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Diffstat (limited to 'alias.c')
| -rw-r--r-- | alias.c | 594 |
1 files changed, 594 insertions, 0 deletions
@@ -0,0 +1,594 @@ +/* alias.c -- Not a full alias, but just the kind that we use in the + shell. Csh style alias is somewhere else (`over there, in a box'). */ + +/* Copyright (C) 1987-2020 Free Software Foundation, Inc. + + This file is part of GNU Bash, the Bourne Again SHell. + + Bash 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. + + Bash 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 Bash. If not, see <http://www.gnu.org/licenses/>. +*/ + +#include "config.h" + +#if defined (ALIAS) + +#if defined (HAVE_UNISTD_H) +# ifdef _MINIX +# include <sys/types.h> +# endif +# include <unistd.h> +#endif + +#include <stdio.h> +#include "chartypes.h" +#include "bashansi.h" +#include "command.h" +#include "general.h" +#include "externs.h" +#include "alias.h" + +#if defined (PROGRAMMABLE_COMPLETION) +# include "pcomplete.h" +#endif + +#if defined (HAVE_MBSTR_H) && defined (HAVE_MBSCHR) +# include <mbstr.h> /* mbschr */ +#endif + +#define ALIAS_HASH_BUCKETS 64 /* must be power of two */ + +typedef int sh_alias_map_func_t PARAMS((alias_t *)); + +static void free_alias_data PARAMS((PTR_T)); +static alias_t **map_over_aliases PARAMS((sh_alias_map_func_t *)); +static void sort_aliases PARAMS((alias_t **)); +static int qsort_alias_compare PARAMS((alias_t **, alias_t **)); + +#if defined (READLINE) +static int skipquotes PARAMS((char *, int)); +static int skipws PARAMS((char *, int)); +static int rd_token PARAMS((char *, int)); +#endif + +/* Non-zero means expand all words on the line. Otherwise, expand + after first expansion if the expansion ends in a space. */ +int alias_expand_all = 0; + +/* The list of aliases that we have. */ +HASH_TABLE *aliases = (HASH_TABLE *)NULL; + +void +initialize_aliases () +{ + if (aliases == 0) + aliases = hash_create (ALIAS_HASH_BUCKETS); +} + +/* Scan the list of aliases looking for one with NAME. Return NULL + if the alias doesn't exist, else a pointer to the alias_t. */ +alias_t * +find_alias (name) + char *name; +{ + BUCKET_CONTENTS *al; + + if (aliases == 0) + return ((alias_t *)NULL); + + al = hash_search (name, aliases, 0); + return (al ? (alias_t *)al->data : (alias_t *)NULL); +} + +/* Return the value of the alias for NAME, or NULL if there is none. */ +char * +get_alias_value (name) + char *name; +{ + alias_t *alias; + + if (aliases == 0) + return ((char *)NULL); + + alias = find_alias (name); + return (alias ? alias->value : (char *)NULL); +} + +/* Make a new alias from NAME and VALUE. If NAME can be found, + then replace its value. */ +void +add_alias (name, value) + char *name, *value; +{ + BUCKET_CONTENTS *elt; + alias_t *temp; + int n; + + if (aliases == 0) + { + initialize_aliases (); + temp = (alias_t *)NULL; + } + else + temp = find_alias (name); + + if (temp) + { + free (temp->value); + temp->value = savestring (value); + temp->flags &= ~AL_EXPANDNEXT; + if (value[0]) + { + n = value[strlen (value) - 1]; + if (n == ' ' || n == '\t') + temp->flags |= AL_EXPANDNEXT; + } + } + else + { + temp = (alias_t *)xmalloc (sizeof (alias_t)); + temp->name = savestring (name); + temp->value = savestring (value); + temp->flags = 0; + + if (value[0]) + { + n = value[strlen (value) - 1]; + if (n == ' ' || n == '\t') + temp->flags |= AL_EXPANDNEXT; + } + + elt = hash_insert (savestring (name), aliases, HASH_NOSRCH); + elt->data = temp; +#if defined (PROGRAMMABLE_COMPLETION) + set_itemlist_dirty (&it_aliases); +#endif + } +} + +/* Delete a single alias structure. */ +static void +free_alias_data (data) + PTR_T data; +{ + register alias_t *a; + + a = (alias_t *)data; + + if (a->flags & AL_BEINGEXPANDED) + clear_string_list_expander (a); /* call back to the parser */ + + free (a->value); + free (a->name); + free (data); +} + +/* Remove the alias with name NAME from the alias table. Returns + the number of aliases left in the table, or -1 if the alias didn't + exist. */ +int +remove_alias (name) + char *name; +{ + BUCKET_CONTENTS *elt; + + if (aliases == 0) + return (-1); + + elt = hash_remove (name, aliases, 0); + if (elt) + { + free_alias_data (elt->data); + free (elt->key); /* alias name */ + free (elt); /* XXX */ +#if defined (PROGRAMMABLE_COMPLETION) + set_itemlist_dirty (&it_aliases); +#endif + return (aliases->nentries); + } + return (-1); +} + +/* Delete all aliases. */ +void +delete_all_aliases () +{ + if (aliases == 0) + return; + + hash_flush (aliases, free_alias_data); + hash_dispose (aliases); + aliases = (HASH_TABLE *)NULL; +#if defined (PROGRAMMABLE_COMPLETION) + set_itemlist_dirty (&it_aliases); +#endif +} + +/* Return an array of aliases that satisfy the conditions tested by FUNCTION. + If FUNCTION is NULL, return all aliases. */ +static alias_t ** +map_over_aliases (function) + sh_alias_map_func_t *function; +{ + register int i; + register BUCKET_CONTENTS *tlist; + alias_t *alias, **list; + int list_index; + + i = HASH_ENTRIES (aliases); + if (i == 0) + return ((alias_t **)NULL); + + list = (alias_t **)xmalloc ((i + 1) * sizeof (alias_t *)); + for (i = list_index = 0; i < aliases->nbuckets; i++) + { + for (tlist = hash_items (i, aliases); tlist; tlist = tlist->next) + { + alias = (alias_t *)tlist->data; + + if (!function || (*function) (alias)) + { + list[list_index++] = alias; + list[list_index] = (alias_t *)NULL; + } + } + } + return (list); +} + +static void +sort_aliases (array) + alias_t **array; +{ + qsort (array, strvec_len ((char **)array), sizeof (alias_t *), (QSFUNC *)qsort_alias_compare); +} + +static int +qsort_alias_compare (as1, as2) + alias_t **as1, **as2; +{ + int result; + + if ((result = (*as1)->name[0] - (*as2)->name[0]) == 0) + result = strcmp ((*as1)->name, (*as2)->name); + + return (result); +} + +/* Return a sorted list of all defined aliases */ +alias_t ** +all_aliases () +{ + alias_t **list; + + if (aliases == 0 || HASH_ENTRIES (aliases) == 0) + return ((alias_t **)NULL); + + list = map_over_aliases ((sh_alias_map_func_t *)NULL); + if (list) + sort_aliases (list); + return (list); +} + +char * +alias_expand_word (s) + char *s; +{ + alias_t *r; + + r = find_alias (s); + return (r ? savestring (r->value) : (char *)NULL); +} + +/* Readline support functions -- expand all aliases in a line. */ + +#if defined (READLINE) + +/* Return non-zero if CHARACTER is a member of the class of characters + that are self-delimiting in the shell (this really means that these + characters delimit tokens). */ +#define self_delimiting(character) (member ((character), " \t\n\r;|&()")) + +/* Return non-zero if CHARACTER is a member of the class of characters + that delimit commands in the shell. */ +#define command_separator(character) (member ((character), "\r\n;|&(")) + +/* If this is 1, we are checking the next token read for alias expansion + because it is the first word in a command. */ +static int command_word; + +/* This is for skipping quoted strings in alias expansions. */ +#define quote_char(c) (((c) == '\'') || ((c) == '"')) + +/* Consume a quoted string from STRING, starting at string[START] (so + string[START] is the opening quote character), and return the index + of the closing quote character matching the opening quote character. + This handles single matching pairs of unquoted quotes; it could afford + to be a little smarter... This skips words between balanced pairs of + quotes, words where the first character is quoted with a `\', and other + backslash-escaped characters. */ + +static int +skipquotes (string, start) + char *string; + int start; +{ + register int i; + int delimiter = string[start]; + + /* i starts at START + 1 because string[START] is the opening quote + character. */ + for (i = start + 1 ; string[i] ; i++) + { + if (string[i] == '\\') + { + i++; /* skip backslash-quoted quote characters, too */ + if (string[i] == 0) + break; + continue; + } + + if (string[i] == delimiter) + return i; + } + return (i); +} + +/* Skip the white space and any quoted characters in STRING, starting at + START. Return the new index into STRING, after zero or more characters + have been skipped. */ +static int +skipws (string, start) + char *string; + int start; +{ + register int i; + int pass_next, backslash_quoted_word; + unsigned char peekc; + + /* skip quoted strings, in ' or ", and words in which a character is quoted + with a `\'. */ + i = backslash_quoted_word = pass_next = 0; + + /* Skip leading whitespace (or separator characters), and quoted words. + But save it in the output. */ + + for (i = start; string[i]; i++) + { + if (pass_next) + { + pass_next = 0; + continue; + } + + if (whitespace (string[i])) + { + backslash_quoted_word = 0; /* we are no longer in a backslash-quoted word */ + continue; + } + + if (string[i] == '\\') + { + peekc = string[i+1]; + if (peekc == 0) + break; + if (ISLETTER (peekc)) + backslash_quoted_word++; /* this is a backslash-quoted word */ + else + pass_next++; + continue; + } + + /* This only handles single pairs of non-escaped quotes. This + overloads backslash_quoted_word to also mean that a word like + ""f is being scanned, so that the quotes will inhibit any expansion + of the word. */ + if (quote_char(string[i])) + { + i = skipquotes (string, i); + /* This could be a line that contains a single quote character, + in which case skipquotes () terminates with string[i] == '\0' + (the end of the string). Check for that here. */ + if (string[i] == '\0') + break; + + peekc = string[i + 1]; + if (ISLETTER (peekc)) + backslash_quoted_word++; + continue; + } + + /* If we're in the middle of some kind of quoted word, let it + pass through. */ + if (backslash_quoted_word) + continue; + + /* If this character is a shell command separator, then set a hint for + alias_expand that the next token is the first word in a command. */ + + if (command_separator (string[i])) + { + command_word++; + continue; + } + break; + } + return (i); +} + +/* Characters that may appear in a token. Basically, anything except white + space and a token separator. */ +#define token_char(c) (!((whitespace (string[i]) || self_delimiting (string[i])))) + +/* Read from START in STRING until the next separator character, and return + the index of that separator. Skip backslash-quoted characters. Call + skipquotes () for quoted strings in the middle or at the end of tokens, + so all characters show up (e.g. foo'' and foo""bar) */ +static int +rd_token (string, start) + char *string; + int start; +{ + register int i; + + /* From here to next separator character is a token. */ + for (i = start; string[i] && token_char (string[i]); i++) + { + if (string[i] == '\\') + { + i++; /* skip backslash-escaped character */ + if (string[i] == 0) + break; + continue; + } + + /* If this character is a quote character, we want to call skipquotes + to get the whole quoted portion as part of this word. That word + will not generally match an alias, even if te unquoted word would + have. The presence of the quotes in the token serves then to + inhibit expansion. */ + if (quote_char (string[i])) + { + i = skipquotes (string, i); + /* This could be a line that contains a single quote character, + in which case skipquotes () terminates with string[i] == '\0' + (the end of the string). Check for that here. */ + if (string[i] == '\0') + break; + + /* Now string[i] is the matching quote character, and the + quoted portion of the token has been scanned. */ + continue; + } + } + return (i); +} + +/* Return a new line, with any aliases substituted. */ +char * +alias_expand (string) + char *string; +{ + register int i, j, start; + char *line, *token; + int line_len, tl, real_start, expand_next, expand_this_token; + alias_t *alias; + + line_len = strlen (string) + 1; + line = (char *)xmalloc (line_len); + token = (char *)xmalloc (line_len); + + line[0] = i = 0; + expand_next = 0; + command_word = 1; /* initialized to expand the first word on the line */ + + /* Each time through the loop we find the next word in line. If it + has an alias, substitute the alias value. If the value ends in ` ', + then try again with the next word. Else, if there is no value, or if + the value does not end in space, we are done. */ + + for (;;) + { + + token[0] = 0; + start = i; + + /* Skip white space and quoted characters */ + i = skipws (string, start); + + if (start == i && string[i] == '\0') + { + free (token); + return (line); + } + + /* copy the just-skipped characters into the output string, + expanding it if there is not enough room. */ + j = strlen (line); + tl = i - start; /* number of characters just skipped */ + RESIZE_MALLOCED_BUFFER (line, j, (tl + 1), line_len, (tl + 50)); + strncpy (line + j, string + start, tl); + line[j + tl] = '\0'; + + real_start = i; + + command_word = command_word || (command_separator (string[i])); + expand_this_token = (command_word || expand_next); + expand_next = 0; + + /* Read the next token, and copy it into TOKEN. */ + start = i; + i = rd_token (string, start); + + tl = i - start; /* token length */ + + /* If tl == 0, but we're not at the end of the string, then we have a + single-character token, probably a delimiter */ + if (tl == 0 && string[i] != '\0') + { + tl = 1; + i++; /* move past it */ + } + + strncpy (token, string + start, tl); + token [tl] = '\0'; + + /* If there is a backslash-escaped character quoted in TOKEN, + then we don't do alias expansion. This should check for all + other quoting characters, too. */ + if (mbschr (token, '\\')) + expand_this_token = 0; + + /* If we should be expanding here, if we are expanding all words, or if + we are in a location in the string where an expansion is supposed to + take place, see if this word has a substitution. If it does, then do + the expansion. Note that we defer the alias value lookup until we + are sure we are expanding this token. */ + + if ((token[0]) && + (expand_this_token || alias_expand_all) && + (alias = find_alias (token))) + { + char *v; + int vlen, llen; + + v = alias->value; + vlen = strlen (v); + llen = strlen (line); + + /* +3 because we possibly add one more character below. */ + RESIZE_MALLOCED_BUFFER (line, llen, (vlen + 3), line_len, (vlen + 50)); + + strcpy (line + llen, v); + + if ((expand_this_token && vlen && whitespace (v[vlen - 1])) || + alias_expand_all) + expand_next = 1; + } + else + { + int llen, tlen; + + llen = strlen (line); + tlen = i - real_start; /* tlen == strlen(token) */ + + RESIZE_MALLOCED_BUFFER (line, llen, (tlen + 1), line_len, (llen + tlen + 50)); + + strncpy (line + llen, string + real_start, tlen); + line[llen + tlen] = '\0'; + } + command_word = 0; + } +} +#endif /* READLINE */ +#endif /* ALIAS */ |