1/* stdbuf -- setup the standard streams for a command 2 Copyright (C) 2009-2010 Free Software Foundation, Inc. 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation, either version 3 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 16 17/* Written by Pádraig Brady. */ 18 19#include <config.h> 20#include <stdio.h> 21#include <getopt.h> 22#include <sys/types.h> 23#include <assert.h> 24 25#include "system.h" 26#include "error.h" 27#include "filenamecat.h" 28#include "posixver.h" 29#include "quote.h" 30#include "xreadlink.h" 31#include "xstrtol.h" 32#include "c-ctype.h" 33 34/* The official name of this program (e.g., no `g' prefix). */ 35#define PROGRAM_NAME "stdbuf" 36#define LIB_NAME "libstdbuf.so" /* FIXME: don't hardcode */ 37 38#define AUTHORS proper_name_utf8 ("Padraig Brady", "P\303\241draig Brady") 39 40static char *program_path; 41 42static struct 43{ 44 size_t size; 45 int optc; 46 char *optarg; 47} stdbuf[3]; 48 49static struct option const longopts[] = 50{ 51 {"input", required_argument, NULL, 'i'}, 52 {"output", required_argument, NULL, 'o'}, 53 {"error", required_argument, NULL, 'e'}, 54 {GETOPT_HELP_OPTION_DECL}, 55 {GETOPT_VERSION_OPTION_DECL}, 56 {NULL, 0, NULL, 0} 57}; 58 59/* Set size to the value of STR, interpreted as a decimal integer, 60 optionally multiplied by various values. 61 Return -1 on error, 0 on success. 62 63 This supports dd BLOCK size suffixes. 64 Note we don't support dd's b=512, c=1, w=2 or 21x512MiB formats. */ 65static int 66parse_size (char const *str, size_t *size) 67{ 68 uintmax_t tmp_size; 69 enum strtol_error e = xstrtoumax (str, NULL, 10, &tmp_size, "EGkKMPTYZ0"); 70 if (e == LONGINT_OK && tmp_size > SIZE_MAX) 71 e = LONGINT_OVERFLOW; 72 73 if (e == LONGINT_OK) 74 { 75 errno = 0; 76 *size = tmp_size; 77 return 0; 78 } 79 80 errno = (e == LONGINT_OVERFLOW ? EOVERFLOW : 0); 81 return -1; 82} 83 84void 85usage (int status) 86{ 87 if (status != EXIT_SUCCESS) 88 fprintf (stderr, _("Try `%s --help' for more information.\n"), 89 program_name); 90 else 91 { 92 printf (_("Usage: %s OPTION... COMMAND\n"), program_name); 93 fputs (_("\ 94Run COMMAND, with modified buffering operations for its standard streams.\n\ 95\n\ 96"), stdout); 97 fputs (_("\ 98Mandatory arguments to long options are mandatory for short options too.\n\ 99"), stdout); 100 fputs (_("\ 101 -i, --input=MODE Adjust standard input stream buffering\n\ 102 -o, --output=MODE Adjust standard output stream buffering\n\ 103 -e, --error=MODE Adjust standard error stream buffering\n\ 104"), stdout); 105 fputs (HELP_OPTION_DESCRIPTION, stdout); 106 fputs (VERSION_OPTION_DESCRIPTION, stdout); 107 fputs (_("\n\ 108If MODE is `L' the corresponding stream will be line buffered.\n\ 109This option is invalid with standard input.\n"), stdout); 110 fputs (_("\n\ 111If MODE is `0' the corresponding stream will be unbuffered.\n\ 112"), stdout); 113 fputs (_("\n\ 114Otherwise MODE is a number which may be followed by one of the following:\n\ 115KB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G, T, P, E, Z, Y.\n\ 116In this case the corresponding stream will be fully buffered with the buffer\n\ 117size set to MODE bytes.\n\ 118"), stdout); 119 fputs (_("\n\ 120NOTE: If COMMAND adjusts the buffering of its standard streams (`tee' does\n\ 121for e.g.) then that will override corresponding settings changed by `stdbuf'.\n\ 122Also some filters (like `dd' and `cat' etc.) don't use streams for I/O,\n\ 123and are thus unaffected by `stdbuf' settings.\n\ 124"), stdout); 125 emit_ancillary_info (); 126 } 127 exit (status); 128} 129 130/* argv[0] can be anything really, but generally it contains 131 the path to the executable or just a name if it was executed 132 using $PATH. In the latter case to get the path we can: 133 search getenv("PATH"), readlink("/prof/self/exe"), getenv("_"), 134 dladdr(), pstat_getpathname(), etc. */ 135 136static void 137set_program_path (const char *arg) 138{ 139 if (strchr (arg, '/')) /* Use absolute or relative paths directly. */ 140 { 141 program_path = dir_name (arg); 142 } 143 else 144 { 145 char *path = xreadlink ("/proc/self/exe"); 146 if (path) 147 program_path = dir_name (path); 148 else if ((path = getenv ("PATH"))) 149 { 150 char *dir; 151 path = xstrdup (path); 152 for (dir = strtok (path, ":"); dir != NULL; dir = strtok (NULL, ":")) 153 { 154 char *candidate = file_name_concat (dir, arg, NULL); 155 if (access (candidate, X_OK) == 0) 156 { 157 program_path = dir_name (candidate); 158 free (candidate); 159 break; 160 } 161 free (candidate); 162 } 163 } 164 free (path); 165 } 166} 167 168static int 169optc_to_fileno (int c) 170{ 171 int ret = -1; 172 173 switch (c) 174 { 175 case 'e': 176 ret = STDERR_FILENO; 177 break; 178 case 'i': 179 ret = STDIN_FILENO; 180 break; 181 case 'o': 182 ret = STDOUT_FILENO; 183 break; 184 } 185 186 return ret; 187} 188 189static void 190set_LD_PRELOAD (void) 191{ 192 int ret; 193 char *old_libs = getenv ("LD_PRELOAD"); 194 char *LD_PRELOAD; 195 196 /* Note this would auto add the appropriate search path for "libstdbuf.so": 197 gcc stdbuf.c -Wl,-rpath,'$ORIGIN' -Wl,-rpath,$PKGLIBDIR 198 However we want the lookup done for the exec'd command not stdbuf. 199 200 Since we don't link against libstdbuf.so add it to LIBDIR rather than 201 LIBEXECDIR, as we'll search for it in the "sys default" case below. */ 202 char const *const search_path[] = { 203 program_path, 204 PKGLIBDIR, 205 "", /* sys default */ 206 NULL 207 }; 208 209 char const *const *path = search_path; 210 char *libstdbuf; 211 212 do 213 { 214 struct stat sb; 215 216 if (!**path) /* system default */ 217 { 218 libstdbuf = xstrdup (LIB_NAME); 219 break; 220 } 221 ret = asprintf (&libstdbuf, "%s/%s", *path, LIB_NAME); 222 if (ret < 0) 223 xalloc_die (); 224 if (stat (libstdbuf, &sb) == 0) /* file_exists */ 225 break; 226 free (libstdbuf); 227 } 228 while (*++path); 229 230 /* FIXME: Do we need to support libstdbuf.dll, c:, '\' separators etc? */ 231 232 if (old_libs) 233 ret = asprintf (&LD_PRELOAD, "LD_PRELOAD=%s:%s", old_libs, libstdbuf); 234 else 235 ret = asprintf (&LD_PRELOAD, "LD_PRELOAD=%s", libstdbuf); 236 237 if (ret < 0) 238 xalloc_die (); 239 240 free (libstdbuf); 241 242 ret = putenv (LD_PRELOAD); 243 244 if (ret != 0) 245 { 246 error (EXIT_CANCELED, errno, 247 _("failed to update the environment with %s"), 248 quote (LD_PRELOAD)); 249 } 250} 251 252/* Populate environ with _STDBUF_I=$MODE _STDBUF_O=$MODE _STDBUF_E=$MODE */ 253 254static void 255set_libstdbuf_options (void) 256{ 257 int i; 258 259 for (i = 0; i < ARRAY_CARDINALITY (stdbuf); i++) 260 { 261 if (stdbuf[i].optarg) 262 { 263 char *var; 264 int ret; 265 266 if (*stdbuf[i].optarg == 'L') 267 ret = asprintf (&var, "%s%c=L", "_STDBUF_", 268 toupper (stdbuf[i].optc)); 269 else 270 ret = asprintf (&var, "%s%c=%" PRIuMAX, "_STDBUF_", 271 toupper (stdbuf[i].optc), 272 (uintmax_t) stdbuf[i].size); 273 if (ret < 0) 274 xalloc_die (); 275 276 if (putenv (var) != 0) 277 { 278 error (EXIT_CANCELED, errno, 279 _("failed to update the environment with %s"), 280 quote (var)); 281 } 282 } 283 } 284} 285 286int 287main (int argc, char **argv) 288{ 289 int c; 290 291 initialize_main (&argc, &argv); 292 set_program_name (argv[0]); 293 setlocale (LC_ALL, ""); 294 bindtextdomain (PACKAGE, LOCALEDIR); 295 textdomain (PACKAGE); 296 297 initialize_exit_failure (EXIT_CANCELED); 298 atexit (close_stdout); 299 300 while ((c = getopt_long (argc, argv, "+i:o:e:", longopts, NULL)) != -1) 301 { 302 int opt_fileno; 303 304 switch (c) 305 { 306 /* Old McDonald had a farm ei... */ 307 case 'e': 308 case 'i': 309 case 'o': 310 opt_fileno = optc_to_fileno (c); 311 assert (0 <= opt_fileno && opt_fileno < ARRAY_CARDINALITY (stdbuf)); 312 stdbuf[opt_fileno].optc = c; 313 while (c_isspace (*optarg)) 314 optarg++; 315 stdbuf[opt_fileno].optarg = optarg; 316 if (c == 'i' && *optarg == 'L') 317 { 318 /* -oL will be by far the most common use of this utility, 319 but one could easily think -iL might have the same affect, 320 so disallow it as it could be confusing. */ 321 error (0, 0, _("line buffering stdin is meaningless")); 322 usage (EXIT_CANCELED); 323 } 324 325 if (!STREQ (optarg, "L") 326 && parse_size (optarg, &stdbuf[opt_fileno].size) == -1) 327 error (EXIT_CANCELED, errno, _("invalid mode %s"), quote (optarg)); 328 329 break; 330 331 case_GETOPT_HELP_CHAR; 332 333 case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS); 334 335 default: 336 usage (EXIT_CANCELED); 337 } 338 } 339 340 argv += optind; 341 argc -= optind; 342 343 /* must specify at least 1 command. */ 344 if (argc < 1) 345 { 346 error (0, 0, _("missing operand")); 347 usage (EXIT_CANCELED); 348 } 349 350 /* FIXME: Should we mandate at least one option? */ 351 352 set_libstdbuf_options (); 353 354 /* Try to preload libstdbuf first from the same path as 355 stdbuf is running from. */ 356 set_program_path (argv[0]); 357 if (!program_path) 358 program_path = xstrdup (PKGLIBDIR); /* Need to init to non NULL. */ 359 set_LD_PRELOAD (); 360 free (program_path); 361 362 execvp (*argv, argv); 363 364 { 365 int exit_status = (errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE); 366 error (0, errno, _("failed to run command %s"), quote (argv[0])); 367 exit (exit_status); 368 } 369} 370