files: Rework the way fdinfos are collected

Now fdinfos are collected independently from reg files and
sockets. During tihs collect we effectively create the mirroring
list of both by checking which type-IDs are added first.

Fix this by removing the fdinfo_desc and attaching fds directly
to collected reg files and sockets. Pipes and unix sockets will
be reworked in the same manner soon.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

files.c

@@ -21,9 +21,6 @@
 #include "lock.h"
 #include "sockets.h"
 
-static struct fdinfo_desc *fdinfo_descs;
-static int nr_fdinfo_descs;
-
 static struct fdinfo_list_entry *fdinfo_list;
 static int nr_fdinfo_list;
 
@@ -31,12 +28,6 @@ static struct fmap_fd *fmap_fds;
 
 int prepare_shared_fdinfo(void)
 {
-	fdinfo_descs = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, 0, 0);
-	if (fdinfo_descs == MAP_FAILED) {
-		pr_perror("Can't map fdinfo_descs");
-		return -1;
-	}
-
 	fdinfo_list = mmap(NULL, 4096, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, 0, 0);
 	if (fdinfo_list == MAP_FAILED) {
 		pr_perror("Can't map fdinfo_list");
@@ -45,24 +36,11 @@ int prepare_shared_fdinfo(void)
 	return 0;
 }
 
-static struct fdinfo_desc *find_fd(struct fdinfo_entry *fe)
-{
-	struct fdinfo_desc *fi;
-	int i;
-
-	for (i = 0; i < nr_fdinfo_descs; i++) {
-		fi = fdinfo_descs + i;
-		if ((fi->id == fe->id) && (fi->type == fe->type))
-			return fi;
-	}
-
-	return NULL;
-}
-
 struct reg_file_info {
 	struct reg_file_entry rfe;
 	char *path;
 	struct list_head list;
+	struct list_head fd_head;
 };
 
 #define REG_FILES_HSIZE	32
@@ -80,6 +58,14 @@ static struct reg_file_info *find_reg_file(int id)
 	return NULL;
 }
 
+static struct list_head *find_reg_fd(int id)
+{
+	struct reg_file_info *rfi;
+
+	rfi = find_reg_file(id);
+	return &rfi->fd_head;
+}
+
 int collect_reg_files(void)
 {
 	struct reg_file_info *rfi = NULL;
@@ -118,6 +104,7 @@ int collect_reg_files(void)
 		rfi->path[len] = '\0';
 
 		pr_info("Collected [%s] ID %x\n", rfi->path, rfi->rfe.id);
+		INIT_LIST_HEAD(&rfi->fd_head);
 		chain = rfi->rfe.id % REG_FILES_HSIZE;
 		list_add_tail(&rfi->list, &reg_files[chain]);
 	}
@@ -131,11 +118,29 @@ int collect_reg_files(void)
 	return ret;
 }
 
+static int collect_fd_reg(int id, struct fdinfo_list_entry *le)
+{
+	struct reg_file_info *rfi;
+	struct fdinfo_list_entry *l;
+
+	rfi = find_reg_file(id);
+	if (rfi == NULL) {
+		pr_err("No file for fd %d, id %d\n", le->fd, id);
+		return -1;
+	}
+
+	list_for_each_entry(l, &rfi->fd_head, list)
+		if (l->pid > le->pid)
+			break;
+
+	list_add_tail(&le->list, &l->list);
+	return 0;
+}
+
 static int collect_fd(int pid, struct fdinfo_entry *e)
 {
 	int i;
 	struct fdinfo_list_entry *le = &fdinfo_list[nr_fdinfo_list];
-	struct fdinfo_desc *desc;
 
 	pr_info("Collect fdinfo pid=%d fd=%ld id=%16x\n",
 		pid, e->addr, e->id);
@@ -148,44 +153,15 @@ static int collect_fd(int pid, struct fdinfo_entry *e)
 
 	le->pid = pid;
 	le->fd = e->addr;
-
 	futex_init(&le->real_pid);
 
-	for (i = 0; i < nr_fdinfo_descs; i++) {
-		desc = &fdinfo_descs[i];
-
-		if ((desc->id != e->id) || (desc->type != e->type))
-			continue;
+	if (e->type == FDINFO_REG)
+		return collect_fd_reg(e->id, le);
+	if (e->type == FDINFO_INETSK)
+		return collect_fd_inetsk(e->id, le);
 
-		list_add(&le->list, &desc->list);
-
-		if (fdinfo_descs[i].pid < pid)
-			return 0;
-
-		desc->pid = pid;
-		desc->addr = e->addr;
-
-		return 0;
-	}
-
-	if ((nr_fdinfo_descs + 1) * sizeof(struct fdinfo_desc) >= 4096) {
-		pr_err("OOM storing fdinfo descriptions\n");
-		return -1;
-	}
-
-	desc = &fdinfo_descs[nr_fdinfo_descs];
-	memzero(desc, sizeof(*desc));
-
-	desc->id	= e->id;
-	desc->type	= e->type;
-	desc->addr	= e->addr;
-	desc->pid	= pid;
-	INIT_LIST_HEAD(&desc->list);
-
-	list_add(&le->list, &desc->list);
-	nr_fdinfo_descs++;
-
-	return 0;
+	BUG_ON(1);
+	return -1;
 }
 
 int prepare_fd_pid(int pid)
@@ -282,12 +258,12 @@ static int restore_exe_early(struct fdinfo_entry *fe, int fd)
 	return reopen_fd_as(self_exe_fd, tmp);
 }
 
-struct fdinfo_list_entry *find_fdinfo_list_entry(int pid, int fd, struct fdinfo_desc *fi)
+struct fdinfo_list_entry *find_fdinfo_list_entry(int pid, int fd, struct list_head *fd_list)
 {
 	struct fdinfo_list_entry *fle;
 	int found = 0;
 
-	list_for_each_entry(fle, &fi->list, list) {
+	list_for_each_entry(fle, fd_list, list) {
 		if (fle->fd == fd && fle->pid == pid) {
 			found = 1;
 			break;
@@ -307,22 +283,31 @@ static inline void transport_name_gen(struct sockaddr_un *addr, int *len,
 	*addr->sun_path = '\0';
 }
 
-static int open_transport_fd(int pid, struct fdinfo_entry *fe,
-				struct fdinfo_desc *fi)
+static struct fdinfo_list_entry *file_master(struct list_head *fd_list)
+{
+	return list_first_entry(fd_list, struct fdinfo_list_entry, list);
+}
+
+static int open_transport_fd(int pid, struct fdinfo_entry *fe, struct list_head *fd_list)
 {
 	struct fdinfo_list_entry *fle;
 	struct sockaddr_un saddr;
 	int sock;
 	int ret, sun_len;
 
-	if (fi->pid == pid)
+	fle = file_master(fd_list);
+	if (fle->pid == pid)
 		return 0;
 
 	transport_name_gen(&saddr, &sun_len, getpid(), fe->addr);
 
 	pr_info("\t%d: Create transport fd for %lx\n", pid, fe->addr);
 
-	fle = find_fdinfo_list_entry(pid, fe->addr, fi);
+	list_for_each_entry(fle, fd_list, list)
+		if ((fle->pid == pid) && (fle->fd == fe->addr))
+			break;
+
+	BUG_ON(fd_list == &fle->list);
 
 	sock = socket(PF_UNIX, SOCK_DGRAM, 0);
 	if (sock < 0) {
@@ -346,14 +331,15 @@ static int open_transport_fd(int pid, struct fdinfo_entry *fe,
 }
 
 static int open_fd(int pid, struct fdinfo_entry *fe,
-				struct fdinfo_desc *fi, int fdinfo_fd)
+		struct list_head *fd_list, int fdinfo_fd)
 {
 	int tmp;
 	int serv, sock;
 	struct sockaddr_un saddr;
 	struct fdinfo_list_entry *fle;
 
-	if ((fi->pid != pid) || (fe->addr != fi->addr))
+	fle = file_master(fd_list);
+	if ((fle->pid != pid) || (fe->addr != fle->fd))
 		return 0;
 
 	switch (fe->type) {
@@ -374,9 +360,6 @@ static int open_fd(int pid, struct fdinfo_entry *fe,
 	if (reopen_fd_as((int)fe->addr, tmp))
 		return -1;
 
-	if (list_empty(&fi->list))
-		goto out;
-
 	sock = socket(PF_UNIX, SOCK_DGRAM, 0);
 	if (sock < 0) {
 		pr_perror("Can't create socket");
@@ -385,7 +368,7 @@ static int open_fd(int pid, struct fdinfo_entry *fe,
 
 	pr_info("\t%d: Create fd for %lx\n", pid, fe->addr);
 
-	list_for_each_entry(fle, &fi->list, list) {
+	list_for_each_entry(fle, fd_list, list) {
 		int len;
 
 		if (pid == fle->pid)
@@ -408,16 +391,19 @@ out:
 	return 0;
 }
 
-static int receive_fd(int pid, struct fdinfo_entry *fe, struct fdinfo_desc *fi)
+static int receive_fd(int pid, struct fdinfo_entry *fe, struct list_head *fd_list)
 {
 	int tmp;
+	struct fdinfo_list_entry *fle;
 
-	if (fi->pid == pid) {
-		if (fi->addr != fe->addr) {
-			tmp = dup2(fi->addr, fe->addr);
+	fle = file_master(fd_list);
+
+	if (fle->pid == pid) {
+		if (fle->fd != fe->addr) {
+			tmp = dup2(fle->fd, fe->addr);
 			if (tmp < 0) {
-				pr_perror("Can't duplicate fd %ld %ld",
-						fi->addr, fe->addr);
+				pr_perror("Can't duplicate fd %d %ld",
+						fle->fd, fe->addr);
 				return -1;
 			}
 		}
@@ -464,12 +450,24 @@ static int open_fmap(int pid, struct fdinfo_entry *fe, int fd)
 	return 0;
 }
 
+static struct list_head *find_fi_list(struct fdinfo_entry *fe)
+{
+	if (fe->type == FDINFO_REG)
+		return find_reg_fd(fe->id);
+	if (fe->type == FDINFO_INETSK)
+		return find_inetsk_fd(fe->id);
+
+	BUG_ON(1);
+	return NULL;
+}
+
 static int open_fdinfo(int pid, struct fdinfo_entry *fe, int *fdinfo_fd, int state)
 {
 	u32 mag;
 	int ret = 0;
-	struct fdinfo_desc *fi = find_fd(fe);
+	struct list_head *fi_list;
 
+	fi_list = find_fi_list(fe);
 	if (move_img_fd(fdinfo_fd, (int)fe->addr))
 		return -1;
 
@@ -479,13 +477,13 @@ static int open_fdinfo(int pid, struct fdinfo_entry *fe, int *fdinfo_fd, int sta
 
 	switch (state) {
 	case FD_STATE_PREP:
-		ret = open_transport_fd(pid, fe, fi);
+		ret = open_transport_fd(pid, fe, fi_list);
 		break;
 	case FD_STATE_CREATE:
-		ret = open_fd(pid, fe, fi, *fdinfo_fd);
+		ret = open_fd(pid, fe, fi_list, *fdinfo_fd);
 		break;
 	case FD_STATE_RECV:
-		ret = receive_fd(pid, fe, fi);
+		ret = receive_fd(pid, fe, fi_list);
 		break;
 	}
 

include/files.h

@@ -32,14 +32,6 @@ struct fmap_fd {
 	int			fd;
 };
 
-struct fdinfo_desc {
-	u32			id;
-	u32			type;
-	u64			addr;
-	int			pid;
-	struct list_head	list;
-};
-
 struct fdinfo_list_entry {
 	struct list_head	list;
 	int			fd;

include/sockets.h

@@ -10,6 +10,9 @@ struct fd_parms;
 extern int dump_socket(struct fd_parms *p, int lfd,
 		const struct cr_fdset *cr_fdset);
 
+struct fdinfo_list_entry;
+int collect_fd_inetsk(int id, struct fdinfo_list_entry *le);
+struct list_head *find_inetsk_fd(int id);
 extern int collect_sockets(void);
 extern int collect_inet_sockets(void);
 extern int collect_unix_sockets(int pid);

sockets.c

@@ -1241,6 +1241,7 @@ static int prepare_unix_sockets(int pid)
 struct inet_sk_info {
 	struct inet_sk_entry ie;
 	struct list_head list;
+	struct list_head fd_head;
 };
 
 #define INET_SK_HSIZE	32
@@ -1258,6 +1259,33 @@ static struct inet_sk_info *find_inet_sk(int id)
 	return NULL;
 }
 
+struct list_head *find_inetsk_fd(int id)
+{
+	struct inet_sk_info *ii;
+
+	ii = find_inet_sk(id);
+	return &ii->fd_head;
+}
+
+int collect_fd_inetsk(int id, struct fdinfo_list_entry *le)
+{
+	struct inet_sk_info *ii;
+	struct fdinfo_list_entry *l;
+
+	ii = find_inet_sk(id);
+	if (ii == NULL) {
+		pr_err("No inet socket for %d id %d\n", le->fd, id);
+		return -1;
+	}
+
+	list_for_each_entry(l, &ii->fd_head, list)
+		if (l->pid > le->pid)
+			break;
+
+	list_add_tail(&le->list, &l->list);
+	return 0;
+}
+
 int collect_inet_sockets(void)
 {
 	struct inet_sk_info *ii = NULL;
@@ -1280,6 +1308,7 @@ int collect_inet_sockets(void)
 		if (ret <= 0)
 			break;
 
+		INIT_LIST_HEAD(&ii->fd_head);
 		chain = ii->ie.id % INET_SK_HSIZE;
 		list_add_tail(&ii->list, &inet_sockets[chain]);
 	}