usage.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6
   7 #include "git-compat-util.h"
   8 #include "gettext.h"
   9 #include "trace2.h"
  10
  11 static void vfreportf(FILE *f, const char *prefix, const char *err, va_list params)
  12 {
  13         char msg[4096];
  14         char *p, *pend = msg + sizeof(msg);
  15         size_t prefix_len = strlen(prefix);
  16
  17         if (sizeof(msg) <= prefix_len) {
  18                 fprintf(stderr, "BUG!!! too long a prefix '%s'\n", prefix);
  19                 abort();
  20         }
  21         memcpy(msg, prefix, prefix_len);
  22         p = msg + prefix_len;
  23         if (vsnprintf(p, pend - p, err, params) < 0) {
  24                 fprintf(stderr, _("error: unable to format message: %s\n"),
  25                         err);
  26                 *p = '\0'; /* vsnprintf() failed, clip at prefix */
  27         }
  28
  29         for (; p != pend - 1 && *p; p++) {
  30                 if (iscntrl(*p) && *p != '\t' && *p != '\n')
  31                         *p = '?';
  32         }
  33
  34         *(p++) = '\n'; /* we no longer need a NUL */
  35         fflush(f);
  36         write_in_full(fileno(f), msg, p - msg);
  37 }
  38
  39 static void vreportf(const char *prefix, const char *err, va_list params)
  40 {
  41         vfreportf(stderr, prefix, err, params);
  42 }
  43
  44 static NORETURN void usage_builtin(const char *err, va_list params)
  45 {
  46         vreportf(_("usage: "), err, params);
  47
  48         /*
  49          * When we detect a usage error *before* the command dispatch in
  50          * cmd_main(), we don't know what verb to report.  Force it to this
  51          * to facilitate post-processing.
  52          */
  53         trace2_cmd_name("_usage_");
  54
  55         /*
  56          * Currently, the (err, params) are usually just the static usage
  57          * string which isn't very useful here.  Usually, the call site
  58          * manually calls fprintf(stderr,...) with the actual detailed
  59          * syntax error before calling usage().
  60          *
  61          * TODO It would be nice to update the call sites to pass both
  62          * the static usage string and the detailed error message.
  63          */
  64
  65         exit(129);
  66 }
  67
  68 static void die_message_builtin(const char *err, va_list params)
  69 {
  70         if (!err)
  71                 return;
  72         trace2_cmd_error_va(err, params);
  73         vreportf(_("fatal: "), err, params);
  74 }
  75
  76 /*
  77  * We call trace2_cmd_error_va() in the below functions first and
  78  * expect it to va_copy 'params' before using it (because an 'ap' can
  79  * only be walked once).
  80  */
  81 static NORETURN void die_builtin(const char *err, va_list params)
  82 {
  83         report_fn die_message_fn = get_die_message_routine();
  84
  85         die_message_fn(err, params);
  86         exit(128);
  87 }
  88
  89 static void error_builtin(const char *err, va_list params)
  90 {
  91         trace2_cmd_error_va(err, params);
  92
  93         vreportf(_("error: "), err, params);
  94 }
  95
  96 static void warn_builtin(const char *warn, va_list params)
  97 {
  98         trace2_cmd_error_va(warn, params);
  99
 100         vreportf(_("warning: "), warn, params);
 101 }
 102
 103 static int die_is_recursing_builtin(void)
 104 {
 105         static int dying;
 106         /*
 107          * Just an arbitrary number X where "a < x < b" where "a" is
 108          * "maximum number of pthreads we'll ever plausibly spawn" and
 109          * "b" is "something less than Inf", since the point is to
 110          * prevent infinite recursion.
 111          */
 112         static const int recursion_limit = 1024;
 113
 114         dying++;
 115         if (dying > recursion_limit) {
 116                 return 1;
 117         } else if (dying == 2) {
 118                 warning("die() called many times. Recursion error or racy threaded death!");
 119                 return 0;
 120         } else {
 121                 return 0;
 122         }
 123 }
 124
 125 /* If we are in a dlopen()ed .so write to a global variable would segfault
 126  * (ugh), so keep things static. */
 127 static NORETURN_PTR report_fn usage_routine = usage_builtin;
 128 static NORETURN_PTR report_fn die_routine = die_builtin;
 129 static report_fn die_message_routine = die_message_builtin;
 130 static report_fn error_routine = error_builtin;
 131 static report_fn warn_routine = warn_builtin;
 132 static int (*die_is_recursing)(void) = die_is_recursing_builtin;
 133
 134 void set_die_routine(NORETURN_PTR report_fn routine)
 135 {
 136         die_routine = routine;
 137 }
 138
 139 report_fn get_die_message_routine(void)
 140 {
 141         return die_message_routine;
 142 }
 143
 144 void set_error_routine(report_fn routine)
 145 {
 146         error_routine = routine;
 147 }
 148
 149 report_fn get_error_routine(void)
 150 {
 151         return error_routine;
 152 }
 153
 154 void set_warn_routine(report_fn routine)
 155 {
 156         warn_routine = routine;
 157 }
 158
 159 report_fn get_warn_routine(void)
 160 {
 161         return warn_routine;
 162 }
 163
 164 void set_die_is_recursing_routine(int (*routine)(void))
 165 {
 166         die_is_recursing = routine;
 167 }
 168
 169 void NORETURN usagef(const char *err, ...)
 170 {
 171         va_list params;
 172
 173         va_start(params, err);
 174         usage_routine(err, params);
 175         va_end(params);
 176 }
 177
 178 void NORETURN usage(const char *err)
 179 {
 180         usagef("%s", err);
 181 }
 182
 183 static void show_usage_if_asked_helper(const char *err, ...)
 184 {
 185         va_list params;
 186
 187         va_start(params, err);
 188         vfreportf(stdout, _("usage: "), err, params);
 189         va_end(params);
 190         exit(129);
 191 }
 192
 193 void show_usage_if_asked(int ac, const char **av, const char *err)
 194 {
 195         if (ac == 2 && !strcmp(av[1], "-h"))
 196                 show_usage_if_asked_helper(err);
 197 }
 198
 199 void NORETURN die(const char *err, ...)
 200 {
 201         va_list params;
 202
 203         if (die_is_recursing()) {
 204                 fputs("fatal: recursion detected in die handler\n", stderr);
 205                 exit(128);
 206         }
 207
 208         va_start(params, err);
 209         die_routine(err, params);
 210         va_end(params);
 211 }
 212
 213 static const char *fmt_with_err(char *buf, int n, const char *fmt)
 214 {
 215         char str_error[256], *err;
 216         size_t i, j;
 217
 218         err = strerror(errno);
 219         for (i = j = 0; err[i] && j < sizeof(str_error) - 1; ) {
 220                 if ((str_error[j++] = err[i++]) != '%')
 221                         continue;
 222                 if (j < sizeof(str_error) - 1) {
 223                         str_error[j++] = '%';
 224                 } else {
 225                         /* No room to double the '%', so we overwrite it with
 226                          * '\0' below */
 227                         j--;
 228                         break;
 229                 }
 230         }
 231         str_error[j] = 0;
 232         /* Truncation is acceptable here */
 233         snprintf(buf, n, "%s: %s", fmt, str_error);
 234         return buf;
 235 }
 236
 237 void NORETURN die_errno(const char *fmt, ...)
 238 {
 239         char buf[1024];
 240         va_list params;
 241
 242         if (die_is_recursing()) {
 243                 fputs("fatal: recursion detected in die_errno handler\n",
 244                         stderr);
 245                 exit(128);
 246         }
 247
 248         va_start(params, fmt);
 249         die_routine(fmt_with_err(buf, sizeof(buf), fmt), params);
 250         va_end(params);
 251 }
 252
 253 #undef die_message
 254 int die_message(const char *err, ...)
 255 {
 256         va_list params;
 257
 258         va_start(params, err);
 259         die_message_routine(err, params);
 260         va_end(params);
 261         return 128;
 262 }
 263
 264 #undef die_message_errno
 265 int die_message_errno(const char *fmt, ...)
 266 {
 267         char buf[1024];
 268         va_list params;
 269
 270         va_start(params, fmt);
 271         die_message_routine(fmt_with_err(buf, sizeof(buf), fmt), params);
 272         va_end(params);
 273         return 128;
 274 }
 275
 276 #undef error_errno
 277 int error_errno(const char *fmt, ...)
 278 {
 279         char buf[1024];
 280         va_list params;
 281
 282         va_start(params, fmt);
 283         error_routine(fmt_with_err(buf, sizeof(buf), fmt), params);
 284         va_end(params);
 285         return -1;
 286 }
 287
 288 #undef error
 289 int error(const char *err, ...)
 290 {
 291         va_list params;
 292
 293         va_start(params, err);
 294         error_routine(err, params);
 295         va_end(params);
 296         return -1;
 297 }
 298
 299 void warning_errno(const char *warn, ...)
 300 {
 301         char buf[1024];
 302         va_list params;
 303
 304         va_start(params, warn);
 305         warn_routine(fmt_with_err(buf, sizeof(buf), warn), params);
 306         va_end(params);
 307 }
 308
 309 void warning(const char *warn, ...)
 310 {
 311         va_list params;
 312
 313         va_start(params, warn);
 314         warn_routine(warn, params);
 315         va_end(params);
 316 }
 317
 318 /* Only set this, ever, from t/helper/, when verifying that bugs are caught. */
 319 int BUG_exit_code;
 320
 321 static void BUG_vfl_common(const char *file, int line, const char *fmt,
 322                            va_list params)
 323 {
 324         char prefix[256];
 325
 326         /* truncation via snprintf is OK here */
 327         snprintf(prefix, sizeof(prefix), "BUG: %s:%d: ", file, line);
 328
 329         vreportf(prefix, fmt, params);
 330 }
 331
 332 static NORETURN void BUG_vfl(const char *file, int line, const char *fmt, va_list params)
 333 {
 334         va_list params_copy;
 335         static int in_bug;
 336
 337         va_copy(params_copy, params);
 338         BUG_vfl_common(file, line, fmt, params);
 339
 340         if (in_bug)
 341                 abort();
 342         in_bug = 1;
 343
 344         trace2_cmd_error_va(fmt, params_copy);
 345
 346         if (BUG_exit_code)
 347                 exit(BUG_exit_code);
 348         abort();
 349 }
 350
 351 NORETURN void BUG_fl(const char *file, int line, const char *fmt, ...)
 352 {
 353         va_list ap;
 354
 355         bug_called_must_BUG = 0;
 356
 357         va_start(ap, fmt);
 358         BUG_vfl(file, line, fmt, ap);
 359         va_end(ap);
 360 }
 361
 362 int bug_called_must_BUG;
 363 void bug_fl(const char *file, int line, const char *fmt, ...)
 364 {
 365         va_list ap;
 366
 367         bug_called_must_BUG = 1;
 368
 369         va_start(ap, fmt);
 370         BUG_vfl_common(file, line, fmt, ap);
 371         va_end(ap);
 372
 373         va_start(ap, fmt);
 374         trace2_cmd_error_va(fmt, ap);
 375         va_end(ap);
 376 }
 377
 378 NORETURN void you_still_use_that(const char *command_name)
 379 {
 380         fprintf(stderr,
 381                 _("'%s' is nominated for removal.\n"
 382                   "If you still use this command, please add an extra\n"
 383                   "option, '--i-still-use-this', on the command line\n"
 384                   "and let us know you still use it by sending an e-mail\n"
 385                   "to <git@vger.kernel.org>.  Thanks.\n"),
 386                 command_name);
 387         die(_("refusing to run without --i-still-use-this"));
 388 }