/*- * 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); }