writer: fix ubuntu problems

src/writer.c

@@ -4,6 +4,7 @@
 
 #include <fcntl.h> /* open */
 #include <unistd.h> /* close, write, read */
+#include <sys/stat.h> /* S_IWUSR, S_IRUSR */
 #include <stdlib.h> /* malloc, free */
 #include <stdio.h> /* sprintf */
 #include <string.h> /* memset */
@@ -21,8 +22,8 @@ int bp__writer_create(bp__writer_t* w, const char* filename) {
   memcpy(w->filename, filename, filename_length);
 
   w->fd = open(filename,
-               O_RDWR | O_APPEND | O_CREAT | O_EXLOCK,
-               S_IWRITE | S_IREAD);
+               O_RDWR | O_APPEND | O_CREAT,
+               S_IWUSR | S_IRUSR);
   if (w->fd == -1) goto error;
 
   /* Determine filesize */
@@ -97,7 +98,7 @@ int bp__writer_read(bp__writer_t* w,
                     const uint64_t offset,
                     uint64_t* size,
                     void** data) {
-  ssize_t read;
+  ssize_t bytes_read;
   char* cdata;
 
   if (w->filesize < offset + *size) return BP_EFILEREAD_OOB;
@@ -111,8 +112,10 @@ int bp__writer_read(bp__writer_t* w,
   cdata = malloc(*size);
   if (cdata == NULL) return BP_EALLOC;
 
-  read = pread(w->fd, cdata, (size_t) *size, (off_t) offset);
-  if ((uint64_t) read != *size) {
+  if (lseek(w->fd, (off_t) offset, SEEK_SET) == -1) return BP_EFILE;
+
+  bytes_read = read(w->fd, cdata, (size_t) *size);
+  if ((uint64_t) bytes_read != *size) {
     free(cdata);
     return BP_EFILEREAD;
   }

test/corruption.cc

@@ -16,7 +16,7 @@ TEST_START("database corruption test", "db-corrupt")
   assert(bp_close(&db) == BP_OK);
 
   /* corrupt file by zeroing last 2k bytes of it */
-  fd = open(__db_file, O_RDWR, S_IWRITE | S_IREAD);
+  fd = open(__db_file, O_RDWR, S_IWUSR | S_IRUSR);
   assert(fd != -1);
 
   char buff[13589];

test/test.h

@@ -1,10 +1,12 @@
 #include <bplus.h>
 #include <stdio.h>
+#include <stdlib.h>
 #include <stdint.h>
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/time.h>
+#include <sys/stat.h>
 
 #include <assert.h>