term_tag.c

   1 /* $Id: term_tag.c,v 1.4 2020/04/18 20:40:10 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 <signal.h>
  26 #include <stddef.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <string.h>
  30 #include <unistd.h>
  31
  32 #include "mandoc.h"
  33 #include "roff.h"
  34 #include "roff_int.h"
  35 #include "tag.h"
  36 #include "term_tag.h"
  37
  38 static void tag_signal(int) __attribute__((__noreturn__));
  39
  40 static struct tag_files tag_files;
  41
  42
  43 /*
  44  * Prepare for using a pager.
  45  * Not all pagers are capable of using a tag file,
  46  * but for simplicity, create it anyway.
  47  */
  48 struct tag_files *
  49 term_tag_init(void)
  50 {
  51         struct sigaction         sa;
  52         int                      ofd;   /* In /tmp/, dup(2)ed to stdout. */
  53         int                      tfd;
  54
  55         ofd = tfd = -1;
  56         tag_files.tfs = NULL;
  57         tag_files.tcpgid = -1;
  58
  59         /* Clean up when dying from a signal. */
  60
  61         memset(&sa, 0, sizeof(sa));
  62         sigfillset(&sa.sa_mask);
  63         sa.sa_handler = tag_signal;
  64         sigaction(SIGHUP, &sa, NULL);
  65         sigaction(SIGINT, &sa, NULL);
  66         sigaction(SIGTERM, &sa, NULL);
  67
  68         /*
  69          * POSIX requires that a process calling tcsetpgrp(3)
  70          * from the background gets a SIGTTOU signal.
  71          * In that case, do not stop.
  72          */
  73
  74         sa.sa_handler = SIG_IGN;
  75         sigaction(SIGTTOU, &sa, NULL);
  76
  77         /* Save the original standard output for use by the pager. */
  78
  79         if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1) {
  80                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
  81                 goto fail;
  82         }
  83
  84         /* Create both temporary output files. */
  85
  86         (void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
  87             sizeof(tag_files.ofn));
  88         (void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
  89             sizeof(tag_files.tfn));
  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         if ((tfd = mkstemp(tag_files.tfn)) == -1) {
  96                 mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
  97                     "%s: %s", tag_files.tfn, strerror(errno));
  98                 goto fail;
  99         }
 100         if ((tag_files.tfs = fdopen(tfd, "w")) == NULL) {
 101                 mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
 102                 goto fail;
 103         }
 104         tfd = -1;
 105         if (dup2(ofd, STDOUT_FILENO) == -1) {
 106                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 107                 goto fail;
 108         }
 109         close(ofd);
 110         return &tag_files;
 111
 112 fail:
 113         term_tag_unlink();
 114         if (ofd != -1)
 115                 close(ofd);
 116         if (tfd != -1)
 117                 close(tfd);
 118         if (tag_files.ofd != -1) {
 119                 close(tag_files.ofd);
 120                 tag_files.ofd = -1;
 121         }
 122         return NULL;
 123 }
 124
 125 void
 126 term_tag_write(struct roff_node *n, size_t line)
 127 {
 128         const char      *cp;
 129         int              len;
 130
 131         if (tag_files.tfs == NULL)
 132                 return;
 133         cp = n->tag == NULL ? n->child->string : n->tag;
 134         if (cp[0] == '\\' && (cp[1] == '&' || cp[1] == 'e'))
 135                 cp += 2;
 136         len = strcspn(cp, " \t\\");
 137         fprintf(tag_files.tfs, "%.*s %s %zu\n",
 138             len, cp, tag_files.ofn, line);
 139 }
 140
 141 /*
 142  * Close both output files and restore the original standard output
 143  * to the terminal.  In the unlikely case that the latter fails,
 144  * trying to start a pager would be useless, so report the failure
 145  * to the main program.
 146  */
 147 int
 148 term_tag_close(void)
 149 {
 150         int irc = 0;
 151
 152         if (tag_files.tfs != NULL) {
 153                 fclose(tag_files.tfs);
 154                 tag_files.tfs = NULL;
 155         }
 156         if (tag_files.ofd != -1) {
 157                 fflush(stdout);
 158                 if ((irc = dup2(tag_files.ofd, STDOUT_FILENO)) == -1)
 159                         mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 160                 close(tag_files.ofd);
 161                 tag_files.ofd = -1;
 162         }
 163         return irc;
 164 }
 165
 166 void
 167 term_tag_unlink(void)
 168 {
 169         pid_t    tc_pgid;
 170
 171         if (tag_files.tcpgid != -1) {
 172                 tc_pgid = tcgetpgrp(STDOUT_FILENO);
 173                 if (tc_pgid == tag_files.pager_pid ||
 174                     tc_pgid == getpgid(0) ||
 175                     getpgid(tc_pgid) == -1)
 176                         (void)tcsetpgrp(STDOUT_FILENO, tag_files.tcpgid);
 177         }
 178         if (*tag_files.ofn != '\0') {
 179                 unlink(tag_files.ofn);
 180                 *tag_files.ofn = '\0';
 181         }
 182         if (*tag_files.tfn != '\0') {
 183                 unlink(tag_files.tfn);
 184                 *tag_files.tfn = '\0';
 185         }
 186 }
 187
 188 static void
 189 tag_signal(int signum)
 190 {
 191         struct sigaction         sa;
 192
 193         term_tag_unlink();
 194         memset(&sa, 0, sizeof(sa));
 195         sigemptyset(&sa.sa_mask);
 196         sa.sa_handler = SIG_DFL;
 197         sigaction(signum, &sa, NULL);
 198         kill(getpid(), signum);
 199         /* NOTREACHED */
 200         _exit(1);
 201 }