1 /* $OpenBSD: which.c,v 1.17 2011/03/11 04:30:21 guenther Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #include <sys/param.h> 20 #include <sys/stat.h> 21 #include <sys/sysctl.h> 22 23 #include <err.h> 24 #include <errno.h> 25 #include <locale.h> 26 #include <stdio.h> 27 #include <stdlib.h> 28 #include <string.h> 29 #include <unistd.h> 30 31 #define PROG_WHICH 1 32 #define PROG_WHEREIS 2 33 34 extern char *__progname; 35 36 int findprog(char *, char *, int, int); 37 __dead void usage(void); 38 39 /* 40 * which(1) -- find an executable(s) in the user's path 41 * whereis(1) -- find an executable(s) in the default user path 42 * 43 * Return values: 44 * 0 - all executables found 45 * 1 - some found, some not 46 * 2 - none found 47 */ 48 49 int 50 main(int argc, char *argv[]) 51 { 52 char *path; 53 size_t n; 54 int ch, allmatches = 0, notfound = 0, progmode = PROG_WHICH; 55 56 (void)setlocale(LC_ALL, ""); 57 58 while ((ch = getopt(argc, argv, "a")) != -1) 59 switch (ch) { 60 case 'a': 61 allmatches = 1; 62 break; 63 default: 64 usage(); 65 } 66 argc -= optind; 67 argv += optind; 68 69 if (argc == 0) 70 usage(); 71 72 /* 73 * which(1) uses user's $PATH. 74 * whereis(1) uses user.cs_path from sysctl(3). 75 */ 76 if (strcmp(__progname, "whereis") == 0) { 77 int mib[2]; 78 79 progmode = PROG_WHEREIS; 80 mib[0] = CTL_USER; 81 mib[1] = USER_CS_PATH; 82 if (sysctl(mib, 2, NULL, &n, NULL, 0) == -1) 83 err(1, "unable to get length of user.cs_path"); 84 if (n == 0) 85 errx(1, "user.cs_path was zero length!"); 86 if ((path = (char *)malloc(n)) == NULL) 87 errx(1, "can't allocate memory."); 88 if (sysctl(mib, 2, path, &n, NULL, 0) == -1) 89 err(1, "unable to get user.cs_path"); 90 } else { 91 if ((path = getenv("PATH")) == NULL) 92 err(1, "can't get $PATH from environment"); 93 } 94 95 /* To make access(2) do what we want */ 96 if (setgid(getegid())) 97 err(1, "Can't set gid to %u", getegid()); 98 if (setuid(geteuid())) 99 err(1, "Can't set uid to %u", geteuid()); 100 101 for (n = 0; n < argc; n++) 102 if (findprog(argv[n], path, progmode, allmatches) == 0) 103 notfound++; 104 105 exit((notfound == 0) ? 0 : ((notfound == argc) ? 2 : 1)); 106 } 107 108 int 109 findprog(char *prog, char *path, int progmode, int allmatches) 110 { 111 char *p, filename[MAXPATHLEN]; 112 int proglen, plen, rval = 0; 113 struct stat sbuf; 114 char *pathcpy; 115 116 /* Special case if prog contains '/' */ 117 if (strchr(prog, '/')) { 118 if ((stat(prog, &sbuf) == 0) && S_ISREG(sbuf.st_mode) && 119 access(prog, X_OK) == 0) { 120 (void)puts(prog); 121 return (1); 122 } else { 123 warnx("%s: Command not found.", prog); 124 return (0); 125 } 126 } 127 128 if ((path = strdup(path)) == NULL) 129 err(1, "strdup"); 130 pathcpy = path; 131 132 proglen = strlen(prog); 133 while ((p = strsep(&pathcpy, ":")) != NULL) { 134 if (*p == '\0') 135 p = "."; 136 137 plen = strlen(p); 138 while (p[plen-1] == '/') 139 p[--plen] = '\0'; /* strip trailing '/' */ 140 141 if (plen + 1 + proglen >= sizeof(filename)) { 142 warnx("%s/%s: %s", p, prog, strerror(ENAMETOOLONG)); 143 free(path); 144 return (0); 145 } 146 147 snprintf(filename, sizeof(filename), "%s/%s", p, prog); 148 if ((stat(filename, &sbuf) == 0) && S_ISREG(sbuf.st_mode) && 149 access(filename, X_OK) == 0) { 150 (void)puts(filename); 151 rval = 1; 152 if (!allmatches) { 153 free(path); 154 return (rval); 155 } 156 } 157 } 158 (void)free(path); 159 160 /* whereis(1) is silent on failure. */ 161 if (!rval && progmode != PROG_WHEREIS) 162 warnx("%s: Command not found.", prog); 163 return (rval); 164 } 165 166 __dead void 167 usage(void) 168 { 169 (void)fprintf(stderr, "usage: %s [-a] name ...\n", __progname); 170 exit(1); 171 } 172