diff options
Diffstat (limited to 'extension/select.c')
| -rw-r--r-- | extension/select.c | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/extension/select.c b/extension/select.c new file mode 100644 index 00000000..f74ae250 --- /dev/null +++ b/extension/select.c @@ -0,0 +1,183 @@ +/* + * select.c - Builtin functions to provide select I/O multiplexing. + */ + +/* + * Copyright (C) 2013 the Free Software Foundation, Inc. + * + * This file is part of GAWK, the GNU implementation of the + * AWK Programming Language. + * + * GAWK 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 3 of the License, or + * (at your option) any later version. + * + * GAWK 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 + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include <stdio.h> +#include <assert.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include <sys/types.h> +#include <sys/stat.h> + +#include "gawkapi.h" + +#include "gettext.h" +#define _(msgid) gettext(msgid) +#define N_(msgid) msgid + +static const gawk_api_t *api; /* for convenience macros to work */ +static awk_ext_id_t *ext_id; +static const char *ext_version = "ordchr extension: version 1.0"; +static awk_bool_t (*init_func)(void) = NULL; + +int plugin_is_GPL_compatible; + +#if defined(HAVE_SELECT) && defined(HAVE_SYS_SELECT_H) +#include <sys/select.h> +#endif + +#ifdef HAVE_SIGNAL_H +#include <signal.h> +#endif + +/* do_ord --- return numeric value of first char of string */ + +static awk_value_t * +do_select(int nargs, awk_value_t *result) +{ + static const char *argname[] = { "read", "write", "except" }; + struct { + awk_value_t array; + awk_flat_array_t *flat; + fd_set bits; + int *array2fd; + } fds[3]; + awk_value_t timeout_arg; + int i; + struct timeval maxwait; + struct timeval *timeout; + int nfds = 0; + int rc; + + if (do_lint && nargs > 5) + lintwarn(ext_id, _("select: called with too many arguments")); + +#define EL fds[i].flat->elements[j] + for (i = 0; i < sizeof(fds)/sizeof(fds[0]); i++) { + size_t j; + + if (! get_argument(i, AWK_ARRAY, & fds[i].array)) { + warning(ext_id, _("select: bad array parameter `%s'"), argname[i]); + update_ERRNO_string(_("select: bad array parameter")); + return make_number(-1, result); + } + /* N.B. flatten_array fails for empty arrays, so that's OK */ + FD_ZERO(&fds[i].bits); + if (flatten_array(fds[i].array.array_cookie, &fds[i].flat)) { + emalloc(fds[i].array2fd, int *, fds[i].flat->count*sizeof(int), "select"); + for (j = 0; j < fds[i].flat->count; j++) { + fds[i].array2fd[j] = -1; + switch (EL.index.val_type) { + case AWK_NUMBER: + if (EL.index.num_value >= 0) + fds[i].array2fd[j] = EL.index.num_value; + if (fds[i].array2fd[j] != EL.index.num_value) + fds[i].array2fd[j] = -1; + break; + case AWK_STRING: + if (EL.value.val_type == AWK_STRING) { + const awk_input_buf_t *buf; + if ((buf = get_file(EL.index.str_value.str, EL.index.str_value.len, EL.value.str_value.str, EL.value.str_value.len)) != NULL) + fds[i].array2fd[j] = buf->fd; + } + break; + } + if (fds[i].array2fd[j] < 0) { + warning(ext_id, _("select: get_file failed")); + update_ERRNO_string(_("select: get_file failed")); + if (! release_flattened_array(fds[i].array.array_cookie, fds[i].flat)) + warning(ext_id, _("select: release_flattened_array failed")); + free(fds[i].array2fd); + return make_number(-1, result); + } + FD_SET(fds[i].array2fd[j], &fds[i].bits); + if (nfds <= fds[i].array2fd[j]) + nfds = fds[i].array2fd[j]+1; + } + } + else + fds[i].flat = NULL; + } + if (get_argument(3, AWK_NUMBER, &timeout_arg)) { + double secs = timeout_arg.num_value; + if (secs < 0) { + warning(ext_id, _("select: treating negative timeout as zero")); + secs = 0; + } + maxwait.tv_sec = secs; + maxwait.tv_usec = (secs-(double)maxwait.tv_sec)*1000000.0; + timeout = &maxwait; + } else + timeout = NULL; + rc = select(nfds, &fds[0].bits, &fds[1].bits, &fds[2].bits, timeout); + + if (rc < 0) { + update_ERRNO_int(errno); + /* bit masks are undefined, so delete all array entries */ + for (i = 0; i < sizeof(fds)/sizeof(fds[0]); i++) { + if (fds[i].flat) { + size_t j; + for (j = 0; j < fds[i].flat->count; j++) + EL.flags |= AWK_ELEMENT_DELETE; + if (! release_flattened_array(fds[i].array.array_cookie, fds[i].flat)) + warning(ext_id, _("select: release_flattened_array failed")); + free(fds[i].array2fd); + } + } + return make_number(rc, result); + } + + for (i = 0; i < sizeof(fds)/sizeof(fds[0]); i++) { + if (fds[i].flat) { + size_t j; + /* remove array elements not set in the bit mask */ + for (j = 0; j < fds[i].flat->count; j++) { + if (! FD_ISSET(fds[i].array2fd[j], &fds[i].bits)) + EL.flags |= AWK_ELEMENT_DELETE; + } + if (! release_flattened_array(fds[i].array.array_cookie, fds[i].flat)) + warning(ext_id, _("select: release_flattened_array failed")); + free(fds[i].array2fd); + } + } +#undef EL + + /* Set the return value */ + return make_number(rc, result); +} + +static awk_ext_func_t func_table[] = { + { "select", do_select, 5 }, +}; + +/* define the dl_load function using the boilerplate macro */ + +dl_load_func(func_table, select, "") |