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Merge "Make tmpfile() respect $TMPDIR."

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Elliott Hughes 2023-04-19 20:01:51 +00:00 committed by Gerrit Code Review
commit 17b2bae190
2 changed files with 31 additions and 23 deletions
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37
libc/bionic/tmpfile.cpp
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@ -51,6 +51,9 @@ static FILE* __fd_to_fp(int fd) {
return nullptr;
}
// O_TMPFILE isn't available until Linux 3.11, so we fall back to this on
// older kernels. AOSP was on a new enough kernel in the Lollipop timeframe,
// so this code should be obsolete by 2025.
static FILE* __tmpfile_dir_legacy(const char* tmp_dir) {
char* path = nullptr;
if (asprintf(&path, "%s/tmp.XXXXXXXXXX", tmp_dir) == -1) {
@ -79,25 +82,18 @@ static FILE* __tmpfile_dir_legacy(const char* tmp_dir) {
return __fd_to_fp(fd);
}
static FILE* __tmpfile_dir(const char* tmp_dir) {
int fd = open(tmp_dir, O_TMPFILE | O_RDWR, S_IRUSR | S_IWUSR);
if (fd == -1) return __tmpfile_dir_legacy(tmp_dir);
return __fd_to_fp(fd);
const char* __get_TMPDIR() {
// Use $TMPDIR if set, or fall back to /data/local/tmp otherwise.
// Useless for apps, but good enough for the shell.
const char* tmpdir = getenv("TMPDIR");
return (tmpdir == nullptr) ? "/data/local/tmp" : tmpdir;
}
FILE* tmpfile() {
// TODO: get this app's temporary directory from the framework ("/data/data/app/cache").
// $EXTERNAL_STORAGE turns out not to be very useful because it doesn't support hard links.
// This means we can't do the usual trick of calling unlink before handing the file back.
FILE* fp = __tmpfile_dir("/data/local/tmp");
if (fp == nullptr) {
// P_tmpdir is "/tmp/", but POSIX explicitly says that tmpdir(3) should try P_tmpdir before
// giving up. This is potentially useful for bionic on the host anyway.
fp = __tmpfile_dir(P_tmpdir);
}
return fp;
const char* tmpdir = __get_TMPDIR();
int fd = open(tmpdir, O_TMPFILE | O_RDWR, S_IRUSR | S_IWUSR);
if (fd == -1) return __tmpfile_dir_legacy(tmpdir);
return __fd_to_fp(fd);
}
__strong_alias(tmpfile64, tmpfile);
@ -107,7 +103,7 @@ char* tempnam(const char* dir, const char* prefix) {
// since we can't easily remove it...
// $TMPDIR overrides any directory passed in.
char* tmpdir = getenv("TMPDIR");
const char* tmpdir = getenv("TMPDIR");
if (tmpdir != nullptr) dir = tmpdir;
// If we still have no directory, we'll give you a default.
@ -136,12 +132,7 @@ char* tmpnam(char* s) {
static char buf[L_tmpnam];
if (s == nullptr) s = buf;
// Use $TMPDIR if set, or fall back to /data/local/tmp otherwise.
// Useless for apps, but good enough for the shell.
const char* dir = getenv("TMPDIR");
if (dir == nullptr) dir = "/data/local/tmp";
// Make up a mktemp(3) template and defer to it for the real work.
snprintf(s, L_tmpnam, "%s/tmpnam.XXXXXXXXXX", dir);
snprintf(s, L_tmpnam, "%s/tmpnam.XXXXXXXXXX", __get_TMPDIR());
return mktemp(s);
}

17
tests/stdio_test.cpp
View file

@ -36,6 +36,7 @@
#include <android-base/file.h>
#include <android-base/silent_death_test.h>
#include <android-base/strings.h>
#include <android-base/test_utils.h>
#include <android-base/unique_fd.h>
@ -140,6 +141,22 @@ TEST(STDIO_TEST, tmpfile64) {
fclose(fp);
}
TEST(STDIO_TEST, tmpfile_TMPDIR) {
TemporaryDir td;
setenv("TMPDIR", td.path, 1);
FILE* fp = tmpfile();
ASSERT_TRUE(fp != nullptr);
std::string fd_path = android::base::StringPrintf("/proc/self/fd/%d", fileno(fp));
char path[PATH_MAX];
ASSERT_GT(readlink(fd_path.c_str(), path, sizeof(path)), 0);
// $TMPDIR influenced where our temporary file ended up?
ASSERT_TRUE(android::base::StartsWith(path, td.path)) << path;
// And we used O_TMPFILE, right?
ASSERT_TRUE(android::base::EndsWith(path, " (deleted)")) << path;
}
TEST(STDIO_TEST, dprintf) {
TemporaryFile tf;