mdw@git.distorted.org.uk Git - misc/blob - stamp.c

   1 /* -*-
   2  *
   3  * Like cat, with datestamps
   4  */
   5
   6 #include <errno.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <string.h>
  10 #include <time.h>
  11
  12 #include <unistd.h>
  13
  14 #include <mLib/mdwopt.h>
  15 #include <mLib/quis.h>
  16 #include <mLib/report.h>
  17
  18 static const char *fmt = "%Y-%m-%d %H:%M:%S %Z: ";
  19 static struct tm *(*cvt)(const time_t *) = localtime;
  20
  21 static void version(void) { pquis(stdout, "$ " VERSION); }
  22 static void usage(FILE *fp)
  23   { pquis(fp, "Usage: $ [-z] [-f FORMAT] [FILE...]"); }
  24
  25 static void help(void)
  26 {
  27   version(); putchar('\n');
  28   usage(stdout);
  29   fputs("\n\
  30 Copy the FILEs (or standard input) to standard output, prefixing each line\n\
  31 with a datestamp.\n\
  32 \n\
  33 -h, --help              Show this help text.\n\
  34 -v, --version           Show the program's version number.\n\
  35 -u, --usage             Show a brief usage message.\n\
  36 \n\
  37 -f, --format=FORMAT     Write datestamps using the strftime(3) FORMAT.\n\
  38 -z, --utc, --zulu       Use UTC rather than local time for datestamps.\n\
  39 ", stdout);
  40 }
  41
  42 static void cat(FILE *in)
  43 {
  44   unsigned ln = 1;
  45   time_t t;
  46   struct tm *tm;
  47   char buf[256];
  48   int ch;
  49
  50   for (;;) {
  51     if ((ch = getc(in)) == EOF)
  52       break;
  53     if (ln) {
  54       t = time(0);
  55       tm = cvt(&t);
  56       strftime(buf, sizeof(buf), fmt, tm);
  57       fwrite(buf, 1, strlen(buf), stdout);
  58     }
  59     putchar(ch);
  60     ln = (ch == '\n');
  61   }
  62   if (!ln)
  63     putchar('\n');
  64 }
  65
  66 int main(int argc, char *argv[])
  67 {
  68   int i;
  69   FILE *fp;
  70   unsigned f = 0;
  71 #define F_BOGUS 1u
  72
  73   ego(argv[0]);
  74   setvbuf(stdin, 0, _IOLBF, 0);
  75
  76   for (;;) {
  77     static const struct option opt[] = {
  78       { "help",         0,              0,      'h' },
  79       { "version",      0,              0,      'v' },
  80       { "usage",        0,              0,      'u' },
  81       { "format",       OPTF_ARGREQ,    0,      'f' },
  82       { "utc",          0,              0,      'z' },
  83       { "zulu",         0,              0,      'z' },
  84       { 0,              0,              0,      0 }
  85     };
  86
  87     if ((i = mdwopt(argc, argv, "hvuf:z", opt, 0, 0, 0)) < 0)
  88       break;
  89     switch (i) {
  90       case 'h':
  91         help();
  92         exit(0);
  93       case 'v':
  94         version();
  95         exit(0);
  96       case 'u':
  97         usage(stdout);
  98         exit(0);
  99       case 'f':
 100         fmt = optarg;
 101         break;
 102       case 'z':
 103         cvt = gmtime;
 104         break;
 105       default:
 106         f |= F_BOGUS;
 107         break;
 108     }
 109   }
 110
 111   if (f & F_BOGUS) {
 112     usage(stderr);
 113     exit(EXIT_FAILURE);
 114   }
 115
 116   if (optind == argc) {
 117     if (isatty(STDIN_FILENO))
 118       die(EXIT_FAILURE, "no arguments, and stdin is a terminal");
 119     cat(stdin);
 120   } else for (i = optind; i < argc; i++) {
 121     if (strcmp(argv[i], "-") == 0)
 122       cat(stdin);
 123     else if ((fp = fopen(argv[i], "r")) == 0) {
 124       moan("failed to open `%s': %s", argv[i], strerror(errno));
 125       f |= F_BOGUS;
 126     } else {
 127       cat(fp);
 128       fclose(fp);
 129     }
 130   }
 131
 132   if (ferror(stdout) || fflush(stdout) || fclose(stdout)) {
 133     moan("error writing output: %s", strerror(errno));
 134     f |= F_BOGUS;
 135   }
 136
 137   return ((f & F_BOGUS) ? EXIT_FAILURE : 0);
 138 }