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/*
* Copyright (C) 2008 The Android Open Source Project
*
* 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);
}
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