X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=fd.c;h=3a8406d9c9fd1454a0807c8584bae78aa1b2f543;hp=31eb638826f93206e7d36814b7d4cd8b8988a898;hb=4744d937c4160898d1fe151257606430750e580c;hpb=7cb521f3eeb7fda02344c523989d5903251e673e

diff --git a/fd.c b/fd.c
index 31eb6388..3a8406d9 100644
--- a/fd.c
+++ b/fd.c
@@ -1,82 +1,295 @@
 /*
- * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2012 Andre Noll <maan@systemlinux.org>
  *
  * Licensed under the GPL v2. For licencing details see COPYING.
  */
 
 /** \file fd.c Helper functions for file descriptor handling. */
 
+#include <regex.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <sys/mman.h>
 #include <fcntl.h>
-#include <sys/select.h>
+#include <sys/uio.h>
 
 #include "para.h"
 #include "error.h"
+#include "string.h"
+#include "fd.h"
 
 /**
- * Write a buffer to a file descriptor, re-write on short writes.
+ * Write an array of buffers to a file descriptor.
  *
  * \param fd The file descriptor.
- * \param buf The buffer to be sent.
- * \param len The length of \a buf.
+ * \param iov Pointer to one or more buffers.
+ * \param iovcnt The number of buffers.
+ *
+ * EAGAIN/EWOULDBLOCK is not considered a fatal error condition. For example
+ * DCCP 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 fatal errors, number of bytes written else.
  *
- * \return Standard. In any case, the number of bytes that have been written is
- * stored in \a len.
+ * For blocking file descriptors, this function returns either the sum of all
+ * buffer sizes, or the error code of the fatal error that caused the last
+ * write call to fail.
+ *
+ * For nonblocking file descriptors there is a third possibility: Any positive
+ * return value less than the sum of the buffer sizes indicates that some bytes
+ * have been written but the next write would block.
+ *
+ * \sa writev(2), \ref xwrite().
  */
-int write_all(int fd, const char *buf, size_t *len)
+int xwritev(int fd, struct iovec *iov, int iovcnt)
 {
-	size_t total = *len;
+	size_t written = 0;
+	int i;
+	struct iovec saved_iov, *curiov;
 
-	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;
+	i = 0;
+	curiov = iov;
+	saved_iov = *curiov;
+	while (i < iovcnt && curiov->iov_len > 0) {
+		ssize_t ret = writev(fd, curiov, iovcnt - i);
+		if (ret >= 0) {
+			written += ret;
+			while (ret > 0) {
+				if (ret < curiov->iov_len) {
+					curiov->iov_base += ret;
+					curiov->iov_len -= ret;
+					break;
+				}
+				ret -= curiov->iov_len;
+				*curiov = saved_iov;
+				i++;
+				if (i >= iovcnt)
+					return written;
+				curiov++;
+				saved_iov = *curiov;
+			}
+			continue;
+		}
+		if (errno == EINTR)
+			/*
+			 * The write() call was interrupted by a signal before
+			 * any data was written. Try again.
+			 */
+			continue;
+		if (errno == EAGAIN || errno == EWOULDBLOCK)
+			/*
+			 * We don't consider this an error. Note that POSIX
+			 * allows either error to be returned, and does not
+			 * require these constants to have the same value.
+			 */
+			return written;
+		/* fatal error */
+		return -ERRNO_TO_PARA_ERROR(errno);
 	}
-	return 1;
+	return written;
 }
 
 /**
- * Write a buffer to a non-blocking file descriptor.
+ * Write a buffer to a file descriptor, re-writing on short writes.
  *
  * \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.
+ * \param buf The buffer to write.
+ * \param len The number of bytes to write.
  *
- * If \a max_bytes_per_write is non-zero, do not send more than that many bytes
- * per write().
+ * This is a simple wrapper for \ref xwritev().
  *
- * 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 The return value of the underlying call to \ref xwritev().
+ */
+int xwrite(int fd, const char *buf, size_t len)
+{
+	struct iovec iov = {.iov_base = (void *)buf, .iov_len = len};
+	return xwritev(fd, &iov, 1);
+}
+
+/**
+ * Write all data to a file descriptor.
  *
- * \return Negative on errors, number of bytes written else.
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
+ *
+ * This is like \ref xwrite() but returns \p -E_SHORT_WRITE if not
+ * all data could be written.
+ *
+ * \return Number of bytes written on success, negative error code else.
  */
-int write_nonblock(int fd, const char *buf, size_t len,
-		size_t max_bytes_per_write)
+int write_all(int fd, const char *buf, size_t len)
 {
-	size_t written = 0;
-	int ret = 0;
+	int ret = xwrite(fd, buf, len);
 
-	while (written < len) {
-		size_t num = len - written;
+	if (ret < 0)
+		return ret;
+	if (ret != len)
+		return -E_SHORT_WRITE;
+	return ret;
+}
 
-		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)
+/**
+ * Write a buffer given by a format string.
+ *
+ * \param fd The file descriptor.
+ * \param fmt A format string.
+ *
+ * \return The return value of the underlying call to \ref write_all().
+ */
+__printf_2_3 int write_va_buffer(int fd, const char *fmt, ...)
+{
+	char *msg;
+	int ret;
+	va_list ap;
+
+	va_start(ap, fmt);
+	ret = xvasprintf(&msg, fmt, ap);
+	ret = write_all(fd, msg, ret);
+	free(msg);
+	return ret;
+}
+
+/**
+ * Read from a non-blocking file descriptor into multiple buffers.
+ *
+ * \param fd The file descriptor to read from.
+ * \param iov Scatter/gather array used in readv().
+ * \param iovcnt Number of elements in \a iov.
+ * \param rfds An optional fd set pointer.
+ * \param num_bytes Result pointer. Contains the number of bytes read from \a fd.
+ *
+ * If \a rfds is not \p NULL and the (non-blocking) file descriptor \a fd is
+ * not set in \a rfds, this function returns early without doing anything.
+ * Otherwise The function tries to read up to \a sz bytes from \a fd. As for
+ * xwrite(), EAGAIN is not considered an error condition. However, EOF
+ * is.
+ *
+ * \return Zero or a negative error code. If the underlying call to readv(2)
+ * returned zero (indicating an end of file condition) or failed for some
+ * reason other than \p EAGAIN, a negative return value is returned.
+ *
+ * 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 occurred. In this case \a num_bytes is
+ * positive.
+ *
+ * \sa \ref xwrite(), read(2), readv(2).
+ */
+int readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds,
+		size_t *num_bytes)
+{
+	int ret, i, j;
+
+	*num_bytes = 0;
+	/*
+	 * Avoid a shortcoming of select(): Reads from a non-blocking fd might
+	 * return EAGAIN even if FD_ISSET() returns true. However, FD_ISSET()
+	 * returning false definitely means that no data can currently be read.
+	 * This is the common case, so it is worth to avoid the overhead of the
+	 * read() system call in this case.
+	 */
+	if (rfds && !FD_ISSET(fd, rfds))
+		return 0;
+
+	for (i = 0, j = 0; i < iovcnt;) {
+
+		/* fix up the first iov */
+		assert(j < iov[i].iov_len);
+		iov[i].iov_base += j;
+		iov[i].iov_len -= j;
+		ret = readv(fd, iov + i, iovcnt - i);
+		iov[i].iov_base -= j;
+		iov[i].iov_len += j;
+
+		if (ret == 0)
+			return -E_EOF;
+		if (ret < 0) {
+			if (errno == EAGAIN)
+				return 0;
 			return -ERRNO_TO_PARA_ERROR(errno);
-		written += ret;
+		}
+		*num_bytes += ret;
+		while (ret > 0) {
+			if (ret < iov[i].iov_len - j) {
+				j += ret;
+				break;
+			}
+			ret -= iov[i].iov_len - j;
+			j = 0;
+			if (++i >= iovcnt)
+				break;
+		}
 	}
-	return written;
+	return 0;
+}
+
+/**
+ * Read from a non-blocking file descriptor into a single buffer.
+ *
+ * \param fd The file descriptor to read from.
+ * \param buf The buffer to read data to.
+ * \param sz The size of \a buf.
+ * \param rfds \see \ref readv_nonblock().
+ * \param num_bytes \see \ref readv_nonblock().
+ *
+ * This is a simple wrapper for readv_nonblock() which uses an iovec with a single
+ * buffer.
+ *
+ * \return The return value of the underlying call to readv_nonblock().
+ */
+int read_nonblock(int fd, void *buf, size_t sz, fd_set *rfds, size_t *num_bytes)
+{
+	struct iovec iov = {.iov_base = buf, .iov_len = sz};
+	return readv_nonblock(fd, &iov, 1, rfds, num_bytes);
+}
+
+/**
+ * Read a buffer and check its content for a pattern.
+ *
+ * \param fd The file descriptor to receive from.
+ * \param pattern The expected pattern.
+ * \param bufsize The size of the internal buffer.
+ * \param rfds Passed to read_nonblock().
+ *
+ * This function tries to read at most \a bufsize bytes from the non-blocking
+ * file descriptor \a fd. If at least \p strlen(\a pattern) bytes have been
+ * received, the beginning of the received buffer is compared with \a pattern,
+ * ignoring case.
+ *
+ * \return Positive if \a pattern was received, negative on errors, zero if no data
+ * was available to read.
+ *
+ * \sa \ref read_nonblock(), \sa strncasecmp(3).
+ */
+int read_pattern(int fd, const char *pattern, size_t bufsize, fd_set *rfds)
+{
+	size_t n, len;
+	char *buf = para_malloc(bufsize + 1);
+	int ret = read_nonblock(fd, buf, bufsize, rfds, &n);
+
+	buf[n] = '\0';
+	if (ret < 0)
+		goto out;
+	ret = 0;
+	if (n == 0)
+		goto out;
+	ret = -E_READ_PATTERN;
+	len = strlen(pattern);
+	if (n < len)
+		goto out;
+	if (strncasecmp(buf, pattern, len) != 0)
+		goto out;
+	ret = 1;
+out:
+	if (ret < 0) {
+		PARA_NOTICE_LOG("%s\n", para_strerror(-ret));
+		PARA_NOTICE_LOG("recvd %zu bytes: %s\n", n, buf);
+	}
+	free(buf);
+	return ret;
 }
 
 /**
@@ -114,11 +327,10 @@ int file_exists(const char *fn)
 int para_select(int n, fd_set *readfds, fd_set *writefds,
 		struct timeval *timeout_tv)
 {
-	int ret, err;
-	do {
+	int ret;
+	do
 		ret = select(n, readfds, writefds, NULL, timeout_tv);
-		err = errno;
-	} while (ret < 0 && err == EINTR);
+	while (ret < 0 && errno == EINTR);
 	if (ret < 0)
 		return -ERRNO_TO_PARA_ERROR(errno);
 	return ret;
@@ -310,7 +522,7 @@ 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;
 
@@ -344,7 +556,7 @@ 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);
@@ -405,6 +617,22 @@ 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)
@@ -427,6 +655,9 @@ out:
 int para_munmap(void *start, size_t length)
 {
 	int err;
+
+	if (!start)
+		return 0;
 	if (munmap(start, length) >= 0)
 		return 1;
 	err = errno;
@@ -446,18 +677,14 @@ int para_munmap(void *start, size_t length)
 
 int write_ok(int fd)
 {
-	struct timeval tv = {0, 0};
+	struct timeval tv;
 	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;
+	return para_select(fd + 1, NULL, &wfds, &tv);
 }
 
 /**
@@ -480,3 +707,65 @@ void valid_fd_012(void)
 		}
 	}
 }
+
+/**
+ * Traverse the given directory recursively.
+ *
+ * \param dirname The directory to traverse.
+ * \param func The function to call for each entry.
+ * \param private_data Pointer to an arbitrary data structure.
+ *
+ * For each regular file under \a dirname, the supplied function \a func is
+ * called.  The full path of the regular file and the \a private_data pointer
+ * are passed to \a func. Directories for which the calling process has no
+ * permissions to change to are silently ignored.
+ *
+ * \return Standard.
+ */
+int for_each_file_in_dir(const char *dirname,
+		int (*func)(const char *, void *), void *private_data)
+{
+	DIR *dir;
+	struct dirent *entry;
+	int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
+
+	if (ret < 0)
+		return ret == -ERRNO_TO_PARA_ERROR(EACCES)? 1 : ret;
+	/* scan cwd recursively */
+	while ((entry = readdir(dir))) {
+		mode_t m;
+		char *tmp;
+		struct stat s;
+
+		if (!strcmp(entry->d_name, "."))
+			continue;
+		if (!strcmp(entry->d_name, ".."))
+			continue;
+		if (lstat(entry->d_name, &s) == -1)
+			continue;
+		m = s.st_mode;
+		if (!S_ISREG(m) && !S_ISDIR(m))
+			continue;
+		tmp = make_message("%s/%s", dirname, entry->d_name);
+		if (!S_ISDIR(m)) {
+			ret = func(tmp, private_data);
+			free(tmp);
+			if (ret < 0)
+				goto out;
+			continue;
+		}
+		/* directory */
+		ret = for_each_file_in_dir(tmp, func, private_data);
+		free(tmp);
+		if (ret < 0)
+			goto out;
+	}
+	ret = 1;
+out:
+	closedir(dir);
+	ret2 = para_fchdir(cwd_fd);
+	if (ret2 < 0 && ret >= 0)
+		ret = ret2;
+	close(cwd_fd);
+	return ret;
+}