-/*
- * Copyright (C) 2006-2014 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. */
#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 "fd.h"
/**
- * Write an array of buffers to a file descriptor.
+ * Change the name or location of a file.
*
- * \param fd The file descriptor.
+ * \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.
+ *
+ * \sa rename(2).
+ */
+int xrename(const char *oldpath, const char *newpath)
+{
+ int ret = rename(oldpath, newpath);
+
+ 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 an array of buffers, handling non-fatal errors.
+ *
+ * \param fd The file descriptor to write to.
* \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, EWOULDBLOCK and EINTR are not considered error conditions. If a
+ * write operation fails with EAGAIN or EWOULDBLOCK, the number of bytes that
+ * have been written so far is returned. In the EINTR case the operation is
+ * retried. Short writes are handled by issuing a subsequent write operation
+ * for the remaining part.
*
* \return Negative on fatal 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.
+ * buffer sizes or a negative error code which indicates the fatal error that
+ * caused a 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.
+ * For nonblocking file descriptors there is a third possibility: Any
+ * non-negative return value less than the sum of the buffer sizes indicates
+ * that a write operation returned EAGAIN/EWOULDBLOCK.
*
* \sa writev(2), \ref xwrite().
*/
}
/**
- * Write all data to a file descriptor.
+ * Write to a file descriptor, fail on short writes.
*
* \param fd The file descriptor.
- * \param buf The buffer to be sent.
- * \param len The length of \a buf.
+ * \param buf The buffer to be written.
+ * \param len The length of the buffer.
*
- * This is like \ref xwrite() but returns \p -E_SHORT_WRITE if not
- * all data could be written.
+ * For blocking file descriptors this function behaves identical to \ref
+ * xwrite(). For non-blocking file descriptors it returns -E_SHORT_WRITE
+ * (rather than a value less than len) if not all data could be written.
*
* \return Number of bytes written on success, negative error code else.
*/
}
/**
- * Write a buffer given by a format string.
+ * A fprintf-like function for raw file descriptors.
+ *
+ * This function creates a string buffer according to the given format and
+ * writes this buffer to a file descriptor.
*
* \param fd The file descriptor.
* \param fmt A format string.
*
+ * The difference to fprintf(3) is that the first argument is a file
+ * descriptor, not a FILE pointer. This function does not rely on stdio.
+ *
* \return The return value of the underlying call to \ref write_all().
+ *
+ * \sa fprintf(3), \ref xvasprintf().
*/
__printf_2_3 int write_va_buffer(int fd, const char *fmt, ...)
{
va_start(ap, fmt);
ret = xvasprintf(&msg, fmt, ap);
+ va_end(ap);
ret = write_all(fd, msg, ret);
free(msg);
return ret;
* \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, 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.
+ * This function tries to read up to sz bytes from fd, where sz is the sum of
+ * the lengths of all vectors in iov. Like \ref xwrite(), EAGAIN and EINTR are
+ * not considered error conditions. 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 error code is returned.
+ * reason other than EAGAIN or EINTR, 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
*
* \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, 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;
if (ret == 0)
return -E_EOF;
if (ret < 0) {
- if (errno == EAGAIN)
+ if (errno == EAGAIN || errno == EINTR)
return 0;
return -ERRNO_TO_PARA_ERROR(errno);
}
* \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
*
* \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)
+int read_nonblock(int fd, void *buf, size_t sz, size_t *num_bytes)
{
struct iovec iov = {.iov_base = buf, .iov_len = sz};
- return readv_nonblock(fd, &iov, 1, rfds, num_bytes);
+ return readv_nonblock(fd, &iov, 1, 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().
+ * Read a buffer and compare its contents to a string, ignoring case.
*
- * 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.
+ * \param fd The file descriptor to read from.
+ * \param expectation The expected string to compare to.
*
- * \return Positive if \a pattern was received, negative on errors, zero if no data
- * was available to read.
+ * The given file descriptor is expected to be in non-blocking mode. The string
+ * comparison is performed using strncasecmp(3).
*
- * \sa \ref read_nonblock(), \sa strncasecmp(3).
+ * \return Zero if no data was available, positive if a buffer was read whose
+ * contents compare as equal to the expected string, negative otherwise.
+ * Possible errors: (a) not enough data was read, (b) the buffer contents
+ * compared as non-equal, (c) a read error occurred. In the first two cases,
+ * -E_READ_PATTERN is returned. In the read error case the (negative) return
+ * value of the underlying call to \ref read_nonblock() is returned.
*/
-int read_pattern(int fd, const char *pattern, size_t bufsize, fd_set *rfds)
+int read_and_compare(int fd, const char *expectation)
{
- size_t n, len;
- char *buf = para_malloc(bufsize + 1);
- int ret = read_nonblock(fd, buf, bufsize, rfds, &n);
+ size_t n, len = strlen(expectation);
+ char *buf = alloc(len + 1);
+ int ret = read_nonblock(fd, buf, len, &n);
- buf[n] = '\0';
if (ret < 0)
goto out;
+ buf[n] = '\0';
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)
+ if (strncasecmp(buf, expectation, 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;
}
-/**
- * Check whether a file exists.
- *
- * \param fn The file name.
- *
- * \return Non-zero iff file exists.
- */
-int file_exists(const char *fn)
-{
- struct stat statbuf;
-
- return !stat(fn, &statbuf);
-}
-
-/**
- * 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 timeout_tv upper bound on the amount of time elapsed before select()
- * returns.
- *
- * \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).
- */
-int para_select(int n, fd_set *readfds, fd_set *writefds,
- struct timeval *timeout_tv)
-{
- int ret;
- do
- ret = select(n, readfds, writefds, NULL, timeout_tv);
- while (ret < 0 && errno == EINTR);
- if (ret < 0)
- return -ERRNO_TO_PARA_ERROR(errno);
- return ret;
-}
-
/**
* Set a file descriptor to blocking mode.
*
return 1;
}
-/**
- * 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.
- *
- * 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.
-*/
-void para_fd_set(int fd, fd_set *fds, int *max_fileno)
-{
- assert(fd >= 0 && fd < FD_SETSIZE);
-#if 0
- {
- int flags = fcntl(fd, F_GETFL);
- if (!(flags & O_NONBLOCK)) {
- PARA_EMERG_LOG("fd %d is a blocking file descriptor\n", fd);
- exit(EXIT_FAILURE);
- }
- }
-#endif
- FD_SET(fd, fds);
- *max_fileno = PARA_MAX(*max_fileno, fd);
-}
-
-/**
- * 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 (fgets(line, size, f))
- return 1;
- if (feof(f))
- return 0;
- if (!ferror(f))
- return -E_FGETS;
- if (errno != EINTR) {
- PARA_ERROR_LOG("%s\n", strerror(errno));
- return -E_FGETS;
- }
- clearerr(f);
- goto again;
-}
-
/**
* Paraslash's wrapper for mmap.
*
* 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).
*/
-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;
- *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:
}
/**
- * 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.
+ * Create a directory, don't fail if it already exists.
*
- * \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.
+ * \param path Name of the directory to create.
*
- * \sa getcwd(3).
+ * This function passes the fixed mode value 0777 to mkdir(3) (which consults
+ * the file creation mask and restricts this value).
*
+ * \return Zero if the path already existed as a directory or as a symbolic
+ * link which leads to a directory, one if the path did not exist and the
+ * directory has been created successfully, negative error code else.
*/
-static int para_opendir(const char *dirname, DIR **dir, int *cwd)
+int para_mkdir(const char *path)
{
- int ret;
+ /*
+ * We call opendir(3) rather than relying on stat(2) because this way
+ * we don't need extra code to get the symlink case right.
+ */
+ DIR *dir = opendir(path);
- *dir = NULL;
- 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) {
- int __a_unused ret2 = fchdir(*cwd); /* STFU, gcc */
+ if (dir) {
+ closedir(dir);
+ return 0;
}
-close_cwd:
- if (cwd)
- close(*cwd);
- return ret;
-}
-
-/**
- * A wrapper for fchdir().
- *
- * \param fd An open file descriptor.
- *
- * \return Standard.
- */
-static int para_fchdir(int fd)
-{
- if (fchdir(fd) < 0)
+ if (errno != ENOENT)
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);
+ return mkdir(path, 0777) == 0? 1 : -ERRNO_TO_PARA_ERROR(errno);
}
/**
if (S_ISDIR(file_status.st_mode))
goto out;
- ret = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
+ ret = para_mmap(*size, mmap_prot, mmap_flags, fd, map);
out:
if (ret < 0 || !fd_ptr)
close(fd);
* \param start The start address of the memory mapping.
* \param length The size of the mapping.
*
- * \return Standard.
+ * If NULL is passed as the start address, the length value is ignored and the
+ * function does nothing.
*
- * \sa munmap(2), mmap_full_file().
+ * \return Zero if NULL was passed, one if the memory area was successfully
+ * unmapped, a negative error code otherwise.
+ *
+ * \sa munmap(2), \ref mmap_full_file().
*/
int para_munmap(void *start, size_t length)
{
- int err;
-
if (!start)
return 0;
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);
+ return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * Simple wrapper for poll(2).
+ *
+ * It calls poll(2) and starts over if the call was interrupted by a signal.
+ *
+ * \param fds See poll(2).
+ * \param nfds See poll(2).
+ * \param timeout See poll(2).
+ *
+ * \return The return value of the underlying poll() call on success, the
+ * negative paraslash error code on errors.
+ *
+ * All arguments are passed verbatim to poll(2).
+ */
+int xpoll(struct pollfd *fds, nfds_t nfds, int timeout)
+{
+ int ret;
+
+ do
+ ret = poll(fds, nfds, timeout);
+ while (ret < 0 && errno == EINTR);
+ return ret < 0? -ERRNO_TO_PARA_ERROR(errno) : ret;
+}
+
+/**
+ * Check a file descriptor for readability.
+ *
+ * \param fd The file descriptor.
+ *
+ * \return positive if fd is ready for reading, zero if it isn't, negative if
+ * an error occurred.
+ *
+ * \sa \ref write_ok().
+ */
+int read_ok(int fd)
+{
+ struct pollfd pfd = {.fd = fd, .events = POLLIN};
+ int ret = xpoll(&pfd, 1, 0);
+ return ret < 0? ret : pfd.revents & POLLIN;
}
/**
*
* \return positive if fd is ready for writing, zero if it isn't, negative if
* an error occurred.
+ *
+ * \sa \ref read_ok().
*/
-
int write_ok(int fd)
{
- struct timeval tv;
- fd_set wfds;
-
- FD_ZERO(&wfds);
- FD_SET(fd, &wfds);
- tv.tv_sec = 0;
- tv.tv_usec = 0;
- return para_select(fd + 1, NULL, &wfds, &tv);
+ struct pollfd pfd = {.fd = fd, .events = POLLOUT};
+ int ret = xpoll(&pfd, 1, 0);
+ return ret < 0? ret : pfd.revents & POLLOUT;
}
/**
*
* 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)
{
}
}
}
-
-/**
- * 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;
-}
projects / paraslash.git / blobdiff