Serialization: Fix serialization of file descriptors. Make sure open

file descriptors are reopened and the file pointer is in the same
place as when the checkpoint occured.

Signed-off by: Ali Saidi

--HG--
extra : convert_revision : d9d2cd388c9c02f60e1269d6845891c35f94fc47
This commit is contained in:
Rick Strong 2007-11-29 00:22:46 -05:00
parent ab598eadbf
commit 376c7285ee
4 changed files with 237 additions and 26 deletions

View file

@ -32,7 +32,6 @@
#include <unistd.h>
#include <fcntl.h>
#include <string>
#include "arch/remote_gdb.hh"
@ -114,13 +113,32 @@ Process::Process(ProcessParams * params)
M5_pid = system->allocatePID();
// initialize first 3 fds (stdin, stdout, stderr)
fd_map[STDIN_FILENO] = stdin_fd;
fd_map[STDOUT_FILENO] = stdout_fd;
fd_map[STDERR_FILENO] = stderr_fd;
Process::FdMap *fdo = &fd_map[STDIN_FILENO];
fdo->fd = stdin_fd;
fdo->filename = in;
fdo->flags = O_RDONLY;
fdo->mode = -1;
fdo->fileOffset = 0;
fdo = &fd_map[STDOUT_FILENO];
fdo->fd = stdout_fd;
fdo->filename = out;
fdo->flags = O_WRONLY | O_CREAT | O_TRUNC;
fdo->mode = 0774;
fdo->fileOffset = 0;
fdo = &fd_map[STDERR_FILENO];
fdo->fd = stderr_fd;
fdo->filename = "STDERR";
fdo->flags = O_WRONLY;
fdo->mode = -1;
fdo->fileOffset = 0;
// mark remaining fds as free
for (int i = 3; i <= MAX_FD; ++i) {
fd_map[i] = -1;
Process::FdMap *fdo = &fd_map[i];
fdo->fd = -1;
}
mmap_start = mmap_end = 0;
@ -230,22 +248,30 @@ Process::dup_fd(int sim_fd, int tgt_fd)
if (tgt_fd < 0 || tgt_fd > MAX_FD)
panic("Process::dup_fd tried to dup past MAX_FD (%d)", tgt_fd);
fd_map[tgt_fd] = sim_fd;
Process::FdMap *fdo = &fd_map[tgt_fd];
fdo->fd = sim_fd;
}
// generate new target fd for sim_fd
int
Process::alloc_fd(int sim_fd)
Process::alloc_fd(int sim_fd, string filename, int flags, int mode, bool pipe)
{
// in case open() returns an error, don't allocate a new fd
if (sim_fd == -1)
return -1;
// find first free target fd
for (int free_fd = 0; free_fd < MAX_FD; ++free_fd) {
if (fd_map[free_fd] == -1) {
fd_map[free_fd] = sim_fd;
for (int free_fd = 0; free_fd <= MAX_FD; ++free_fd) {
Process::FdMap *fdo = &fd_map[free_fd];
if (fdo->fd == -1) {
fdo->fd = sim_fd;
fdo->filename = filename;
fdo->mode = mode;
fdo->fileOffset = 0;
fdo->flags = flags;
fdo->isPipe = pipe;
fdo->readPipeSource = 0;
return free_fd;
}
}
@ -258,10 +284,17 @@ Process::alloc_fd(int sim_fd)
void
Process::free_fd(int tgt_fd)
{
if (fd_map[tgt_fd] == -1)
Process::FdMap *fdo = &fd_map[tgt_fd];
if (fdo->fd == -1)
warn("Process::free_fd: request to free unused fd %d", tgt_fd);
fd_map[tgt_fd] = -1;
fdo->fd = -1;
fdo->filename = "NULL";
fdo->mode = 0;
fdo->fileOffset = 0;
fdo->flags = 0;
fdo->isPipe = false;
fdo->readPipeSource = 0;
}
@ -272,9 +305,17 @@ Process::sim_fd(int tgt_fd)
if (tgt_fd > MAX_FD)
return -1;
return fd_map[tgt_fd];
return fd_map[tgt_fd].fd;
}
Process::FdMap *
Process::sim_fd_obj(int tgt_fd)
{
if (tgt_fd > MAX_FD)
panic("sim_fd_obj called in fd out of range.");
return &fd_map[tgt_fd];
}
bool
Process::checkAndAllocNextPage(Addr vaddr)
{
@ -301,6 +342,127 @@ Process::checkAndAllocNextPage(Addr vaddr)
return false;
}
// find all offsets for currently open files and save them
void
Process::fix_file_offsets() {
Process::FdMap *fdo_stdin = &fd_map[STDIN_FILENO];
Process::FdMap *fdo_stdout = &fd_map[STDOUT_FILENO];
Process::FdMap *fdo_stderr = &fd_map[STDERR_FILENO];
string in = fdo_stdin->filename;
string out = fdo_stdout->filename;
// initialize file descriptors to default: same as simulator
int stdin_fd, stdout_fd, stderr_fd;
if (in == "stdin" || in == "cin")
stdin_fd = STDIN_FILENO;
else if (in == "None")
stdin_fd = -1;
else{
//OPEN standard in and seek to the right location
stdin_fd = Process::openInputFile(in);
if (lseek(stdin_fd, fdo_stdin->fileOffset, SEEK_SET) < 0)
panic("Unable to seek to correct location in file: %s", in);
}
if (out == "stdout" || out == "cout")
stdout_fd = STDOUT_FILENO;
else if (out == "stderr" || out == "cerr")
stdout_fd = STDERR_FILENO;
else if (out == "None")
stdout_fd = -1;
else{
stdout_fd = Process::openOutputFile(out);
if (lseek(stdin_fd, fdo_stdout->fileOffset, SEEK_SET) < 0)
panic("Unable to seek to correct in file: %s", out);
}
stderr_fd = (stdout_fd != STDOUT_FILENO) ? stdout_fd : STDERR_FILENO;
fdo_stdin->fd = stdin_fd;
fdo_stdout->fd = stdout_fd;
fdo_stderr->fd = stderr_fd;
for (int free_fd = 3; free_fd <= MAX_FD; ++free_fd) {
Process::FdMap *fdo = &fd_map[free_fd];
if (fdo->fd != -1) {
if (fdo->isPipe){
if (fdo->filename == "PIPE-WRITE")
continue;
else {
assert (fdo->filename == "PIPE-READ");
//create a new pipe
int fds[2];
int pipe_retval = pipe(fds);
if (pipe_retval < 0) {
// error
panic("Unable to create new pipe.");
}
fdo->fd = fds[0]; //set read pipe
Process::FdMap *fdo_write = &fd_map[fdo->readPipeSource];
if (fdo_write->filename != "PIPE-WRITE")
panic ("Couldn't find write end of the pipe");
fdo_write->fd = fds[1];//set write pipe
}
} else {
//Open file
int fd = open(fdo->filename.c_str(), fdo->flags, fdo->mode);
if (fd == -1)
panic("Unable to open file: %s", fdo->filename);
fdo->fd = fd;
//Seek to correct location before checkpoint
if (lseek(fd,fdo->fileOffset, SEEK_SET) < 0)
panic("Unable to seek to correct location in file: %s", fdo->filename);
}
}
}
}
void
Process::find_file_offsets(){
for (int free_fd = 0; free_fd <= MAX_FD; ++free_fd) {
Process::FdMap *fdo = &fd_map[free_fd];
if (fdo->fd != -1) {
fdo->fileOffset = lseek(fdo->fd, 0, SEEK_CUR);
} else {
fdo->filename = "NULL";
fdo->fileOffset = 0;
}
}
}
void
Process::setReadPipeSource(int read_pipe_fd, int source_fd){
Process::FdMap *fdo = &fd_map[read_pipe_fd];
fdo->readPipeSource = source_fd;
}
void
Process::FdMap::serialize(std::ostream &os)
{
SERIALIZE_SCALAR(fd);
SERIALIZE_SCALAR(isPipe);
SERIALIZE_SCALAR(filename);
SERIALIZE_SCALAR(flags);
SERIALIZE_SCALAR(readPipeSource);
SERIALIZE_SCALAR(fileOffset);
}
void
Process::FdMap::unserialize(Checkpoint *cp, const std::string &section)
{
UNSERIALIZE_SCALAR(fd);
UNSERIALIZE_SCALAR(isPipe);
UNSERIALIZE_SCALAR(filename);
UNSERIALIZE_SCALAR(flags);
UNSERIALIZE_SCALAR(readPipeSource);
UNSERIALIZE_SCALAR(fileOffset);
}
void
Process::serialize(std::ostream &os)
{
@ -314,9 +476,13 @@ Process::serialize(std::ostream &os)
SERIALIZE_SCALAR(mmap_end);
SERIALIZE_SCALAR(nxm_start);
SERIALIZE_SCALAR(nxm_end);
SERIALIZE_ARRAY(fd_map, MAX_FD);
find_file_offsets();
pTable->serialize(os);
for (int x = 0; x <= MAX_FD; x++) {
nameOut(os, csprintf("%s.FdMap%d", name(), x));
fd_map[x].serialize(os);
}
}
void
@ -332,10 +498,11 @@ Process::unserialize(Checkpoint *cp, const std::string &section)
UNSERIALIZE_SCALAR(mmap_end);
UNSERIALIZE_SCALAR(nxm_start);
UNSERIALIZE_SCALAR(nxm_end);
UNSERIALIZE_ARRAY(fd_map, MAX_FD);
pTable->unserialize(cp, section);
for (int x = 0; x <= MAX_FD; x++) {
fd_map[x].unserialize(cp, csprintf("%s.FdMap%d", section, x));
}
fix_file_offsets();
checkpointRestored = true;

View file

@ -144,10 +144,40 @@ class Process : public SimObject
//separated.
uint64_t M5_pid;
class FdMap
{
public:
int fd;
std::string filename;
int mode;
int flags;
bool isPipe;
int readPipeSource;
uint64_t fileOffset;
FdMap()
{
fd = -1;
filename = "NULL";
mode = 0;
flags = 0;
isPipe = false;
readPipeSource = 0;
fileOffset = 0;
}
void serialize(std::ostream &os);
void unserialize(Checkpoint *cp, const std::string &section);
};
private:
// file descriptor remapping support
static const int MAX_FD = 256; // max legal fd value
int fd_map[MAX_FD+1];
static const int MAX_FD = 256; // max legal fd value
FdMap fd_map[MAX_FD+1];
public:
// static helper functions to generate file descriptors for constructor
@ -168,7 +198,7 @@ class Process : public SimObject
void dup_fd(int sim_fd, int tgt_fd);
// generate new target fd for sim_fd
int alloc_fd(int sim_fd);
int alloc_fd(int sim_fd, std::string filename, int flags, int mode, bool pipe);
// free target fd (e.g., after close)
void free_fd(int tgt_fd);
@ -176,6 +206,18 @@ class Process : public SimObject
// look up simulator fd for given target fd
int sim_fd(int tgt_fd);
// look up simulator fd_map object for a given target fd
FdMap * sim_fd_obj(int tgt_fd);
// fix all offsets for currently open files and save them
void fix_file_offsets();
// find all offsets for currently open files and save them
void find_file_offsets();
// set the source of this read pipe for a checkpoint resume
void setReadPipeSource(int read_pipe_fd, int source_fd);
virtual void syscall(int64_t callnum, ThreadContext *tc) = 0;
// check if the this addr is on the next available page and allocate it

View file

@ -350,12 +350,13 @@ SyscallReturn
dupFunc(SyscallDesc *desc, int num, LiveProcess *process, ThreadContext *tc)
{
int fd = process->sim_fd(tc->getSyscallArg(0));
if (fd < 0)
return -EBADF;
Process::FdMap *fdo = process->sim_fd_obj(tc->getSyscallArg(0));
int result = dup(fd);
return (result == -1) ? -errno : process->alloc_fd(result);
return (result == -1) ? -errno : process->alloc_fd(result, fdo->filename, fdo->flags, fdo->mode, false);
}
@ -442,9 +443,10 @@ pipePseudoFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
return pipe_retval;
}
sim_fds[0] = process->alloc_fd(fds[0]);
sim_fds[1] = process->alloc_fd(fds[1]);
sim_fds[0] = process->alloc_fd(fds[0], "PIPE-READ", O_WRONLY, -1, true);
sim_fds[1] = process->alloc_fd(fds[1], "PIPE-WRITE", O_RDONLY, -1, true);
process->setReadPipeSource(sim_fds[0], sim_fds[1]);
// 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, sim_fds[1]);

View file

@ -518,7 +518,7 @@ openFunc(SyscallDesc *desc, int callnum, LiveProcess *process,
// open the file
int fd = open(path.c_str(), hostFlags, mode);
return (fd == -1) ? -errno : process->alloc_fd(fd);
return (fd == -1) ? -errno : process->alloc_fd(fd,path.c_str(),hostFlags,mode, false);
}