X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=31eb638826f93206e7d36814b7d4cd8b8988a898;hp=d0b5c895a5f25d02b9f566fbe693a38898057203;hb=3f9051d22fcf6e968259946eaf521ac3daac470e;hpb=cb4dd13c2327c13d486b6abe572f4af2398b65de

diff --git a/fd.c b/fd.c
index d0b5c895..31eb6388 100644
--- a/fd.c
+++ b/fd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -40,6 +40,45 @@ int write_all(int fd, const char *buf, size_t *len)
 	return 1;
 }
 
+/**
+ * Write a buffer to a non-blocking file descriptor.
+ *
+ * \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
+ * case means that there is currently no space in the wait queue, but this can
+ * change at any moment.
+ *
+ * \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)
+{
+	size_t written = 0;
+	int ret = 0;
+
+	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;
+		if (ret < 0)
+			return -ERRNO_TO_PARA_ERROR(errno);
+		written += ret;
+	}
+	return written;
+}
+
 /**
  * Check whether a file exists.
  *
@@ -135,11 +174,7 @@ __must_check int mark_fd_nonblocking(int fd)
 */
 void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 {
-
-	if (fd < 0 || fd >= FD_SETSIZE) {
-		PARA_EMERG_LOG("fatal: tried to add invalid fd %d\n", fd);
-		exit(EXIT_FAILURE);
-	}
+	assert(fd >= 0 && fd < FD_SETSIZE);
 #if 0
 	{
 		int flags = fcntl(fd, F_GETFL);
@@ -190,19 +225,26 @@ again:
  * \param flags Exactly one of MAP_SHARED and MAP_PRIVATE.
  * \param fd The file to mmap from.
  * \param offset Mmap start.
+ * \param map Result pointer.
+ *
+ * \return Standard.
  *
- * \return This function either returns a valid pointer to the mapped area
- * or calls exit() on errors.
+ * \sa mmap(2).
  */
-void *para_mmap(size_t length, int prot, int flags, int fd, off_t offset)
+int para_mmap(size_t length, int prot, int flags, int fd, off_t offset,
+		void *map)
 {
-	void *ret = mmap(NULL, length, prot, flags, fd, offset);
-	if (ret != MAP_FAILED)
-		return ret;
-	PARA_EMERG_LOG("mmap failed: %s\n", strerror(errno));
-	PARA_EMERG_LOG("length: %zu, flags: %d, fd: %d, offset: %zu\n",
-		length, flags, fd, (size_t)offset);
-	exit(EXIT_FAILURE);
+	void **m = map;
+
+	errno = EINVAL;
+	if (!length)
+		goto err;
+	*m = mmap(NULL, length, prot, flags, fd, offset);
+	if (*m != MAP_FAILED)
+		return 1;
+err:
+	*m = NULL;
+	return -ERRNO_TO_PARA_ERROR(errno);
 }
 
 /**
@@ -363,17 +405,7 @@ int mmap_full_file(const char *path, int open_mode, void **map,
 		goto out;
 	}
 	*size = file_status.st_size;
-	ret = -E_EMPTY;
-	PARA_DEBUG_LOG("%s: size %zu\n", path, *size);
-	if (!*size)
-		goto out;
-	*map = mmap(NULL, *size, mmap_prot, mmap_flags, fd, 0);
-	if (*map == MAP_FAILED) {
-		*map = NULL;
-		ret = -E_MMAP;
-		goto out;
-	}
-	ret = 1;
+	ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
 out:
 	if (ret < 0 || !fd_ptr)
 		close(fd);
@@ -388,7 +420,7 @@ out:
  * \param start The start address of the memory mapping.
  * \param length The size of the mapping.
  *
- * \return Positive on success, \p -E_MUNMAP on errors.
+ * \return Standard.
  *
  * \sa munmap(2), mmap_full_file().
  */
@@ -427,3 +459,24 @@ again:
 		goto again;
 	return ret;
 }
+
+/**
+ * Ensure that file descriptors 0, 1, and 2 are valid.
+ *
+ * Common approach that opens /dev/null until it gets a file descriptor greater
+ * than two.
+ *
+ * \sa okir's Black Hats Manual.
+ */
+void valid_fd_012(void)
+{
+	while (1) {
+		int fd = open("/dev/null", O_RDWR);
+		if (fd < 0)
+			exit(EXIT_FAILURE);
+		if (fd > 2) {
+			close(fd);
+			break;
+		}
+	}
+}