diff options
| -rw-r--r-- | Makefrag.am | 2 | ||||
| -rw-r--r-- | kern/arg.c | 162 | ||||
| -rw-r--r-- | kern/arg.h | 57 |
3 files changed, 221 insertions, 0 deletions
diff --git a/Makefrag.am b/Makefrag.am index 90c146b8..55bf93b5 100644 --- a/Makefrag.am +++ b/Makefrag.am @@ -8,6 +8,8 @@ x15_SOURCES += \ include/string.h x15_SOURCES += \ + kern/arg.c \ + kern/arg.h \ kern/assert.h \ kern/atomic.h \ kern/bitmap.c \ diff --git a/kern/arg.c b/kern/arg.c new file mode 100644 index 00000000..02ed4b7b --- /dev/null +++ b/kern/arg.c @@ -0,0 +1,162 @@ +/* + * Copyright (c) 2017 Richard Braun. + * + * 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 3 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, see <http://www.gnu.org/licenses/>. + */ + +#include <stdbool.h> +#include <stddef.h> +#include <stdio.h> +#include <string.h> + +#include <kern/arg.h> +#include <kern/assert.h> +#include <kern/init.h> +#include <kern/macros.h> +#include <kern/panic.h> + +/* + * Internally, all space characters are turned into null bytes so that + * values returned to callers directly point in the command line string, + * with no need for dynamic allocation. + */ +static char arg_cmdline[ARG_CMDLINE_MAX_SIZE] __initdata; +static const char *arg_cmdline_end __initdata; + +void __init +arg_setup(const char *cmdline) +{ + size_t i, length; + + if (cmdline == NULL) { + arg_cmdline[0] = '\0'; + return; + } + + length = strlen(cmdline); + + if ((length + 1) > ARRAY_SIZE(arg_cmdline)) { + panic("arg: command line too long"); + } + + memcpy(arg_cmdline, cmdline, length + 1); + + for (i = 0; i < length; i++) { + if (arg_cmdline[i] == ' ') { + arg_cmdline[i] = '\0'; + } + } + + arg_cmdline_end = arg_cmdline + length; +} + +void __init +arg_info(void) +{ + printf("arg: %s\n", arg_cmdline); +} + +static const char * __init +arg_walk(const char *s) +{ + if (s == NULL) { + s = arg_cmdline; + } else { + for (;;) { + if (s >= arg_cmdline_end) { + return NULL; + } + + if (*s == '\0') { + break; + } + + s++; + } + } + + for (;;) { + if (s >= arg_cmdline_end) { + return NULL; + } + + if (*s != '\0') { + return s; + } + + s++; + } +} + +static const char * __init +arg_find_name_end(const char *arg) +{ + const char *end; + + end = strchr(arg, '='); + + if (end == NULL) { + end = arg + strlen(arg); + } + + return end; +} + +static const char * __init +arg_find(const char *name) +{ + const char *arg, *arg_name_end; + size_t arg_name_length, name_length; + + name_length = strlen(name); + assert(name_length != 0); + + for (arg = arg_walk(NULL); arg != NULL; arg = arg_walk(arg)) { + arg_name_end = arg_find_name_end(arg); + arg_name_length = arg_name_end - arg; + + if ((arg_name_length == name_length) + && (memcmp(arg, name, name_length) == 0)) { + return arg; + } + } + + return NULL; +} + +bool __init +arg_present(const char *name) +{ + return (arg_find(name) != NULL); +} + +const char * __init +arg_value(const char *name) +{ + const char *arg, *value; + + arg = arg_find(name); + + if (arg == NULL) { + return NULL; + } + + value = strchr(arg, '='); + + if (value == NULL) { + return ""; + } + + return value + 1; +} diff --git a/kern/arg.h b/kern/arg.h new file mode 100644 index 00000000..937f596b --- /dev/null +++ b/kern/arg.h @@ -0,0 +1,57 @@ +/* + * Copyright (c) 2017 Richard Braun. + * + * 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 3 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, see <http://www.gnu.org/licenses/>. + * + * + * Kernel command line argument parsing. + * + * Arguments are separated by spaces (there is no escape character). + * They can be of the form "name" when used as boolean values (present + * or not), or "name=value". + */ + +#ifndef _KERN_ARG_H +#define _KERN_ARG_H + +#include <stdbool.h> + +#define ARG_CMDLINE_MAX_SIZE 256 + +/* + * Initialize the arg module. + */ +void arg_setup(const char *cmdline); + +/* + * Display command line information. + */ +void arg_info(void); + +/* + * Return true if an argument with the given name is present in the + * command line. + */ +bool arg_present(const char *name); + +/* + * Return the value of the argument with the given name in the command + * line. + * + * If the argument form is "name", the empty string is returned. If the + * argument isn't present, NULL is returned. + */ +const char * arg_value(const char *name); + +#endif /* _KERN_ARG_H */ |