term_tag.c

   1 /* $Id: term_tag.c,v 1.5 2020/07/21 15:10:01 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2015,2016,2018,2019,2020 Ingo Schwarze <schwarze@openbsd.org>
   4  *
   5  * Permission to use, copy, modify, and distribute this software for any
   6  * purpose with or without fee is hereby granted, provided that the above
   7  * copyright notice and this permission notice appear in all copies.
   8  *
   9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  *
  17  * Functions to write a ctags(1) file.
  18  * For use by the mandoc(1) ASCII and UTF-8 formatters only.
  19  */
  20 #include "config.h"
  21
  22 #include <sys/types.h>
  23
  24 #include <errno.h>
  25 #include <fcntl.h>
  26 #include <signal.h>
  27 #include <stddef.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32
  33 #include "mandoc.h"
  34 #include "roff.h"
  35 #include "roff_int.h"
  36 #include "tag.h"
  37 #include "term_tag.h"
  38
  39 static void tag_signal(int) __attribute__((__noreturn__));
  40
  41 static struct tag_files tag_files;
  42
  43
  44 /*
  45  * Prepare for using a pager.
  46  * Not all pagers are capable of using a tag file,
  47  * but for simplicity, create it anyway.
  48  */
  49 struct tag_files *
  50 term_tag_init(const char *outfilename, const char *tagfilename)
  51 {
  52         struct sigaction         sa;
  53         int                      ofd;   /* In /tmp/, dup(2)ed to stdout. */
  54         int                      tfd;
  55
  56         ofd = tfd = -1;
  57         tag_files.tfs = NULL;
  58         tag_files.tcpgid = -1;
  59
  60         /* Clean up when dying from a signal. */
  61
  62         memset(&sa, 0, sizeof(sa));
  63         sigfillset(&sa.sa_mask);
  64         sa.sa_handler = tag_signal;
  65         sigaction(SIGHUP, &sa, NULL);
  66         sigaction(SIGINT, &sa, NULL);
  67         sigaction(SIGTERM, &sa, NULL);
  68
  69         /*
  70          * POSIX requires that a process calling tcsetpgrp(3)
  71          * from the background gets a SIGTTOU signal.
  72          * In that case, do not stop.
  73          */
  74
  75         sa.sa_handler = SIG_IGN;
  76         sigaction(SIGTTOU, &sa, NULL);
  77
  78         /* Save the original standard output for use by the pager. */
  79
  80         if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1) {
  81                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
  82                 goto fail;
  83         }
  84
  85         /* Create both temporary output files. */
  86
  87         if (outfilename == NULL) {
  88                 (void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
  89                     sizeof(tag_files.ofn));
  90                 if ((ofd = mkstemp(tag_files.ofn)) == -1) {
  91                         mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
  92                             "%s: %s", tag_files.ofn, strerror(errno));
  93                         goto fail;
  94                 }
  95         } else {
  96                 (void)strlcpy(tag_files.ofn, outfilename,
  97                    sizeof(tag_files.ofn));
  98                 unlink(outfilename);
  99                 ofd = open(outfilename, O_WRONLY | O_CREAT | O_EXCL, 0644);
 100                 if (ofd == -1) {
 101                         mandoc_msg(MANDOCERR_OPEN, 0, 0,
 102                             "%s: %s", outfilename, strerror(errno));
 103                         goto fail;
 104                 }
 105         }
 106         if (tagfilename == NULL) {
 107                 (void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
 108                     sizeof(tag_files.tfn));
 109                 if ((tfd = mkstemp(tag_files.tfn)) == -1) {
 110                         mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
 111                             "%s: %s", tag_files.tfn, strerror(errno));
 112                         goto fail;
 113                 }
 114         } else {
 115                 (void)strlcpy(tag_files.tfn, tagfilename,
 116                     sizeof(tag_files.tfn));
 117                 unlink(tagfilename);
 118                 tfd = open(tagfilename, O_WRONLY | O_CREAT | O_EXCL, 0644);
 119                 if (tfd == -1) {
 120                         mandoc_msg(MANDOCERR_OPEN, 0, 0,
 121                             "%s: %s", tagfilename, strerror(errno));
 122                         goto fail;
 123                 }
 124         }
 125         if ((tag_files.tfs = fdopen(tfd, "w")) == NULL) {
 126                 mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
 127                 goto fail;
 128         }
 129         tfd = -1;
 130         if (dup2(ofd, STDOUT_FILENO) == -1) {
 131                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 132                 goto fail;
 133         }
 134         close(ofd);
 135         return &tag_files;
 136
 137 fail:
 138         term_tag_unlink();
 139         if (ofd != -1)
 140                 close(ofd);
 141         if (tfd != -1)
 142                 close(tfd);
 143         if (tag_files.ofd != -1) {
 144                 close(tag_files.ofd);
 145                 tag_files.ofd = -1;
 146         }
 147         return NULL;
 148 }
 149
 150 void
 151 term_tag_write(struct roff_node *n, size_t line)
 152 {
 153         const char      *cp;
 154         int              len;
 155
 156         if (tag_files.tfs == NULL)
 157                 return;
 158         cp = n->tag == NULL ? n->child->string : n->tag;
 159         if (cp[0] == '\\' && (cp[1] == '&' || cp[1] == 'e'))
 160                 cp += 2;
 161         len = strcspn(cp, " \t\\");
 162         fprintf(tag_files.tfs, "%.*s %s %zu\n",
 163             len, cp, tag_files.ofn, line);
 164 }
 165
 166 /*
 167  * Close both output files and restore the original standard output
 168  * to the terminal.  In the unlikely case that the latter fails,
 169  * trying to start a pager would be useless, so report the failure
 170  * to the main program.
 171  */
 172 int
 173 term_tag_close(void)
 174 {
 175         int irc = 0;
 176
 177         if (tag_files.tfs != NULL) {
 178                 fclose(tag_files.tfs);
 179                 tag_files.tfs = NULL;
 180         }
 181         if (tag_files.ofd != -1) {
 182                 fflush(stdout);
 183                 if ((irc = dup2(tag_files.ofd, STDOUT_FILENO)) == -1)
 184                         mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 185                 close(tag_files.ofd);
 186                 tag_files.ofd = -1;
 187         }
 188         return irc;
 189 }
 190
 191 void
 192 term_tag_unlink(void)
 193 {
 194         pid_t    tc_pgid;
 195
 196         if (tag_files.tcpgid != -1) {
 197                 tc_pgid = tcgetpgrp(STDOUT_FILENO);
 198                 if (tc_pgid == tag_files.pager_pid ||
 199                     tc_pgid == getpgid(0) ||
 200                     getpgid(tc_pgid) == -1)
 201                         (void)tcsetpgrp(STDOUT_FILENO, tag_files.tcpgid);
 202         }
 203         if (strncmp(tag_files.ofn, "/tmp/man.", 9) == 0) {
 204                 unlink(tag_files.ofn);
 205                 *tag_files.ofn = '\0';
 206         }
 207         if (strncmp(tag_files.tfn, "/tmp/man.", 9) == 0) {
 208                 unlink(tag_files.tfn);
 209                 *tag_files.tfn = '\0';
 210         }
 211 }
 212
 213 static void
 214 tag_signal(int signum)
 215 {
 216         struct sigaction         sa;
 217
 218         term_tag_unlink();
 219         memset(&sa, 0, sizeof(sa));
 220         sigemptyset(&sa.sa_mask);
 221         sa.sa_handler = SIG_DFL;
 222         sigaction(signum, &sa, NULL);
 223         kill(getpid(), signum);
 224         /* NOTREACHED */
 225         _exit(1);
 226 }