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9afe6a5bf9
Noticed by: Dave Hart MFC plans: after checking with re@
469 lines
14 KiB
C
469 lines
14 KiB
C
/*-
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* Copyright (c) 2005 - Garance Alistair Drosehn <gad@FreeBSD.org>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* The views and conclusions contained in the software and documentation
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* are those of the authors and should not be interpreted as representing
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* official policies, either expressed or implied, of the FreeBSD Project.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/stat.h>
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#include <sys/param.h>
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#include <err.h>
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#include <errno.h>
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#include <ctype.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "envopts.h"
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static const char *
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expand_vars(int in_thisarg, char **thisarg_p, char **dest_p,
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const char **src_p);
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static int is_there(char *candidate);
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/*
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* The is*() routines take a parameter of 'int', but expect values in the range
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* of unsigned char. Define some wrappers which take a value of type 'char',
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* whether signed or unsigned, and ensure the value ends up in the right range.
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*/
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#define isalnumch(Anychar) isalnum((u_char)(Anychar))
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#define isalphach(Anychar) isalpha((u_char)(Anychar))
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#define isspacech(Anychar) isspace((u_char)(Anychar))
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/*
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* Routine to determine if a given fully-qualified filename is executable.
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* This is copied almost verbatim from FreeBSD's usr.bin/which/which.c.
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*/
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static int
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is_there(char *candidate)
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{
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struct stat fin;
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/* XXX work around access(2) false positives for superuser */
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if (access(candidate, X_OK) == 0 &&
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stat(candidate, &fin) == 0 &&
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S_ISREG(fin.st_mode) &&
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(getuid() != 0 ||
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(fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
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if (env_verbosity > 1)
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fprintf(stderr, "#env matched:\t'%s'\n", candidate);
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return (1);
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}
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return (0);
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}
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/**
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* Routine to search through an alternate path-list, looking for a given
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* filename to execute. If the file is found, replace the original
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* unqualified name with a fully-qualified path. This allows `env' to
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* execute programs from a specific strict list of possible paths, without
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* changing the value of PATH seen by the program which will be executed.
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* E.G.:
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* #!/usr/bin/env -S-P/usr/local/bin:/usr/bin perl
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* will execute /usr/local/bin/perl or /usr/bin/perl (whichever is found
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* first), no matter what the current value of PATH is, and without
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* changing the value of PATH that the script will see when it runs.
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*
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* This is similar to the print_matches() routine in usr.bin/which/which.c.
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*/
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void
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search_paths(char *path, char **argv)
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{
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char candidate[PATH_MAX];
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const char *d;
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char *filename, *fqname;
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/* If the file has a `/' in it, then no search is done */
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filename = *argv;
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if (strchr(filename, '/') != NULL)
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return;
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if (env_verbosity > 1) {
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fprintf(stderr, "#env Searching:\t'%s'\n", path);
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fprintf(stderr, "#env for file:\t'%s'\n", filename);
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}
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fqname = NULL;
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while ((d = strsep(&path, ":")) != NULL) {
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if (*d == '\0')
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d = ".";
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if (snprintf(candidate, sizeof(candidate), "%s/%s", d,
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filename) >= (int)sizeof(candidate))
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continue;
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if (is_there(candidate)) {
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fqname = candidate;
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break;
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}
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}
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if (fqname == NULL) {
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errno = ENOENT;
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err(127, "%s", filename);
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}
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*argv = strdup(candidate);
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}
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/**
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* Routine to split a string into multiple parameters, while recognizing a
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* few special characters. It recognizes both single and double-quoted
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* strings. This processing is designed entirely for the benefit of the
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* parsing of "#!"-lines (aka "shebang" lines == the first line of an
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* executable script). Different operating systems parse that line in very
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* different ways, and this split-on-spaces processing is meant to provide
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* ways to specify arbitrary arguments on that line, no matter how the OS
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* parses it.
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*
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* Within a single-quoted string, the two characters "\'" are treated as
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* a literal "'" character to add to the string, and "\\" are treated as
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* a literal "\" character to add. Other than that, all characters are
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* copied until the processing gets to a terminating "'".
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*
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* Within a double-quoted string, many more "\"-style escape sequences
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* are recognized, mostly copied from what is recognized in the `printf'
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* command. Some OS's will not allow a literal blank character to be
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* included in the one argument that they recognize on a shebang-line,
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* so a few additional escape-sequences are defined to provide ways to
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* specify blanks.
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*
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* Within a double-quoted string "\_" is turned into a literal blank.
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* (Inside of a single-quoted string, the two characters are just copied)
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* Outside of a quoted string, "\_" is treated as both a blank, and the
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* end of the current argument. So with a shelbang-line of:
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* #!/usr/bin/env -SA=avalue\_perl
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* the -S value would be broken up into arguments "A=avalue" and "perl".
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*/
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void
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split_spaces(const char *str, int *origind, int *origc, char ***origv)
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{
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static const char *nullarg = "";
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const char *bq_src, *copystr, *src;
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char *dest, **newargv, *newstr, **nextarg, **oldarg;
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int addcount, bq_destlen, copychar, found_sep, in_arg, in_dq, in_sq;
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/*
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* Ignore leading space on the string, and then malloc enough room
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* to build a copy of it. The copy might end up shorter than the
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* original, due to quoted strings and '\'-processing.
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*/
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while (isspacech(*str))
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str++;
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if (*str == '\0')
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return;
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newstr = malloc(strlen(str) + 1);
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/*
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* Allocate plenty of space for the new array of arg-pointers,
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* and start that array off with the first element of the old
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* array.
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*/
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newargv = malloc((*origc + (strlen(str) / 2) + 2) * sizeof(char *));
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nextarg = newargv;
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*nextarg++ = **origv;
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/* Come up with the new args by splitting up the given string. */
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addcount = 0;
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bq_destlen = in_arg = in_dq = in_sq = 0;
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bq_src = NULL;
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for (src = str, dest = newstr; *src != '\0'; src++) {
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/*
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* This switch will look at a character in *src, and decide
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* what should be copied to *dest. It only decides what
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* character(s) to copy, it should not modify *dest. In some
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* cases, it will look at multiple characters from *src.
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*/
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copychar = found_sep = 0;
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copystr = NULL;
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switch (*src) {
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case '"':
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if (in_sq)
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copychar = *src;
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else if (in_dq)
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in_dq = 0;
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else {
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/*
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* Referencing nullarg ensures that a new
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* argument is created, even if this quoted
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* string ends up with zero characters.
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*/
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copystr = nullarg;
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in_dq = 1;
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bq_destlen = dest - *(nextarg - 1);
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bq_src = src;
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}
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break;
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case '$':
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if (in_sq)
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copychar = *src;
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else {
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copystr = expand_vars(in_arg, (nextarg - 1),
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&dest, &src);
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}
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break;
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case '\'':
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if (in_dq)
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copychar = *src;
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else if (in_sq)
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in_sq = 0;
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else {
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/*
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* Referencing nullarg ensures that a new
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* argument is created, even if this quoted
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* string ends up with zero characters.
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*/
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copystr = nullarg;
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in_sq = 1;
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bq_destlen = dest - *(nextarg - 1);
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bq_src = src;
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}
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break;
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case '\\':
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if (in_sq) {
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/*
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* Inside single-quoted strings, only the
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* "\'" and "\\" are recognized as special
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* strings.
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*/
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copychar = *(src + 1);
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if (copychar == '\'' || copychar == '\\')
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src++;
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else
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copychar = *src;
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break;
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}
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src++;
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switch (*src) {
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case '"':
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case '#':
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case '$':
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case '\'':
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case '\\':
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copychar = *src;
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break;
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case '_':
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/*
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* Alternate way to get a blank, which allows
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* that blank be used to separate arguments
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* when it is not inside a quoted string.
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*/
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if (in_dq)
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copychar = ' ';
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else {
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found_sep = 1;
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src++;
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}
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break;
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case 'c':
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/*
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* Ignore remaining characters in the -S string.
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* This would not make sense if found in the
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* middle of a quoted string.
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*/
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if (in_dq)
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errx(1, "Sequence '\\%c' is not allowed"
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" in quoted strings", *src);
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goto str_done;
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case 'f':
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copychar = '\f';
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break;
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case 'n':
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copychar = '\n';
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break;
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case 'r':
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copychar = '\r';
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break;
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case 't':
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copychar = '\t';
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break;
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case 'v':
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copychar = '\v';
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break;
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default:
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if (isspacech(*src))
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copychar = *src;
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else
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errx(1, "Invalid sequence '\\%c' in -S",
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*src);
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}
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break;
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default:
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if ((in_dq || in_sq) && in_arg)
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copychar = *src;
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else if (isspacech(*src))
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found_sep = 1;
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else {
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/*
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* If the first character of a new argument
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* is `#', then ignore the remaining chars.
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*/
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if (!in_arg && *src == '#')
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goto str_done;
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copychar = *src;
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}
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}
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/*
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* Now that the switch has determined what (if anything)
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* needs to be copied, copy whatever that is to *dest.
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*/
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if (copychar || copystr != NULL) {
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if (!in_arg) {
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/* This is the first byte of a new argument */
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*nextarg++ = dest;
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addcount++;
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in_arg = 1;
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}
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if (copychar)
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*dest++ = (char)copychar;
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else if (copystr != NULL)
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while (*copystr != '\0')
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*dest++ = *copystr++;
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} else if (found_sep) {
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*dest++ = '\0';
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while (isspacech(*src))
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src++;
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--src;
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in_arg = 0;
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}
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}
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str_done:
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*dest = '\0';
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*nextarg = NULL;
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if (in_dq || in_sq) {
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errx(1, "No terminating quote for string: %.*s%s",
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bq_destlen, *(nextarg - 1), bq_src);
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}
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if (env_verbosity > 1) {
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fprintf(stderr, "#env split -S:\t'%s'\n", str);
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oldarg = newargv + 1;
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fprintf(stderr, "#env into:\t'%s'\n", *oldarg);
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for (oldarg++; *oldarg; oldarg++)
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fprintf(stderr, "#env &\t'%s'\n", *oldarg);
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}
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/* Copy the unprocessed arg-pointers from the original array */
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for (oldarg = *origv + *origind; *oldarg; oldarg++)
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*nextarg++ = *oldarg;
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*nextarg = NULL;
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/* Update optind/argc/argv in the calling routine */
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*origind = 1;
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*origc += addcount;
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*origv = newargv;
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}
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/**
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* Routine to split expand any environment variables referenced in the string
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* that -S is processing. For now it only supports the form ${VARNAME}. It
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* explicitly does not support $VARNAME, and obviously can not handle special
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* shell-variables such as $?, $*, $1, etc. It is called with *src_p pointing
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* at the initial '$', and if successful it will update *src_p, *dest_p, and
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* possibly *thisarg_p in the calling routine.
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*/
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static const char *
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expand_vars(int in_thisarg, char **thisarg_p, char **dest_p, const char **src_p)
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{
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const char *vbegin, *vend, *vvalue;
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char *newstr, *vname;
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int bad_reference;
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size_t namelen, newlen;
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bad_reference = 1;
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vbegin = vend = (*src_p) + 1;
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if (*vbegin++ == '{')
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if (*vbegin == '_' || isalphach(*vbegin)) {
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vend = vbegin + 1;
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while (*vend == '_' || isalnumch(*vend))
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vend++;
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if (*vend == '}')
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bad_reference = 0;
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}
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if (bad_reference)
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errx(1, "Only ${VARNAME} expansion is supported, error at: %s",
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*src_p);
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/*
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* We now know we have a valid environment variable name, so update
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* the caller's source-pointer to the last character in that reference,
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* and then pick up the matching value. If the variable is not found,
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* or if it has a null value, then our work here is done.
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*/
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*src_p = vend;
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namelen = vend - vbegin + 1;
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vname = malloc(namelen);
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strlcpy(vname, vbegin, namelen);
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vvalue = getenv(vname);
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if (vvalue == NULL || *vvalue == '\0') {
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if (env_verbosity > 2)
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fprintf(stderr,
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"#env replacing ${%s} with null string\n",
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vname);
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free(vname);
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return (NULL);
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}
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if (env_verbosity > 2)
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fprintf(stderr, "#env expanding ${%s} into '%s'\n", vname,
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vvalue);
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/*
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* There is some value to copy to the destination. If the value is
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* shorter than the ${VARNAME} reference that it replaces, then our
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* caller can just copy the value to the existing destination.
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*/
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if (strlen(vname) + 3 >= strlen(vvalue)) {
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free(vname);
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return (vvalue);
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}
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/*
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* The value is longer than the string it replaces, which means the
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* present destination area is too small to hold it. Create a new
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* destination area, and update the caller's 'dest' variable to match.
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* If the caller has already started copying some info for 'thisarg'
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* into the present destination, then the new destination area must
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* include a copy of that data, and the pointer to 'thisarg' must also
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* be updated. Note that it is still the caller which copies this
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* vvalue to the new *dest.
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*/
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newlen = strlen(vvalue) + strlen(*src_p) + 1;
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if (in_thisarg) {
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**dest_p = '\0'; /* Provide terminator for 'thisarg' */
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newlen += strlen(*thisarg_p);
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newstr = malloc(newlen);
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strcpy(newstr, *thisarg_p);
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*thisarg_p = newstr;
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} else {
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newstr = malloc(newlen);
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*newstr = '\0';
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}
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*dest_p = strchr(newstr, '\0');
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free(vname);
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return (vvalue);
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}
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