2 * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file fd.c \brief Helper functions for file descriptor handling. */
19 * Wrapper for the write system call.
21 * \param fd The file descriptor to write to.
22 * \param buf The buffer to write.
23 * \param size The length of \a buf in bytes.
25 * This function writes out the given buffer and retries if an interrupt
26 * occurred during the write.
32 ssize_t __write(int fd, const void *buf, size_t size)
37 ret = write(fd, buf, size);
38 if ((ret < 0) && (errno == EAGAIN || errno == EINTR))
40 return ret >= 0? ret : -ERRNO_TO_ERROR(errno);
45 * Write the whole buffer to a file descriptor.
47 * \param fd The file descriptor to write to.
48 * \param buf The buffer to write.
49 * \param size The length of \a buf in bytes.
51 * This function writes the given buffer and continues on short writes and
52 * when interrupted by a signal.
56 static ssize_t write_all(int fd, const void *buf, size_t size)
58 // DEBUG_LOG("writing %zu bytes\n", size);
61 ssize_t ret = __write(fd, b, size);
62 // DEBUG_LOG("ret: %zd\n", ret);
72 * Wrapper for the open(2) system call.
74 * \param path The filename.
75 * \param flags The usual open(2) flags.
76 * \param mode Specifies the permissions to use.
78 * The mode parameter must be specified when O_CREAT is in the flags, and is
81 * \return The file descriptor on success, negative on errors.
85 static int __open(const char *path, int flags, mode_t mode)
87 int ret = open(path, flags, mode);
91 return -ERRNO_TO_ERROR(errno);
95 * Open a file, write the given buffer and close the file.
97 * \param filename Full path to the file to open.
98 * \param buf The buffer to write to the file.
99 * \param size The size of \a buf.
103 int adu_write_file(const char *filename, const void *buf, size_t size)
107 ret = __open(filename, O_WRONLY | O_CREAT | O_EXCL, 0644);
111 ret = write_all(fd, buf, size);
121 * Wrapper for chdir(2).
123 * \param path The specified directory.
127 int __chdir(const char *path)
129 int ret = chdir(path);
133 return -ERRNO_TO_ERROR(errno);
137 * Save the cwd and open a given directory.
139 * \param dirname Path to the directory to open.
140 * \param dir Result pointer.
141 * \param cwd File descriptor of the current working directory.
145 * Opening the current directory (".") and calling fchdir() to return is
146 * usually faster and more reliable than saving cwd in some buffer and calling
147 * chdir() afterwards.
149 * If \a cwd is not \p NULL "." is opened and the resulting file descriptor is
150 * stored in \a cwd. If the function returns success, and \a cwd is not \p
151 * NULL, the caller must close this file descriptor (probably after calling
154 * On errors, the function undos everything, so the caller needs neither close
155 * any files, nor change back to the original working directory.
160 int adu_opendir(const char *dirname, DIR **dir, int *cwd)
165 ret = __open(".", O_RDONLY, 0);
170 ret = __chdir(dirname);
176 ret = -ERRNO_TO_ERROR(errno);
177 /* Ignore return value of fchdir() and close(). We're busted anyway. */
187 * A wrapper for fchdir().
189 * \param fd An open file descriptor.
193 int adu_fchdir(int fd)
196 return -ERRNO_TO_ERROR(errno);
201 * Open a file and map it into memory.
203 * \param path Name of the regular file to map.
204 * \param open_mode Either \p O_RDONLY or \p O_RDWR.
205 * \param map On success, the mapping is returned here.
206 * \param size size of the mapping.
207 * \param fd_ptr The file descriptor of the mapping.
209 * If \a fd_ptr is \p NULL, the file descriptor resulting from the underlying
210 * open call is closed after mmap(). Otherwise the file is kept open and the
211 * file descriptor is returned in \a fd_ptr.
217 int mmap_full_file(const char *path, int open_mode, void **map,
218 size_t *size, int *fd_ptr)
220 int fd, ret, mmap_prot, mmap_flags;
221 struct stat file_status;
223 if (open_mode == O_RDONLY) {
224 mmap_prot = PROT_READ;
225 mmap_flags = MAP_PRIVATE;
227 mmap_prot = PROT_READ | PROT_WRITE;
228 mmap_flags = MAP_SHARED;
230 ret = __open(path, open_mode, 0);
234 if (fstat(fd, &file_status) < 0) {
235 ret = -ERRNO_TO_ERROR(errno);
238 *size = file_status.st_size;
240 DEBUG_LOG("%s: size %zu\n", path, *size);
243 *map = mmap(NULL, *size, mmap_prot, mmap_flags, fd, 0);
244 if (*map == MAP_FAILED) {
251 if (ret < 0 || !fd_ptr)
259 * A wrapper for munmap(2).
261 * \param start The start address of the memory mapping.
262 * \param length The size of the mapping.
264 * \return Positive on success, \p -E_MUNMAP on errors.
266 * \sa munmap(2), mmap_full_file().
268 int adu_munmap(void *start, size_t length)
271 if (munmap(start, length) >= 0)
274 ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
276 return -ERRNO_TO_ERROR(err);
279 __must_check __malloc static char *adu_dirname(const char *name)
285 ret = adu_strdup(name);
286 p = strrchr(ret, '/');
297 * \param p Full path that should be created.
299 * \param mode Use this mode when creating directories.
301 * \return 0 if successful, -E_MKDIR on errors.
303 int mkpath(const char *p, mode_t mode)
308 DEBUG_LOG("%s\n", p);
309 if (strcmp(p, ".") == 0 || strcmp(p, "/") == 0 || strcmp(p, "") == 0) {
310 DEBUG_LOG("reached beginning of path\n");
313 path = adu_strdup(p);
314 parent = adu_dirname(p);
317 ret = mkpath(parent, mode);
320 INFO_LOG("making dir %s\n", path);
322 if ((mkdir(path, mode) == -1) && (errno != EEXIST))