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Diffstat (limited to 'mountd/ProcessKiller.c')
| -rw-r--r-- | mountd/ProcessKiller.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/mountd/ProcessKiller.c b/mountd/ProcessKiller.c new file mode 100644 index 000000000..e37777446 --- /dev/null +++ b/mountd/ProcessKiller.c @@ -0,0 +1,222 @@ +/* + * 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. + */ + +/* +** mountd process killer +*/ + +#include "mountd.h" + +#include <stdio.h> +#include <unistd.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> + + +static boolean ReadSymLink(const char* path, char* link) +{ + struct stat s; + int length; + + if (lstat(path, &s) < 0) + return false; + if ((s.st_mode & S_IFMT) != S_IFLNK) + return false; + + // we have a symlink + length = readlink(path, link, PATH_MAX - 1); + if (length <= 0) + return false; + link[length] = 0; + return true; +} + +static boolean 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 true; + // 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 false; +} + +static void GetProcessName(int pid, char buffer[PATH_MAX]) +{ + int fd; + sprintf(buffer, "/proc/%d/cmdline", pid); + fd = open(buffer, O_RDONLY); + if (fd < 0) { + strcpy(buffer, "???"); + } else { + int length = read(fd, buffer, PATH_MAX - 1); + buffer[length] = 0; + close(fd); + } +} + +static boolean CheckFileDescriptorSymLinks(int pid, const char* mountPoint) +{ + DIR* dir; + struct dirent* de; + boolean fileOpen = false; + char path[PATH_MAX]; + char link[PATH_MAX]; + int parent_length; + + // compute path to process's directory of open files + sprintf(path, "/proc/%d/fd", pid); + dir = opendir(path); + if (!dir) + return false; + + // remember length of the path + parent_length = strlen(path); + // append a trailing '/' + path[parent_length++] = '/'; + + while ((de = readdir(dir)) != 0 && !fileOpen) { + if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) + continue; + + // append the file name, after truncating to parent directory + path[parent_length] = 0; + strcat(path, de->d_name); + + if (ReadSymLink(path, link) && PathMatchesMountPoint(link, mountPoint)) + { + char name[PATH_MAX]; + GetProcessName(pid, name); + LOG_ERROR("process %s (%d) has open file %s\n", name, pid, link); + fileOpen = true; + } + } + + closedir(dir); + return fileOpen; +} + +static boolean CheckFileMaps(int pid, const char* mountPoint) +{ + FILE* file; + char buffer[PATH_MAX + 100]; + boolean mapOpen = false; + + sprintf(buffer, "/proc/%d/maps", pid); + file = fopen(buffer, "r"); + if (!file) + return false; + + while (!mapOpen && fgets(buffer, sizeof(buffer), file)) + { + // skip to the path + const char* path = strchr(buffer, '/'); + if (path && PathMatchesMountPoint(path, mountPoint)) + { + char name[PATH_MAX]; + GetProcessName(pid, name); + LOG_ERROR("process %s (%d) has open file map for %s\n", name, pid, path); + mapOpen = true; + } + } + + fclose(file); + return mapOpen; +} + +static boolean CheckSymLink(int pid, const char* mountPoint, const char* name, const char* message) +{ + char path[PATH_MAX]; + char link[PATH_MAX]; + + sprintf(path, "/proc/%d/%s", pid, name); + if (ReadSymLink(path, link) && PathMatchesMountPoint(link, mountPoint)) + { + char name[PATH_MAX]; + GetProcessName(pid, name); + LOG_ERROR("process %s (%d) has %s in %s\n", name, pid, message, mountPoint); + return true; + } + else + return false; +} + +static int get_pid(const char* s) +{ + int result = 0; + while (*s) { + if (!isdigit(*s)) return -1; + result = 10 * result + (*s++ - '0'); + } + return result; +} + +// hunt down and kill processes that have files open on the given mount point +void KillProcessesWithOpenFiles(const char* mountPoint, boolean sigkill, int *excluded, int num_excluded) +{ + DIR* dir; + struct dirent* de; + + LOG_ERROR("KillProcessesWithOpenFiles %s\n", mountPoint); + dir = opendir("/proc"); + if (!dir) return; + + while ((de = readdir(dir)) != 0) + { + boolean killed = false; + // does the name look like a process ID? + int pid = get_pid(de->d_name); + if (pid == -1) continue; + + if (CheckFileDescriptorSymLinks(pid, mountPoint) // check for open files + || CheckFileMaps(pid, mountPoint) // check for mmap() + || CheckSymLink(pid, mountPoint, "cwd", "working directory") // check working directory + || CheckSymLink(pid, mountPoint, "root", "chroot") // check for chroot() + || CheckSymLink(pid, mountPoint, "exe", "executable path") // check executable path + ) + { + int i; + boolean hit = false; + + for (i = 0; i < num_excluded; i++) { + if (pid == excluded[i]) { + LOG_ERROR("I just need a little more TIME captain!\n"); + hit = true; + break; + } + } + + if (!hit) { + LOG_ERROR("Killing process %d\n", pid); + kill(pid, (sigkill ? SIGKILL : SIGTERM)); + } + } + } + + closedir(dir); +} |