term_tag.c

   1 /* $Id: term_tag.c,v 1.6 2021/03/30 17:16:55 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 *suffix,
  51     const char *tagfilename)
  52 {
  53         struct sigaction         sa;
  54         int                      ofd;   /* In /tmp/, dup(2)ed to stdout. */
  55         int                      tfd;
  56
  57         ofd = tfd = -1;
  58         tag_files.tfs = NULL;
  59         tag_files.tcpgid = -1;
  60
  61         /* Clean up when dying from a signal. */
  62
  63         memset(&sa, 0, sizeof(sa));
  64         sigfillset(&sa.sa_mask);
  65         sa.sa_handler = tag_signal;
  66         sigaction(SIGHUP, &sa, NULL);
  67         sigaction(SIGINT, &sa, NULL);
  68         sigaction(SIGTERM, &sa, NULL);
  69
  70         /*
  71          * POSIX requires that a process calling tcsetpgrp(3)
  72          * from the background gets a SIGTTOU signal.
  73          * In that case, do not stop.
  74          */
  75
  76         sa.sa_handler = SIG_IGN;
  77         sigaction(SIGTTOU, &sa, NULL);
  78
  79         /* Save the original standard output for use by the pager. */
  80
  81         if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1) {
  82                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
  83                 goto fail;
  84         }
  85
  86         /* Create both temporary output files. */
  87
  88         if (outfilename == NULL) {
  89                 (void)snprintf(tag_files.ofn, sizeof(tag_files.ofn),
  90                     "/tmp/man.XXXXXXXXXX%s", suffix);
  91                 if ((ofd = mkstemps(tag_files.ofn, strlen(suffix))) == -1) {
  92                         mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
  93                             "%s: %s", tag_files.ofn, strerror(errno));
  94                         goto fail;
  95                 }
  96         } else {
  97                 (void)strlcpy(tag_files.ofn, outfilename,
  98                    sizeof(tag_files.ofn));
  99                 unlink(outfilename);
 100                 ofd = open(outfilename, O_WRONLY | O_CREAT | O_EXCL, 0644);
 101                 if (ofd == -1) {
 102                         mandoc_msg(MANDOCERR_OPEN, 0, 0,
 103                             "%s: %s", outfilename, strerror(errno));
 104                         goto fail;
 105                 }
 106         }
 107         if (tagfilename == NULL) {
 108                 (void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
 109                     sizeof(tag_files.tfn));
 110                 if ((tfd = mkstemp(tag_files.tfn)) == -1) {
 111                         mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
 112                             "%s: %s", tag_files.tfn, strerror(errno));
 113                         goto fail;
 114                 }
 115         } else {
 116                 (void)strlcpy(tag_files.tfn, tagfilename,
 117                     sizeof(tag_files.tfn));
 118                 unlink(tagfilename);
 119                 tfd = open(tagfilename, O_WRONLY | O_CREAT | O_EXCL, 0644);
 120                 if (tfd == -1) {
 121                         mandoc_msg(MANDOCERR_OPEN, 0, 0,
 122                             "%s: %s", tagfilename, strerror(errno));
 123                         goto fail;
 124                 }
 125         }
 126         if ((tag_files.tfs = fdopen(tfd, "w")) == NULL) {
 127                 mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
 128                 goto fail;
 129         }
 130         tfd = -1;
 131         if (dup2(ofd, STDOUT_FILENO) == -1) {
 132                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 133                 goto fail;
 134         }
 135         close(ofd);
 136         return &tag_files;
 137
 138 fail:
 139         term_tag_unlink();
 140         if (ofd != -1)
 141                 close(ofd);
 142         if (tfd != -1)
 143                 close(tfd);
 144         if (tag_files.ofd != -1) {
 145                 close(tag_files.ofd);
 146                 tag_files.ofd = -1;
 147         }
 148         return NULL;
 149 }
 150
 151 void
 152 term_tag_write(struct roff_node *n, size_t line)
 153 {
 154         const char      *cp;
 155         int              len;
 156
 157         if (tag_files.tfs == NULL)
 158                 return;
 159         cp = n->tag == NULL ? n->child->string : n->tag;
 160         if (cp[0] == '\\' && (cp[1] == '&' || cp[1] == 'e'))
 161                 cp += 2;
 162         len = strcspn(cp, " \t\\");
 163         fprintf(tag_files.tfs, "%.*s %s %zu\n",
 164             len, cp, tag_files.ofn, line);
 165 }
 166
 167 /*
 168  * Close both output files and restore the original standard output
 169  * to the terminal.  In the unlikely case that the latter fails,
 170  * trying to start a pager would be useless, so report the failure
 171  * to the main program.
 172  */
 173 int
 174 term_tag_close(void)
 175 {
 176         int irc = 0;
 177
 178         if (tag_files.tfs != NULL) {
 179                 fclose(tag_files.tfs);
 180                 tag_files.tfs = NULL;
 181         }
 182         if (tag_files.ofd != -1) {
 183                 fflush(stdout);
 184                 if ((irc = dup2(tag_files.ofd, STDOUT_FILENO)) == -1)
 185                         mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 186                 close(tag_files.ofd);
 187                 tag_files.ofd = -1;
 188         }
 189         return irc;
 190 }
 191
 192 void
 193 term_tag_unlink(void)
 194 {
 195         pid_t    tc_pgid;
 196
 197         if (tag_files.tcpgid != -1) {
 198                 tc_pgid = tcgetpgrp(STDOUT_FILENO);
 199                 if (tc_pgid == tag_files.pager_pid ||
 200                     tc_pgid == getpgid(0) ||
 201                     getpgid(tc_pgid) == -1)
 202                         (void)tcsetpgrp(STDOUT_FILENO, tag_files.tcpgid);
 203         }
 204         if (strncmp(tag_files.ofn, "/tmp/man.", 9) == 0) {
 205                 unlink(tag_files.ofn);
 206                 *tag_files.ofn = '\0';
 207         }
 208         if (strncmp(tag_files.tfn, "/tmp/man.", 9) == 0) {
 209                 unlink(tag_files.tfn);
 210                 *tag_files.tfn = '\0';
 211         }
 212 }
 213
 214 static void
 215 tag_signal(int signum)
 216 {
 217         struct sigaction         sa;
 218
 219         term_tag_unlink();
 220         memset(&sa, 0, sizeof(sa));
 221         sigemptyset(&sa.sa_mask);
 222         sa.sa_handler = SIG_DFL;
 223         sigaction(signum, &sa, NULL);
 224         kill(getpid(), signum);
 225         /* NOTREACHED */
 226         _exit(1);
 227 }