312 lines
7.1 KiB
C++
312 lines
7.1 KiB
C++
/*
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nsjail - useful procedures
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-----------------------------------------
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Copyright 2016 Google Inc. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#include "util.h"
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#include <ctype.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <pthread.h>
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#include <signal.h>
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#include <stdarg.h>
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/stat.h>
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#include <sys/syscall.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <time.h>
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#include <unistd.h>
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#include "log.h"
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#include "macros.h"
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namespace util {
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void* memAlloc(size_t sz) {
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void* ret = malloc(sz);
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if (ret == NULL) {
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LOG_F("malloc(sz=%zu) failed", sz);
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}
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return ret;
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}
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void* clearAlloc(size_t sz) {
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void* r = malloc(sz);
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memset(r, '\0', sz);
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return r;
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}
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char* strDup(const char* str) {
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if (str == NULL) {
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return NULL;
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}
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char* ret = strdup(str);
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if (ret == NULL) {
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LOG_E("Cannot allocate memory for strdup(sz=%zu)", strlen(str));
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}
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return ret;
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}
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uint8_t* memDup(const uint8_t* src, size_t len) {
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if (src == NULL) {
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return NULL;
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}
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uint8_t* ret = reinterpret_cast<uint8_t*>(malloc(len));
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memcpy(ret, src, len);
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return ret;
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}
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ssize_t readFromFd(int fd, void* buf, size_t len) {
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uint8_t* charbuf = (uint8_t*)buf;
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size_t readSz = 0;
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while (readSz < len) {
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ssize_t sz = read(fd, &charbuf[readSz], len - readSz);
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if (sz < 0 && errno == EINTR) continue;
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if (sz <= 0) break;
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readSz += sz;
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}
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return readSz;
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}
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ssize_t readFromFile(const char* fname, void* buf, size_t len) {
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int fd;
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TEMP_FAILURE_RETRY(fd = open(fname, O_RDONLY | O_CLOEXEC));
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if (fd == -1) {
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LOG_E("open('%s', O_RDONLY|O_CLOEXEC)", fname);
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return -1;
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}
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ssize_t ret = readFromFd(fd, buf, len);
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close(fd);
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return ret;
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}
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ssize_t writeToFd(int fd, const void* buf, size_t len) {
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const uint8_t* charbuf = (const uint8_t*)buf;
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size_t writtenSz = 0;
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while (writtenSz < len) {
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ssize_t sz = write(fd, &charbuf[writtenSz], len - writtenSz);
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if (sz < 0 && errno == EINTR) continue;
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if (sz < 0) return false;
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writtenSz += sz;
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}
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return true;
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}
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bool writeBufToFile(const char* filename, const void* buf, size_t len, int open_flags) {
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int fd;
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TEMP_FAILURE_RETRY(fd = open(filename, open_flags, 0644));
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if (fd == -1) {
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PLOG_E("Couldn't open '%s' for writing", filename);
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return false;
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}
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if (writeToFd(fd, buf, len) == false) {
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PLOG_E("Couldn't write '%zu' bytes to file '%s' (fd='%d')", len, filename, fd);
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close(fd);
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unlink(filename);
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return false;
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}
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LOG_D("Written '%zu' bytes to '%s'", len, filename);
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close(fd);
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return true;
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}
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bool createDirRecursively(const char* dir) {
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if (dir[0] != '/') {
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LOG_W("The directory path must start with '/': '%s' provided", dir);
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return false;
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}
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int prev_dir_fd = open("/", O_RDONLY | O_CLOEXEC);
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if (prev_dir_fd == -1) {
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PLOG_W("open('/', O_RDONLY | O_CLOEXEC)");
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return false;
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}
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char path[PATH_MAX];
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snprintf(path, sizeof(path), "%s", dir);
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char* curr = path;
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for (;;) {
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while (*curr == '/') {
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curr++;
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}
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char* next = strchr(curr, '/');
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if (next == NULL) {
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close(prev_dir_fd);
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return true;
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}
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*next = '\0';
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if (mkdirat(prev_dir_fd, curr, 0755) == -1 && errno != EEXIST) {
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PLOG_W("mkdir('%s', 0755)", curr);
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close(prev_dir_fd);
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return false;
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}
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int dir_fd = TEMP_FAILURE_RETRY(openat(prev_dir_fd, curr, O_DIRECTORY | O_CLOEXEC));
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if (dir_fd == -1) {
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PLOG_W("openat('%d', '%s', O_DIRECTORY | O_CLOEXEC)", prev_dir_fd, curr);
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close(prev_dir_fd);
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return false;
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}
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close(prev_dir_fd);
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prev_dir_fd = dir_fd;
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curr = next + 1;
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}
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}
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int sSnPrintf(char* str, size_t size, const char* format, ...) {
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char buf1[size];
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char buf2[size];
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snprintf(buf1, sizeof(buf1), "%s", str);
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va_list args;
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va_start(args, format);
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vsnprintf(buf2, size, format, args);
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va_end(args);
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return snprintf(str, size, "%s%s", buf1, buf2);
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}
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bool isANumber(const char* s) {
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for (int i = 0; s[i]; s++) {
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if (!isdigit(s[i]) && s[i] != 'x') {
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return false;
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}
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}
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return true;
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}
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static __thread pthread_once_t rndThreadOnce = PTHREAD_ONCE_INIT;
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static __thread uint64_t rndX;
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/* MMIX LCG PRNG */
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static const uint64_t a = 6364136223846793005ULL;
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static const uint64_t c = 1442695040888963407ULL;
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static void rndInitThread(void) {
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#if defined(__NR_getrandom)
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if (syscall(__NR_getrandom, &rndX, sizeof(rndX), 0) == sizeof(rndX)) {
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return;
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}
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#endif /* defined(__NR_getrandom) */
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int fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
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if (fd == -1) {
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PLOG_D("Couldn't open /dev/urandom for reading. Using gettimeofday fall-back");
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struct timeval tv;
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gettimeofday(&tv, NULL);
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rndX = tv.tv_usec + ((uint64_t)tv.tv_sec << 32);
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return;
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}
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if (readFromFd(fd, (uint8_t*)&rndX, sizeof(rndX)) != sizeof(rndX)) {
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PLOG_F("Couldn't read '%zu' bytes from /dev/urandom", sizeof(rndX));
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close(fd);
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}
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close(fd);
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}
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uint64_t rnd64(void) {
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pthread_once(&rndThreadOnce, rndInitThread);
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rndX = a * rndX + c;
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return rndX;
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}
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const char* sigName(int signo) {
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static __thread char sigstr[32];
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sigstr[0] = '\0';
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static struct {
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const int signo;
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const char* const name;
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} const sigNames[] = {
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NS_VALSTR_STRUCT(SIGINT),
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NS_VALSTR_STRUCT(SIGILL),
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NS_VALSTR_STRUCT(SIGABRT),
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NS_VALSTR_STRUCT(SIGFPE),
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NS_VALSTR_STRUCT(SIGSEGV),
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NS_VALSTR_STRUCT(SIGTERM),
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NS_VALSTR_STRUCT(SIGHUP),
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NS_VALSTR_STRUCT(SIGQUIT),
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NS_VALSTR_STRUCT(SIGTRAP),
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NS_VALSTR_STRUCT(SIGKILL),
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NS_VALSTR_STRUCT(SIGBUS),
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NS_VALSTR_STRUCT(SIGSYS),
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NS_VALSTR_STRUCT(SIGPIPE),
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NS_VALSTR_STRUCT(SIGALRM),
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NS_VALSTR_STRUCT(SIGURG),
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NS_VALSTR_STRUCT(SIGSTOP),
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NS_VALSTR_STRUCT(SIGTSTP),
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NS_VALSTR_STRUCT(SIGCONT),
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NS_VALSTR_STRUCT(SIGCHLD),
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NS_VALSTR_STRUCT(SIGTTIN),
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NS_VALSTR_STRUCT(SIGTTOU),
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NS_VALSTR_STRUCT(SIGPOLL),
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NS_VALSTR_STRUCT(SIGXCPU),
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NS_VALSTR_STRUCT(SIGXFSZ),
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NS_VALSTR_STRUCT(SIGVTALRM),
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NS_VALSTR_STRUCT(SIGPROF),
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NS_VALSTR_STRUCT(SIGUSR1),
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NS_VALSTR_STRUCT(SIGUSR2),
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NS_VALSTR_STRUCT(SIGWINCH),
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};
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for (size_t i = 0; i < ARRAYSIZE(sigNames); i++) {
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if (signo == sigNames[i].signo) {
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snprintf(sigstr, sizeof(sigstr), "%s", sigNames[i].name);
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return sigstr;
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}
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}
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if (signo > SIGRTMIN) {
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snprintf(sigstr, sizeof(sigstr), "SIG%d-RTMIN+%d", signo, signo - SIGRTMIN);
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return sigstr;
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}
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snprintf(sigstr, sizeof(sigstr), "UNKNOWN-%d", signo);
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return sigstr;
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}
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static __thread char timestr[64];
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const char* timeToStr(time_t t) {
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struct tm utctime;
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localtime_r(&t, &utctime);
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if (strftime(timestr, sizeof(timestr) - 1, "%FT%T%z", &utctime) == 0) {
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return "[Time conv error]";
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}
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return timestr;
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}
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} // namespace util
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