<typename OS::tgt_stat64> tgt_stat)
{
auto process = tc->getProcessPtr();
if (dirfd != OS::TGT_AT_FDCWD)
warn("fstatat64: first argument not AT_FDCWD; unlikely to work");
std::string path;
if (!SETranslatingPortProxy(tc).tryReadString(path, pathname))
return -EFAULT;
// Modifying path from the directory descriptor
if (auto res = atSyscallPath<OS>(tc, dirfd, path); !res.successful()) {
return res;
}
auto p = tc->getProcessPtr();
// Adjust path for cwd and redirection
path = process->checkPathRedirect(path);
path = p->checkPathRedirect(path);
#if NO_STAT64
struct stat hostBuf;
@@ -1300,6 +1299,14 @@ fstatat64Func(SyscallDesc *desc, ThreadContext *tc,
return 0;
}
/// Target stat64() handler.
template <class OS>
SyscallReturn
stat64Func(SyscallDesc *desc, ThreadContext *tc,
VPtr<> pathname, VPtr<typename OS::tgt_stat64> tgt_stat)
{
return fstatat64Func<OS>(desc, tc, OS::TGT_AT_FDCWD, pathname, tgt_stat);
}
/// Target fstat64() handler.
template <class OS>