package/toolbox/src/cat/cat.c

   1 /*-
   2  * Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
   3  *               2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017
   4  *      mirabilos <m@mirbsd.org>
   5  *
   6  * Provided that these terms and disclaimer and all copyright notices
   7  * are retained or reproduced in an accompanying document, permission
   8  * is granted to deal in this work without restriction, including un-
   9  * limited rights to use, publicly perform, distribute, sell, modify,
  10  * merge, give away, or sublicence.
  11  *
  12  * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
  13  * the utmost extent permitted by applicable law, neither express nor
  14  * implied; without malicious intent or gross negligence. In no event
  15  * may a licensor, author or contributor be held liable for indirect,
  16  * direct, other damage, loss, or other issues arising in any way out
  17  * of dealing in the work, even if advised of the possibility of such
  18  * damage or existence of a defect, except proven that it results out
  19  * of said person's immediate fault when using the work as intended.
  20  */
  21
  22 #include <errno.h>
  23 #include <fcntl.h>
  24 #include <signal.h>
  25 #include <stdint.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28
  29 #define MKSH_CAT_BUFSIZ 256
  30
  31 #ifndef O_BINARY
  32 #define O_BINARY        0
  33 #endif
  34
  35 #define ksh_sigmask(sig) (((sig) < 1 || (sig) > 127) ? 255 : 128 + (sig))
  36
  37 static char buf[MKSH_CAT_BUFSIZ];
  38 static volatile sig_atomic_t intrsig;
  39
  40 static const char Tsynerr[] = "cat: syntax error\n";
  41 static const char unkerr_msg[] = "Unknown error";
  42 static const char sigint_msg[] = " ...\ncat: Interrupted\n";
  43
  44 static void
  45 disperr(const char *fn)
  46 {
  47         int e = errno;
  48
  49         write(2, "cat: ", 5);
  50         write(2, fn, strlen(fn));
  51         write(2, ": ", 2);
  52         if (strerror_r(e, buf, MKSH_CAT_BUFSIZ))
  53                 write(2, unkerr_msg, sizeof(unkerr_msg) - 1);
  54         else
  55                 write(2, buf, strlen(buf));
  56         write(2, "\n", 1);
  57 }
  58
  59 static void
  60 sighandler(int signo __attribute__((__unused__)))
  61 {
  62         intrsig = 1;
  63 }
  64
  65 int
  66 main(int argc __attribute__((__unused__)), char *wp[])
  67 {
  68         int fd = 0, rv;
  69         ssize_t n, w;
  70         const char *fn = "<stdin>";
  71         char *cp;
  72
  73         ++wp;
  74         /* parse options (POSIX demands this) */
  75         while ((cp = *wp) && *cp++ == '-') {
  76                 if (!cp[0])
  77                         break;
  78                 if (cp[0] == '-' && !cp[1]) {
  79                         ++wp;
  80                         break;
  81                 }
  82                 while (*cp == 'u')
  83                         ++cp;
  84                 if (*cp) {
  85                         write(2, Tsynerr, sizeof(Tsynerr) - 1);
  86                         return (1);
  87                 }
  88                 ++wp;
  89         }
  90         rv = 0;
  91
  92         /* catch SIGPIPE */
  93         signal(SIGPIPE, SIG_IGN);
  94
  95         /* abort on SIGINT */
  96         signal(SIGINT, sighandler);
  97
  98         do {
  99                 if (*wp) {
 100                         fn = *wp++;
 101                         if (fn[0] == '-' && !fn[1])
 102                                 fd = 0;
 103                         else if ((fd = open(fn, O_RDONLY | O_BINARY)) < 0) {
 104                                 disperr(fn);
 105                                 rv = 1;
 106                                 continue;
 107                         }
 108                 }
 109                 while (/* CONSTCOND */ 1) {
 110                         if ((n = read(fd, (cp = buf), MKSH_CAT_BUFSIZ)) == -1) {
 111                                 if (errno == EINTR) {
 112                                         /* give the user a chance to ^C out */
 113                                         if (intrsig)
 114                                                 goto has_intrsig;
 115                                         /* interrupted, try again */
 116                                         continue;
 117                                 }
 118                                 /* an error occured during reading */
 119                                 disperr(fn);
 120                                 rv = 1;
 121                                 break;
 122                         } else if (n == 0)
 123                                 /* end of file reached */
 124                                 break;
 125                         while (n) {
 126                                 if (intrsig)
 127                                         goto has_intrsig;
 128                                 if ((w = write(1, cp, n)) != -1) {
 129                                         n -= w;
 130                                         cp += w;
 131                                         continue;
 132                                 }
 133                                 if (errno == EINTR) {
 134  has_intrsig:
 135                                         /* give the user a chance to ^C out */
 136                                         if (intrsig) {
 137                                                 write(2, sigint_msg,
 138                                                     sizeof(sigint_msg) - 1);
 139                                                 return (ksh_sigmask(SIGINT));
 140                                         }
 141                                         /* interrupted, try again */
 142                                         continue;
 143                                 }
 144                                 if (errno == EPIPE) {
 145                                         /* fake receiving signal */
 146                                         rv = ksh_sigmask(SIGPIPE);
 147                                 } else {
 148                                         /* an error occured during writing */
 149                                         disperr("<stdout>");
 150                                         rv = 1;
 151                                 }
 152                                 if (fd != 0)
 153                                         close(fd);
 154                                 goto out;
 155                         }
 156                 }
 157                 if (fd != 0)
 158                         close(fd);
 159         } while (*wp);
 160
 161  out:
 162         return (rv);
 163 }