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author | Cameron Katri <me@cameronkatri.com> | 2021-05-09 14:20:58 -0400 |
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committer | Cameron Katri <me@cameronkatri.com> | 2021-05-09 14:20:58 -0400 |
commit | 5fd83771641d15c418f747bd343ba6738d3875f7 (patch) | |
tree | 5abf0f78f680d9837dbd93d4d4c3933bb7509599 /shell_cmds/env/envopts.c | |
download | apple_cmds-5fd83771641d15c418f747bd343ba6738d3875f7.tar.gz apple_cmds-5fd83771641d15c418f747bd343ba6738d3875f7.tar.zst apple_cmds-5fd83771641d15c418f747bd343ba6738d3875f7.zip |
Import macOS userland
adv_cmds-176
basic_cmds-55
bootstrap_cmds-116.100.1
developer_cmds-66
diskdev_cmds-667.40.1
doc_cmds-53.60.1
file_cmds-321.40.3
mail_cmds-35
misc_cmds-34
network_cmds-606.40.1
patch_cmds-17
remote_cmds-63
shell_cmds-216.60.1
system_cmds-880.60.2
text_cmds-106
Diffstat (limited to 'shell_cmds/env/envopts.c')
-rw-r--r-- | shell_cmds/env/envopts.c | 468 |
1 files changed, 468 insertions, 0 deletions
diff --git a/shell_cmds/env/envopts.c b/shell_cmds/env/envopts.c new file mode 100644 index 0000000..f821430 --- /dev/null +++ b/shell_cmds/env/envopts.c @@ -0,0 +1,468 @@ +/*- + * 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); +} |