X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=8f506ff83044dd23ec098961d9607908bc7ce402;hp=556f3e96c073b12de38496c595042616a96bafa0;hb=5b972aabaf27931cae6ac318c9b920d33593f07b;hpb=471684761a2039bbc89aa1e3c33c62de6bef86cf;ds=sidebyside

diff --git a/fd.c b/fd.c
index 556f3e96..8f506ff8 100644
--- a/fd.c
+++ b/fd.c
@@ -4,18 +4,21 @@
  * 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 "para.h"
+#include <sys/types.h>
+#include <dirent.h>
 #include <sys/mman.h>
 #include <fcntl.h>
 #include <sys/select.h>
 
+#include "para.h"
 #include "error.h"
+
 /**
- * check whether a file exists
+ * Check whether a file exists.
  *
- * \param fn the file name
+ * \param fn The file name.
  *
  * \return Non-zero iff file exists.
  */
@@ -27,21 +30,22 @@ int file_exists(const char *fn)
 }
 
 /**
- * paraslash's wrapper for select(2)
+ * Paraslash's wrapper for select(2).
  *
  * It calls select(2) (with no exceptfds) and starts over if select() was
  * interrupted by a signal.
  *
- * \param n the highest-numbered descriptor in any of the two sets, plus 1
- * \param readfds fds that should be checked for readability
- * \param writefds fds that should be checked for writablility
+ * \param n The highest-numbered descriptor in any of the two sets, plus 1.
+ * \param readfds fds that should be checked for readability.
+ * \param writefds fds that should be checked for writablility.
  * \param timeout_tv upper bound on the amount of time elapsed before select()
- * returns
+ * returns.
  *
- * \return The return value of the underlying select() call.
+ * \return The return value of the underlying select() call on success, the
+ * negative system error code on errors.
  *
  * All arguments are passed verbatim to select(2).
- * \sa select(2) select_tut(2)
+ * \sa select(2) select_tut(2).
  */
 int para_select(int n, fd_set *readfds, fd_set *writefds,
 		struct timeval *timeout_tv)
@@ -52,39 +56,57 @@ int para_select(int n, fd_set *readfds, fd_set *writefds,
 		err = errno;
 	} while (ret < 0 && err == EINTR);
 	if (ret < 0)
-		PARA_CRIT_LOG("select error: %s, max_fileno: %d\n",
-			strerror(err), n);
+		return -ERRNO_TO_PARA_ERROR(errno);
 	return ret;
 }
 
 /**
- * set a file descriptor to non-blocking mode
+ * Set a file descriptor to blocking mode.
+ *
+ * \param fd The file descriptor.
+ *
+ * \return Standard.
+ */
+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.
  *
- * \param fd The file descriptor
+ * \param fd The file descriptor.
  *
- * \returns 1 on success, -E_F_GETFL, -E_F_SETFL, on errors.
+ * \return Standard.
  */
-int mark_fd_nonblock(int fd)
+int mark_fd_nonblocking(int fd)
 {
 	int flags = fcntl(fd, F_GETFL);
 	if (flags < 0)
-		return -E_F_GETFL;
-	if (fcntl(fd, F_SETFL, ((long)flags) | O_NONBLOCK) < 0)
-		return -E_F_SETFL;
+		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 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)
 {
@@ -107,10 +129,11 @@ 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
+* 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
@@ -134,14 +157,14 @@ again:
 }
 
 /**
- * *paraslash's wrapper for mmap
+ * 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.
@@ -157,3 +180,222 @@ void *para_mmap(size_t length, int prot, int flags, int fd, off_t offset)
 	exit(EXIT_FAILURE);
 }
 
+/**
+ * Wrapper for the open(2) system call.
+ *
+ * \param path The filename.
+ * \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.
+ *
+ * \return The file descriptor on success, negative on errors.
+ *
+ * \sa open(2).
+ */
+int para_open(const char *path, int flags, mode_t mode)
+{
+	int ret = open(path, flags, mode);
+
+	if (ret >= 0)
+		return ret;
+	return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * Wrapper for chdir(2).
+ *
+ * \param path The specified directory.
+ *
+ * \return Standard.
+ */
+int para_chdir(const char *path)
+{
+	int ret = chdir(path);
+
+	if (ret >= 0)
+		return 1;
+	return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * Save the cwd and open a given directory.
+ *
+ * \param dirname Path to the directory to open.
+ * \param dir Result pointer.
+ * \param cwd File descriptor of the current working directory.
+ *
+ * \return Standard.
+ *
+ * Opening the current directory (".") and calling fchdir() to return is
+ * usually faster and more reliable than saving cwd in some buffer and calling
+ * chdir() afterwards.
+ *
+ * If \a cwd is not \p NULL "." is opened and the resulting file descriptor is
+ * stored in \a cwd. If the function returns success, and \a cwd is not \p
+ * NULL, the caller must close this file descriptor (probably after calling
+ * fchdir(*cwd)).
+ *
+ * On errors, the function undos everything, so the caller needs neither close
+ * any files, nor change back to the original working directory.
+ *
+ * \sa getcwd(3).
+ *
+ */
+int para_opendir(const char *dirname, DIR **dir, int *cwd)
+{
+	int ret;
+
+	if (cwd) {
+		ret = para_open(".", O_RDONLY, 0);
+		if (ret < 0)
+			return ret;
+		*cwd = ret;
+	}
+	ret = para_chdir(dirname);
+	if (ret < 0)
+		goto close_cwd;
+	*dir = opendir(".");
+	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);
+close_cwd:
+	if (cwd)
+		close(*cwd);
+	return ret;
+}
+
+/**
+ * A wrapper for fchdir().
+ *
+ * \param fd An open file descriptor.
+ *
+ * \return Standard.
+ */
+int para_fchdir(int fd)
+{
+	if (fchdir(fd) < 0)
+		return -ERRNO_TO_PARA_ERROR(errno);
+	return 1;
+}
+
+/**
+ * A wrapper for mkdir(2).
+ *
+ * \param path Name of the directory to create.
+ * \param mode The permissions to use.
+ *
+ * \return Standard.
+ */
+int para_mkdir(const char *path, mode_t mode)
+{
+	if (!mkdir(path, 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)
+{
+	if (munmap(start, length) >= 0)
+		return 1;
+	PARA_ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
+		strerror(errno));
+	return -E_MUNMAP;
+}
+
+/**
+ * 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;
+}