Support filesystems that do not support O_TMPFILE, even on Linux.

Evidently, overlayfs does not support O_TMPFILE. Reported by Daniel Lewart.

diff --git a/database-builder.cpp b/database-builder.cpp
index da52cdb57764b6d60247c74e4318a84872503c49..75b05f6a2cf1a898c014fd1227b4c6471c4f0148 100644 (file)
--- a/database-builder.cpp
+++ b/database-builder.cpp
@@ -485,24 +485,26 @@ DatabaseBuilder::DatabaseBuilder(const char *outfile, gid_t owner, int block_siz
        if (path.empty()) {
                path = ".";
        }
+       int fd = -1;
 #ifdef O_TMPFILE
-       int fd = open(path.c_str(), O_WRONLY | O_TMPFILE, 0640);
-       if (fd == -1) {
+       fd = open(path.c_str(), O_WRONLY | O_TMPFILE, 0640);
+       if (fd == -1 && errno != EOPNOTSUPP) {
                perror(path.c_str());
                exit(1);
        }
-#else
-       temp_filename = string(outfile) + ".XXXXXX";
-       int fd = mkstemp(&temp_filename[0]);
+#endif
        if (fd == -1) {
-               perror(temp_filename.c_str());
-               exit(1);
-       }
-       if (fchmod(fd, 0640) == -1) {
-               perror("fchmod");
-               exit(1);
+               temp_filename = string(outfile) + ".XXXXXX";
+               fd = mkstemp(&temp_filename[0]);
+               if (fd == -1) {
+                       perror(temp_filename.c_str());
+                       exit(1);
+               }
+               if (fchmod(fd, 0640) == -1) {
+                       perror("fchmod");
+                       exit(1);
+               }
        }
-#endif
 
        if (owner != (gid_t)-1) {
                if (fchown(fd, (uid_t)-1, owner) == -1) {
@@ -679,22 +681,24 @@ void DatabaseBuilder::finish_corpus()
        fseek(outfp, 0, SEEK_SET);
        fwrite(&hdr, sizeof(hdr), 1, outfp);
 
+       if (!temp_filename.empty()) {
+               if (rename(temp_filename.c_str(), outfile.c_str()) == -1) {
+                       perror("rename");
+                       exit(1);
+               }
+       } else {
 #ifdef O_TMPFILE
-       // Give the file a proper name, making it visible in the file system.
-       // TODO: It would be nice to be able to do this atomically, like with rename.
-       unlink(outfile.c_str());
-       char procpath[256];
-       snprintf(procpath, sizeof(procpath), "/proc/self/fd/%d", fileno(outfp));
-       if (linkat(AT_FDCWD, procpath, AT_FDCWD, outfile.c_str(), AT_SYMLINK_FOLLOW) == -1) {
-               perror("linkat");
-               exit(1);
-       }
-#else
-       if (rename(temp_filename.c_str(), outfile.c_str()) == -1) {
-               perror("rename");
-               exit(1);
-       }
+               // Give the file a proper name, making it visible in the file system.
+               // TODO: It would be nice to be able to do this atomically, like with rename.
+               unlink(outfile.c_str());
+               char procpath[256];
+               snprintf(procpath, sizeof(procpath), "/proc/self/fd/%d", fileno(outfp));
+               if (linkat(AT_FDCWD, procpath, AT_FDCWD, outfile.c_str(), AT_SYMLINK_FOLLOW) == -1) {
+                       perror("linkat");
+                       exit(1);
+               }
 #endif
+       }
 
        fclose(outfp);
 

diff --git a/database-builder.h b/database-builder.h
index 0c25476145086f1793f7e6324a41e6a097f25de0..89fbc7c5d2a17481e601436f0c8e84a3b05ce568 100644 (file)
--- a/database-builder.h
+++ b/database-builder.h
@@ -81,9 +81,7 @@ public:
 private:
        FILE *outfp;
        std::string outfile;
-#ifndef O_TMPFILE
        std::string temp_filename;
-#endif
        Header hdr;
        const int block_size;
        std::chrono::steady_clock::time_point corpus_start;