diff options
Diffstat (limited to 'scripts/kconfig/preprocess.c')
| -rw-r--r-- | scripts/kconfig/preprocess.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/scripts/kconfig/preprocess.c b/scripts/kconfig/preprocess.c new file mode 100644 index 000000000000..a2eb2eb02929 --- /dev/null +++ b/scripts/kconfig/preprocess.c @@ -0,0 +1,238 @@ +// SPDX-License-Identifier: GPL-2.0 +// +// Copyright (C) 2018 Masahiro Yamada <yamada.masahiro@socionext.com> + +#include <stdarg.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +#include "list.h" + +static void __attribute__((noreturn)) pperror(const char *format, ...) +{ + va_list ap; + + fprintf(stderr, "%s:%d: ", current_file->name, yylineno); + va_start(ap, format); + vfprintf(stderr, format, ap); + va_end(ap); + fprintf(stderr, "\n"); + + exit(1); +} + +/* + * Environment variables + */ +static LIST_HEAD(env_list); + +struct env { + char *name; + char *value; + struct list_head node; +}; + +static void env_add(const char *name, const char *value) +{ + struct env *e; + + e = xmalloc(sizeof(*e)); + e->name = xstrdup(name); + e->value = xstrdup(value); + + list_add_tail(&e->node, &env_list); +} + +static void env_del(struct env *e) +{ + list_del(&e->node); + free(e->name); + free(e->value); + free(e); +} + +/* The returned pointer must be freed when done */ +static char *env_expand(const char *name) +{ + struct env *e; + const char *value; + + if (!*name) + return NULL; + + list_for_each_entry(e, &env_list, node) { + if (!strcmp(name, e->name)) + return xstrdup(e->value); + } + + value = getenv(name); + if (!value) + return NULL; + + /* + * We need to remember all referenced environment variables. + * They will be written out to include/config/auto.conf.cmd + */ + env_add(name, value); + + return xstrdup(value); +} + +void env_write_dep(FILE *f, const char *autoconfig_name) +{ + struct env *e, *tmp; + + list_for_each_entry_safe(e, tmp, &env_list, node) { + fprintf(f, "ifneq \"$(%s)\" \"%s\"\n", e->name, e->value); + fprintf(f, "%s: FORCE\n", autoconfig_name); + fprintf(f, "endif\n"); + env_del(e); + } +} + +static char *eval_clause(const char *str, size_t len) +{ + char *tmp, *name, *res; + + tmp = xstrndup(str, len); + + name = expand_string(tmp); + + res = env_expand(name); + if (res) + goto free; + + res = xstrdup(""); +free: + free(name); + free(tmp); + + return res; +} + +/* + * Expand a string that follows '$' + * + * For example, if the input string is + * ($(FOO)$($(BAR)))$(BAZ) + * this helper evaluates + * $($(FOO)$($(BAR))) + * and returns a new string containing the expansion (note that the string is + * recursively expanded), also advancing 'str' to point to the next character + * after the corresponding closing parenthesis, in this case, *str will be + * $(BAR) + */ +char *expand_dollar(const char **str) +{ + const char *p = *str; + const char *q; + int nest = 0; + + /* + * In Kconfig, variable references always start with "$(". + * Neither single-letter variables as in $A nor curly braces as in ${CC} + * are supported. '$' not followed by '(' loses its special meaning. + */ + if (*p != '(') { + *str = p; + return xstrdup("$"); + } + + p++; + q = p; + while (*q) { + if (*q == '(') { + nest++; + } else if (*q == ')') { + if (nest-- == 0) + break; + } + q++; + } + + if (!*q) + pperror("unterminated reference to '%s': missing ')'", p); + + /* Advance 'str' to after the expanded initial portion of the string */ + *str = q + 1; + + return eval_clause(p, q - p); +} + +static char *__expand_string(const char **str, bool (*is_end)(char c)) +{ + const char *in, *p; + char *expansion, *out; + size_t in_len, out_len; + + out = xmalloc(1); + *out = 0; + out_len = 1; + + p = in = *str; + + while (1) { + if (*p == '$') { + in_len = p - in; + p++; + expansion = expand_dollar(&p); + out_len += in_len + strlen(expansion); + out = xrealloc(out, out_len); + strncat(out, in, in_len); + strcat(out, expansion); + free(expansion); + in = p; + continue; + } + + if (is_end(*p)) + break; + + p++; + } + + in_len = p - in; + out_len += in_len; + out = xrealloc(out, out_len); + strncat(out, in, in_len); + + /* Advance 'str' to the end character */ + *str = p; + + return out; +} + +static bool is_end_of_str(char c) +{ + return !c; +} + +/* + * Expand variables in the given string. Undefined variables + * expand to an empty string. + * The returned string must be freed when done. + */ +char *expand_string(const char *in) +{ + return __expand_string(&in, is_end_of_str); +} + +static bool is_end_of_token(char c) +{ + /* Why are '.' and '/' valid characters for symbols? */ + return !(isalnum(c) || c == '_' || c == '-' || c == '.' || c == '/'); +} + +/* + * Expand variables in a token. The parsing stops when a token separater + * (in most cases, it is a whitespace) is encountered. 'str' is updated to + * point to the next character. + * + * The returned string must be freed when done. + */ +char *expand_one_token(const char **str) +{ + return __expand_string(str, is_end_of_token); +} |