--- /dev/null
+/*
+ * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
+ *
+ * Licensed under the GPL v2. For licencing details see COPYING.
+ */
+
+/** \file util.c Helper functions needed by both libosl and oslfsck. */
+
+#include <sys/types.h>
+#include <dirent.h>
+#include <sys/mman.h>
+#include <fcntl.h>
+#include <sys/select.h>
+
+#include "log.h"
+#include "osl.h"
+#include "error.h"
+#include "util.h"
+
+/**
+ * Wrapper for the write system call.
+ *
+ * \param fd The file descriptor to write to.
+ * \param buf The buffer to write.
+ * \param size The length of \a buf in bytes.
+ *
+ * This function writes out the given buffer and retries if an interrupt
+ * occurred during the write.
+ *
+ * \return On success, the number of bytes written is returned, otherwise, a
+ * negative error code is returned.
+ *
+ * \sa write(2).
+ */
+static ssize_t __write(int fd, const void *buf, size_t size)
+{
+ ssize_t ret;
+
+ for (;;) {
+ ret = write(fd, buf, size);
+ if ((ret < 0) && (errno == EAGAIN || errno == EINTR))
+ continue;
+ return ret >= 0? ret : -ERRNO_TO_ERROR(errno);
+ }
+}
+
+/**
+ * Write a buffer to a file descriptor, re-write on short writes.
+ *
+ * \param fd The file descriptor.
+ * \param buf The buffer to be sent.
+ * \param len The length of \a buf.
+ *
+ * \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;
+
+ assert(total);
+ *len = 0;
+ while (*len < total) {
+ int ret = __write(fd, buf + *len, total - *len);
+ if (ret < 0)
+ return ret;
+ *len += ret;
+ }
+ return 1;
+}
+
+/**
+ * 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 osl_open(const char *path, int flags, mode_t mode)
+{
+ int ret = open(path, flags, mode);
+
+ if (ret >= 0)
+ return ret;
+ return -ERRNO_TO_ERROR(errno);
+}
+
+/**
+ * Open a file, write the given buffer and close the file.
+ *
+ * \param filename Full path to the file to open.
+ * \param buf The buffer to write to the file.
+ * \param size The size of \a buf.
+ *
+ * \return Standard.
+ */
+int write_file(const char *filename, const void *buf, size_t size)
+{
+ int ret, fd;
+
+ ret = osl_open(filename, O_WRONLY | O_CREAT | O_EXCL, 0644);
+ if (ret < 0)
+ return ret;
+ fd = ret;
+ ret = write_all(fd, buf, &size);
+ if (ret < 0)
+ goto out;
+ ret = 1;
+out:
+ close(fd);
+ return ret;
+}
+
+/**
+ * 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 osl_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 = osl_open(path, open_mode, 0);
+ if (ret < 0)
+ return ret;
+ fd = ret;
+ if (fstat(fd, &file_status) < 0) {
+ ret = -ERRNO_TO_ERROR(errno);
+ goto out;
+ }
+ *size = file_status.st_size;
+ ret = -E_OSL_EMPTY;
+ DEBUG_LOG("%s: size %zu\n", path, *size);
+ if (!*size)
+ goto out;
+ *map = mmap(NULL, *size, mmap_prot, mmap_flags, fd, 0);
+ if (*map == MAP_FAILED) {
+ *map = NULL;
+ ret = -E_OSL_MMAP;
+ goto out;
+ }
+ ret = 1;
+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 osl_munmap(void *start, size_t length)
+{
+ int err;
+ if (munmap(start, length) >= 0)
+ return 1;
+ err = errno;
+ ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
+ strerror(err));
+ return -ERRNO_TO_ERROR(err);
+}
+
+/**
+ * Allocate a sufficiently large string and print into it.
+ *
+ * \param fmt A usual format string.
+ *
+ * Produce output according to \p fmt. No artificial bound on the length of the
+ * resulting string is imposed.
+ *
+ * \return This function either returns a pointer to a string that must be
+ * freed by the caller or \p NULL if memory allocation failed.
+ *
+ * \sa printf(3).
+ */
+__must_check __printf_1_2 __malloc char *make_message(const char *fmt, ...)
+{
+ int n;
+ size_t size = 100;
+ char *p = malloc(size);
+
+ if (!p)
+ return NULL;
+ while (1) {
+ char *q;
+ va_list ap;
+ /* Try to print in the allocated space. */
+ va_start(ap, fmt);
+ n = vsnprintf(p, size, fmt, ap);
+ va_end(ap);
+ /* If that worked, return the string. */
+ if (n > -1 && n < size)
+ break;
+ /* Else try again with more space. */
+ if (n > -1) /* glibc 2.1 */
+ size = n + 1; /* precisely what is needed */
+ else /* glibc 2.0 */
+ size *= 2; /* twice the old size */
+ q = realloc(p, size);
+ if (!q) {
+ free(p);
+ return NULL;
+ }
+ p = q;
+ }
+ return p;
+}
+
+/**
+ * A wrapper for truncate(2)
+ *
+ * \param path Name of the regular file to truncate
+ * \param size Number of bytes to \b shave \b off
+ *
+ * Truncate the regular file named by \a path by \a size bytes.
+ *
+ * \return Standard.
+ *
+ * \sa truncate(2)
+ */
+int truncate_file(const char *path, off_t size)
+{
+ int ret;
+ struct stat statbuf;
+
+ ret = osl_stat(path, &statbuf);
+ if (ret < 0)
+ return ret;
+ ret = -E_OSL_BAD_SIZE;
+ if (statbuf.st_size < size)
+ return ret;
+ if (truncate(path, statbuf.st_size - size) < 0)
+ return -ERRNO_TO_ERROR(errno);
+ return 1;
+}
projects / osl.git / blobdiff