diff options
Diffstat (limited to 'REORG.TODO/sysdeps/unix/sysv/linux/pathconf.c')
| -rw-r--r-- | REORG.TODO/sysdeps/unix/sysv/linux/pathconf.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/unix/sysv/linux/pathconf.c b/REORG.TODO/sysdeps/unix/sysv/linux/pathconf.c new file mode 100644 index 0000000000..01d8c2bedd --- /dev/null +++ b/REORG.TODO/sysdeps/unix/sysv/linux/pathconf.c @@ -0,0 +1,293 @@ +/* Get file-specific information about a file. Linux version. + Copyright (C) 1991-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ + +#include <errno.h> +#include <mntent.h> +#include <stdio_ext.h> +#include <string.h> +#include <unistd.h> +#include <sys/sysmacros.h> + +#include "pathconf.h" +#include "linux_fsinfo.h" +#include <not-cancel.h> + +static long int posix_pathconf (const char *file, int name); + +/* Define this first, so it can be inlined. */ +#define __pathconf static posix_pathconf +#include <sysdeps/posix/pathconf.c> + + +/* Get file-specific information about FILE. */ +long int +__pathconf (const char *file, int name) +{ + struct statfs fsbuf; + + switch (name) + { + case _PC_LINK_MAX: + return __statfs_link_max (__statfs (file, &fsbuf), &fsbuf, file, -1); + + case _PC_FILESIZEBITS: + return __statfs_filesize_max (__statfs (file, &fsbuf), &fsbuf); + + case _PC_2_SYMLINKS: + return __statfs_symlinks (__statfs (file, &fsbuf), &fsbuf); + + case _PC_CHOWN_RESTRICTED: + return __statfs_chown_restricted (__statfs (file, &fsbuf), &fsbuf); + + default: + return posix_pathconf (file, name); + } +} + + +static long int +distinguish_extX (const struct statfs *fsbuf, const char *file, int fd) +{ + char buf[64]; + char path[PATH_MAX]; + struct stat64 st; + + if ((file == NULL ? fstat64 (fd, &st) : stat64 (file, &st)) != 0) + /* Strange. The statfd call worked, but stat fails. Default to + the more pessimistic value. */ + return EXT2_LINK_MAX; + + __snprintf (buf, sizeof (buf), "/sys/dev/block/%u:%u", + gnu_dev_major (st.st_dev), gnu_dev_minor (st.st_dev)); + + ssize_t n = __readlink (buf, path, sizeof (path)); + if (n != -1 && n < sizeof (path)) + { + path[n] = '\0'; + char *base = strdupa (__basename (path)); + __snprintf (path, sizeof (path), "/sys/fs/ext4/%s", base); + + return __access (path, F_OK) == 0 ? EXT4_LINK_MAX : EXT2_LINK_MAX; + } + + /* XXX Is there a better way to distinguish ext2/3 from ext4 than + iterating over the mounted filesystems and compare the device + numbers? */ + FILE *mtab = __setmntent ("/proc/mounts", "r"); + if (mtab == NULL) + mtab = __setmntent (_PATH_MOUNTED, "r"); + + /* By default be conservative. */ + long int result = EXT2_LINK_MAX; + if (mtab != NULL) + { + struct mntent mntbuf; + char tmpbuf[1024]; + + /* No locking needed. */ + (void) __fsetlocking (mtab, FSETLOCKING_BYCALLER); + + while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf))) + { + if (strcmp (mntbuf.mnt_type, "ext2") != 0 + && strcmp (mntbuf.mnt_type, "ext3") != 0 + && strcmp (mntbuf.mnt_type, "ext4") != 0) + continue; + + struct stat64 fsst; + if (stat64 (mntbuf.mnt_dir, &fsst) >= 0 + && st.st_dev == fsst.st_dev) + { + if (strcmp (mntbuf.mnt_type, "ext4") == 0) + result = EXT4_LINK_MAX; + break; + } + } + + /* Close the file. */ + __endmntent (mtab); + } + + return result; +} + + +/* Used like: return statfs_link_max (__statfs (name, &buf), &buf); */ +long int +__statfs_link_max (int result, const struct statfs *fsbuf, const char *file, + int fd) +{ + if (result < 0) + { + if (errno == ENOSYS) + /* Not possible, return the default value. */ + return LINUX_LINK_MAX; + + /* Some error occured. */ + return -1; + } + + switch (fsbuf->f_type) + { + case EXT2_SUPER_MAGIC: + /* Unfortunately the kernel does not return a different magic number + for ext4. This would be necessary to easily detect etx4 since it + has a different LINK_MAX value. Therefore we have to find it out + the hard way. */ + return distinguish_extX (fsbuf, file, fd); + + case F2FS_SUPER_MAGIC: + return F2FS_LINK_MAX; + + case MINIX_SUPER_MAGIC: + case MINIX_SUPER_MAGIC2: + return MINIX_LINK_MAX; + + case MINIX2_SUPER_MAGIC: + case MINIX2_SUPER_MAGIC2: + return MINIX2_LINK_MAX; + + case XENIX_SUPER_MAGIC: + return XENIX_LINK_MAX; + + case SYSV4_SUPER_MAGIC: + case SYSV2_SUPER_MAGIC: + return SYSV_LINK_MAX; + + case COH_SUPER_MAGIC: + return COH_LINK_MAX; + + case UFS_MAGIC: + case UFS_CIGAM: + return UFS_LINK_MAX; + + case REISERFS_SUPER_MAGIC: + return REISERFS_LINK_MAX; + + case XFS_SUPER_MAGIC: + return XFS_LINK_MAX; + + case LUSTRE_SUPER_MAGIC: + return LUSTRE_LINK_MAX; + + default: + return LINUX_LINK_MAX; + } +} + + +/* Used like: return statfs_filesize_max (__statfs (name, &buf), &buf); */ +long int +__statfs_filesize_max (int result, const struct statfs *fsbuf) +{ + if (result < 0) + { + if (errno == ENOSYS) + /* Not possible, return the default value. */ + return 32; + + /* Some error occured. */ + return -1; + } + + switch (fsbuf->f_type) + { + case F2FS_SUPER_MAGIC: + return 256; + + case BTRFS_SUPER_MAGIC: + return 255; + + case EXT2_SUPER_MAGIC: + case UFS_MAGIC: + case UFS_CIGAM: + case REISERFS_SUPER_MAGIC: + case XFS_SUPER_MAGIC: + case SMB_SUPER_MAGIC: + case NTFS_SUPER_MAGIC: + case UDF_SUPER_MAGIC: + case JFS_SUPER_MAGIC: + case VXFS_SUPER_MAGIC: + case CGROUP_SUPER_MAGIC: + case LUSTRE_SUPER_MAGIC: + return 64; + + case MSDOS_SUPER_MAGIC: + case JFFS_SUPER_MAGIC: + case JFFS2_SUPER_MAGIC: + case NCP_SUPER_MAGIC: + case ROMFS_SUPER_MAGIC: + return 32; + + default: + return 32; + } +} + + +/* Used like: return statfs_link_max (__statfs (name, &buf), &buf); */ +long int +__statfs_symlinks (int result, const struct statfs *fsbuf) +{ + if (result < 0) + { + if (errno == ENOSYS) + /* Not possible, return the default value. */ + return 1; + + /* Some error occured. */ + return -1; + } + + switch (fsbuf->f_type) + { + case ADFS_SUPER_MAGIC: + case BFS_MAGIC: + case CRAMFS_MAGIC: + case DEVPTS_SUPER_MAGIC: + case EFS_SUPER_MAGIC: + case EFS_MAGIC: + case MSDOS_SUPER_MAGIC: + case NTFS_SUPER_MAGIC: + case QNX4_SUPER_MAGIC: + case ROMFS_SUPER_MAGIC: + /* No symlink support. */ + return 0; + + default: + return 1; + } +} + + +/* Used like: return __statfs_chown_restricted (__statfs (name, &buf), &buf);*/ +long int +__statfs_chown_restricted (int result, const struct statfs *fsbuf) +{ + if (result < 0) + { + if (errno == ENOSYS) + /* Not possible, return the default value. */ + return 1; + + /* Some error occured. */ + return -1; + } + + return 1; +} |