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- /*
- * libuci - Library for the Unified Configuration Interface
- * Copyright (C) 2008 Felix Fietkau <nbd@openwrt.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License version 2.1
- * as published by the Free Software Foundation
- *
- * 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.
- */
- /*
- * This file contains misc utility functions and wrappers to standard
- * functions, which throw exceptions upon failure.
- */
- #include <sys/types.h>
- #include <sys/stat.h>
- #include <sys/file.h>
- #include <stdbool.h>
- #include <unistd.h>
- #include <ctype.h>
- #include <fcntl.h>
- #define LINEBUF 32
- #define LINEBUF_MAX 4096
- __plugin void *uci_malloc(struct uci_context *ctx, size_t size)
- {
- void *ptr;
- ptr = malloc(size);
- if (!ptr)
- UCI_THROW(ctx, UCI_ERR_MEM);
- memset(ptr, 0, size);
- return ptr;
- }
- __plugin void *uci_realloc(struct uci_context *ctx, void *ptr, size_t size)
- {
- ptr = realloc(ptr, size);
- if (!ptr)
- UCI_THROW(ctx, UCI_ERR_MEM);
- return ptr;
- }
- __plugin char *uci_strdup(struct uci_context *ctx, const char *str)
- {
- char *ptr;
- ptr = strdup(str);
- if (!ptr)
- UCI_THROW(ctx, UCI_ERR_MEM);
- return ptr;
- }
- /* Based on an efficient hash function published by D. J. Bernstein */
- static unsigned int djbhash(unsigned int hash, char *str)
- {
- int len = strlen(str);
- int i;
- /* initial value */
- if (hash == ~0)
- hash = 5381;
- for(i = 0; i < len; i++) {
- hash = ((hash << 5) + hash) + str[i];
- }
- return (hash & 0x7FFFFFFF);
- }
- /*
- * validate strings for names and types, reject special characters
- * for names, only alphanum and _ is allowed (shell compatibility)
- * for types, we allow more characters
- */
- static bool uci_validate_str(const char *str, bool name)
- {
- if (!*str)
- return false;
- while (*str) {
- char c = *str;
- if (!isalnum(c) && c != '_') {
- if (name || (c < 33) || (c > 126))
- return false;
- }
- str++;
- }
- return true;
- }
- static inline bool uci_validate_name(const char *str)
- {
- return uci_validate_str(str, true);
- }
- static void uci_alloc_parse_context(struct uci_context *ctx)
- {
- ctx->pctx = (struct uci_parse_context *) uci_malloc(ctx, sizeof(struct uci_parse_context));
- }
- int uci_parse_tuple(struct uci_context *ctx, char *str, char **package, char **section, char **option, char **value)
- {
- char *last = NULL;
- UCI_HANDLE_ERR(ctx);
- UCI_ASSERT(ctx, str && package && section && option);
- last = strchr(str, '=');
- if (last) {
- *last = 0;
- last++;
- }
- *package = strsep(&str, ".");
- if (!*package || !uci_validate_name(*package))
- goto error;
- *section = strsep(&str, ".");
- if (!*section)
- goto lastval;
- *option = strsep(&str, ".");
- if (!*option)
- goto lastval;
- lastval:
- if (last) {
- if (!value)
- goto error;
- if (!*last)
- goto error;
- *value = last;
- }
- if (*section && *section[0] && !uci_validate_name(*section))
- goto error;
- if (*option && !uci_validate_name(*option))
- goto error;
- goto done;
- error:
- UCI_THROW(ctx, UCI_ERR_PARSE);
- done:
- return 0;
- }
- static void uci_parse_error(struct uci_context *ctx, char *pos, char *reason)
- {
- struct uci_parse_context *pctx = ctx->pctx;
- pctx->reason = reason;
- pctx->byte = pos - pctx->buf;
- UCI_THROW(ctx, UCI_ERR_PARSE);
- }
- /*
- * Fetch a new line from the input stream and resize buffer if necessary
- */
- static void uci_getln(struct uci_context *ctx, int offset)
- {
- struct uci_parse_context *pctx = ctx->pctx;
- char *p;
- int ofs;
- if (pctx->buf == NULL) {
- pctx->buf = uci_malloc(ctx, LINEBUF);
- pctx->bufsz = LINEBUF;
- }
- ofs = offset;
- do {
- p = &pctx->buf[ofs];
- p[ofs] = 0;
- p = fgets(p, pctx->bufsz - ofs, pctx->file);
- if (!p || !*p)
- return;
- ofs += strlen(p);
- if (pctx->buf[ofs - 1] == '\n') {
- pctx->line++;
- pctx->buf[ofs - 1] = 0;
- return;
- }
- if (pctx->bufsz > LINEBUF_MAX/2)
- uci_parse_error(ctx, p, "line too long");
- pctx->bufsz *= 2;
- pctx->buf = uci_realloc(ctx, pctx->buf, pctx->bufsz);
- } while (1);
- }
- /*
- * parse a character escaped by '\'
- * returns true if the escaped character is to be parsed
- * returns false if the escaped character is to be ignored
- */
- static inline bool parse_backslash(struct uci_context *ctx, char **str)
- {
- /* skip backslash */
- *str += 1;
- /* undecoded backslash at the end of line, fetch the next line */
- if (!**str) {
- *str += 1;
- uci_getln(ctx, *str - ctx->pctx->buf);
- return false;
- }
- /* FIXME: decode escaped char, necessary? */
- return true;
- }
- /*
- * move the string pointer forward until a non-whitespace character or
- * EOL is reached
- */
- static void skip_whitespace(struct uci_context *ctx, char **str)
- {
- restart:
- while (**str && isspace(**str))
- *str += 1;
- if (**str == '\\') {
- if (!parse_backslash(ctx, str))
- goto restart;
- }
- }
- static inline void addc(char **dest, char **src)
- {
- **dest = **src;
- *dest += 1;
- *src += 1;
- }
- /*
- * parse a double quoted string argument from the command line
- */
- static void parse_double_quote(struct uci_context *ctx, char **str, char **target)
- {
- char c;
- /* skip quote character */
- *str += 1;
- while ((c = **str)) {
- switch(c) {
- case '"':
- **target = 0;
- *str += 1;
- return;
- case '\\':
- if (!parse_backslash(ctx, str))
- continue;
- /* fall through */
- default:
- addc(target, str);
- break;
- }
- }
- uci_parse_error(ctx, *str, "unterminated \"");
- }
- /*
- * parse a single quoted string argument from the command line
- */
- static void parse_single_quote(struct uci_context *ctx, char **str, char **target)
- {
- char c;
- /* skip quote character */
- *str += 1;
- while ((c = **str)) {
- switch(c) {
- case '\'':
- **target = 0;
- *str += 1;
- return;
- default:
- addc(target, str);
- }
- }
- uci_parse_error(ctx, *str, "unterminated '");
- }
- /*
- * parse a string from the command line and detect the quoting style
- */
- static void parse_str(struct uci_context *ctx, char **str, char **target)
- {
- do {
- switch(**str) {
- case '\'':
- parse_single_quote(ctx, str, target);
- break;
- case '"':
- parse_double_quote(ctx, str, target);
- break;
- case '#':
- **str = 0;
- /* fall through */
- case 0:
- goto done;
- case '\\':
- if (!parse_backslash(ctx, str))
- continue;
- /* fall through */
- default:
- addc(target, str);
- break;
- }
- } while (**str && !isspace(**str));
- done:
- /*
- * if the string was unquoted and we've stopped at a whitespace
- * character, skip to the next one, because the whitespace will
- * be overwritten by a null byte here
- */
- if (**str)
- *str += 1;
- /* terminate the parsed string */
- **target = 0;
- }
- /*
- * extract the next argument from the command line
- */
- static char *next_arg(struct uci_context *ctx, char **str, bool required, bool name)
- {
- char *val;
- char *ptr;
- val = ptr = *str;
- skip_whitespace(ctx, str);
- parse_str(ctx, str, &ptr);
- if (!*val) {
- if (required)
- uci_parse_error(ctx, *str, "insufficient arguments");
- goto done;
- }
- if (name && !uci_validate_name(val))
- uci_parse_error(ctx, val, "invalid character in field");
- done:
- return val;
- }
- int uci_parse_argument(struct uci_context *ctx, FILE *stream, char **str, char **result)
- {
- UCI_HANDLE_ERR(ctx);
- UCI_ASSERT(ctx, str != NULL);
- UCI_ASSERT(ctx, result != NULL);
- if (ctx->pctx) {
- if (ctx->pctx->file != stream) {
- uci_cleanup(ctx);
- }
- } else {
- uci_alloc_parse_context(ctx);
- ctx->pctx->file = stream;
- }
- if (!*str) {
- uci_getln(ctx, 0);
- *str = ctx->pctx->buf;
- }
- *result = next_arg(ctx, str, false, false);
- return 0;
- }
- /*
- * open a stream and go to the right position
- *
- * note: when opening for write and seeking to the beginning of
- * the stream, truncate the file
- */
- static FILE *uci_open_stream(struct uci_context *ctx, const char *filename, int pos, bool write, bool create)
- {
- struct stat statbuf;
- FILE *file = NULL;
- int fd, ret;
- int mode = (write ? O_RDWR : O_RDONLY);
- if (create)
- mode |= O_CREAT;
- if (!write && ((stat(filename, &statbuf) < 0) ||
- ((statbuf.st_mode & S_IFMT) != S_IFREG))) {
- UCI_THROW(ctx, UCI_ERR_NOTFOUND);
- }
- fd = open(filename, mode, UCI_FILEMODE);
- if (fd < 0)
- goto error;
- if (flock(fd, (write ? LOCK_EX : LOCK_SH)) < 0)
- goto error;
- ret = lseek(fd, 0, pos);
- if (ret < 0)
- goto error;
- file = fdopen(fd, (write ? "w+" : "r"));
- if (file)
- goto done;
- error:
- UCI_THROW(ctx, UCI_ERR_IO);
- done:
- return file;
- }
- static void uci_close_stream(FILE *stream)
- {
- int fd;
- if (!stream)
- return;
- fd = fileno(stream);
- flock(fd, LOCK_UN);
- fclose(stream);
- }
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