/*
- * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
#include "para.h"
#include "error.h"
-/*
+/**
* Write a buffer to a file descriptor, re-write on short writes.
*
* \param fd The file descriptor.
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.
*
}
/**
-* 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:
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);
*/
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.
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;
+ }
+ }
+}