X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=6042a58f531af44e941f012fdc273d78c2f9fb37;hp=22550286d57747ec90bcdc4aa050c8bea8259e65;hb=6bdac07456cb5872f824028912d1049883a9c21f;hpb=6ce3524dbc2e688aca298836cef0d3f314f70d9b

diff --git a/fd.c b/fd.c
index 22550286..6042a58f 100644
--- a/fd.c
+++ b/fd.c
@@ -1,10 +1,10 @@
 /*
- * 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.
  */
 
-/** \file fd.c helper functions for file descriptor handling */
+/** \file fd.c Helper functions for file descriptor handling. */
 
 #include <sys/types.h>
 #include <dirent.h>
@@ -14,10 +14,36 @@
 
 #include "para.h"
 #include "error.h"
+
 /**
- * check whether a file exists
+ * 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.
  *
- * \param fn the file name
+ * \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;
+}
+
+/**
+ * Check whether a file exists.
+ *
+ * \param fn The file name.
  *
  * \return Non-zero iff file exists.
  */
@@ -59,6 +85,24 @@ int para_select(int n, fd_set *readfds, fd_set *writefds,
 	return ret;
 }
 
+/**
+ * Set a file descriptor to blocking mode.
+ *
+ * \param fd The file descriptor.
+ *
+ * \return Standard.
+ */
+__must_check int mark_fd_blocking(int fd)
+{
+	int flags = fcntl(fd, F_GETFL);
+	if (flags < 0)
+		return -ERRNO_TO_PARA_ERROR(errno);
+	flags = fcntl(fd, F_SETFL, ((long)flags) & ~O_NONBLOCK);
+	if (flags < 0)
+		return -ERRNO_TO_PARA_ERROR(errno);
+	return 1;
+}
+
 /**
  * Set a file descriptor to non-blocking mode.
  *
@@ -66,7 +110,7 @@ int para_select(int n, fd_set *readfds, fd_set *writefds,
  *
  * \return Standard.
  */
-int mark_fd_nonblock(int fd)
+__must_check int mark_fd_nonblocking(int fd)
 {
 	int flags = fcntl(fd, F_GETFL);
 	if (flags < 0)
@@ -78,16 +122,16 @@ int mark_fd_nonblock(int fd)
 }
 
 /**
- * set a file descriptor in a fd_set
+ * Set a file descriptor in a fd_set.
  *
- * \param fd the file descriptor to be set
- * \param fds the file descriptor set
- * \param max_fileno highest-numbered file descriptor
+ * \param fd The file descriptor to be set.
+ * \param fds The file descriptor set.
+ * \param max_fileno Highest-numbered file descriptor.
  *
  * This wrapper for FD_SET() passes its first two arguments to \p FD_SET. Upon
  * return, \a max_fileno contains the maximum of the old_value and \a fd.
  *
- * \sa para_select
+ * \sa para_select.
 */
 void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 {
@@ -110,15 +154,16 @@ 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:
@@ -139,12 +184,12 @@ again:
 /**
  * Paraslash's wrapper for mmap.
  *
- * \param length number of bytes to mmap
- * \param prot either PROT_NONE or the bitwise OR of one or more of
- * PROT_EXEC PROT_READ PROT_WRITE
- * \param flags exactly one of MAP_SHARED and MAP_PRIVATE
- * \param fd the file to mmap from
- * \param offset mmap start
+ * \param length Number of bytes to mmap.
+ * \param prot Either PROT_NONE or the bitwise OR of one or more of
+ * PROT_EXEC PROT_READ PROT_WRITE.
+ * \param flags Exactly one of MAP_SHARED and MAP_PRIVATE.
+ * \param fd The file to mmap from.
+ * \param offset Mmap start.
  *
  * \return This function either returns a valid pointer to the mapped area
  * or calls exit() on errors.
@@ -167,8 +212,8 @@ void *para_mmap(size_t length, int prot, int flags, int fd, off_t offset)
  * \param flags The usual open(2) flags.
  * \param mode Specifies the permissions to use.
  *
- * The mode parameter must be specified when O_CREAT is in the flags, and is ignored
- * otherwise.
+ * The mode parameter must be specified when O_CREAT is in the flags, and is
+ * ignored otherwise.
  *
  * \return The file descriptor on success, negative on errors.
  *
@@ -186,9 +231,9 @@ int para_open(const char *path, int flags, mode_t mode)
 /**
  * Wrapper for chdir(2).
  *
- * \param path the specified directory.
+ * \param path The specified directory.
  *
- * \return Positive on success, negative on errors.
+ * \return Standard.
  */
 int para_chdir(const char *path)
 {
@@ -240,10 +285,10 @@ 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. */
-change_to_orig_dir:
-	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);
@@ -253,7 +298,7 @@ close_cwd:
 /**
  * A wrapper for fchdir().
  *
- * \param fd An open file descriptor
+ * \param fd An open file descriptor.
  *
  * \return Standard.
  */
@@ -278,3 +323,128 @@ int para_mkdir(const char *path, mode_t mode)
 		return 1;
 	return -ERRNO_TO_PARA_ERROR(errno);
 }
+
+/**
+ * Open a file and map it into memory.
+ *
+ * \param path Name of the regular file to map.
+ * \param open_mode Either \p O_RDONLY or \p O_RDWR.
+ * \param map On success, the mapping is returned here.
+ * \param size size of the mapping.
+ * \param fd_ptr The file descriptor of the mapping.
+ *
+ * If \a fd_ptr is \p NULL, the file descriptor resulting from the underlying
+ * open call is closed after mmap().  Otherwise the file is kept open and the
+ * file descriptor is returned in \a fd_ptr.
+ *
+ * \return Standard.
+ *
+ * \sa para_open(), mmap(2).
+ */
+int mmap_full_file(const char *path, int open_mode, void **map,
+		size_t *size, int *fd_ptr)
+{
+	int fd, ret, mmap_prot, mmap_flags;
+	struct stat file_status;
+
+	if (open_mode == O_RDONLY) {
+		mmap_prot = PROT_READ;
+		mmap_flags = MAP_PRIVATE;
+	} else {
+		mmap_prot = PROT_READ | PROT_WRITE;
+		mmap_flags = MAP_SHARED;
+	}
+	ret = para_open(path, open_mode, 0);
+	if (ret < 0)
+		return ret;
+	fd = ret;
+	if (fstat(fd, &file_status) < 0) {
+		ret = -ERRNO_TO_PARA_ERROR(errno);
+		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;
+out:
+	if (ret < 0 || !fd_ptr)
+		close(fd);
+	else
+		*fd_ptr = fd;
+	return ret;
+}
+
+/**
+ * A wrapper for munmap(2).
+ *
+ * \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.
+ *
+ * \sa munmap(2), mmap_full_file().
+ */
+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(err));
+	return -ERRNO_TO_PARA_ERROR(err);
+}
+
+/**
+ * Check a file descriptor for writability.
+ *
+ * \param fd The file descriptor.
+ *
+ * \return positive if fd is ready for writing, zero if it isn't, negative if
+ * an error occurred.
+ */
+
+int write_ok(int fd)
+{
+	struct timeval tv = {0, 0};
+	fd_set wfds;
+	int ret;
+again:
+	FD_ZERO(&wfds);
+	FD_SET(fd, &wfds);
+	tv.tv_sec = 0;
+	tv.tv_usec = 0;
+	ret = select(fd + 1, NULL, &wfds, NULL, &tv);
+	if (ret < 0 && errno == EINTR)
+		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;
+		}
+	}
+}