Improve error diagnostics of mmap_full_file().

[paraslash.git] / fd.c

diff --git a/fd.c b/fd.c
index 7336bd51de6182c8b6899bbca82420db2fd32d08..9b6c6917232eb5063bb3acaad51a24ea53226389 100644 (file)
--- a/fd.c
+++ b/fd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2010 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -49,10 +49,6 @@ int write_all(int fd, const char *buf, size_t *len)
  * \param fd The file descriptor.
  * \param buf the buffer to write.
  * \param len the number of bytes of \a buf.
- * \param max_bytes_per_write Do not write more than that many bytes at once.
- *
- * If \a max_bytes_per_write is non-zero, do not send more than that many bytes
- * per write().
  *
  * EAGAIN is not considered an error condition.  For example CCID3 has a
  * sending wait queue which fills up and is emptied asynchronously. The EAGAIN
@@ -61,8 +57,7 @@ int write_all(int fd, const char *buf, size_t *len)
  *
  * \return Negative on errors, number of bytes written else.
  */
-int write_nonblock(int fd, const char *buf, size_t len,
-               size_t max_bytes_per_write)
+int write_nonblock(int fd, const char *buf, size_t len)
 {
        size_t written = 0;
        int ret = 0;
@@ -70,8 +65,6 @@ int write_nonblock(int fd, const char *buf, size_t len,
        while (written < len) {
                size_t num = len - written;
 
-               if (max_bytes_per_write && max_bytes_per_write < num)
-                       num = max_bytes_per_write;
                ret = write(fd, buf + written, num);
                if (ret < 0 && errno == EAGAIN)
                        return written;
@@ -104,7 +97,7 @@ int write_nonblock(int fd, const char *buf, size_t len,
  * In any case, \a num_bytes contains the number of bytes that have been
  * successfully read from \a fd (zero if the first readv() call failed with
  * EAGAIN). Note that even if the function returns negative, some data might
- * have been read before the error occured. In this case \a num_bytes is
+ * have been read before the error occurred. In this case \a num_bytes is
  * positive.
  *
  * \sa \ref write_nonblock(), read(2), readv(2).
@@ -453,7 +446,7 @@ int para_chdir(const char *path)
  * \sa getcwd(3).
  *
  */
-int para_opendir(const char *dirname, DIR **dir, int *cwd)
+static int para_opendir(const char *dirname, DIR **dir, int *cwd)
 {
        int ret;
 
@@ -487,7 +480,7 @@ close_cwd:
  *
  * \return Standard.
  */
-int para_fchdir(int fd)
+static int para_fchdir(int fd)
 {
        if (fchdir(fd) < 0)
                return -ERRNO_TO_PARA_ERROR(errno);
@@ -548,6 +541,22 @@ int mmap_full_file(const char *path, int open_mode, void **map,
                goto out;
        }
        *size = file_status.st_size;
+       /*
+        * If the file is empty, *size is zero and mmap() would return EINVAL
+        * (Invalid argument). This error is common enough to spend an extra
+        * error code which explicitly states the problem.
+        */
+       ret = -E_EMPTY;
+       if (*size == 0)
+               goto out;
+       /*
+        * If fd refers to a directory, mmap() returns ENODEV (No such device),
+        * at least on Linux. "Is a directory" seems to be more to the point.
+        */
+       ret = -ERRNO_TO_PARA_ERROR(EISDIR);
+       if (S_ISDIR(file_status.st_mode))
+               goto out;
+
        ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
 out:
        if (ret < 0 || !fd_ptr)
@@ -570,6 +579,9 @@ out:
 int para_munmap(void *start, size_t length)
 {
        int err;
+
+       if (!start)
+               return 0;
        if (munmap(start, length) >= 0)
                return 1;
        err = errno;