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#include "beos/beosish.h"
#include "beos/beos_flock_server.h"
#undef waitpid
#undef close
#undef kill
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
#include <OS.h>
/* We cache, for which FDs we got a lock. This will especially speed up close(),
since we won't have to contact the server. */
#define FLOCK_TABLE_SIZE 256
static int flockTable[FLOCK_TABLE_SIZE];
/* In BeOS 5.0 the waitpid() seems to misbehave in that the status
* has the upper and lower bytes swapped compared with the usual
* POSIX/UNIX implementations. To undo the surpise effect to the
* rest of Perl we need this wrapper. (The rest of BeOS might be
* surprised because of this, though.) */
pid_t beos_waitpid(pid_t process_id, int *status_location, int options) {
pid_t got = waitpid(process_id, status_location, options);
if (status_location)
*status_location =
(*status_location & 0x00FF) << 8 |
(*status_location & 0xFF00) >> 8;
return got;
}
/* The flock() emulation worker function. */
static status_t beos_flock(int fd, int operation) {
static int serverPortInitialized = 0;
static port_id serverPort = -1;
struct stat st;
int blocking;
port_id replyPort;
sem_id lockSem = -1;
status_t error;
flock_server_request request;
flock_server_reply *reply = NULL;
if (fd < 0)
return B_BAD_VALUE;
blocking = !(operation & LOCK_NB);
operation &= LOCK_SH | LOCK_EX | LOCK_UN;
/* don't try to unlock something that isn't locked */
if (operation == LOCK_UN && fd < FLOCK_TABLE_SIZE && !flockTable[fd])
return B_OK;
/* if not yet initialized, get the server port */
if (!serverPortInitialized) {
serverPort = find_port(FLOCK_SERVER_PORT_NAME);
/* bonefish: If the port wasn't present at this point, we could start
* the server. In fact, I tried this and in works, but unfortunately
* it also seems to confuse our pipes (with both load_image() and
* system()). So, we can't help it, the server has to be started
* manually. */
serverPortInitialized = ~0;
}
if (serverPort < 0)
return B_ERROR;
/* stat() the file to get the node_ref */
if (fstat(fd, &st) < 0)
return errno;
/* create a reply port */
replyPort = create_port(1, "flock reply port");
if (replyPort < 0)
return replyPort;
/* create a semaphore others will wait on while we own the lock */
if (operation != LOCK_UN) {
char semName[64];
sprintf(semName, "flock %ld:%lld\n", st.st_dev, st.st_ino);
lockSem = create_sem(0, semName);
if (lockSem < 0) {
delete_port(replyPort);
return lockSem;
}
}
/* prepare the request */
request.replyPort = replyPort;
request.lockSem = lockSem;
request.device = st.st_dev;
request.node = st.st_ino;
request.fd = fd;
request.operation = operation;
request.blocking = blocking;
/* We ask the server to get us the requested lock for the file.
* The server returns semaphores for all existing locks (or will exist
* before it's our turn) that prevent us from getting the lock just now.
* We block on them one after the other and after that officially own the
* lock. If we told the server that we don't want to block, it will send
* an error code, if that is not possible. */
/* send the request */
error = write_port(serverPort, 0, &request, sizeof(request));
if (error == B_OK) {
/* get the reply size */
int replySize = port_buffer_size(replyPort);
if (replySize < 0)
error = replySize;
/* allocate reply buffer */
if (error == B_OK) {
reply = (flock_server_reply*)malloc(replySize);
if (!reply)
error = B_NO_MEMORY;
}
/* read the reply */
if (error == B_OK) {
int32 code;
ssize_t bytesRead = read_port(replyPort, &code, reply, replySize);
if (bytesRead < 0) {
error = bytesRead;
} else if (bytesRead != replySize) {
error = B_ERROR;
}
}
}
/* get the error returned by the server */
if (error == B_OK)
error = reply->error;
/* wait for all lockers before us */
if (error == B_OK) {
int i;
for (i = 0; i < reply->semaphoreCount; i++)
while (acquire_sem(reply->semaphores[i]) == B_INTERRUPTED);
}
/* free the reply buffer */
free(reply);
/* delete the reply port */
delete_port(replyPort);
/* on failure delete the semaphore */
if (error != B_OK)
delete_sem(lockSem);
/* update the entry in the flock table */
if (error == B_OK && fd < FLOCK_TABLE_SIZE) {
if (operation == LOCK_UN)
flockTable[fd] = 0;
else
flockTable[fd] = 1;
}
return error;
}
/* We implement flock() using a server. It is not really compliant with, since
* it would be very hard to track dup()ed FDs and those cloned as side-effect
* of fork(). Our locks are bound to the process (team) and a particular FD.
* I.e. a lock acquired by a team using a FD can only be unlocked by the same
* team using exactly the same FD (no other one pointing to the same file, not
* even when dup()ed from the original one). close()ing the FD releases the
* lock (that's why we need to override close()). On termination of the team
* all locks owned by the team will automatically be released. */
int flock(int fd, int operation) {
status_t error = beos_flock(fd, operation);
return (error == B_OK ? 0 : (errno = error, -1));
}
/* We need to override close() to release a potential lock on the FD. See
flock() for details */
int beos_close(int fd) {
flock(fd, LOCK_UN);
return close(fd);
}
/* BeOS kill() doesn't like the combination of the pseudo-signal 0 and
* specifying a process group (i.e. pid < -1 || pid == 0). We work around
* by changing pid to the respective process group leader. That should work
* well enough in most cases. */
int beos_kill(pid_t pid, int sig)
{
if (sig == 0) {
if (pid == 0) {
/* it's our process group */
pid = getpgrp();
} else if (pid < -1) {
/* just address the process group leader */
pid = -pid;
}
}
return kill(pid, sig);
}
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