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syscall-emul: Add or extend dup, dup2, and pipe

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This changeset extends the pipe system call to work with
architectures other than Alpha (and enables the syscall for
x86). For the dup system call, it sets the clone-on-exec
flag by default. For the dup2 system call, the changeset
adds an implementation (and enables it for x86).

Change-Id: I00ddb416744ee7dd61a5cd02c4c3d97f30543878
Reviewed-on: https://gem5-review.googlesource.com/2266
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Tony Gutierrez <anthony.gutierrez@amd.com>
Reviewed-by: Michael LeBeane <Michael.Lebeane@amd.com>
This commit is contained in:
Brandon Potter 2017-03-01 13:35:02 -06:00
parent acce7b0dc0
commit 198c515b97
3 changed files with 95 additions and 23 deletions
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8
src/arch/x86/linux/process.cc
View file

@ -242,7 +242,7 @@ static SyscallDesc syscallDescs64[] = {
/* 19 */ SyscallDesc("readv", unimplementedFunc),
/* 20 */ SyscallDesc("writev", writevFunc<X86Linux64>),
/* 21 */ SyscallDesc("access", ignoreFunc),
/* 22 */ SyscallDesc("pipe", unimplementedFunc),
/* 22 */ SyscallDesc("pipe", pipeFunc),
/* 23 */ SyscallDesc("select", unimplementedFunc),
/* 24 */ SyscallDesc("sched_yield", unimplementedFunc),
/* 25 */ SyscallDesc("mremap", mremapFunc<X86Linux64>),
@ -253,7 +253,7 @@ static SyscallDesc syscallDescs64[] = {
/* 30 */ SyscallDesc("shmat", unimplementedFunc),
/* 31 */ SyscallDesc("shmctl", unimplementedFunc),
/* 32 */ SyscallDesc("dup", dupFunc),
/* 33 */ SyscallDesc("dup2", unimplementedFunc),
/* 33 */ SyscallDesc("dup2", dup2Func),
/* 34 */ SyscallDesc("pause", unimplementedFunc),
/* 35 */ SyscallDesc("nanosleep", ignoreFunc, SyscallDesc::WarnOnce),
/* 36 */ SyscallDesc("getitimer", unimplementedFunc),
@ -591,7 +591,7 @@ static SyscallDesc syscallDescs32[] = {
/* 39 */ SyscallDesc("mkdir", unimplementedFunc),
/* 40 */ SyscallDesc("rmdir", unimplementedFunc),
/* 41 */ SyscallDesc("dup", dupFunc),
/* 42 */ SyscallDesc("pipe", unimplementedFunc),
/* 42 */ SyscallDesc("pipe", pipeFunc),
/* 43 */ SyscallDesc("times", timesFunc<X86Linux32>),
/* 44 */ SyscallDesc("prof", unimplementedFunc),
/* 45 */ SyscallDesc("brk", brkFunc),
@ -612,7 +612,7 @@ static SyscallDesc syscallDescs32[] = {
/* 60 */ SyscallDesc("umask", unimplementedFunc),
/* 61 */ SyscallDesc("chroot", unimplementedFunc),
/* 62 */ SyscallDesc("ustat", unimplementedFunc),
/* 63 */ SyscallDesc("dup2", unimplementedFunc),
/* 63 */ SyscallDesc("dup2", dup2Func),
/* 64 */ SyscallDesc("getppid", unimplementedFunc),
/* 65 */ SyscallDesc("getpgrp", unimplementedFunc),
/* 66 */ SyscallDesc("setsid", unimplementedFunc),

98
src/sim/syscall_emul.cc
View file

@ -626,13 +626,11 @@ fchownFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
return (result == -1) ? -errno : result;
}
/**
* TODO: there's a bit more involved here since file descriptors created with
* dup are supposed to share a file description. So, there is a problem with
* maintaining fields like file offset or flags since an update to such a
* field won't be reflected in the metadata for the fd entries that we
* maintain to hold metadata for checkpoint restoration.
* FIXME: The file description is not shared among file descriptors created
* with dup. Really, it's difficult to maintain fields like file offset or
* flags since an update to such a field won't be reflected in the metadata
* for the fd entries that we maintain for checkpoint restoration.
*/
SyscallReturn
dupFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
@ -646,13 +644,44 @@ dupFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
int sim_fd = old_hbfdp->getSimFD();
int result = dup(sim_fd);
int local_errno = errno;
if (result == -1)
return -errno;
std::shared_ptr<FDEntry> new_fdep = old_hbfdp->clone();
auto new_hbfdp = std::dynamic_pointer_cast<HBFDEntry>(new_fdep);
auto new_hbfdp = std::dynamic_pointer_cast<HBFDEntry>(old_hbfdp->clone());
new_hbfdp->setSimFD(result);
new_hbfdp->setCOE(false);
return p->fds->allocFD(new_hbfdp);
}
return (result == -1) ? -local_errno : p->fds->allocFD(new_fdep);
SyscallReturn
dup2Func(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
{
int index = 0;
int old_tgt_fd = p->getSyscallArg(tc, index);
auto old_hbp = std::dynamic_pointer_cast<HBFDEntry>((*p->fds)[old_tgt_fd]);
if (!old_hbp)
return -EBADF;
int old_sim_fd = old_hbp->getSimFD();
/**
* We need a valid host file descriptor number to be able to pass into
* the second parameter for dup2 (newfd), but we don't know what the
* viable numbers are; we execute the open call to retrieve one.
*/
int res_fd = dup2(old_sim_fd, open("/dev/null", O_RDONLY));
if (res_fd == -1)
return -errno;
int new_tgt_fd = p->getSyscallArg(tc, index);
auto new_hbp = std::dynamic_pointer_cast<HBFDEntry>((*p->fds)[new_tgt_fd]);
if (new_hbp)
p->fds->closeFDEntry(new_tgt_fd);
new_hbp = std::dynamic_pointer_cast<HBFDEntry>(old_hbp->clone());
new_hbp->setSimFD(res_fd);
new_hbp->setCOE(false);
return p->fds->allocFD(new_hbp);
}
SyscallReturn
@ -731,23 +760,28 @@ fcntl64Func(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
}
SyscallReturn
pipePseudoFunc(SyscallDesc *desc, int callnum, Process *process,
ThreadContext *tc)
pipeImpl(SyscallDesc *desc, int callnum, Process *p, ThreadContext *tc,
bool pseudoPipe)
{
Addr tgt_addr = 0;
if (!pseudoPipe) {
int index = 0;
tgt_addr = p->getSyscallArg(tc, index);
}
int sim_fds[2], tgt_fds[2];
int pipe_retval = pipe(sim_fds);
if (pipe_retval < 0)
return pipe_retval;
if (pipe_retval == -1)
return -errno;
auto rend = PipeFDEntry::EndType::read;
auto rpfd = std::make_shared<PipeFDEntry>(sim_fds[0], O_WRONLY, rend);
tgt_fds[0] = p->fds->allocFD(rpfd);
auto wend = PipeFDEntry::EndType::write;
auto wpfd = std::make_shared<PipeFDEntry>(sim_fds[1], O_RDONLY, wend);
tgt_fds[0] = process->fds->allocFD(rpfd);
tgt_fds[1] = process->fds->allocFD(wpfd);
tgt_fds[1] = p->fds->allocFD(wpfd);
/**
* Now patch the read object to record the target file descriptor chosen
@ -759,8 +793,34 @@ pipePseudoFunc(SyscallDesc *desc, int callnum, Process *process,
* Alpha Linux convention for pipe() is that fd[0] is returned as
* the return value of the function, and fd[1] is returned in r20.
*/
tc->setIntReg(SyscallPseudoReturnReg, tgt_fds[1]);
return sim_fds[0];
if (pseudoPipe) {
tc->setIntReg(SyscallPseudoReturnReg, tgt_fds[1]);
return tgt_fds[0];
}
/**
* Copy the target file descriptors into buffer space and then copy
* the buffer space back into the target address space.
*/
BufferArg tgt_handle(tgt_addr, sizeof(int[2]));
int *buf_ptr = (int*)tgt_handle.bufferPtr();
buf_ptr[0] = tgt_fds[0];
buf_ptr[1] = tgt_fds[1];
tgt_handle.copyOut(tc->getMemProxy());
return 0;
}
SyscallReturn
pipePseudoFunc(SyscallDesc *desc, int callnum, Process *process,
ThreadContext *tc)
{
return pipeImpl(desc, callnum, process, tc, true);
}
SyscallReturn
pipeFunc(SyscallDesc *desc, int callnum, Process *process, ThreadContext *tc)
{
return pipeImpl(desc, callnum, process, tc, false);
}
SyscallReturn

12
src/sim/syscall_emul.hh
View file

@ -241,6 +241,10 @@ SyscallReturn fchownFunc(SyscallDesc *desc, int num,
SyscallReturn dupFunc(SyscallDesc *desc, int num,
Process *process, ThreadContext *tc);
/// Target dup2() handler.
SyscallReturn dup2Func(SyscallDesc *desc, int num,
Process *process, ThreadContext *tc);
/// Target fcntl() handler.
SyscallReturn fcntlFunc(SyscallDesc *desc, int num,
Process *process, ThreadContext *tc);
@ -253,6 +257,14 @@ SyscallReturn fcntl64Func(SyscallDesc *desc, int num,
SyscallReturn setuidFunc(SyscallDesc *desc, int num,
Process *p, ThreadContext *tc);
/// Target pipe() handler.
SyscallReturn pipeFunc(SyscallDesc *desc, int num,
Process *p, ThreadContext *tc);
/// Internal pipe() handler.
SyscallReturn pipeImpl(SyscallDesc *desc, int num, Process *p,
ThreadContext *tc, bool pseudoPipe);
/// Target getpid() handler.
SyscallReturn getpidFunc(SyscallDesc *desc, int num,
Process *p, ThreadContext *tc);