/* * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public * License v2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public * License along with this program; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 021110-1307, USA. */ #include "kerncompat.h" #include <unistd.h> #include <fcntl.h> #include <uuid/uuid.h> #include "common/sysfs-utils.h" #include "common/path-utils.h" #include "common/utils.h" /* * Open a file in fsid directory in sysfs and return the file descriptor or * error */ static int sysfs_open_fsid_file_flags(int fd, const char *filename, int flags) { u8 fsid[BTRFS_UUID_SIZE]; char fsid_str[BTRFS_UUID_UNPARSED_SIZE]; char sysfs_file[PATH_MAX]; int ret; ret = get_fsid_fd(fd, fsid); if (ret < 0) return ret; uuid_unparse(fsid, fsid_str); ret = path_cat3_out(sysfs_file, "/sys/fs/btrfs", fsid_str, filename); if (ret < 0) return ret; ret = open(sysfs_file, flags); return (ret < 0 ? -errno : ret); } int sysfs_open_fsid_file(int fd, const char *filename) { return sysfs_open_fsid_file_flags(fd, filename, O_RDONLY); } int sysfs_open_fsid_file_rw(int fd, const char *filename) { return sysfs_open_fsid_file_flags(fd, filename, O_RDWR); } /* * Open a file in the toplevel sysfs directory and return the file descriptor * or error. */ static int sysfs_open_file_flags(const char *name, int flags) { char path[PATH_MAX]; int ret; ret = path_cat_out(path, "/sys/fs/btrfs", name); if (ret < 0) return ret; ret = open(path, flags); return (ret < 0 ? -errno : ret); } int sysfs_open_file(const char *name) { return sysfs_open_file_flags(name, O_RDONLY); } int sysfs_open_file_rw(const char *name) { return sysfs_open_file_flags(name, O_RDWR); } /* * Open a directory by name in fsid directory in sysfs and return the file * descriptor or error, filedescriptor suitable for fdreaddir. The @dirname * must be a directory name. */ int sysfs_open_fsid_dir(int fd, const char *dirname) { u8 fsid[BTRFS_UUID_SIZE]; char fsid_str[BTRFS_UUID_UNPARSED_SIZE]; char sysfs_file[PATH_MAX]; int ret; ret = get_fsid_fd(fd, fsid); if (ret < 0) return ret; uuid_unparse(fsid, fsid_str); ret = path_cat3_out(sysfs_file, "/sys/fs/btrfs", fsid_str, dirname); if (ret < 0) return ret; ret = open(sysfs_file, O_DIRECTORY | O_RDONLY); return (ret < 0 ? -errno : ret); } /* * Read up to @size bytes to @buf from @fd */ int sysfs_read_file(int fd, char *buf, size_t size) { int ret; lseek(fd, 0, SEEK_SET); memset(buf, 0, size); ret = read(fd, buf, size); return (ret < 0 ? -errno : ret); } int sysfs_write_file(int fd, const char *buf, size_t size) { int ret; lseek(fd, 0, SEEK_SET); ret = write(fd, buf, size); return (ret < 0 ? -errno : ret); } int sysfs_read_file_u64(const char *name, u64 *value) { int fd = -1; int ret; char str[32] = { 0 }; fd = sysfs_open_file(name); if (fd < 0) return fd; ret = sysfs_read_file(fd, str, sizeof(str)); if (ret < 0) goto out; /* Raw value in any numeric format should work, followed by a newline. */ errno = 0; *value = strtoull(str, NULL, 0); ret = -errno; out: close(fd); return ret; } int sysfs_write_file_u64(const char *name, u64 value) { int fd; int ret; char str[32] = { 0 }; fd = sysfs_open_file_rw(name); if (fd < 0) return fd; ret = snprintf(str, sizeof(str), "%llu", value); ret = sysfs_write_file(fd, str, ret); close(fd); return ret; } int sysfs_read_fsid_file_u64(int fd, const char *name, u64 *value) { int ret; char str[32] = { 0 }; fd = sysfs_open_fsid_file(fd, name); if (fd < 0) return fd; ret = sysfs_read_file(fd, str, sizeof(str)); if (ret < 0) goto out; /* Raw value in any numeric format should work, followed by a newline. */ errno = 0; *value = strtoull(str, NULL, 0); ret = -errno; out: close(fd); return ret; } int sysfs_write_fsid_file_u64(int fd, const char *name, u64 value) { int ret; char str[32] = { 0 }; fd = sysfs_open_fsid_file_rw(fd, name); if (fd < 0) return fd; ret = snprintf(str, sizeof(str), "%llu", value); ret = sysfs_write_file(fd, str, ret); close(fd); return ret; }