/* Serval DNA native Operating System interface Copyright (C) 2012 Serval Project Inc. 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. 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. 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #ifndef __SERVAL_DNA__OS_H #define __SERVAL_DNA__OS_H #include #include #include #include #include #include "log.h" #ifndef __SERVAL_DNA__OS_INLINE # if __GNUC__ && !__GNUC_STDC_INLINE__ # define __SERVAL_DNA__OS_INLINE extern inline # else # define __SERVAL_DNA__OS_INLINE inline # endif #endif /* All wall clock times in the Serval daemon are represented in milliseconds * since the Unix epoch. The gettime_ms() function uses gettimeofday(2) to * return this value when called. The time_ms_t typedef should be used * wherever this time value is handled or stored. * * This type could perfectly well be unsigned, but is defined as signed to * avoid the need to cast or define a special signed timedelta_ms_t type at ** * (1): * * static time_ms_t then = 0; * time_ms_t now = gettime_ms(); * time_ms_t ago = now - then; // ** (1) * if (then && ago < 0) { * ... time going backwards ... * } else { * ... time has advanced ... * then = now; * } */ typedef int64_t time_ms_t; #define PRItime_ms_t PRId64 #define TIME_NEVER_WILL INT64_MAX #define TIME_NEVER_HAS INT64_MIN time_ms_t gettime_ms(); time_ms_t sleep_ms(time_ms_t milliseconds); #ifndef HAVE_BZERO __SERVAL_DNA__OS_INLINE void bzero(void *buf, size_t len) { memset(buf, 0, len); } #endif #ifndef HAVE_BCOPY __SERVAL_DNA__OS_INLINE void bcopy(const void *src, void *dst, size_t len) { memcpy(dst, src, len); } #endif #ifndef HAVE_BCMP __SERVAL_DNA__OS_INLINE int bcmp(const void *s1, const void *s2, size_t n) { // bcmp() is only an equality test, not an order test, so its return value // is not specified as negative or positive, only non-zero. Hoewver // memcmp() is an order test. We deliberately discard negative return // values from memcmp(), to avoid misleading developers into assuming that // bcmp() is an ordering operator and writing code that depends on that, // which of course would fail on platforms with a native bcmp() function. return memcmp(s1, s2, n) != 0; } #endif /* If there is no lseek64(2) system call but off_t is 64 bits, then we can use * lseek(2) instead. */ #ifndef HAVE_LSEEK64 # if SIZEOF_OFF_T != 8 # error "lseek64(2) system call is not available and `sizeof(off_t) is not 8" # endif # ifndef HAVE_OFF64_T typedef off_t off64_t; __SERVAL_DNA__OS_INLINE off64_t lseek64(int fd, off64_t offset, int whence) { return lseek(fd, offset, whence); } # endif #endif /* The "e" variants log the error before returning -1. */ typedef void MKDIR_LOG_FUNC(struct __sourceloc, const char *, mode_t); MKDIR_LOG_FUNC log_info_mkdir; int _mkdirs(struct __sourceloc, const char *path, mode_t mode, MKDIR_LOG_FUNC *); int _mkdirsn(struct __sourceloc, const char *path, size_t len, mode_t mode, MKDIR_LOG_FUNC *); int _emkdirs(struct __sourceloc, const char *path, mode_t mode, MKDIR_LOG_FUNC *); int _emkdirsn(struct __sourceloc, const char *path, size_t len, mode_t mode, MKDIR_LOG_FUNC *); #define mkdirs_log(path, mode, func) _mkdirs(__WHENCE__, (path), (mode), (func)) #define mkdirsn_log(path, len, mode, func) _mkdirsn(__WHENCE__, (path), (len), (mode), (func)) #define emkdirs_log(path, mode, func) _emkdirs(__WHENCE__, (path), (mode), (func)) #define emkdirsn_log(path, len, mode, func) _emkdirsn(__WHENCE__, (path), (len), (mode), (func)) #define mkdirs(path, mode) mkdirs_log((path), (mode), NULL) #define mkdirsn(path, len, mode) mkdirsn_log((path), (len), (mode), NULL) #define emkdirs(path, mode) emkdirs_log((path), (mode), NULL) #define emkdirsn(path, len, mode) emkdirsn_log((path), (len), (mode), NULL) #define mkdirs_info(path, mode) mkdirs_log((path), (mode), log_info_mkdir) #define mkdirsn_info(path, len, mode) mkdirsn_log((path), (len), (mode), log_info_mkdir) #define emkdirs_info(path, mode) emkdirs_log((path), (mode), log_info_mkdir) #define emkdirsn_info(path, len, mode) emkdirsn_log((path), (len), (mode), log_info_mkdir) void srandomdev(); int urandombytes(unsigned char *buf, size_t len); /* Read the symbolic link into the supplied buffer and add a terminating nul. * Logs an ERROR and returns -1 if the buffer is too short to hold the link * content and the terminating nul. If readlink(2) returns an error, then logs * an ERROR and returns -1. Otherwise, returns the number of bytes read, * including the terminating nul, ie, returns what readlink(2) returns plus * one. If the 'len' argument is given as zero, then returns the number of * bytes that would be read, by calling lstat(2) instead of readlink(2), plus * one for the terminating nul. Beware of the following race condition: a * symbolic link may be altered between calling the lstat(2) and readlink(2), * so the following apparently overflow-proof code may still fail from a buffer * overflow in the second call to read_symlink(): * * char *readlink_malloc(const char *path) { * ssize_t len = read_symlink(path, NULL, 0); * if (len == -1) * return NULL; * char *buf = malloc(len); * if (buf == NULL) * return NULL; * if (read_symlink(path, buf, len) == -1) { * free(buf); * return NULL; * } * return buf; * } * * @author Andrew Bettison */ ssize_t read_symlink(const char *path, char *buf, size_t len); /* Read the whole file into the given buffer. If the file will not fit into * the buffer or if there is an error opening or reading the file, logs an * error and returns -1. Otherwise, returns the number of bytes read. * * @author Andrew Bettison */ ssize_t read_whole_file(const char *path, unsigned char *buffer, size_t buffer_size); /* Read the whole file into a buffer. If *bufp is NULL then uses malloc(3) to * create a buffer first, the size of the file (up to a maximum of *sizp if * *sizp is not zero), and assigns the address to *bufp. If the file will not * fit into the buffer or if there is an error from malloc(3) or opening or * reading the file, logs an error and returns -1. Otherwise, returns 0. * * @author Andrew Bettison */ int malloc_read_whole_file(const char *path, unsigned char **bufp, size_t *sizp); /* File metadata primitives, used for detecting when a file has changed. * * @author Andrew Bettison */ struct file_meta { struct timespec mtime; off_t size; }; #define FILE_META_UNKNOWN ((struct file_meta){ .mtime = { .tv_sec = -1, .tv_nsec = -1 }, .size = -1 }) // A non-existent file is treated as size == 0 and an impossible modification // time, so that cmp_file_meta() will not compare it as equal with any existing // file. #define FILE_META_NONEXIST ((struct file_meta){ .mtime = { .tv_sec = -1, .tv_nsec = -1 }, .size = 0 }) __SERVAL_DNA__OS_INLINE int is_file_meta_nonexist(const struct file_meta *m) { return m->mtime.tv_sec == -1 && m->mtime.tv_nsec == -1 && m->size == 0; } int get_file_meta(const char *path, struct file_meta *metap); int cmp_file_meta(const struct file_meta *a, const struct file_meta *b); // Ensure that the metadata of a file differs from a given original metadata, // by bumping the file's modification time or altering its inode. int alter_file_meta(const char *path, const struct file_meta *origp, struct file_meta *metap); #endif //__SERVAL_DNA__OS_H