| Current Path : /usr/src/usr.bin/env/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/usr.bin/env/envopts.c |
/*-
* Copyright (c) 2005 - Garance Alistair Drosehn <gad@FreeBSD.org>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The views and conclusions contained in the software and documentation
* are those of the authors and should not be interpreted as representing
* official policies, either expressed or implied, of the FreeBSD Project.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/usr.bin/env/envopts.c 148142 2005-07-18 22:18:16Z gad $");
#include <sys/stat.h>
#include <sys/param.h>
#include <err.h>
#include <errno.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "envopts.h"
static const char *
expand_vars(int in_thisarg, char **thisarg_p, char **dest_p,
const char **src_p);
static int is_there(char *candidate);
/*
* The is*() routines take a parameter of 'int', but expect values in the range
* of unsigned char. Define some wrappers which take a value of type 'char',
* whether signed or unsigned, and ensure the value ends up in the right range.
*/
#define isalnumch(Anychar) isalnum((u_char)(Anychar))
#define isalphach(Anychar) isalpha((u_char)(Anychar))
#define isspacech(Anychar) isspace((u_char)(Anychar))
/*
* Routine to determine if a given fully-qualified filename is executable.
* This is copied almost verbatim from FreeBSD's usr.bin/which/which.c.
*/
static int
is_there(char *candidate)
{
struct stat fin;
/* XXX work around access(2) false positives for superuser */
if (access(candidate, X_OK) == 0 &&
stat(candidate, &fin) == 0 &&
S_ISREG(fin.st_mode) &&
(getuid() != 0 ||
(fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
if (env_verbosity > 1)
fprintf(stderr, "#env matched:\t'%s'\n", candidate);
return (1);
}
return (0);
}
/**
* Routine to search through an alternate path-list, looking for a given
* filename to execute. If the file is found, replace the original
* unqualified name with a fully-qualified path. This allows `env' to
* execute programs from a specific strict list of possible paths, without
* changing the value of PATH seen by the program which will be executed.
* E.G.:
* #!/usr/bin/env -S-P/usr/local/bin:/usr/bin perl
* will execute /usr/local/bin/perl or /usr/bin/perl (whichever is found
* first), no matter what the current value of PATH is, and without
* changing the value of PATH that the script will see when it runs.
*
* This is similar to the print_matches() routine in usr.bin/which/which.c.
*/
void
search_paths(char *path, char **argv)
{
char candidate[PATH_MAX];
const char *d;
char *filename, *fqname;
/* If the file has a `/' in it, then no search is done */
filename = *argv;
if (strchr(filename, '/') != NULL)
return;
if (env_verbosity > 1) {
fprintf(stderr, "#env Searching:\t'%s'\n", path);
fprintf(stderr, "#env for file:\t'%s'\n", filename);
}
fqname = NULL;
while ((d = strsep(&path, ":")) != NULL) {
if (*d == '\0')
d = ".";
if (snprintf(candidate, sizeof(candidate), "%s/%s", d,
filename) >= (int)sizeof(candidate))
continue;
if (is_there(candidate)) {
fqname = candidate;
break;
}
}
if (fqname == NULL) {
errno = ENOENT;
err(127, "%s", filename);
}
*argv = strdup(candidate);
}
/**
* Routine to split a string into multiple parameters, while recognizing a
* few special characters. It recognizes both single and double-quoted
* strings. This processing is designed entirely for the benefit of the
* parsing of "#!"-lines (aka "shebang" lines == the first line of an
* executable script). Different operating systems parse that line in very
* different ways, and this split-on-spaces processing is meant to provide
* ways to specify arbitrary arguments on that line, no matter how the OS
* parses it.
*
* Within a single-quoted string, the two characters "\'" are treated as
* a literal "'" character to add to the string, and "\\" are treated as
* a literal "\" character to add. Other than that, all characters are
* copied until the processing gets to a terminating "'".
*
* Within a double-quoted string, many more "\"-style escape sequences
* are recognized, mostly copied from what is recognized in the `printf'
* command. Some OS's will not allow a literal blank character to be
* included in the one argument that they recognize on a shebang-line,
* so a few additional escape-sequences are defined to provide ways to
* specify blanks.
*
* Within a double-quoted string "\_" is turned into a literal blank.
* (Inside of a single-quoted string, the two characters are just copied)
* Outside of a quoted string, "\_" is treated as both a blank, and the
* end of the current argument. So with a shelbang-line of:
* #!/usr/bin/env -SA=avalue\_perl
* the -S value would be broken up into arguments "A=avalue" and "perl".
*/
void
split_spaces(const char *str, int *origind, int *origc, char ***origv)
{
static const char *nullarg = "";
const char *bq_src, *copystr, *src;
char *dest, **newargv, *newstr, **nextarg, **oldarg;
int addcount, bq_destlen, copychar, found_sep, in_arg, in_dq, in_sq;
/*
* Ignore leading space on the string, and then malloc enough room
* to build a copy of it. The copy might end up shorter than the
* original, due to quoted strings and '\'-processing.
*/
while (isspacech(*str))
str++;
if (*str == '\0')
return;
newstr = malloc(strlen(str) + 1);
/*
* Allocate plenty of space for the new array of arg-pointers,
* and start that array off with the first element of the old
* array.
*/
newargv = malloc((*origc + (strlen(str) / 2) + 2) * sizeof(char *));
nextarg = newargv;
*nextarg++ = **origv;
/* Come up with the new args by splitting up the given string. */
addcount = 0;
bq_destlen = in_arg = in_dq = in_sq = 0;
bq_src = NULL;
for (src = str, dest = newstr; *src != '\0'; src++) {
/*
* This switch will look at a character in *src, and decide
* what should be copied to *dest. It only decides what
* character(s) to copy, it should not modify *dest. In some
* cases, it will look at multiple characters from *src.
*/
copychar = found_sep = 0;
copystr = NULL;
switch (*src) {
case '"':
if (in_sq)
copychar = *src;
else if (in_dq)
in_dq = 0;
else {
/*
* Referencing nullarg ensures that a new
* argument is created, even if this quoted
* string ends up with zero characters.
*/
copystr = nullarg;
in_dq = 1;
bq_destlen = dest - *(nextarg - 1);
bq_src = src;
}
break;
case '$':
if (in_sq)
copychar = *src;
else {
copystr = expand_vars(in_arg, (nextarg - 1),
&dest, &src);
}
break;
case '\'':
if (in_dq)
copychar = *src;
else if (in_sq)
in_sq = 0;
else {
/*
* Referencing nullarg ensures that a new
* argument is created, even if this quoted
* string ends up with zero characters.
*/
copystr = nullarg;
in_sq = 1;
bq_destlen = dest - *(nextarg - 1);
bq_src = src;
}
break;
case '\\':
if (in_sq) {
/*
* Inside single-quoted strings, only the
* "\'" and "\\" are recognized as special
* strings.
*/
copychar = *(src + 1);
if (copychar == '\'' || copychar == '\\')
src++;
else
copychar = *src;
break;
}
src++;
switch (*src) {
case '"':
case '#':
case '$':
case '\'':
case '\\':
copychar = *src;
break;
case '_':
/*
* Alternate way to get a blank, which allows
* that blank be used to separate arguments
* when it is not inside a quoted string.
*/
if (in_dq)
copychar = ' ';
else {
found_sep = 1;
src++;
}
break;
case 'c':
/*
* Ignore remaining characters in the -S string.
* This would not make sense if found in the
* middle of a quoted string.
*/
if (in_dq)
errx(1, "Sequence '\\%c' is not allowed"
" in quoted strings", *src);
goto str_done;
case 'f':
copychar = '\f';
break;
case 'n':
copychar = '\n';
break;
case 'r':
copychar = '\r';
break;
case 't':
copychar = '\t';
break;
case 'v':
copychar = '\v';
break;
default:
if (isspacech(*src))
copychar = *src;
else
errx(1, "Invalid sequence '\\%c' in -S",
*src);
}
break;
default:
if ((in_dq || in_sq) && in_arg)
copychar = *src;
else if (isspacech(*src))
found_sep = 1;
else {
/*
* If the first character of a new argument
* is `#', then ignore the remaining chars.
*/
if (!in_arg && *src == '#')
goto str_done;
copychar = *src;
}
}
/*
* Now that the switch has determined what (if anything)
* needs to be copied, copy whatever that is to *dest.
*/
if (copychar || copystr != NULL) {
if (!in_arg) {
/* This is the first byte of a new argument */
*nextarg++ = dest;
addcount++;
in_arg = 1;
}
if (copychar)
*dest++ = (char)copychar;
else if (copystr != NULL)
while (*copystr != '\0')
*dest++ = *copystr++;
} else if (found_sep) {
*dest++ = '\0';
while (isspacech(*src))
src++;
--src;
in_arg = 0;
}
}
str_done:
*dest = '\0';
*nextarg = NULL;
if (in_dq || in_sq) {
errx(1, "No terminating quote for string: %.*s%s",
bq_destlen, *(nextarg - 1), bq_src);
}
if (env_verbosity > 1) {
fprintf(stderr, "#env split -S:\t'%s'\n", str);
oldarg = newargv + 1;
fprintf(stderr, "#env into:\t'%s'\n", *oldarg);
for (oldarg++; *oldarg; oldarg++)
fprintf(stderr, "#env &\t'%s'\n", *oldarg);
}
/* Copy the unprocessed arg-pointers from the original array */
for (oldarg = *origv + *origind; *oldarg; oldarg++)
*nextarg++ = *oldarg;
*nextarg = NULL;
/* Update optind/argc/argv in the calling routine */
*origind = 1;
*origc += addcount;
*origv = newargv;
}
/**
* Routine to split expand any environment variables referenced in the string
* that -S is processing. For now it only supports the form ${VARNAME}. It
* explicitly does not support $VARNAME, and obviously can not handle special
* shell-variables such as $?, $*, $1, etc. It is called with *src_p pointing
* at the initial '$', and if successful it will update *src_p, *dest_p, and
* possibly *thisarg_p in the calling routine.
*/
static const char *
expand_vars(int in_thisarg, char **thisarg_p, char **dest_p, const char **src_p)
{
const char *vbegin, *vend, *vvalue;
char *newstr, *vname;
int bad_reference;
size_t namelen, newlen;
bad_reference = 1;
vbegin = vend = (*src_p) + 1;
if (*vbegin++ == '{')
if (*vbegin == '_' || isalphach(*vbegin)) {
vend = vbegin + 1;
while (*vend == '_' || isalnumch(*vend))
vend++;
if (*vend == '}')
bad_reference = 0;
}
if (bad_reference)
errx(1, "Only ${VARNAME} expansion is supported, error at: %s",
*src_p);
/*
* We now know we have a valid environment variable name, so update
* the caller's source-pointer to the last character in that reference,
* and then pick up the matching value. If the variable is not found,
* or if it has a null value, then our work here is done.
*/
*src_p = vend;
namelen = vend - vbegin + 1;
vname = malloc(namelen);
strlcpy(vname, vbegin, namelen);
vvalue = getenv(vname);
if (vvalue == NULL || *vvalue == '\0') {
if (env_verbosity > 2)
fprintf(stderr,
"#env replacing ${%s} with null string\n",
vname);
free(vname);
return (NULL);
}
if (env_verbosity > 2)
fprintf(stderr, "#env expanding ${%s} into '%s'\n", vname,
vvalue);
/*
* There is some value to copy to the destination. If the value is
* shorter than the ${VARNAME} reference that it replaces, then our
* caller can just copy the value to the existing destination.
*/
if (strlen(vname) + 3 >= strlen(vvalue)) {
free(vname);
return (vvalue);
}
/*
* The value is longer than the string it replaces, which means the
* present destination area is too small to hold it. Create a new
* destination area, and update the caller's 'dest' variable to match.
* If the caller has already started copying some info for 'thisarg'
* into the present destination, then the new destination area must
* include a copy of that data, and the pointer to 'thisarg' must also
* be updated. Note that it is still the caller which copies this
* vvalue to the new *dest.
*/
newlen = strlen(vvalue) + strlen(*src_p) + 1;
if (in_thisarg) {
**dest_p = '\0'; /* Provide terminator for 'thisarg' */
newlen += strlen(*thisarg_p);
newstr = malloc(newlen);
strcpy(newstr, *thisarg_p);
*thisarg_p = newstr;
} else {
newstr = malloc(newlen);
*newstr = '\0';
}
*dest_p = strchr(newstr, '\0');
free(vname);
return (vvalue);
}