afs: Document ->lpr of struct afs_callback_arg.

[paraslash.git] / fd.c

diff --git a/fd.c b/fd.c
index 6f9266f47a56cd8dee3e99b8651d12a89bb4069b..86a1f10541f8ca64ffb659d2fc637ea61865e7ff 100644 (file)
--- a/fd.c
+++ b/fd.c
@@ -1,8 +1,4 @@
-/*
- * Copyright (C) 2006-2011 Andre Noll <maan@systemlinux.org>
- *
- * Licensed under the GPL v2. For licencing details see COPYING.
- */
+/* Copyright (C) 2006 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */

 
 /** \file fd.c Helper functions for file descriptor handling. */
 
 
 /** \file fd.c Helper functions for file descriptor handling. */
 


@@ -10,8 +6,6 @@
 #include <sys/types.h>
 #include <dirent.h>
 #include <sys/mman.h>
 #include <sys/types.h>
 #include <dirent.h>
 #include <sys/mman.h>

-#include <fcntl.h>
-#include <sys/uio.h>

 
 #include "para.h"
 #include "error.h"
 
 #include "para.h"
 #include "error.h"


@@ -19,62 +13,163 @@
 #include "fd.h"
 
 /**
 #include "fd.h"
 
 /**

- * Write a buffer to a file descriptor, re-write on short writes.
+ * Change the name or location of a file.

  *
  *

- * \param fd The file descriptor.
- * \param buf The buffer to be sent.
- * \param len The length of \a buf.
+ * \param oldpath File to be moved.
+ * \param newpath Destination.
+ *
+ * This is just a simple wrapper for the rename(2) system call which returns a
+ * paraslash error code and prints an error message on failure.

  *
  *

- * \return Standard. In any case, the number of bytes that have been written is
- * stored in \a len.
+ * \return Standard.
+ *
+ * \sa rename(2).

  */
  */

-int write_all(int fd, const char *buf, size_t *len)
+int xrename(const char *oldpath, const char *newpath)

 {
 {

-       size_t total = *len;
+       int ret = rename(oldpath, newpath);

 
 

-       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;
+       if (ret >= 0)
+               return 1;
+       ret = -ERRNO_TO_PARA_ERROR(errno);
+       PARA_ERROR_LOG("failed to rename %s -> %s\n", oldpath, newpath);
+       return ret;

 }
 
 /**
 }
 
 /**

- * Write a buffer to a non-blocking file descriptor.
+ * Write an array of buffers to a file descriptor.

  *
  * \param fd The file descriptor.
  *
  * \param fd The file descriptor.

- * \param buf the buffer to write.
- * \param len the number of bytes 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.

  *
  *

- * 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 fatal errors, number of bytes written else.

  *
  *

- * \return Negative on errors, number of bytes written else.
+ * 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_nonblock(int fd, const char *buf, size_t len)
+int xwritev(int fd, struct iovec *iov, int iovcnt)

 {
        size_t written = 0;
 {
        size_t written = 0;

-       int ret = 0;
-
-       while (written < len) {
-               size_t num = len - written;
-
-               ret = write(fd, buf + written, num);
-               if (ret < 0 && errno == EAGAIN)
+       int i;
+       struct iovec saved_iov, *curiov;
+
+       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;
                        return written;

-               if (ret < 0)
-                       return -ERRNO_TO_PARA_ERROR(errno);
-               written += ret;
+               /* fatal error */
+               return -ERRNO_TO_PARA_ERROR(errno);

        }
        return written;
 }
 
        }
        return written;
 }
 

+/**
+ * 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 to write.
+ *
+ * This is a simple wrapper for \ref xwritev().
+ *
+ * \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.
+ *
+ * \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_all(int fd, const char *buf, size_t len)
+{
+       int ret = xwrite(fd, buf, len);
+
+       if (ret < 0)
+               return ret;
+       if (ret != len)
+               return -E_SHORT_WRITE;
+       return ret;
+}
+
+/**
+ * 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);
+       va_end(ap);
+       ret = write_all(fd, msg, ret);
+       free(msg);
+       return ret;
+}
+

 /**
  * Read from a non-blocking file descriptor into multiple buffers.
  *
 /**
  * Read from a non-blocking file descriptor into multiple buffers.
  *


@@ -86,13 +181,13 @@ int write_nonblock(int fd, const char *buf, size_t len)
  *
  * 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.
  *
  * 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
- * write_nonblock(), EAGAIN is not considered an error condition. However, EOF
- * is.
+ * Otherwise The function tries to read up to \a sz bytes from \a fd, where \a
+ * sz is the sum of the lengths of all vectors in \a iov. As for xwrite(),
+ * \p EAGAIN is not considered an error condition. However, \p 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
  *
  * \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.
+ * reason other than \p EAGAIN, a negative error code 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
  *
  * 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


@@ -100,7 +195,7 @@ int write_nonblock(int fd, const char *buf, size_t len)
  * have been read before the error occurred. In this case \a num_bytes is
  * positive.
  *
  * have been read before the error occurred. In this case \a num_bytes is
  * positive.
  *

- * \sa \ref write_nonblock(), read(2), readv(2).
+ * \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 readv_nonblock(int fd, struct iovec *iov, int iovcnt, fd_set *rfds,
                size_t *num_bytes)


@@ -221,9 +316,9 @@ out:
  *
  * \param fn The file name.
  *
  *
  * \param fn The file name.
  *

- * \return Non-zero iff file exists.
+ * \return True iff file exists.

  */
  */

-int file_exists(const char *fn)
+bool file_exists(const char *fn)

 {
        struct stat statbuf;
 
 {
        struct stat statbuf;
 


@@ -306,7 +401,7 @@ __must_check int mark_fd_nonblocking(int fd)
  * 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.
  *
  * 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 \ref para_select.

 */
 void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 {
 */
 void para_fd_set(int fd, fd_set *fds, int *max_fileno)
 {


@@ -360,22 +455,20 @@ again:
  * PROT_EXEC PROT_READ PROT_WRITE.
  * \param flags Exactly one of MAP_SHARED and MAP_PRIVATE.
  * \param fd The file to mmap from.
  * 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 map Result pointer.
  *
  * \return Standard.
  *
  * \sa mmap(2).
  */
  * \param map Result pointer.
  *
  * \return Standard.
  *
  * \sa mmap(2).
  */

-int para_mmap(size_t length, int prot, int flags, int fd, off_t offset,
-               void *map)
+int para_mmap(size_t length, int prot, int flags, int fd, void *map)

 {
        void **m = map;
 
        errno = EINVAL;
        if (!length)
                goto err;
 {
        void **m = map;
 
        errno = EINVAL;
        if (!length)
                goto err;

-       *m = mmap(NULL, length, prot, flags, fd, offset);
+       *m = mmap(NULL, length, prot, flags, fd, (off_t)0);

        if (*m != MAP_FAILED)
                return 1;
 err:
        if (*m != MAP_FAILED)
                return 1;
 err:


@@ -450,6 +543,7 @@ static int para_opendir(const char *dirname, DIR **dir, int *cwd)
 {
        int ret;
 
 {
        int ret;
 

+       *dir = NULL;

        if (cwd) {
                ret = para_open(".", O_RDONLY, 0);
                if (ret < 0)
        if (cwd) {
                ret = para_open(".", O_RDONLY, 0);
                if (ret < 0)


@@ -473,20 +567,6 @@ close_cwd:
        return ret;
 }
 
        return ret;
 }
 

-/**
- * A wrapper for fchdir().
- *
- * \param fd An open file descriptor.
- *
- * \return Standard.
- */
-static int para_fchdir(int fd)
-{
-       if (fchdir(fd) < 0)
-               return -ERRNO_TO_PARA_ERROR(errno);
-       return 1;
-}
-

 /**
  * A wrapper for mkdir(2).
  *
 /**
  * A wrapper for mkdir(2).
  *


@@ -541,7 +621,23 @@ int mmap_full_file(const char *path, int open_mode, void **map,
                goto out;
        }
        *size = file_status.st_size;
                goto out;
        }
        *size = file_status.st_size;

-       ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
+       /*
+        * 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, map);

 out:
        if (ret < 0 || !fd_ptr)
                close(fd);
 out:
        if (ret < 0 || !fd_ptr)
                close(fd);


@@ -558,11 +654,14 @@ out:
  *
  * \return Standard.
  *
  *
  * \return Standard.
  *

- * \sa munmap(2), mmap_full_file().
+ * \sa munmap(2), \ref mmap_full_file().

  */
 int para_munmap(void *start, size_t length)
 {
        int err;
  */
 int para_munmap(void *start, size_t length)
 {
        int err;

+
+       if (!start)
+               return 0;

        if (munmap(start, length) >= 0)
                return 1;
        err = errno;
        if (munmap(start, length) >= 0)
                return 1;
        err = errno;


@@ -597,8 +696,6 @@ int write_ok(int fd)
  *
  * Common approach that opens /dev/null until it gets a file descriptor greater
  * than two.
  *
  * 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)
 {
  */
 void valid_fd_012(void)
 {


@@ -632,7 +729,7 @@ int for_each_file_in_dir(const char *dirname,
 {
        DIR *dir;
        struct dirent *entry;
 {
        DIR *dir;
        struct dirent *entry;

-       int cwd_fd, ret2, ret = para_opendir(dirname, &dir, &cwd_fd);
+       int cwd_fd, ret = para_opendir(dirname, &dir, &cwd_fd);

 
        if (ret < 0)
                return ret == -ERRNO_TO_PARA_ERROR(EACCES)? 1 : ret;
 
        if (ret < 0)
                return ret == -ERRNO_TO_PARA_ERROR(EACCES)? 1 : ret;


@@ -668,9 +765,8 @@ int for_each_file_in_dir(const char *dirname,
        ret = 1;
 out:
        closedir(dir);
        ret = 1;
 out:
        closedir(dir);

-       ret2 = para_fchdir(cwd_fd);
-       if (ret2 < 0 && ret >= 0)
-               ret = ret2;
+       if (fchdir(cwd_fd) < 0 && ret >= 0)
+               ret = -ERRNO_TO_PARA_ERROR(errno);

        close(cwd_fd);
        return ret;
 }
        close(cwd_fd);
        return ret;
 }