/*!
* \brief Unmount filesystem
*
* This function takes the same arguments as umount(2), but returns true on
* success and false on failure.
*
* This function will /proc/mounts for the mountpoint (using an exact string
* compare). If the source path of the mountpoint is a block device and the
* block device is a loop device, then it will be disassociated from the
* previously attached file. Note that the return value of
* loopdev_remove_device() is ignored and this function will always return true
* if umount(2) is successful.
*
* \param target See man umount(2)
*
* \return True if umount(2) is successful. False if umount(2) is unsuccessful.
*/
bool umount(const char *target)
{
struct mntent ent;
std::string source;
autoclose::file fp(setmntent("/proc/mounts", "r"), endmntent);
if (fp) {
char buf[1024];
while (getmntent_r(fp.get(), &ent, buf, sizeof(buf))) {
if (strcmp(ent.mnt_dir, target) == 0) {
source = ent.mnt_fsname;
}
}
} else {
LOGW("Failed to read /proc/mounts: %s", strerror(errno));
}
int ret = ::umount(target);
if (!source.empty()) {
struct stat sb;
if (stat(source.c_str(), &sb) == 0
&& S_ISBLK(sb.st_mode) && major(sb.st_rdev) == 7) {
// If the source path is a loop block device, then disassociate it
// from the image
loopdev_remove_device(source);
}
}
return ret == 0;
}
/*!
* \brief Unmount filesystem
*
* This function takes the same arguments as umount(2), but returns true on
* success and false on failure.
*
* This function will /proc/mounts for the mountpoint (using an exact string
* compare). If the source path of the mountpoint is a block device and the
* block device is a loop device, then it will be disassociated from the
* previously attached file. Note that the return value of
* loopdev_remove_device() is ignored and this function will always return true
* if umount(2) is successful.
*
* \param target See man umount(2)
*
* \return True if umount(2) is successful. False if umount(2) is unsuccessful.
*/
bool umount(const char *target)
{
std::string source;
std::string mnt_dir;
autoclose::file fp(std::fopen(PROC_MOUNTS, "r"), std::fclose);
if (fp) {
for (MountEntry entry; get_mount_entry(fp.get(), entry);) {
if (entry.dir == target) {
source = entry.fsname;
}
}
} else {
LOGW(PROC_MOUNTS ": Failed to read file: %s", strerror(errno));
}
int ret = ::umount(target);
int saved_errno = errno;
if (!source.empty()) {
struct stat sb;
if (stat(source.c_str(), &sb) == 0
&& S_ISBLK(sb.st_mode) && major(sb.st_rdev) == 7) {
// If the source path is a loop block device, then disassociate it
// from the image
LOGD("Clearing loop device %s", source.c_str());
if (!loopdev_remove_device(source)) {
LOGW("Failed to clear loop device: %s", strerror(errno));
}
}
}
errno = saved_errno;
return ret == 0;
}
