/* * file.c * * file system operations * * Copyright (c) 2010-2012, PostgreSQL Global Development Group * contrib/pg_upgrade/file.c */ #include "postgres.h" #include "pg_upgrade.h" #include #ifndef WIN32 static int copy_file(const char *fromfile, const char *tofile, bool force); #else static int win32_pghardlink(const char *src, const char *dst); #endif /* * copyAndUpdateFile() * * Copies a relation file from src to dst. If pageConverter is non-NULL, this function * uses that pageConverter to do a page-by-page conversion. */ const char * copyAndUpdateFile(pageCnvCtx *pageConverter, const char *src, const char *dst, bool force) { if (pageConverter == NULL) { if (pg_copy_file(src, dst, force) == -1) return getErrorText(errno); else return NULL; } else { /* * We have a pageConverter object - that implies that the * PageLayoutVersion differs between the two clusters so we have to * perform a page-by-page conversion. * * If the pageConverter can convert the entire file at once, invoke * that plugin function, otherwise, read each page in the relation * file and call the convertPage plugin function. */ #ifdef PAGE_CONVERSION if (pageConverter->convertFile) return pageConverter->convertFile(pageConverter->pluginData, dst, src); else #endif { int src_fd; int dstfd; char buf[BLCKSZ]; ssize_t bytesRead; const char *msg = NULL; if ((src_fd = open(src, O_RDONLY, 0)) < 0) return "could not open source file"; if ((dstfd = open(dst, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR)) < 0) { close(src_fd); return "could not create destination file"; } while ((bytesRead = read(src_fd, buf, BLCKSZ)) == BLCKSZ) { #ifdef PAGE_CONVERSION if ((msg = pageConverter->convertPage(pageConverter->pluginData, buf, buf)) != NULL) break; #endif if (write(dstfd, buf, BLCKSZ) != BLCKSZ) { msg = "could not write new page to destination"; break; } } close(src_fd); close(dstfd); if (msg) return msg; else if (bytesRead != 0) return "found partial page in source file"; else return NULL; } } } /* * linkAndUpdateFile() * * Creates a hard link between the given relation files. We use * this function to perform a true in-place update. If the on-disk * format of the new cluster is bit-for-bit compatible with the on-disk * format of the old cluster, we can simply link each relation * instead of copying the data from the old cluster to the new cluster. */ const char * linkAndUpdateFile(pageCnvCtx *pageConverter, const char *src, const char *dst) { if (pageConverter != NULL) return "Cannot in-place update this cluster, page-by-page conversion is required"; if (pg_link_file(src, dst) == -1) return getErrorText(errno); else return NULL; } #ifndef WIN32 static int copy_file(const char *srcfile, const char *dstfile, bool force) { #define COPY_BUF_SIZE (50 * BLCKSZ) int src_fd; int dest_fd; char *buffer; if ((srcfile == NULL) || (dstfile == NULL)) return -1; if ((src_fd = open(srcfile, O_RDONLY, 0)) < 0) return -1; if ((dest_fd = open(dstfile, O_RDWR | O_CREAT | (force ? 0 : O_EXCL), S_IRUSR | S_IWUSR)) < 0) { if (src_fd != 0) close(src_fd); return -1; } buffer = (char *) malloc(COPY_BUF_SIZE); if (buffer == NULL) { if (src_fd != 0) close(src_fd); if (dest_fd != 0) close(dest_fd); return -1; } /* perform data copying i.e read src source, write to destination */ while (true) { ssize_t nbytes = read(src_fd, buffer, COPY_BUF_SIZE); if (nbytes < 0) { int save_errno = errno; if (buffer != NULL) free(buffer); if (src_fd != 0) close(src_fd); if (dest_fd != 0) close(dest_fd); errno = save_errno; return -1; } if (nbytes == 0) break; errno = 0; if (write(dest_fd, buffer, nbytes) != nbytes) { /* if write didn't set errno, assume problem is no disk space */ int save_errno = errno ? errno : ENOSPC; if (buffer != NULL) free(buffer); if (src_fd != 0) close(src_fd); if (dest_fd != 0) close(dest_fd); errno = save_errno; return -1; } } if (buffer != NULL) free(buffer); if (src_fd != 0) close(src_fd); if (dest_fd != 0) close(dest_fd); return 1; } #endif /* * load_directory() * * Read all the file names in the specified directory, and return them as * an array of "char *" pointers. The array address is returned in * *namelist, and the function result is the count of file names. * * To free the result data, free each (char *) array member, then free the * namelist array itself. */ int load_directory(const char *dirname, char ***namelist) { DIR *dirdesc; struct dirent *direntry; int count = 0; int allocsize = 64; /* initial array size */ *namelist = (char **) pg_malloc(allocsize * sizeof(char *)); if ((dirdesc = opendir(dirname)) == NULL) pg_log(PG_FATAL, "could not open directory \"%s\": %s\n", dirname, getErrorText(errno)); while (errno = 0, (direntry = readdir(dirdesc)) != NULL) { if (count >= allocsize) { allocsize *= 2; *namelist = (char **) pg_realloc(*namelist, allocsize * sizeof(char *)); } (*namelist)[count++] = pg_strdup(direntry->d_name); } #ifdef WIN32 /* * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in * released version */ if (GetLastError() == ERROR_NO_MORE_FILES) errno = 0; #endif if (errno) pg_log(PG_FATAL, "could not read directory \"%s\": %s\n", dirname, getErrorText(errno)); closedir(dirdesc); return count; } void check_hard_link(void) { char existing_file[MAXPGPATH]; char new_link_file[MAXPGPATH]; snprintf(existing_file, sizeof(existing_file), "%s/PG_VERSION", old_cluster.pgdata); snprintf(new_link_file, sizeof(new_link_file), "%s/PG_VERSION.linktest", new_cluster.pgdata); unlink(new_link_file); /* might fail */ if (pg_link_file(existing_file, new_link_file) == -1) { pg_log(PG_FATAL, "Could not create hard link between old and new data directories: %s\n" "In link mode the old and new data directories must be on the same file system volume.\n", getErrorText(errno)); } unlink(new_link_file); } #ifdef WIN32 static int win32_pghardlink(const char *src, const char *dst) { /* * CreateHardLinkA returns zero for failure * http://msdn.microsoft.com/en-us/library/aa363860(VS.85).aspx */ if (CreateHardLinkA(dst, src, NULL) == 0) return -1; else return 0; } #endif /* fopen() file with no group/other permissions */ FILE * fopen_priv(const char *path, const char *mode) { mode_t old_umask = umask(S_IRWXG | S_IRWXO); FILE *fp; fp = fopen(path, mode); umask(old_umask); return fp; }