Move to modern utility methods from android::base.
Moves away from crufty char* operations to std::string utility
methods, including android::base methods for splitting/parsing.
Rewrite of how Process handles scanning procfs for filesystem
references; now uses fts(3) for more sane traversal.
Replace sscanf() with new FindValue() method, also has unit tests.
Remove some unused methods. Switch almost everyone over to using
modern logging library.
Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.storage.cts.StorageManagerTest
Test: cts-tradefed run commandAndExit cts-dev --abi armeabi-v7a -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.AdoptableHostTest
Bug: 67041047
Change-Id: I70dc512f21459d1e25b187f24289002b2c7bc7af
diff --git a/Process.cpp b/Process.cpp
index 1c0f504..042ba2d 100644
--- a/Process.cpp
+++ b/Process.cpp
@@ -19,6 +19,7 @@
#include <errno.h>
#include <string.h>
#include <fcntl.h>
+#include <fts.h>
#include <dirent.h>
#include <ctype.h>
#include <pwd.h>
@@ -27,196 +28,98 @@
#include <sys/stat.h>
#include <signal.h>
-#define LOG_TAG "ProcessKiller"
+#include <fstream>
+#include <unordered_set>
#include <android-base/file.h>
+#include <android-base/parseint.h>
+#include <android-base/strings.h>
#include <android-base/stringprintf.h>
#include <android-base/logging.h>
-#include <cutils/log.h>
#include "Process.h"
-using android::base::ReadFileToString;
using android::base::StringPrintf;
-int Process::readSymLink(const char *path, char *link, size_t max) {
- struct stat s;
- int length;
+namespace android {
+namespace vold {
- 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, std::string& out_name) {
- if (!ReadFileToString(StringPrintf("/proc/%d/cmdline", pid), &out_name)) {
- out_name = "???";
- }
-}
-
-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];
- snprintf(path, sizeof(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;
- strlcat(path, de->d_name, PATH_MAX);
-
- char link[PATH_MAX];
-
- if (readSymLink(path, link, sizeof(link)) && pathMatchesMountPoint(link, mountPoint)) {
- if (openFilename) {
- memset(openFilename, 0, max);
- strlcpy(openFilename, link, max);
+static bool checkMaps(const std::string& path, const std::string& prefix) {
+ bool found = false;
+ std::ifstream infile(path);
+ std::string line;
+ while (std::getline(infile, line)) {
+ std::string::size_type pos = line.find('/');
+ if (pos != std::string::npos) {
+ line = line.substr(pos);
+ if (android::base::StartsWith(line, prefix.c_str())) {
+ LOG(WARNING) << "Found map " << path << " referencing " << line;
+ found = true;
}
- closedir(dir);
- return 1;
}
}
-
- closedir(dir);
- return 0;
+ return found;
}
-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];
-
- snprintf(buffer, sizeof(buffer), "/proc/%d/maps", pid);
- file = fopen(buffer, "re");
- 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);
- strlcpy(openFilename, path, max);
- }
- fclose(file);
- return 1;
+static bool checkSymlink(const std::string& path, const std::string& prefix) {
+ std::string res;
+ if (android::base::Readlink(path, &res)) {
+ if (android::base::StartsWith(res, prefix.c_str())) {
+ LOG(WARNING) << "Found symlink " << path << " referencing " << res;
+ return true;
}
}
-
- fclose(file);
- return 0;
+ return false;
}
-int Process::checkSymLink(int pid, const char *mountPoint, const char *name) {
- char path[PATH_MAX];
- char link[PATH_MAX];
+int KillProcessesWithOpenFiles(const std::string& prefix, int signal) {
+ std::unordered_set<pid_t> pids;
- snprintf(path, sizeof(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;
-}
-
-extern "C" void vold_killProcessesWithOpenFiles(const char *path, int signal) {
- Process::killProcessesWithOpenFiles(path, signal);
-}
-
-/*
- * Hunt down processes that have files open at the given mount point.
- */
-int Process::killProcessesWithOpenFiles(const char *path, int signal) {
- int count = 0;
- DIR* dir;
- struct dirent* de;
-
- if (!(dir = opendir("/proc"))) {
- SLOGE("opendir failed (%s)", strerror(errno));
- return count;
+ auto proc_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/proc"), closedir);
+ if (!proc_d) {
+ PLOG(ERROR) << "Failed to open proc";
+ return -1;
}
- while ((de = readdir(dir))) {
- int pid = getPid(de->d_name);
- if (pid == -1)
- continue;
+ struct dirent* proc_de;
+ while ((proc_de = readdir(proc_d.get())) != nullptr) {
+ // We only care about valid PIDs
+ pid_t pid;
+ if (proc_de->d_type != DT_DIR) continue;
+ if (!android::base::ParseInt(proc_de->d_name, &pid)) continue;
- std::string name;
- getProcessName(pid, name);
+ // Look for references to prefix
+ bool found = false;
+ auto path = StringPrintf("/proc/%d", pid);
+ found |= checkMaps(path + "/maps", prefix);
+ found |= checkSymlink(path + "/cwd", prefix);
+ found |= checkSymlink(path + "/root", prefix);
+ found |= checkSymlink(path + "/exe", prefix);
- char openfile[PATH_MAX];
-
- if (checkFileDescriptorSymLinks(pid, path, openfile, sizeof(openfile))) {
- SLOGE("Process %s (%d) has open file %s", name.c_str(), pid, openfile);
- } else if (checkFileMaps(pid, path, openfile, sizeof(openfile))) {
- SLOGE("Process %s (%d) has open filemap for %s", name.c_str(), pid, openfile);
- } else if (checkSymLink(pid, path, "cwd")) {
- SLOGE("Process %s (%d) has cwd within %s", name.c_str(), pid, path);
- } else if (checkSymLink(pid, path, "root")) {
- SLOGE("Process %s (%d) has chroot within %s", name.c_str(), pid, path);
- } else if (checkSymLink(pid, path, "exe")) {
- SLOGE("Process %s (%d) has executable path within %s", name.c_str(), pid, path);
+ auto fd_path = path + "/fd";
+ auto fd_d = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(fd_path.c_str()), closedir);
+ if (!fd_d) {
+ PLOG(WARNING) << "Failed to open " << fd_path;
} else {
- continue;
+ struct dirent* fd_de;
+ while ((fd_de = readdir(fd_d.get())) != nullptr) {
+ if (fd_de->d_type != DT_LNK) continue;
+ found |= checkSymlink(fd_path + "/" + fd_de->d_name, prefix);
+ }
}
- if (signal != 0) {
- SLOGW("Sending %s to process %d", strsignal(signal), pid);
- kill(pid, signal);
- count++;
+ if (found) {
+ pids.insert(pid);
}
}
- closedir(dir);
- return count;
+ if (signal != 0) {
+ for (const auto& pid : pids) {
+ LOG(WARNING) << "Sending " << strsignal(signal) << " to " << pid;
+ kill(pid, signal);
+ }
+ }
+ return pids.size();
}
+
+} // namespace vold
+} // namespace android