#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
(*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);
+}
--- /dev/null
+/* Server required for the flock() emulation under BeOS. */
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <hash_map.h>
+
+#include "beos_flock_server.h"
+
+/* debugging... */
+//#define PRINT(x) { printf x; }
+#define PRINT(x) ;
+
+/* flock() operation flags */
+#define LOCK_SH (0x00)
+#define LOCK_EX (0x01)
+#define LOCK_UN (0x02)
+#define LOCK_NB (0x04)
+
+enum {
+ MAX_WAITERS = 1024,
+ MAX_REPLY_SIZE = sizeof(flock_server_reply) + MAX_WAITERS * sizeof(sem_id)
+};
+
+/* A node_ref equivalent, so we don't need to link against libbe.so. */
+struct NodeRef {
+ NodeRef() : device(-1), node(-1) {}
+ NodeRef(dev_t device, ino_t node) : device(device), node(node) {}
+
+ NodeRef& operator=(const NodeRef& other)
+ {
+ device = other.device;
+ node = other.node;
+ return *this;
+ }
+
+ bool operator==(const NodeRef& other) const
+ {
+ return (device == other.device && node == other.node);
+ }
+
+ dev_t device;
+ ino_t node;
+};
+
+/* Class representing a (potential) lock. */
+struct FlockEntry {
+
+ FlockEntry(team_id team, sem_id lockSem, int fd, bool shared)
+ : team(team),
+ lockSem(lockSem),
+ fd(fd),
+ shared(shared),
+ next(NULL)
+ {
+ }
+
+ ~FlockEntry()
+ {
+ if (lockSem >= 0)
+ delete_sem(lockSem);
+ }
+
+ team_id team;
+ sem_id lockSem;
+ int fd;
+ bool shared;
+
+ FlockEntry *next;
+};
+
+struct NodeRefHash
+{
+ size_t operator()(const NodeRef &nodeRef) const
+ {
+ uint32 hash = nodeRef.device;
+ hash = hash * 17 + (uint32)nodeRef.node;
+ hash = hash * 17 + (uint32)(nodeRef.node >> 32);
+ return hash;
+ }
+};
+
+typedef hash_map<NodeRef, FlockEntry*, NodeRefHash> FlockEntryMap;
+static FlockEntryMap sFlockEntries;
+
+
+static status_t remove_lock(team_id team, flock_server_request &request,
+ flock_server_reply &reply);
+
+static void put_flock_entry(const NodeRef &nodeRef, FlockEntry *entry)
+{
+ sFlockEntries[nodeRef] = entry;
+}
+
+static void remove_flock_entry(const NodeRef &nodeRef)
+{
+ sFlockEntries.erase(nodeRef);
+}
+
+
+static FlockEntry *get_flock_entry(const NodeRef &nodeRef)
+{
+ FlockEntryMap::iterator it = sFlockEntries.find(nodeRef);
+ if (it == sFlockEntries.end())
+ return NULL;
+ FlockEntry *entry = it->second;
+
+ /* remove all entries that are obsolete */
+ FlockEntry *firstEntry = entry;
+ FlockEntry *previousEntry = NULL;
+ sem_info semInfo;
+ while (entry) {
+ if (get_sem_info(entry->lockSem, &semInfo) != B_OK) {
+ FlockEntry *oldEntry = entry;
+ entry = entry->next;
+ if (previousEntry)
+ previousEntry->next = oldEntry->next;
+ else
+ firstEntry = entry;
+ delete oldEntry;
+ } else {
+ previousEntry = entry;
+ entry = entry->next;
+ }
+ }
+ if (firstEntry)
+ put_flock_entry(nodeRef, firstEntry);
+ else
+ remove_flock_entry(nodeRef);
+
+ return firstEntry;
+}
+
+static FlockEntry *find_flock_entry(FlockEntry *entry, team_id team, int fd,
+ FlockEntry **_previousEntry = NULL)
+{
+ FlockEntry *previousEntry = NULL;
+ while (entry) {
+ if (entry->team == team && entry->fd == fd) {
+ /* found it */
+ if (_previousEntry)
+ *_previousEntry = previousEntry;
+ return entry;
+ }
+
+ previousEntry = entry;
+ entry = entry->next;
+ }
+ return entry;
+}
+
+static status_t add_lock(team_id team, flock_server_request &request,
+ flock_server_reply &reply)
+{
+ bool shared = (request.operation == LOCK_SH);
+
+ PRINT(("add_lock(): shared: %d, blocking: %d, file: (%ld, %lld), "
+ "team: %ld, fd: %d\n", shared, request.blocking, request.device,
+ request.node, team, request.fd));
+
+ // get the flock entry list
+ NodeRef nodeRef(request.device, request.node);
+
+ FlockEntry *entry = get_flock_entry(nodeRef);
+
+ reply.semaphoreCount = 0;
+
+ /* special case: the caller already has the lock */
+ if (entry && entry->team == team && entry->fd == request.fd) {
+ if (shared == entry->shared)
+ return B_OK;
+
+ FlockEntry *nextEntry = entry->next;
+ if (!nextEntry) {
+ /* noone is waiting: just relabel the entry */
+ entry->shared = shared;
+ delete_sem(request.lockSem); /* re-use the old semaphore */
+ return B_OK;
+ } else if (shared) {
+ /* downgrade to shared lock: this is simple, if only share or
+ * exclusive lockers were waiting, but in mixed case we can
+ * neither just replace the semaphore nor just relabel the entry,
+ * but if mixed we have to surrender the exclusive lock and apply
+ * for a new one */
+
+ /* check, if there are only exclusive lockers waiting */
+ FlockEntry *waiting = nextEntry;
+ bool onlyExclusiveWaiters = true;
+ while (waiting && onlyExclusiveWaiters) {
+ onlyExclusiveWaiters &= !waiting->shared;
+ waiting = waiting->next;
+ }
+
+ if (onlyExclusiveWaiters) {
+ /* just relabel the entry */
+ entry->shared = shared;
+ delete_sem(request.lockSem); /* re-use the old semaphore */
+ return B_OK;
+ }
+
+ /* check, if there are only shared lockers waiting */
+ waiting = nextEntry;
+ bool onlySharedWaiters = true;
+ while (waiting && onlySharedWaiters) {
+ onlySharedWaiters &= waiting->shared;
+ waiting = waiting->next;
+ }
+
+ if (onlySharedWaiters) {
+ /* replace the semaphore */
+ delete_sem(entry->lockSem);
+ entry->lockSem = request.lockSem;
+ entry->shared = shared;
+ return B_OK;
+ }
+
+ /* mixed waiters: fall through... */
+ } else {
+ /* upgrade to exclusive lock: fall through... */
+ }
+
+ /* surrender the lock and re-lock */
+ if (!request.blocking)
+ return B_WOULD_BLOCK;
+ flock_server_reply dummyReply;
+ remove_lock(team, request, dummyReply);
+ entry = nextEntry;
+
+ /* fall through... */
+ }
+
+ /* add the semaphores of the preceding exclusive locks to the reply */
+ FlockEntry* lastEntry = entry;
+ while (entry) {
+ if (!shared || !entry->shared) {
+ if (!request.blocking)
+ return B_WOULD_BLOCK;
+
+ reply.semaphores[reply.semaphoreCount++] = entry->lockSem;
+ }
+
+ lastEntry = entry;
+ entry = entry->next;
+ }
+
+ /* create a flock entry and add it */
+ FlockEntry *newEntry = new FlockEntry(team, request.lockSem, request.fd,
+ shared);
+ if (lastEntry)
+ lastEntry->next = newEntry;
+ else
+ put_flock_entry(nodeRef, newEntry);
+
+ return B_OK;
+}
+
+static status_t remove_lock(team_id team, flock_server_request &request,
+ flock_server_reply &reply)
+{
+ // get the flock entry list
+ NodeRef nodeRef(request.device, request.node);
+
+ PRINT(("remove_lock(): file: (%ld, %lld), team: %ld, fd: %d\n",
+ request.device, request.node, team, request.fd));
+
+ // find the entry to be removed
+ FlockEntry *previousEntry = NULL;
+ FlockEntry *entry = find_flock_entry(get_flock_entry(nodeRef), team,
+ request.fd, &previousEntry);
+
+ if (!entry)
+ return B_BAD_VALUE;
+
+ /* remove the entry */
+ if (previousEntry) {
+ previousEntry->next = entry->next;
+ } else {
+ if (entry->next) {
+ put_flock_entry(nodeRef, entry->next);
+ } else {
+ remove_flock_entry(nodeRef);
+ }
+ }
+ delete entry;
+ return B_OK;
+
+}
+
+int main(int argc, char** argv) {
+ /* get independent of our creator */
+ setpgid(0, 0);
+
+ /* create the request port */
+ port_id requestPort = create_port(10, FLOCK_SERVER_PORT_NAME);
+ if (requestPort < 0) {
+ fprintf(stderr, "Failed to create request port: %s\n",
+ strerror(requestPort));
+ exit(1);
+ }
+
+ /* Check whether we are the first instance of the server. We do this by
+ * iterating through all teams and check, whether another team has a
+ * port with the respective port name. */
+ {
+ /* get our team ID */
+ thread_info threadInfo;
+ get_thread_info(find_thread(NULL), &threadInfo);
+ team_id thisTeam = threadInfo.team;
+
+ /* iterate through all existing teams */
+ int32 teamCookie = 0;
+ team_info teamInfo;
+ while (get_next_team_info(&teamCookie, &teamInfo) == B_OK) {
+ /* skip our own team */
+ team_id team = teamInfo.team;
+ if (team == thisTeam)
+ continue;
+
+ /* iterate through the team's ports */
+ int32 portCookie = 0;
+ port_info portInfo;
+ while (get_next_port_info(team, &portCookie, &portInfo) == B_OK) {
+ if (strcmp(portInfo.name, FLOCK_SERVER_PORT_NAME) == 0) {
+ fprintf(stderr, "There's already a flock server running: "
+ "team: %ld\n", team);
+ delete_port(requestPort);
+ exit(1);
+ }
+ }
+ }
+
+ /* Our creator might have supplied a semaphore we shall delete, when
+ * we're initialized. Note that this is still supported here, but
+ * due to problems with pipes the server is no longer started from
+ * our flock() in libperl.so, so it is not really used anymore. */
+ if (argc >= 2) {
+ sem_id creatorSem = (argc >= 2 ? atol(argv[1]) : -1);
+
+ /* check whether the semaphore really exists and belongs to our team
+ (our creator has transferred it to us) */
+ sem_info semInfo;
+ if (creatorSem > 0 && get_sem_info(creatorSem, &semInfo) == B_OK
+ && semInfo.team == thisTeam) {
+ delete_sem(creatorSem);
+ }
+ }
+ }
+
+ /* main request handling loop */
+ while (true) {
+ /* read the request */
+ flock_server_request request;
+ int32 code;
+ ssize_t bytesRead = read_port(requestPort, &code, &request,
+ sizeof(request));
+ if (bytesRead != (int32)sizeof(request))
+ continue;
+
+ /* get the team */
+ port_info portInfo;
+ if (get_port_info(request.replyPort, &portInfo) != B_OK)
+ continue;
+ team_id team = portInfo.team;
+
+ char replyBuffer[MAX_REPLY_SIZE];
+ flock_server_reply &reply = *(flock_server_reply*)replyBuffer;
+
+ /* handle the request */
+ status_t error = B_ERROR;
+ switch (request.operation) {
+ case LOCK_SH:
+ case LOCK_EX:
+ error = add_lock(team, request, reply);
+ break;
+ case LOCK_UN:
+ error = remove_lock(team, request, reply);
+ break;
+ }
+
+ if (error == B_OK) {
+ PRINT((" -> successful\n"));
+ } else {
+ PRINT((" -> failed: %s\n", strerror(error)));
+ }
+
+ /* prepare the reply */
+ reply.error = error;
+ int32 replySize = sizeof(flock_server_reply);
+ if (error == B_OK)
+ replySize += reply.semaphoreCount * sizeof(sem_id) ;
+
+ /* send the reply */
+ write_port(request.replyPort, 0, &reply, replySize);
+ }
+
+ return 0;
+}
https://perl5.git.perl.org / perl5.git / commitdiff