X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=vbig.cc;h=1823dd316aaacba1cc7d1efb7bea0d6d4e300e29;hb=f5cf02c54821c02adcdaa5c88a33050fab5fea01;hp=190dbf0254ee4c30a804d27e8e3082d58bc8ed31;hpb=ee2905c89a4955a8211c19248762b1f1ce8ed5b4;p=vbig.git

diff --git a/vbig.cc b/vbig.cc
index 190dbf0..1823dd3 100644
--- a/vbig.cc
+++ b/vbig.cc
@@ -1,3 +1,20 @@
+/*
+ * This file is part of vbig.
+ * Copyright (C) 2011 Richard Kettlewell
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
 #include <config.h>
 #include <cstdio>
 #include <cstring>
@@ -7,17 +24,19 @@
 #include <getopt.h>
 #include <unistd.h>
 #include <fcntl.h>
+#include <limits.h>
+#include <assert.h>
+#include <sys/stat.h>
 #include "Arcfour.h"
 
-// Path to magic file to drop filesystem caches
-static const char dropCaches[] = "/proc/sys/vm/drop_caches";
-
 // Command line options
 const struct option opts[] = {
   { "seed", required_argument, 0, 's' },
+  { "both", no_argument, 0, 'b' },
   { "verify", no_argument, 0, 'v' },
   { "create", no_argument, 0, 'c' },
   { "flush", no_argument, 0, 'f' },
+  { "entire", no_argument, 0, 'e' },
   { "help", no_argument, 0, 'h' },
   { "version", no_argument, 0, 'V' },
   { 0, 0, 0, 0 },
@@ -28,22 +47,23 @@ static void help(void) {
   printf("vbig - create or verify a large but pseudo-random file\n"
          "\n"
          "Usage:\n"
-         "  vbig [--seed SEED] --verify|--create PATH SIZE\n"
+         "  vbig [--seed SEED] --verify|--create PATH [SIZE]\n"
          "\n"
          "Options:\n"
-         "  --seed         Specify random seed\n"
-         "  --verify       Verify that PATH contains the expected contents\n"
-         "  --create       Create PATH with psuedo-random contents\n"
-         "  --flush        Flush cache\n"
-         "  --help         Display usage message\n"
-         "  --version      Display version string\n");
+         "  --seed, -s     Specify random seed\n"
+         "  --verify, -v   Verify that PATH contains the expected contents\n"
+         "  --create, -c   Create PATH with psuedo-random contents\n"
+         "  --flush, -f    Flush cache\n"
+         "  --entire, -e   Write until full; read until EOF\n"
+         "  --help, -h     Display usage message\n"
+         "  --version, -V  Display version string\n");
 }
 
 // Possible modes of operation
 enum mode_type {
-  NONE,
   VERIFY,
-  CREATE
+  CREATE,
+  BOTH
 };
 
 // Report an error and exit
@@ -65,24 +85,47 @@ static void flushCache(FILE *fp) {
   // synced.
   if(fsync(fileno(fp)) < 0)
     fatal(errno, "fsync");
+#if defined DROP_CACHE_FILE
   int fd;
-  if((fd = open(dropCaches, O_WRONLY, 0)) < 0)
-    fatal(errno, "%s", dropCaches);
+  if((fd = open(DROP_CACHE_FILE, O_WRONLY, 0)) < 0)
+    fatal(errno, "%s", DROP_CACHE_FILE);
   if(write(fd, "3\n", 2) < 0)
-    fatal(errno, "%s", dropCaches);
+    fatal(errno, "%s", DROP_CACHE_FILE);
   close(fd);
+#elif defined PURGE_COMMAND
+  int rc;
+  if((rc = system(PURGE_COMMAND)) < 0)
+    fatal(errno, "executing %s", PURGE_COMMAND);
+  else if(rc) {
+    if(WIFSIGNALED(rc)) {
+      fprintf(stderr, "%s%s\n", 
+	      strsignal(WTERMSIG(rc)),
+	      WCOREDUMP(rc) ? " (core dumped)" : "");
+      exit(WTERMSIG(rc) + 128);
+    } else
+      exit(WEXITSTATUS(rc));
+  }
+#endif
 }
 
+static long long execute(mode_type mode, bool entire, const char *show);
+
+static const char *seed = "hexapodia as the key insight";
+static const char *path;
+static bool entireopt = false;
+static bool flush = false;
+static long long size;
+
 int main(int argc, char **argv) {
-  const char *seed = "hexapodia as the key insight";
-  mode_type mode = NONE;
-  bool flush = false;
+  mode_type mode = BOTH;
   int n;
-  while((n = getopt_long(argc, argv, "+s:vcfhV", opts, 0)) >= 0) {
+  while((n = getopt_long(argc, argv, "+s:vcefhV", opts, 0)) >= 0) {
     switch(n) {
     case 's': seed = optarg; break;
+    case 'b': mode = BOTH; break;
     case 'v': mode = VERIFY; break;
     case 'c': mode = CREATE; break;
+    case 'e': entireopt = true; break;
     case 'f': flush = true; break;
     case 'h': help(); exit(0);
     case 'V': puts(VERSION); exit(0);
@@ -90,93 +133,122 @@ int main(int argc, char **argv) {
       fatal(0, "unknown option");
     }
   }
-  if(mode == NONE) {
-    fatal(0, "must specify one of --verify or --create");
-    exit(1);
-  }
-  if(optind + 2 != argc) {
-    fatal(0, "must specify a path and size");
-    exit(1);
+  argc -= optind;
+  argv += optind;
+  if(argc > 2)
+    fatal(0, "excess arguments");
+  if(argc == 1 && mode == BOTH)
+    entireopt = true;
+  if(entireopt) {
+    if(argc != 1)
+      fatal(0, "with --entire, size should not be specified");
+  } else {
+    if(argc < (mode == VERIFY ? 1 : 2))
+      fatal(0, "insufficient arguments");
   }
-  const char *path = argv[optind];
-  errno = 0;
-  char *end;
-  long long size = strtoll(argv[optind + 1], &end, 10);
-  if(errno) {
-    fatal(errno, "invalid size");
-    exit(1);
+  path = argv[0];
+  if(argc > 1) {
+    errno = 0;
+    char *end;
+    size = strtoll(argv[1], &end, 10);
+    if(errno)
+      fatal(errno, "invalid size");
+    if(end == argv[1])
+      fatal(0, "invalid size");
+    if(!strcmp(end, "K"))
+      size *= 1024;
+    else if(!strcmp(end, "M"))
+      size *= 1024 * 1024;
+    else if(!strcmp(end, "G"))
+      size *= 1024 * 1024 * 1024;
+    else if(*end)
+      fatal(0, "invalid size");
+  } else if(entireopt) {
+    size = LONG_LONG_MAX;
+  } else {
+    struct stat sb;
+    if(stat(path, &sb) < 0)
+      fatal(errno, "stat %s", path);
+    size = sb.st_size;
   }
-  if(end == argv[optind + 1]) {
-    fatal(0, "invalid size");
-    exit(1);
+  const char *show = entireopt ? (mode == CREATE ? "written" : "verified") : 0;
+  if(mode == BOTH) {
+    size = execute(CREATE, entireopt, 0);
+    execute(VERIFY, false, show);
+  } else {
+    execute(mode, entireopt, show);
   }
-  if(!strcmp(end, "K"))
-    size *= 1024;
-  else if(!strcmp(end, "M"))
-    size *= 1024 * 1024;
-  else if(!strcmp(end, "G"))
-    size *= 1024 * 1024 * 1024;
-  else if(*end) {
-    fatal(0, "invalid size");
-    exit(1);
-  } 
+  return 0;
+}
+
+static long long execute(mode_type mode, bool entire, const char *show) {
   Arcfour rng(seed, strlen(seed));
   FILE *fp = fopen(path, mode == VERIFY ? "rb" : "wb");
-  if(!fp) {
+  if(!fp)
     fatal(errno, "%s", path);
-    exit(1);
-  }
   if(mode == VERIFY && flush)
     flushCache(fp);
+  if(mode == CREATE && entire)
+    setvbuf(fp, 0, _IONBF, 0);
   char generated[4096], input[4096];
   long long remain = size;
+  static const size_t rc4drop = 3072; // en.wikipedia.org/wiki/RC4#Security
+  assert(rc4drop <= sizeof(generated));
+  rng.stream(generated, rc4drop);
   while(remain > 0) {
     size_t bytesGenerated = (remain > (ssize_t)sizeof generated
                              ? sizeof generated
                              : remain);
     rng.stream(generated, bytesGenerated);
     if(mode == CREATE) {
-      fwrite(generated, 1, bytesGenerated, fp);
+      size_t bytesWritten = fwrite(generated, 1, bytesGenerated, fp);
       if(ferror(fp)) {
-        fatal(errno, "%s", path);
-        exit(1);
+	if(!entire || errno != ENOSPC)
+	  fatal(errno, "%s", path);
+	remain -= bytesWritten;
+	break;
       }
+      assert(bytesWritten == bytesGenerated);
     } else {
       size_t bytesRead = fread(input, 1, bytesGenerated, fp);
-      if(ferror(fp)) {
+      if(ferror(fp))
         fatal(errno, "%s", path);
-        exit(1);
+      if(memcmp(generated, input, bytesRead)) {
+        for(size_t n = 0; n < bytesRead; ++n)
+          if(generated[n] != input[n])
+            fatal(0, "%s corrupted at %lld/%lld bytes (expected %d got %d)",
+                    path, size - remain + n, size,
+                    (unsigned char)generated[n], (unsigned char)input[n]);
       }
       if(bytesRead < bytesGenerated) {
+	if(entire) {
+	  assert(feof(fp));
+	  remain -= bytesRead;
+	  break;
+	}
         fatal(0, "%s: truncated at %lld/%lld bytes",
                 path, (size - remain + bytesRead), size);
-        exit(1);
-      }
-      if(memcmp(generated, input, bytesGenerated)) {
-        for(size_t n = 0; n < bytesGenerated; ++n)
-          if(generated[n] != input[n]){
-            fatal(0, "%s corrupted at %lld/%lld bytes (expected %d got %d)",
-                    path, size - remain + n, size,
-                    (unsigned char)generated[n], (unsigned char)input[n]);
-            exit(1);
-          }
       }
     }
     remain -= bytesGenerated;
   }
-  if(mode == VERIFY && getc(fp) != EOF) {
+  if(mode == VERIFY && !entire && getc(fp) != EOF)
     fatal(0, "%s: extended beyond %lld bytes",
             path, size);
-    exit(1);
-  }
   if(mode == CREATE && flush) {
     if(fflush(fp) < 0)
       fatal(errno, "%s", path);
     flushCache(fp);
   }
-  if(fclose(fp) < 0) {
+  if(fclose(fp) < 0)
     fatal(errno, "%s", path);
-    exit(1);
+  long long done = size - remain;
+  if(show) {
+    printf("%lld bytes (%lldM, %lldG) %s\n",
+	   done, done >> 20, done >> 30,
+	   show);
+    if(ferror(stdout) || fflush(stdout))
+      fatal(errno, "flush stdout");
   }
-  return 0;
+  return done;
 }