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-rw-r--r--shell_cmds/env/envopts.c468
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diff --git a/shell_cmds/env/envopts.c b/shell_cmds/env/envopts.c
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+/*-
+ * 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("$FreeBSD$");
+
+#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);
+}
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