97 lines
2.3 KiB
C
97 lines
2.3 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <fcntl.h>
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#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include <linux/fs.h>
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#include "chattr-util.h"
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#include "fd-util.h"
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#include "macro.h"
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int chattr_fd(int fd, unsigned value, unsigned mask, unsigned *previous) {
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unsigned old_attr, new_attr;
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struct stat st;
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assert(fd >= 0);
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if (fstat(fd, &st) < 0)
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return -errno;
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/* Explicitly check whether this is a regular file or
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* directory. If it is anything else (such as a device node or
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* fifo), then the ioctl will not hit the file systems but
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* possibly drivers, where the ioctl might have different
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* effects. Notably, DRM is using the same ioctl() number. */
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if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
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return -ENOTTY;
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if (mask == 0 && !previous)
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return 0;
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if (ioctl(fd, FS_IOC_GETFLAGS, &old_attr) < 0)
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return -errno;
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new_attr = (old_attr & ~mask) | (value & mask);
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if (new_attr == old_attr) {
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if (previous)
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*previous = old_attr;
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return 0;
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}
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if (ioctl(fd, FS_IOC_SETFLAGS, &new_attr) < 0)
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return -errno;
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if (previous)
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*previous = old_attr;
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return 1;
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}
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int chattr_path(const char *p, unsigned value, unsigned mask, unsigned *previous) {
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_cleanup_close_ int fd = -1;
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assert(p);
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if (mask == 0)
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return 0;
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fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
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if (fd < 0)
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return -errno;
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return chattr_fd(fd, value, mask, previous);
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}
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int read_attr_fd(int fd, unsigned *ret) {
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struct stat st;
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assert(fd >= 0);
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if (fstat(fd, &st) < 0)
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return -errno;
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if (!S_ISDIR(st.st_mode) && !S_ISREG(st.st_mode))
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return -ENOTTY;
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if (ioctl(fd, FS_IOC_GETFLAGS, ret) < 0)
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return -errno;
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return 0;
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}
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int read_attr_path(const char *p, unsigned *ret) {
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_cleanup_close_ int fd = -1;
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assert(p);
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assert(ret);
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fd = open(p, O_RDONLY|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW);
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if (fd < 0)
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return -errno;
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return read_attr_fd(fd, ret);
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}
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