changeset 8e928c0f98d1 in /z/repo/gem5
details: http://repo.gem5.org/gem5?cmd=changeset;node=8e928c0f98d1
description:
syscall_emul: [patch 11/22] extend functionality of fcntl
This changeset adds the ability to set a close-on-exec flag for a given
file descriptor. It also reworks some of the logic surrounding setting
and
retrieving flags from the file description.
diffstat:
src/arch/x86/linux/process.cc | 2 +-
src/sim/syscall_emul.cc | 47 +++++++++++++++++++++---------------------
src/sim/syscall_emul.hh | 2 +-
3 files changed, 25 insertions(+), 26 deletions(-)
diffs (98 lines):
diff -r 663bac0bb1c9 -r 8e928c0f98d1 src/arch/x86/linux/process.cc
--- a/src/arch/x86/linux/process.cc Thu Feb 23 13:27:48 2017 -0500
+++ b/src/arch/x86/linux/process.cc Mon Jul 20 09:15:21 2015 -0500
@@ -598,7 +598,7 @@
/* 52 */ SyscallDesc("umount2", unimplementedFunc),
/* 53 */ SyscallDesc("lock", unimplementedFunc),
/* 54 */ SyscallDesc("ioctl", ioctlFunc<X86Linux32>),
- /* 55 */ SyscallDesc("fcntl", unimplementedFunc),
+ /* 55 */ SyscallDesc("fcntl", fcntlFunc),
/* 56 */ SyscallDesc("mpx", unimplementedFunc),
/* 57 */ SyscallDesc("setpgid", unimplementedFunc),
/* 58 */ SyscallDesc("ulimit", unimplementedFunc),
diff -r 663bac0bb1c9 -r 8e928c0f98d1 src/sim/syscall_emul.cc
--- a/src/sim/syscall_emul.cc Thu Feb 23 13:27:48 2017 -0500
+++ b/src/sim/syscall_emul.cc Mon Jul 20 09:15:21 2015 -0500
@@ -620,47 +620,46 @@
return (result == -1) ? -local_errno : p->fds->allocFD(new_fdep);
}
-
SyscallReturn
fcntlFunc(SyscallDesc *desc, int num, Process *p, ThreadContext *tc)
{
+ int arg;
int index = 0;
int tgt_fd = p->getSyscallArg(tc, index);
+ int cmd = p->getSyscallArg(tc, index);
auto hbfdp = std::dynamic_pointer_cast<HBFDEntry>((*p->fds)[tgt_fd]);
if (!hbfdp)
return -EBADF;
int sim_fd = hbfdp->getSimFD();
- int cmd = p->getSyscallArg(tc, index);
+ int coe = hbfdp->getCOE();
+
switch (cmd) {
- case 0: // F_DUPFD
- // if we really wanted to support this, we'd need to do it
- // in the target fd space.
- warn("fcntl(%d, F_DUPFD) not supported, error returned\n", tgt_fd);
- return -EMFILE;
+ case F_GETFD:
+ return coe & FD_CLOEXEC;
- case 1: // F_GETFD (get close-on-exec flag)
- case 2: // F_SETFD (set close-on-exec flag)
+ case F_SETFD: {
+ arg = p->getSyscallArg(tc, index);
+ arg ? hbfdp->setCOE(true) : hbfdp->setCOE(false);
return 0;
+ }
- case 3: // F_GETFL (get file flags)
- case 4: // F_SETFL (set file flags)
- // not sure if this is totally valid, but we'll pass it through
- // to the underlying OS
- warn("fcntl(%d, %d) passed through to host\n", tgt_fd, cmd);
- return fcntl(sim_fd, cmd);
- // return 0;
-
- case 7: // F_GETLK (get lock)
- case 8: // F_SETLK (set lock)
- case 9: // F_SETLKW (set lock and wait)
- // don't mess with file locking... just act like it's OK
- warn("File lock call (fcntl(%d, %d)) ignored.\n", tgt_fd, cmd);
- return 0;
+ // Rely on the host to maintain the file status flags for this file
+ // description rather than maintain it ourselves. Admittedly, this
+ // is suboptimal (and possibly error prone), but it is difficult to
+ // maintain the flags by tracking them across the different descriptors
+ // (that refer to this file description) caused by clone, dup, and
+ // subsequent fcntls.
+ case F_GETFL:
+ case F_SETFL: {
+ arg = p->getSyscallArg(tc, index);
+ int rv = fcntl(sim_fd, cmd, arg);
+ return (rv == -1) ? -errno : rv;
+ }
default:
- warn("Unknown fcntl command %d\n", cmd);
+ warn("fcntl: unsupported command %d\n", cmd);
return 0;
}
}
diff -r 663bac0bb1c9 -r 8e928c0f98d1 src/sim/syscall_emul.hh
--- a/src/sim/syscall_emul.hh Thu Feb 23 13:27:48 2017 -0500
+++ b/src/sim/syscall_emul.hh Mon Jul 20 09:15:21 2015 -0500
@@ -230,7 +230,7 @@
SyscallReturn dupFunc(SyscallDesc *desc, int num,
Process *process, ThreadContext *tc);
-/// Target fnctl() handler.
+/// Target fcntl() handler.
SyscallReturn fcntlFunc(SyscallDesc *desc, int num,
Process *process, ThreadContext *tc);
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