X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=8759d5099200c4f6c1b6c31e84b66da3372b5540;hp=0adab0f2c0732862f03201119f975873211b5c38;hb=e9e6150fdba1687366956d358cc30ad9b0552523;hpb=89b30ef7b5ee1bb73b8efa3ccbb53c229066439e

diff --git a/fd.c b/fd.c
index 0adab0f2..8759d509 100644
--- a/fd.c
+++ b/fd.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
@@ -15,6 +15,70 @@
 #include "para.h"
 #include "error.h"
 
+/**
+ * Write a buffer to a file descriptor, re-write on short writes.
+ *
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
+ *
+ * \return Standard. In any case, the number of bytes that have been written is
+ * stored in \a len.
+ */
+int write_all(int fd, const char *buf, size_t *len)
+{
+	size_t total = *len;
+
+	assert(total);
+	*len = 0;
+	while (*len < total) {
+		int ret = write(fd, buf + *len, total - *len);
+		if (ret == -1)
+			return -ERRNO_TO_PARA_ERROR(errno);
+		*len += ret;
+	}
+	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.
  *
@@ -67,7 +131,7 @@ int para_select(int n, fd_set *readfds, fd_set *writefds,
  *
  * \return Standard.
  */
-int mark_fd_blocking(int fd)
+__must_check int mark_fd_blocking(int fd)
 {
 	int flags = fcntl(fd, F_GETFL);
 	if (flags < 0)
@@ -85,7 +149,7 @@ int mark_fd_blocking(int fd)
  *
  * \return Standard.
  */
-int mark_fd_nonblocking(int fd)
+__must_check int mark_fd_nonblocking(int fd)
 {
 	int flags = fcntl(fd, F_GETFL);
 	if (flags < 0)
@@ -110,11 +174,7 @@ 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);
@@ -129,16 +189,16 @@ void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 }
 
 /**
-* Paraslash's wrapper for fgets(3).
-
-* \param line Pointer to the buffer to store the line.
-* \param size The size of the buffer given by \a line.
-* \param f The stream to read from.
-*
-* \return Unlike the standard fgets() function, an integer value
-* is returned. On success, this function returns 1. On errors, -E_FGETS
-* is returned. A zero return value indicates an end of file condition.
-*/
+ * Paraslash's wrapper for fgets(3).
+ *
+ * \param line Pointer to the buffer to store the line.
+ * \param size The size of the buffer given by \a line.
+ * \param f The stream to read from.
+ *
+ * \return Unlike the standard fgets() function, an integer value
+ * is returned. On success, this function returns 1. On errors, -E_FGETS
+ * is returned. A zero return value indicates an end of file condition.
+ */
 __must_check int para_fgets(char *line, int size, FILE *f)
 {
 again:
@@ -165,19 +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 This function either returns a valid pointer to the mapped area
- * or calls exit() on errors.
+ * \return Standard.
+ *
+ * \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);
 }
 
 /**
@@ -260,9 +327,10 @@ int para_opendir(const char *dirname, DIR **dir, int *cwd)
 	if (*dir)
 		return 1;
 	ret = -ERRNO_TO_PARA_ERROR(errno);
-/* Ignore return value of fchdir() and close(). We're busted anyway. */
-	if (cwd)
-		fchdir(*cwd);
+	/* Ignore return value of fchdir() and close(). We're busted anyway. */
+	if (cwd) {
+		int __a_unused ret2 = fchdir(*cwd); /* STFU, gcc */
+	}
 close_cwd:
 	if (cwd)
 		close(*cwd);
@@ -311,8 +379,7 @@ int para_mkdir(const char *path, mode_t mode)
  * open call is closed after mmap().  Otherwise the file is kept open and the
  * file descriptor is returned in \a fd_ptr.
  *
- * \return Positive on success, negative on errors. Possible errors include: \p
- * E_FSTAT, any errors returned by para_open(), \p E_EMPTY, \p E_MMAP.
+ * \return Standard.
  *
  * \sa para_open(), mmap(2).
  */
@@ -338,17 +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);
@@ -369,17 +426,19 @@ out:
  */
 int para_munmap(void *start, size_t length)
 {
+	int err;
 	if (munmap(start, length) >= 0)
 		return 1;
+	err = errno;
 	PARA_ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
-		strerror(errno));
-	return -E_MUNMAP;
+		strerror(err));
+	return -ERRNO_TO_PARA_ERROR(err);
 }
 
 /**
- * check a file descriptor for writability
+ * Check a file descriptor for writability.
  *
- * \param fd the file descriptor
+ * \param fd The file descriptor.
  *
  * \return positive if fd is ready for writing, zero if it isn't, negative if
  * an error occurred.
@@ -400,3 +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;
+		}
+	}
+}