journalctl: Make temporary files directory configurable (#3574)

journalctl: Use env variable TMPDIR to save temporary files

src/basic/fs-util.c

@@ -38,6 +38,7 @@
 #include "mkdir.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "stat-util.h"
 #include "stdio-util.h"
 #include "string-util.h"
 #include "strv.h"
@@ -495,6 +496,34 @@ int get_files_in_directory(const char *path, char ***list) {
         return n;
 }
 
+int var_tmp(char **ret) {
+        const char *tmp_dir = NULL;
+        const char *env_tmp_dir = NULL;
+        char *c = NULL;
+        int r;
+
+        assert(ret);
+
+        env_tmp_dir = getenv("TMPDIR");
+        if (env_tmp_dir != NULL) {
+                r = is_dir(env_tmp_dir, true);
+                if (r < 0 && r != -ENOENT)
+                        return r;
+                if (r > 0)
+                        tmp_dir = env_tmp_dir;
+        }
+
+        if (!tmp_dir)
+                tmp_dir = "/var/tmp";
+
+        c = strdup(tmp_dir);
+        if (!c)
+                return -ENOMEM;
+        *ret = c;
+
+        return 0;
+}
+
 int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
         char path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
         int r;

src/basic/fs-util.h

@@ -61,6 +61,8 @@ int mkfifo_atomic(const char *path, mode_t mode);
 
 int get_files_in_directory(const char *path, char ***list);
 
+int var_tmp(char **ret);
+
 #define INOTIFY_EVENT_MAX (sizeof(struct inotify_event) + NAME_MAX + 1)
 
 #define FOREACH_INOTIFY_EVENT(e, buffer, sz) \

src/journal/journal-verify.c

@@ -26,6 +26,7 @@
 #include "compress.h"
 #include "fd-util.h"
 #include "fileio.h"
+#include "fs-util.h"
 #include "journal-authenticate.h"
 #include "journal-def.h"
 #include "journal-file.h"
@@ -825,6 +826,8 @@ int journal_file_verify(
         int data_fd = -1, entry_fd = -1, entry_array_fd = -1;
         unsigned i;
         bool found_last = false;
+        _cleanup_free_ char *tmp_dir = NULL;
+
 #ifdef HAVE_GCRYPT
         uint64_t last_tag = 0;
 #endif
@@ -843,19 +846,25 @@ int journal_file_verify(
         } else if (f->seal)
                 return -ENOKEY;
 
-        data_fd = open_tmpfile_unlinkable("/var/tmp", O_RDWR | O_CLOEXEC);
+        r = var_tmp(&tmp_dir);
+        if (r < 0) {
+                log_error_errno(r, "Failed to determine temporary directory: %m");
+                goto fail;
+        }
+
+        data_fd = open_tmpfile_unlinkable(tmp_dir, O_RDWR | O_CLOEXEC);
         if (data_fd < 0) {
                 r = log_error_errno(data_fd, "Failed to create data file: %m");
                 goto fail;
         }
 
-        entry_fd = open_tmpfile_unlinkable("/var/tmp", O_RDWR | O_CLOEXEC);
+        entry_fd = open_tmpfile_unlinkable(tmp_dir, O_RDWR | O_CLOEXEC);
         if (entry_fd < 0) {
                 r = log_error_errno(entry_fd, "Failed to create entry file: %m");
                 goto fail;
         }
 
-        entry_array_fd = open_tmpfile_unlinkable("/var/tmp", O_RDWR | O_CLOEXEC);
+        entry_array_fd = open_tmpfile_unlinkable(tmp_dir, O_RDWR | O_CLOEXEC);
         if (entry_array_fd < 0) {
                 r = log_error_errno(entry_array_fd,
                                     "Failed to create entry array file: %m");

src/test/test-fs-util.c

@@ -82,10 +82,56 @@ static void test_get_files_in_directory(void) {
         assert_se(get_files_in_directory(".", NULL) >= 0);
 }
 
+static void test_var_tmp(void) {
+        char *tmp_dir = NULL;
+        char *tmpdir_backup = NULL;
+        const char *default_var_tmp = NULL;
+        const char *var_name;
+        bool do_overwrite = true;
+
+        default_var_tmp = "/var/tmp";
+        var_name = "TMPDIR";
+
+        if (getenv(var_name) != NULL) {
+                tmpdir_backup = strdup(getenv(var_name));
+                assert_se(tmpdir_backup != NULL);
+        }
+
+        unsetenv(var_name);
+
+        var_tmp(&tmp_dir);
+        assert_se(!strcmp(tmp_dir, default_var_tmp));
+
+        free(tmp_dir);
+
+        setenv(var_name, "/tmp", do_overwrite);
+        assert_se(!strcmp(getenv(var_name), "/tmp"));
+
+        var_tmp(&tmp_dir);
+        assert_se(!strcmp(tmp_dir, "/tmp"));
+
+        free(tmp_dir);
+
+        setenv(var_name, "/88_does_not_exist_88", do_overwrite);
+        assert_se(!strcmp(getenv(var_name), "/88_does_not_exist_88"));
+
+        var_tmp(&tmp_dir);
+        assert_se(!strcmp(tmp_dir, default_var_tmp));
+
+        free(tmp_dir);
+
+        if (tmpdir_backup != NULL)  {
+                setenv(var_name, tmpdir_backup, do_overwrite);
+                assert_se(!strcmp(getenv(var_name), tmpdir_backup));
+                free(tmpdir_backup);
+        }
+}
+
 int main(int argc, char *argv[]) {
         test_unlink_noerrno();
         test_readlink_and_make_absolute();
         test_get_files_in_directory();
+        test_var_tmp();
 
         return 0;
 }