usage.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6 #include "git-compat-util.h"
   7 #include "cache.h"
   8
   9 void vreportf(const char *prefix, const char *err, va_list params)
  10 {
  11         char msg[4096];
  12         char *p, *pend = msg + sizeof(msg);
  13         size_t prefix_len = strlen(prefix);
  14
  15         if (sizeof(msg) <= prefix_len) {
  16                 fprintf(stderr, "BUG!!! too long a prefix '%s'\n", prefix);
  17                 abort();
  18         }
  19         memcpy(msg, prefix, prefix_len);
  20         p = msg + prefix_len;
  21         if (vsnprintf(p, pend - p, err, params) < 0)
  22                 *p = '\0'; /* vsnprintf() failed, clip at prefix */
  23
  24         for (; p != pend - 1 && *p; p++) {
  25                 if (iscntrl(*p) && *p != '\t' && *p != '\n')
  26                         *p = '?';
  27         }
  28
  29         *(p++) = '\n'; /* we no longer need a NUL */
  30         fflush(stderr);
  31         write_in_full(2, msg, p - msg);
  32 }
  33
  34 static NORETURN void usage_builtin(const char *err, va_list params)
  35 {
  36         vreportf("usage: ", err, params);
  37
  38         /*
  39          * When we detect a usage error *before* the command dispatch in
  40          * cmd_main(), we don't know what verb to report.  Force it to this
  41          * to facilitate post-processing.
  42          */
  43         trace2_cmd_name("_usage_");
  44
  45         /*
  46          * Currently, the (err, params) are usually just the static usage
  47          * string which isn't very useful here.  Usually, the call site
  48          * manually calls fprintf(stderr,...) with the actual detailed
  49          * syntax error before calling usage().
  50          *
  51          * TODO It would be nice to update the call sites to pass both
  52          * the static usage string and the detailed error message.
  53          */
  54
  55         exit(129);
  56 }
  57
  58 /*
  59  * We call trace2_cmd_error_va() in the below functions first and
  60  * expect it to va_copy 'params' before using it (because an 'ap' can
  61  * only be walked once).
  62  */
  63 static NORETURN void die_builtin(const char *err, va_list params)
  64 {
  65         trace2_cmd_error_va(err, params);
  66
  67         vreportf("fatal: ", err, params);
  68
  69         exit(128);
  70 }
  71
  72 static void error_builtin(const char *err, va_list params)
  73 {
  74         trace2_cmd_error_va(err, params);
  75
  76         vreportf("error: ", err, params);
  77 }
  78
  79 static void warn_builtin(const char *warn, va_list params)
  80 {
  81         trace2_cmd_error_va(warn, params);
  82
  83         vreportf("warning: ", warn, params);
  84 }
  85
  86 static int die_is_recursing_builtin(void)
  87 {
  88         static int dying;
  89         /*
  90          * Just an arbitrary number X where "a < x < b" where "a" is
  91          * "maximum number of pthreads we'll ever plausibly spawn" and
  92          * "b" is "something less than Inf", since the point is to
  93          * prevent infinite recursion.
  94          */
  95         static const int recursion_limit = 1024;
  96
  97         dying++;
  98         if (dying > recursion_limit) {
  99                 return 1;
 100         } else if (dying == 2) {
 101                 warning("die() called many times. Recursion error or racy threaded death!");
 102                 return 0;
 103         } else {
 104                 return 0;
 105         }
 106 }
 107
 108 /* If we are in a dlopen()ed .so write to a global variable would segfault
 109  * (ugh), so keep things static. */
 110 static NORETURN_PTR report_fn usage_routine = usage_builtin;
 111 static NORETURN_PTR report_fn die_routine = die_builtin;
 112 static report_fn error_routine = error_builtin;
 113 static report_fn warn_routine = warn_builtin;
 114 static int (*die_is_recursing)(void) = die_is_recursing_builtin;
 115
 116 void set_die_routine(NORETURN_PTR report_fn routine)
 117 {
 118         die_routine = routine;
 119 }
 120
 121 void set_error_routine(report_fn routine)
 122 {
 123         error_routine = routine;
 124 }
 125
 126 report_fn get_error_routine(void)
 127 {
 128         return error_routine;
 129 }
 130
 131 void set_warn_routine(report_fn routine)
 132 {
 133         warn_routine = routine;
 134 }
 135
 136 report_fn get_warn_routine(void)
 137 {
 138         return warn_routine;
 139 }
 140
 141 void set_die_is_recursing_routine(int (*routine)(void))
 142 {
 143         die_is_recursing = routine;
 144 }
 145
 146 void NORETURN usagef(const char *err, ...)
 147 {
 148         va_list params;
 149
 150         va_start(params, err);
 151         usage_routine(err, params);
 152         va_end(params);
 153 }
 154
 155 void NORETURN usage(const char *err)
 156 {
 157         usagef("%s", err);
 158 }
 159
 160 void NORETURN die(const char *err, ...)
 161 {
 162         va_list params;
 163
 164         if (die_is_recursing()) {
 165                 fputs("fatal: recursion detected in die handler\n", stderr);
 166                 exit(128);
 167         }
 168
 169         va_start(params, err);
 170         die_routine(err, params);
 171         va_end(params);
 172 }
 173
 174 static const char *fmt_with_err(char *buf, int n, const char *fmt)
 175 {
 176         char str_error[256], *err;
 177         int i, j;
 178
 179         err = strerror(errno);
 180         for (i = j = 0; err[i] && j < sizeof(str_error) - 1; ) {
 181                 if ((str_error[j++] = err[i++]) != '%')
 182                         continue;
 183                 if (j < sizeof(str_error) - 1) {
 184                         str_error[j++] = '%';
 185                 } else {
 186                         /* No room to double the '%', so we overwrite it with
 187                          * '\0' below */
 188                         j--;
 189                         break;
 190                 }
 191         }
 192         str_error[j] = 0;
 193         /* Truncation is acceptable here */
 194         snprintf(buf, n, "%s: %s", fmt, str_error);
 195         return buf;
 196 }
 197
 198 void NORETURN die_errno(const char *fmt, ...)
 199 {
 200         char buf[1024];
 201         va_list params;
 202
 203         if (die_is_recursing()) {
 204                 fputs("fatal: recursion detected in die_errno handler\n",
 205                         stderr);
 206                 exit(128);
 207         }
 208
 209         va_start(params, fmt);
 210         die_routine(fmt_with_err(buf, sizeof(buf), fmt), params);
 211         va_end(params);
 212 }
 213
 214 #undef error_errno
 215 int error_errno(const char *fmt, ...)
 216 {
 217         char buf[1024];
 218         va_list params;
 219
 220         va_start(params, fmt);
 221         error_routine(fmt_with_err(buf, sizeof(buf), fmt), params);
 222         va_end(params);
 223         return -1;
 224 }
 225
 226 #undef error
 227 int error(const char *err, ...)
 228 {
 229         va_list params;
 230
 231         va_start(params, err);
 232         error_routine(err, params);
 233         va_end(params);
 234         return -1;
 235 }
 236
 237 void warning_errno(const char *warn, ...)
 238 {
 239         char buf[1024];
 240         va_list params;
 241
 242         va_start(params, warn);
 243         warn_routine(fmt_with_err(buf, sizeof(buf), warn), params);
 244         va_end(params);
 245 }
 246
 247 void warning(const char *warn, ...)
 248 {
 249         va_list params;
 250
 251         va_start(params, warn);
 252         warn_routine(warn, params);
 253         va_end(params);
 254 }
 255
 256 /* Only set this, ever, from t/helper/, when verifying that bugs are caught. */
 257 int BUG_exit_code;
 258
 259 static NORETURN void BUG_vfl(const char *file, int line, const char *fmt, va_list params)
 260 {
 261         char prefix[256];
 262         va_list params_copy;
 263         static int in_bug;
 264
 265         va_copy(params_copy, params);
 266
 267         /* truncation via snprintf is OK here */
 268         if (file)
 269                 snprintf(prefix, sizeof(prefix), "BUG: %s:%d: ", file, line);
 270         else
 271                 snprintf(prefix, sizeof(prefix), "BUG: ");
 272
 273         vreportf(prefix, fmt, params);
 274
 275         if (in_bug)
 276                 abort();
 277         in_bug = 1;
 278
 279         trace2_cmd_error_va(fmt, params_copy);
 280
 281         if (BUG_exit_code)
 282                 exit(BUG_exit_code);
 283         abort();
 284 }
 285
 286 #ifdef HAVE_VARIADIC_MACROS
 287 NORETURN void BUG_fl(const char *file, int line, const char *fmt, ...)
 288 {
 289         va_list ap;
 290         va_start(ap, fmt);
 291         BUG_vfl(file, line, fmt, ap);
 292         va_end(ap);
 293 }
 294 #else
 295 NORETURN void BUG(const char *fmt, ...)
 296 {
 297         va_list ap;
 298         va_start(ap, fmt);
 299         BUG_vfl(NULL, 0, fmt, ap);
 300         va_end(ap);
 301 }
 302 #endif
 303
 304 #ifdef SUPPRESS_ANNOTATED_LEAKS
 305 void unleak_memory(const void *ptr, size_t len)
 306 {
 307         static struct suppressed_leak_root {
 308                 struct suppressed_leak_root *next;
 309                 char data[FLEX_ARRAY];
 310         } *suppressed_leaks;
 311         struct suppressed_leak_root *root;
 312
 313         FLEX_ALLOC_MEM(root, data, ptr, len);
 314         root->next = suppressed_leaks;
 315         suppressed_leaks = root;
 316 }
 317 #endif