mm: Move exe file id on mm_entry

This is mm_struct entity, so save one there. Also gets rid
of special FDINFO-s.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

cr-dump.c

@@ -343,22 +343,26 @@ static int dump_one_fdinfo(struct fd_parms *p, int lfd,
 	return do_dump_one_fdinfo(p, lfd, cr_fdset);
 }
 
-static int dump_task_special_files(pid_t pid, const struct cr_fdset *cr_fdset)
+static int dump_task_exe_link(pid_t pid, struct mm_entry *mm)
 {
 	struct fd_parms params;
 	int fd, ret;
 
-	/* Dump /proc/pid/exe */
-	params = (struct fd_parms) {
-		.id		= FD_ID_INVALID,
-		.pid		= FD_PID_INVALID,
-		.type		= FDINFO_EXE,
-	};
-
 	fd = open_proc(pid, "exe");
 	if (fd < 0)
 		return -1;
-	ret = do_dump_one_fdinfo(&params, fd, cr_fdset);
+
+	if (fstat(fd, &params.stat) < 0) {
+		pr_perror("Can't fstat exe link");
+		return -1;
+	}
+
+	params.type = FDINFO_REG;
+	params.flags = 0;
+	params.pos = 0;
+	mm->exe_file_id = fd_id_generate_special();
+
+	ret = dump_one_reg_file(fd, mm->exe_file_id, &params);
 	close(fd);
 
 	return ret;
@@ -449,17 +453,6 @@ static int dump_task_files_seized(struct parasite_ctl *ctl, const struct cr_fdse
 	if (ret)
 		goto err;
 
-	/*
-	 * Dump special files at the beginning. We might need
-	 * to re-read them in restorer, so better to make it
-	 * fast.
-	 */
-	ret = dump_task_special_files(ctl->pid, cr_fdset);
-	if (ret) {
-		pr_err("Can't dump special files\n");
-		goto err;
-	}
-
 	for (i = 0; i < nr_fds; i++) {
 		ret = dump_one_fd(ctl->pid, fds[i], lfds[i], cr_fdset);
 		close(lfds[i]);
@@ -734,6 +727,9 @@ static int dump_task_mm(pid_t pid, const struct proc_pid_stat *stat,
 	if (get_task_auxv(pid, &mme))
 		return -1;
 
+	if (dump_task_exe_link(pid, &mme))
+		return -1;
+
 	return write_img(fdset_fd(fdset, CR_FD_MM), &mme);
 }
 

cr-restore.c

@@ -1028,7 +1028,7 @@ static struct vma_entry *vma_list_remap(void *addr, unsigned long len, struct li
 
 static int prepare_mm(pid_t pid, struct task_restore_core_args *args)
 {
-	int fd;
+	int fd, exe_fd;
 
 	fd = open_image_ro(CR_FD_MM, pid);
 	if (fd < 0)
@@ -1037,6 +1037,12 @@ static int prepare_mm(pid_t pid, struct task_restore_core_args *args)
 	if (read_img(fd, &args->mm) < 0)
 		return -1;
 
+	exe_fd = open_reg_by_id(args->mm.exe_file_id);
+	if (exe_fd < 0)
+		return -1;
+
+	args->fd_exe_link = exe_fd;
+
 	close(fd);
 	return 0;
 }
@@ -1209,7 +1215,6 @@ static int sigreturn_restore(pid_t pid, struct list_head *tgt_vmas, int nr_vmas)
 	task_args->fd_core	= fd_core;
 	task_args->logfd	= log_get_fd();
 	task_args->sigchld_act	= sigchld_act;
-	task_args->fd_exe_link	= self_exe_fd;
 	task_args->fd_pages	= fd_pages;
 
 	ret = prepare_itimers(pid, task_args);

cr-show.c

@@ -59,7 +59,6 @@ static char *fdtype2s(u8 type)
 	static char und[4];
 	static char *fdtypes[] = {
 		[FDINFO_REG] = "reg",
-		[FDINFO_EXE] = "exe",
 		[FDINFO_INETSK] = "isk",
 		[FDINFO_PIPE] = "pipe",
 		[FDINFO_UNIXSK] = "usk",
@@ -523,6 +522,7 @@ void show_mm(int fd_mm, struct cr_options *o)
 	pr_msg("\tArg end:      %lx\n", mme.mm_arg_end);
 	pr_msg("\tEnv start:    %lx\n", mme.mm_env_start);
 	pr_msg("\tEnv end:      %lx\n", mme.mm_env_end);
+	pr_msg("\tExe file ID   %x\n", mme.exe_file_id);
 out:
 	pr_img_tail(CR_FD_MM);
 }

files.c

@@ -245,6 +245,19 @@ static int open_fe_fd(struct file_desc *d)
 
 	return tmp;
 }
+int open_reg_by_id(u32 id)
+{
+	struct file_desc *fd;
+
+	fd = find_file_desc_raw(FDINFO_REG, id);
+	if (fd == NULL) {
+		pr_perror("Can't find regfile for %x\n", id);
+		return -1;
+	}
+
+	return open_fe_fd(fd);
+}
+
 static int find_open_fe_fd(struct fdinfo_entry *fe)
 {
 	struct reg_file_info *rfi;
@@ -259,29 +272,6 @@ static int find_open_fe_fd(struct fdinfo_entry *fe)
 	return open_fe_fd(&rfi->d);
 }
 
-int self_exe_fd;
-
-static int restore_exe_early(struct fdinfo_entry *fe, int fd)
-{
-	int tmp;
-
-	/*
-	 * We restore the EXE symlink at very late stage
-	 * because of restrictions applied from kernel side,
-	 * so keep this fd open till then.
-	 */
-
-	self_exe_fd = get_service_fd(SELF_EXE_FD_OFF);
-	if (self_exe_fd < 0)
-		return self_exe_fd;
-
-	tmp = find_open_fe_fd(fe);
-	if (tmp < 0)
-		return tmp;
-
-	return reopen_fd_as(self_exe_fd, tmp);
-}
-
 static void transport_name_gen(struct sockaddr_un *addr, int *len,
 		int pid, long fd)
 {
@@ -476,9 +466,6 @@ static int open_special_fdinfo(int pid, struct fdinfo_entry *fe,
 	if (state != FD_STATE_RECV)
 		return 0;
 
-	if (fe->type == FDINFO_EXE)
-		return restore_exe_early(fe, fdinfo_fd);
-
 	pr_info("%d: fe->type: %d\n", pid,  fe->type);
 	BUG_ON(1);
 	return -1;

include/files.h

@@ -67,6 +67,7 @@ extern int prepare_fd_pid(int pid);
 extern int prepare_shared_fdinfo(void);
 extern int get_filemap_fd(int pid, struct vma_entry *vma_entry);
 extern int prepare_fs(int pid);
+extern int open_reg_by_id(u32 id);
 
 extern int self_exe_fd;
 

include/image.h

@@ -39,7 +39,6 @@ enum fd_types {
 	FDINFO_PIPE,
 	FDINFO_INETSK,
 	FDINFO_UNIXSK,
-	FDINFO_EXE,
 
 	FD_INFO_MAX
 };
@@ -62,7 +61,7 @@ struct fdinfo_entry {
 	u32	id;
 } __packed;
 
-#define fd_is_special(fe) ((fe)->type == FDINFO_EXE)
+#define fd_is_special(fe) (0)
 
 struct fs_entry {
 	u32	cwd_id;
@@ -370,6 +369,7 @@ struct mm_entry {
 	u64	mm_env_start;
 	u64	mm_env_end;
 	u64	mm_saved_auxv[AT_VECTOR_SIZE];
+	u32	exe_file_id;
 } __packed;
 
 struct core_entry {