tag.c

   1 /*      $Id: tag.c,v 1.23 2019/07/19 20:27:25 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2015, 2016, 2018, 2019 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 #include "config.h"
  18
  19 #include <sys/types.h>
  20
  21 #include <errno.h>
  22 #include <limits.h>
  23 #include <signal.h>
  24 #include <stddef.h>
  25 #include <stdint.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <unistd.h>
  30
  31 #include "mandoc_aux.h"
  32 #include "mandoc_ohash.h"
  33 #include "mandoc.h"
  34 #include "tag.h"
  35
  36 struct tag_entry {
  37         size_t  *lines;
  38         size_t   maxlines;
  39         size_t   nlines;
  40         int      prio;
  41         char     s[];
  42 };
  43
  44 static  void     tag_signal(int) __attribute__((__noreturn__));
  45
  46 static struct ohash      tag_data;
  47 static struct tag_files  tag_files;
  48
  49
  50 /*
  51  * Prepare for using a pager.
  52  * Not all pagers are capable of using a tag file,
  53  * but for simplicity, create it anyway.
  54  */
  55 struct tag_files *
  56 tag_init(void)
  57 {
  58         struct sigaction         sa;
  59         int                      ofd;
  60
  61         ofd = -1;
  62         tag_files.tfd = -1;
  63         tag_files.tcpgid = -1;
  64
  65         /* Clean up when dying from a signal. */
  66
  67         memset(&sa, 0, sizeof(sa));
  68         sigfillset(&sa.sa_mask);
  69         sa.sa_handler = tag_signal;
  70         sigaction(SIGHUP, &sa, NULL);
  71         sigaction(SIGINT, &sa, NULL);
  72         sigaction(SIGTERM, &sa, NULL);
  73
  74         /*
  75          * POSIX requires that a process calling tcsetpgrp(3)
  76          * from the background gets a SIGTTOU signal.
  77          * In that case, do not stop.
  78          */
  79
  80         sa.sa_handler = SIG_IGN;
  81         sigaction(SIGTTOU, &sa, NULL);
  82
  83         /* Save the original standard output for use by the pager. */
  84
  85         if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1) {
  86                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
  87                 goto fail;
  88         }
  89
  90         /* Create both temporary output files. */
  91
  92         (void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
  93             sizeof(tag_files.ofn));
  94         (void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
  95             sizeof(tag_files.tfn));
  96         if ((ofd = mkstemp(tag_files.ofn)) == -1) {
  97                 mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
  98                     "%s: %s", tag_files.ofn, strerror(errno));
  99                 goto fail;
 100         }
 101         if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1) {
 102                 mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
 103                     "%s: %s", tag_files.tfn, strerror(errno));
 104                 goto fail;
 105         }
 106         if (dup2(ofd, STDOUT_FILENO) == -1) {
 107                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 108                 goto fail;
 109         }
 110         close(ofd);
 111
 112         /*
 113          * Set up the ohash table to collect output line numbers
 114          * where various marked-up terms are documented.
 115          */
 116
 117         mandoc_ohash_init(&tag_data, 4, offsetof(struct tag_entry, s));
 118         return &tag_files;
 119
 120 fail:
 121         tag_unlink();
 122         if (ofd != -1)
 123                 close(ofd);
 124         if (tag_files.ofd != -1)
 125                 close(tag_files.ofd);
 126         if (tag_files.tfd != -1)
 127                 close(tag_files.tfd);
 128         *tag_files.ofn = '\0';
 129         *tag_files.tfn = '\0';
 130         tag_files.ofd = -1;
 131         tag_files.tfd = -1;
 132         return NULL;
 133 }
 134
 135 /*
 136  * Set the line number where a term is defined,
 137  * unless it is already defined at a lower priority.
 138  */
 139 void
 140 tag_put(const char *s, int prio, size_t line)
 141 {
 142         struct tag_entry        *entry;
 143         const char              *se;
 144         size_t                   len;
 145         unsigned int             slot;
 146
 147         if (tag_files.tfd <= 0)
 148                 return;
 149
 150         if (s[0] == '\\' && (s[1] == '&' || s[1] == 'e'))
 151                 s += 2;
 152
 153         /*
 154          * Skip whitespace and whatever follows it,
 155          * and if there is any, downgrade the priority.
 156          */
 157
 158         len = strcspn(s, " \t");
 159         if (len == 0)
 160                 return;
 161
 162         se = s + len;
 163         if (*se != '\0')
 164                 prio = INT_MAX;
 165
 166         slot = ohash_qlookupi(&tag_data, s, &se);
 167         entry = ohash_find(&tag_data, slot);
 168
 169         if (entry == NULL) {
 170
 171                 /* Build a new entry. */
 172
 173                 entry = mandoc_malloc(sizeof(*entry) + len + 1);
 174                 memcpy(entry->s, s, len);
 175                 entry->s[len] = '\0';
 176                 entry->lines = NULL;
 177                 entry->maxlines = entry->nlines = 0;
 178                 ohash_insert(&tag_data, slot, entry);
 179
 180         } else {
 181
 182                 /*
 183                  * Lower priority numbers take precedence,
 184                  * but 0 is special.
 185                  * A tag with priority 0 is only used
 186                  * if the tag occurs exactly once.
 187                  */
 188
 189                 if (prio == 0) {
 190                         if (entry->prio == 0)
 191                                 entry->prio = -1;
 192                         return;
 193                 }
 194
 195                 /* A better entry is already present, ignore the new one. */
 196
 197                 if (entry->prio > 0 && entry->prio < prio)
 198                         return;
 199
 200                 /* The existing entry is worse, clear it. */
 201
 202                 if (entry->prio < 1 || entry->prio > prio)
 203                         entry->nlines = 0;
 204         }
 205
 206         /* Remember the new line. */
 207
 208         if (entry->maxlines == entry->nlines) {
 209                 entry->maxlines += 4;
 210                 entry->lines = mandoc_reallocarray(entry->lines,
 211                     entry->maxlines, sizeof(*entry->lines));
 212         }
 213         entry->lines[entry->nlines++] = line;
 214         entry->prio = prio;
 215 }
 216
 217 /*
 218  * Write out the tags file using the previously collected
 219  * information and clear the ohash table while going along.
 220  */
 221 void
 222 tag_write(void)
 223 {
 224         FILE                    *stream;
 225         struct tag_entry        *entry;
 226         size_t                   i;
 227         unsigned int             slot;
 228         int                      empty;
 229
 230         if (tag_files.tfd <= 0)
 231                 return;
 232         if (tag_files.tagname != NULL && ohash_find(&tag_data,
 233             ohash_qlookup(&tag_data, tag_files.tagname)) == NULL) {
 234                 mandoc_msg(MANDOCERR_TAG, 0, 0, "%s", tag_files.tagname);
 235                 tag_files.tagname = NULL;
 236         }
 237         if ((stream = fdopen(tag_files.tfd, "w")) == NULL)
 238                 mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
 239         empty = 1;
 240         entry = ohash_first(&tag_data, &slot);
 241         while (entry != NULL) {
 242                 if (stream != NULL && entry->prio >= 0) {
 243                         for (i = 0; i < entry->nlines; i++) {
 244                                 fprintf(stream, "%s %s %zu\n",
 245                                     entry->s, tag_files.ofn, entry->lines[i]);
 246                                 empty = 0;
 247                         }
 248                 }
 249                 free(entry->lines);
 250                 free(entry);
 251                 entry = ohash_next(&tag_data, &slot);
 252         }
 253         ohash_delete(&tag_data);
 254         if (stream != NULL)
 255                 fclose(stream);
 256         else
 257                 close(tag_files.tfd);
 258         tag_files.tfd = -1;
 259         if (empty) {
 260                 unlink(tag_files.tfn);
 261                 *tag_files.tfn = '\0';
 262         }
 263 }
 264
 265 void
 266 tag_unlink(void)
 267 {
 268         pid_t    tc_pgid;
 269
 270         if (tag_files.tcpgid != -1) {
 271                 tc_pgid = tcgetpgrp(tag_files.ofd);
 272                 if (tc_pgid == tag_files.pager_pid ||
 273                     tc_pgid == getpgid(0) ||
 274                     getpgid(tc_pgid) == -1)
 275                         (void)tcsetpgrp(tag_files.ofd, tag_files.tcpgid);
 276         }
 277         if (*tag_files.ofn != '\0')
 278                 unlink(tag_files.ofn);
 279         if (*tag_files.tfn != '\0')
 280                 unlink(tag_files.tfn);
 281 }
 282
 283 static void
 284 tag_signal(int signum)
 285 {
 286         struct sigaction         sa;
 287
 288         tag_unlink();
 289         memset(&sa, 0, sizeof(sa));
 290         sigemptyset(&sa.sa_mask);
 291         sa.sa_handler = SIG_DFL;
 292         sigaction(signum, &sa, NULL);
 293         kill(getpid(), signum);
 294         /* NOTREACHED */
 295         _exit(1);
 296 }