android_system_vold/Process.cpp at master · NameLessJedi/android_system_vold · GitHub

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* Licensed under the Apache License, Version 2.0 (the "License");

* you may not use this file except in compliance with the License.

* You may obtain a copy of the License at

* http://www.apache.org/licenses/LICENSE-2.0

* Unless required by applicable law or agreed to in writing, software

* distributed under the License is distributed on an "AS IS" BASIS,

* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

* See the License for the specific language governing permissions and

* limitations under the License.

#include <stdio.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <fcntl.h>

#include <dirent.h>

#include <ctype.h>

#include <pwd.h>

#include <stdlib.h>

#include <poll.h>

#include <sys/stat.h>

#include <signal.h>

#define LOG_TAG "ProcessKiller"

#include <cutils/log.h>

#include "Process.h"

int Process::readSymLink(const char *path, char *link, size_t max) {

struct stat s;

int length;

if (lstat(path, &s) < 0)

return 0;

if ((s.st_mode & S_IFMT) != S_IFLNK)

return 0;

// we have a symlink

length = readlink(path, link, max- 1);

if (length <= 0)

return 0;

link[length] = 0;

return 1;

}

int Process::pathMatchesMountPoint(const char* path, const char* mountPoint) {

int length = strlen(mountPoint);

if (length > 1 && strncmp(path, mountPoint, length) == 0) {

// we need to do extra checking if mountPoint does not end in a '/'

if (mountPoint[length - 1] == '/')

return 1;

// if mountPoint does not have a trailing slash, we need to make sure

// there is one in the path to avoid partial matches.

return (path[length] == 0 || path[length] == '/');

}

return 0;

}

void Process::getProcessName(int pid, char *buffer, size_t max) {

int fd;

snprintf(buffer, max, "/proc/%d/cmdline", pid);

fd = open(buffer, O_RDONLY);

if (fd < 0) {

strcpy(buffer, "???");

} else {

int length = read(fd, buffer, max - 1);

buffer[length] = 0;

close(fd);

}

int Process::checkFileDescriptorSymLinks(int pid, const char *mountPoint) {

return checkFileDescriptorSymLinks(pid, mountPoint, NULL, 0);

}

int Process::checkFileDescriptorSymLinks(int pid, const char *mountPoint, char *openFilename, size_t max) {

// compute path to process's directory of open files

char path[PATH_MAX];

sprintf(path, "/proc/%d/fd", pid);

DIR *dir = opendir(path);

if (!dir)

return 0;

// remember length of the path

int parent_length = strlen(path);

// append a trailing '/'

path[parent_length++] = '/';

struct dirent* de;

while ((de = readdir(dir))) {

if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")

|| strlen(de->d_name) + parent_length + 1 >= PATH_MAX)

continue;

// append the file name, after truncating to parent directory

path[parent_length] = 0;

strcat(path, de->d_name);

char link[PATH_MAX];

if (readSymLink(path, link, sizeof(link)) && pathMatchesMountPoint(link, mountPoint)) {

if (openFilename) {

memset(openFilename, 0, max);

strncpy(openFilename, link, max-1);

}

closedir(dir);

return 1;

}

closedir(dir);

return 0;

}

int Process::checkFileMaps(int pid, const char *mountPoint) {

return checkFileMaps(pid, mountPoint, NULL, 0);

}

int Process::checkFileMaps(int pid, const char *mountPoint, char *openFilename, size_t max) {

FILE *file;

char buffer[PATH_MAX + 100];

sprintf(buffer, "/proc/%d/maps", pid);

file = fopen(buffer, "r");

if (!file)

return 0;

while (fgets(buffer, sizeof(buffer), file)) {

// skip to the path

const char* path = strchr(buffer, '/');

if (path && pathMatchesMountPoint(path, mountPoint)) {

if (openFilename) {

memset(openFilename, 0, max);

strncpy(openFilename, path, max-1);

}

fclose(file);

return 1;

}

fclose(file);

return 0;

}

int Process::checkSymLink(int pid, const char *mountPoint, const char *name) {

char path[PATH_MAX];

char link[PATH_MAX];

sprintf(path, "/proc/%d/%s", pid, name);

if (readSymLink(path, link, sizeof(link)) && pathMatchesMountPoint(link, mountPoint))

return 1;

return 0;

}

int Process::getPid(const char *s) {

int result = 0;

while (*s) {

if (!isdigit(*s)) return -1;

result = 10 * result + (*s++ - '0');

}

return result;

}

* Hunt down processes that have files open at the given mount point.

* action = 0 to just warn,

* action = 1 to SIGHUP,

* action = 2 to SIGKILL

// hunt down and kill processes that have files open on the given mount point

void Process::killProcessesWithOpenFiles(const char *path, int action) {

DIR* dir;

struct dirent* de;

if (!(dir = opendir("/proc"))) {

SLOGE("opendir failed (%s)", strerror(errno));

return;

}

while ((de = readdir(dir))) {

int killed = 0;

int pid = getPid(de->d_name);

char name[PATH_MAX];

if (pid == -1)

continue;

getProcessName(pid, name, sizeof(name));

char openfile[PATH_MAX];

if (checkFileDescriptorSymLinks(pid, path, openfile, sizeof(openfile))) {

SLOGE("Process %s (%d) has open file %s", name, pid, openfile);

} else if (checkFileMaps(pid, path, openfile, sizeof(openfile))) {

SLOGE("Process %s (%d) has open filemap for %s", name, pid, openfile);

} else if (checkSymLink(pid, path, "cwd")) {

SLOGE("Process %s (%d) has cwd within %s", name, pid, path);

} else if (checkSymLink(pid, path, "root")) {

SLOGE("Process %s (%d) has chroot within %s", name, pid, path);

} else if (checkSymLink(pid, path, "exe")) {

SLOGE("Process %s (%d) has executable path within %s", name, pid, path);

} else {

continue;

}

if (action == 1) {

SLOGW("Sending SIGHUP to process %d", pid);

kill(pid, SIGTERM);

} else if (action == 2) {

SLOGE("Sending SIGKILL to process %d", pid);

kill(pid, SIGKILL);

}

closedir(dir);

}

android_system_vold/Process.cpp at master · NameLessJedi/android_system_vold · GitHub

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