/*
- * Copyright (C) 2006 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2006-2009 Andre Noll <maan@systemlinux.org>
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * 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 "para.h"
+#include "error.h"
+#include "string.h"
+
+/**
+ * Write a buffer to a file descriptor, re-write on short writes.
*
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
*
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
+ * \return Standard. In any case, the number of bytes that have been written is
+ * stored in \a len.
*/
+int write_all(int fd, const char *buf, size_t *len)
+{
+ size_t total = *len;
-/** \file fd.c helper functions for file descriptor handling */
+ 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;
+}
-#include "para.h"
+/**
+ * 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;
-#include <sys/select.h>
+ 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;
+}
-#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.
*/
}
/**
- * 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 timeout upper bound on the amount of time elapsed before select()
- * returns
+ * \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.
+ * \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)
+ struct timeval *timeout_tv)
{
- int ret, err;
- do {
- ret = select(n, readfds, writefds, NULL, timeout);
- err = errno;
- } while (ret < 0 && err == EINTR);
+ int ret;
+ do
+ ret = select(n, readfds, writefds, NULL, timeout_tv);
+ while (ret < 0 && errno == EINTR);
if (ret < 0)
- PARA_CRIT_LOG("select error (%s)\n", strerror(err));
+ 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
+ * \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)
+__must_check int mark_fd_blocking(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 to non-blocking mode.
*
- * \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.
+ *
+ * \return Standard.
+ */
+__must_check int mark_fd_nonblocking(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 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 = MAX(*max_fileno, fd);
+ *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.
+ *
+ * \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 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)
+{
+ void **m = map;
+
+ errno = EINVAL;
+ if (!length)
+ goto err;
+ *m = mmap(NULL, length, prot, flags, fd, offset);
+ if (*m != MAP_FAILED)
+ return 1;
+err:
+ *m = NULL;
+ return -ERRNO_TO_PARA_ERROR(errno);
+}
+
+/**
+ * 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) {
+ int __a_unused ret2 = fchdir(*cwd); /* STFU, gcc */
+ }
+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 = para_mmap(*size, mmap_prot, mmap_flags, fd, 0, map);
+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)
+{
+ int err;
+ 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);
+}
+
+/**
+ * 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;
+ 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);
+}
+
+/**
+ * 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;
+ }
+ }
+}
+
+/**
+ * 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