crtools: Collect dumping fd parameters into one place

Introduce the fd_parms structure, that contains all we need to describe
open fd during dump -- its name (int), pos, flags and id. The read_fd_parms
routing fills one once and passes along the stack. This reduces the amount
of arguments significantly.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>

cr-dump.c

@@ -92,9 +92,15 @@ err_bogus_mapping:
 	goto err;
 }
 
-static int dump_one_reg_file(int type, unsigned long fd_name, int lfd,
-			     bool do_close, unsigned long pos, unsigned int flags,
-			     char *id, struct cr_fdset *cr_fdset)
+struct fd_parms {
+	unsigned long fd_name;
+	unsigned long pos;
+	unsigned int flags;
+	char *id;
+};
+
+static int dump_one_reg_file(int type, struct fd_parms *p, int lfd,
+		struct cr_fdset *cr_fdset, bool do_close)
 {
 	struct fdinfo_entry e;
 	char fd_str[128];
@@ -110,23 +116,23 @@ static int dump_one_reg_file(int type, unsigned long fd_name, int lfd,
 
 	big_buffer[len] = '\0';
 	pr_info("Dumping path for %lx fd via self %d [%s]\n",
-		fd_name, lfd, big_buffer);
+		p->fd_name, lfd, big_buffer);
 
 	if (do_close)
 		close(lfd);
 
 	e.type	= type;
 	e.len	= len;
-	e.flags = flags;
-	e.pos	= pos;
-	e.addr	= fd_name;
-	if (id)
-		memcpy(e.id, id, FD_ID_SIZE);
+	e.flags = p->flags;
+	e.pos	= p->pos;
+	e.addr	= p->fd_name;
+	if (p->id)
+		memcpy(e.id, p->id, FD_ID_SIZE);
 	else
 		memzero(e.id, FD_ID_SIZE);
 
 	pr_info("fdinfo: type: %2x len: %2x flags: %4x pos: %8x addr: %16lx\n",
-		type, len, flags, pos, fd_name);
+		type, len, p->flags, p->pos, p->fd_name);
 
 	write_ptr_safe(cr_fdset->fds[CR_FD_FDINFO], &e, err);
 	write_safe(cr_fdset->fds[CR_FD_FDINFO], big_buffer, e.len, err);
@@ -140,6 +146,12 @@ static int dump_cwd(char *path, struct cr_fdset *cr_fdset)
 {
 	int ret = -1;
 	int fd;
+	struct fd_parms p = {
+		.fd_name = ~0L,
+		.pos = 0,
+		.flags = 0,
+		.id = NULL,
+	};
 
 	fd = open(path, O_RDONLY | O_DIRECTORY);
 	if (fd < 0) {
@@ -147,7 +159,7 @@ static int dump_cwd(char *path, struct cr_fdset *cr_fdset)
 		return -1;
 	}
 
-	return dump_one_reg_file(FDINFO_FD, ~0L, fd, 1, 0, 0, NULL, cr_fdset);
+	return dump_one_reg_file(FDINFO_FD, &p, fd, cr_fdset, 1);
 }
 
 
@@ -205,19 +217,19 @@ err:
 	return ret;
 }
 
-static int dump_one_pipe(int fd, int lfd, unsigned int id, unsigned int flags,
-			 struct cr_fdset *cr_fdset)
+static int dump_one_pipe(struct fd_parms *p, unsigned int id, int lfd,
+		struct cr_fdset *cr_fdset)
 {
 	struct pipe_entry e;
 	int ret = -1;
 
-	pr_info("Dumping pipe %d/%x flags %x\n", fd, id, flags);
+	pr_info("Dumping pipe %d/%x flags %x\n", p->fd_name, id, p->flags);
 
-	e.fd		= fd;
+	e.fd		= p->fd_name;
 	e.pipeid	= id;
-	e.flags		= flags;
+	e.flags		= p->flags;
 
-	if (flags & O_WRONLY) {
+	if (p->flags & O_WRONLY) {
 		e.bytes = 0;
 		write_ptr_safe(cr_fdset->fds[CR_FD_PIPES], &e, err);
 		ret = 0;
@@ -229,29 +241,29 @@ err:
 		pr_info("Dumped pipe: fd: %8lx pipeid: %8lx flags: %8lx bytes: %8lx\n",
 			e.fd, e.pipeid, e.flags, e.bytes);
 	else
-		pr_err("Dumping pipe %d/%x flags %x\n", fd, id, flags);
+		pr_err("Dumping pipe %d/%x flags %x\n", p->fd_name, id, p->flags);
 
 	return ret;
 }
 
-static int dump_one_fd(char *pid_fd_dir, int lfd, int fd, unsigned long pos,
-		       unsigned int flags, char *id, struct cr_fdset *cr_fdset)
+static int dump_one_fd(char *pid_fd_dir, int lfd,
+		struct fd_parms *p, struct cr_fdset *cr_fdset)
 {
 	struct statfs stfs_buf;
 	struct stat st_buf;
 	int err = -1;
 
 	if (lfd < 0) {
-		err = try_dump_socket(pid_fd_dir, fd, cr_fdset);
+		err = try_dump_socket(pid_fd_dir, p->fd_name, cr_fdset);
 		if (err != 1)
 			return err;
 
-		pr_perror("Failed to openat %s/%d\n", pid_fd_dir, fd);
+		pr_perror("Failed to open %s/%d\n", pid_fd_dir, p->fd_name);
 		return -1;
 	}
 
 	if (fstat(lfd, &st_buf) < 0) {
-		pr_perror("Can't get stat on %d\n", fd);
+		pr_perror("Can't get stat on %d\n", p->fd_name);
 		goto out_close;
 	}
 
@@ -259,9 +271,9 @@ static int dump_one_fd(char *pid_fd_dir, int lfd, int fd, unsigned long pos,
 	    (major(st_buf.st_rdev) == TTY_MAJOR ||
 	     major(st_buf.st_rdev) == UNIX98_PTY_SLAVE_MAJOR)) {
 		/* skip only standard destriptors */
-		if (fd < 3) {
+		if (p->fd_name < 3) {
 			err = 0;
-			pr_info("... Skipping tty ... %s/%d\n", pid_fd_dir, fd);
+			pr_info("... Skipping tty ... %s/%d\n", pid_fd_dir, p->fd_name);
 			goto out_close;
 		}
 		goto err;
@@ -270,30 +282,27 @@ static int dump_one_fd(char *pid_fd_dir, int lfd, int fd, unsigned long pos,
 	if (S_ISREG(st_buf.st_mode) ||
 	    S_ISDIR(st_buf.st_mode) ||
 	    (S_ISCHR(st_buf.st_mode) && major(st_buf.st_rdev) == MEM_MAJOR))
-		return dump_one_reg_file(FDINFO_FD, fd,
-					 lfd, 1, pos, flags, id, cr_fdset);
+		return dump_one_reg_file(FDINFO_FD, p, lfd, cr_fdset, 1);
 
 	if (S_ISFIFO(st_buf.st_mode)) {
 		if (fstatfs(lfd, &stfs_buf) < 0) {
-			pr_perror("Can't fstatfs on %d\n", fd);
+			pr_perror("Can't fstatfs on %d\n", p->fd_name);
 			return -1;
 		}
 
 		if (stfs_buf.f_type == PIPEFS_MAGIC)
-			return dump_one_pipe(fd, lfd,
-					     st_buf.st_ino, flags, cr_fdset);
+			return dump_one_pipe(p, st_buf.st_ino, lfd, cr_fdset);
 	}
 
 err:
-	pr_err("Can't dump file %d of that type [%x]\n", fd, st_buf.st_mode);
+	pr_err("Can't dump file %d of that type [%x]\n", p->fd_name, st_buf.st_mode);
 
 out_close:
 	close_safe(&lfd);
 	return err;
 }
 
-static int read_fd_params(pid_t pid, char *fd, unsigned long *pos,
-					unsigned int *flags, char *id)
+static int read_fd_params(pid_t pid, char *fd, struct fd_parms *p)
 {
 	FILE *file;
 	unsigned int f;
@@ -304,11 +313,12 @@ static int read_fd_params(pid_t pid, char *fd, unsigned long *pos,
 		return -1;
 	}
 
-	fscanf(file, "pos:\t%li\nflags:\t%o\nid:\t%s\n", pos, flags, id);
+	p->fd_name = atoi(fd);
+	fscanf(file, "pos:\t%li\nflags:\t%o\nid:\t%s\n", &p->pos, &p->flags, p->id);
 	fclose(file);
 
 	pr_info("%d fdinfo %s: pos: %16lx flags: %16o id %s\n",
-					pid, fd, *pos, *flags, id);
+					pid, fd, p->pos, p->flags, p->id);
 
 	return 0;
 }
@@ -319,7 +329,6 @@ static int dump_task_files(pid_t pid, struct cr_fdset *cr_fdset)
 	struct dirent *de;
 	unsigned long pos;
 	unsigned int flags;
-	char id[FD_ID_SIZE];
 	DIR *fd_dir;
 
 	pr_info("\n");
@@ -340,16 +349,17 @@ static int dump_task_files(pid_t pid, struct cr_fdset *cr_fdset)
 	}
 
 	while ((de = readdir(fd_dir))) {
+		char id[FD_ID_SIZE];
+		struct fd_parms p = { .id = id };
 		int lfd;
 
 		if (de->d_name[0] == '.')
 			continue;
-		if (read_fd_params(pid, de->d_name, &pos, &flags, id))
+		if (read_fd_params(pid, de->d_name, &p))
 			return -1;
 
 		lfd = openat(dirfd(fd_dir), de->d_name, O_RDONLY);
-		if (dump_one_fd(pid_fd_dir, lfd, atoi(de->d_name),
-						pos, flags, id, cr_fdset))
+		if (dump_one_fd(pid_fd_dir, lfd, &p, cr_fdset))
 			return -1;
 	}
 
@@ -392,20 +402,19 @@ static int dump_task_mappings(pid_t pid, struct list_head *vma_area_list, struct
 				write_ptr_safe(cr_fdset->fds[CR_FD_SHMEM], &e, err);
 			} else if (vma_entry_is(vma, VMA_FILE_PRIVATE) ||
 				   vma_entry_is(vma, VMA_FILE_SHARED)) {
-
-				unsigned int flags;
+				struct fd_parms p = {
+					.fd_name = vma->start,
+					.pos = 0,
+					.id = NULL,
+				};
 
 				if (vma->prot & PROT_WRITE &&
 				    vma_entry_is(vma, VMA_FILE_SHARED))
-					flags = O_RDWR;
+					p.flags = O_RDWR;
 				else
-					flags = O_RDONLY;
+					p.flags = O_RDONLY;
 
-				ret = dump_one_reg_file(FDINFO_MAP,
-							vma->start,
-							vma_area->vm_file_fd,
-							0, 0, flags, NULL,
-							cr_fdset);
+				ret = dump_one_reg_file(FDINFO_MAP, &p, vma_area->vm_file_fd, cr_fdset, 0);
 				if (ret)
 					goto err;
 			}