tag.c

   1 /*      $Id: tag.c,v 1.21 2018/11/22 11:30:23 schwarze Exp $ */
   2 /*
   3  * Copyright (c) 2015, 2016, 2018 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 #if HAVE_ERR
  22 #include <err.h>
  23 #endif
  24 #include <limits.h>
  25 #include <signal.h>
  26 #include <stddef.h>
  27 #include <stdint.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h>
  32
  33 #include "mandoc_aux.h"
  34 #include "mandoc_ohash.h"
  35 #include "tag.h"
  36
  37 struct tag_entry {
  38         size_t  *lines;
  39         size_t   maxlines;
  40         size_t   nlines;
  41         int      prio;
  42         char     s[];
  43 };
  44
  45 static  void     tag_signal(int) __attribute__((__noreturn__));
  46
  47 static struct ohash      tag_data;
  48 static struct tag_files  tag_files;
  49
  50
  51 /*
  52  * Prepare for using a pager.
  53  * Not all pagers are capable of using a tag file,
  54  * but for simplicity, create it anyway.
  55  */
  56 struct tag_files *
  57 tag_init(void)
  58 {
  59         struct sigaction         sa;
  60         int                      ofd;
  61
  62         ofd = -1;
  63         tag_files.tfd = -1;
  64         tag_files.tcpgid = -1;
  65
  66         /* Clean up when dying from a signal. */
  67
  68         memset(&sa, 0, sizeof(sa));
  69         sigfillset(&sa.sa_mask);
  70         sa.sa_handler = tag_signal;
  71         sigaction(SIGHUP, &sa, NULL);
  72         sigaction(SIGINT, &sa, NULL);
  73         sigaction(SIGTERM, &sa, NULL);
  74
  75         /*
  76          * POSIX requires that a process calling tcsetpgrp(3)
  77          * from the background gets a SIGTTOU signal.
  78          * In that case, do not stop.
  79          */
  80
  81         sa.sa_handler = SIG_IGN;
  82         sigaction(SIGTTOU, &sa, NULL);
  83
  84         /* Save the original standard output for use by the pager. */
  85
  86         if ((tag_files.ofd = dup(STDOUT_FILENO)) == -1)
  87                 goto fail;
  88
  89         /* Create both temporary output files. */
  90
  91         (void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
  92             sizeof(tag_files.ofn));
  93         (void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
  94             sizeof(tag_files.tfn));
  95         if ((ofd = mkstemp(tag_files.ofn)) == -1)
  96                 goto fail;
  97         if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1)
  98                 goto fail;
  99         if (dup2(ofd, STDOUT_FILENO) == -1)
 100                 goto fail;
 101         close(ofd);
 102
 103         /*
 104          * Set up the ohash table to collect output line numbers
 105          * where various marked-up terms are documented.
 106          */
 107
 108         mandoc_ohash_init(&tag_data, 4, offsetof(struct tag_entry, s));
 109         return &tag_files;
 110
 111 fail:
 112         tag_unlink();
 113         if (ofd != -1)
 114                 close(ofd);
 115         if (tag_files.ofd != -1)
 116                 close(tag_files.ofd);
 117         if (tag_files.tfd != -1)
 118                 close(tag_files.tfd);
 119         *tag_files.ofn = '\0';
 120         *tag_files.tfn = '\0';
 121         tag_files.ofd = -1;
 122         tag_files.tfd = -1;
 123         return NULL;
 124 }
 125
 126 /*
 127  * Set the line number where a term is defined,
 128  * unless it is already defined at a lower priority.
 129  */
 130 void
 131 tag_put(const char *s, int prio, size_t line)
 132 {
 133         struct tag_entry        *entry;
 134         const char              *se;
 135         size_t                   len;
 136         unsigned int             slot;
 137
 138         if (tag_files.tfd <= 0)
 139                 return;
 140
 141         if (s[0] == '\\' && (s[1] == '&' || s[1] == 'e'))
 142                 s += 2;
 143
 144         /*
 145          * Skip whitespace and whatever follows it,
 146          * and if there is any, downgrade the priority.
 147          */
 148
 149         len = strcspn(s, " \t");
 150         if (len == 0)
 151                 return;
 152
 153         se = s + len;
 154         if (*se != '\0')
 155                 prio = INT_MAX;
 156
 157         slot = ohash_qlookupi(&tag_data, s, &se);
 158         entry = ohash_find(&tag_data, slot);
 159
 160         if (entry == NULL) {
 161
 162                 /* Build a new entry. */
 163
 164                 entry = mandoc_malloc(sizeof(*entry) + len + 1);
 165                 memcpy(entry->s, s, len);
 166                 entry->s[len] = '\0';
 167                 entry->lines = NULL;
 168                 entry->maxlines = entry->nlines = 0;
 169                 ohash_insert(&tag_data, slot, entry);
 170
 171         } else {
 172
 173                 /*
 174                  * Lower priority numbers take precedence,
 175                  * but 0 is special.
 176                  * A tag with priority 0 is only used
 177                  * if the tag occurs exactly once.
 178                  */
 179
 180                 if (prio == 0) {
 181                         if (entry->prio == 0)
 182                                 entry->prio = -1;
 183                         return;
 184                 }
 185
 186                 /* A better entry is already present, ignore the new one. */
 187
 188                 if (entry->prio > 0 && entry->prio < prio)
 189                         return;
 190
 191                 /* The existing entry is worse, clear it. */
 192
 193                 if (entry->prio < 1 || entry->prio > prio)
 194                         entry->nlines = 0;
 195         }
 196
 197         /* Remember the new line. */
 198
 199         if (entry->maxlines == entry->nlines) {
 200                 entry->maxlines += 4;
 201                 entry->lines = mandoc_reallocarray(entry->lines,
 202                     entry->maxlines, sizeof(*entry->lines));
 203         }
 204         entry->lines[entry->nlines++] = line;
 205         entry->prio = prio;
 206 }
 207
 208 /*
 209  * Write out the tags file using the previously collected
 210  * information and clear the ohash table while going along.
 211  */
 212 void
 213 tag_write(void)
 214 {
 215         FILE                    *stream;
 216         struct tag_entry        *entry;
 217         size_t                   i;
 218         unsigned int             slot;
 219
 220         if (tag_files.tfd <= 0)
 221                 return;
 222         if (tag_files.tagname != NULL && ohash_find(&tag_data,
 223             ohash_qlookup(&tag_data, tag_files.tagname)) == NULL) {
 224                 warnx("%s: no such tag", tag_files.tagname);
 225                 tag_files.tagname = NULL;
 226         }
 227         stream = fdopen(tag_files.tfd, "w");
 228         entry = ohash_first(&tag_data, &slot);
 229         while (entry != NULL) {
 230                 if (stream != NULL && entry->prio >= 0)
 231                         for (i = 0; i < entry->nlines; i++)
 232                                 fprintf(stream, "%s %s %zu\n",
 233                                     entry->s, tag_files.ofn, entry->lines[i]);
 234                 free(entry->lines);
 235                 free(entry);
 236                 entry = ohash_next(&tag_data, &slot);
 237         }
 238         ohash_delete(&tag_data);
 239         if (stream != NULL)
 240                 fclose(stream);
 241         else
 242                 close(tag_files.tfd);
 243         tag_files.tfd = -1;
 244 }
 245
 246 void
 247 tag_unlink(void)
 248 {
 249         pid_t    tc_pgid;
 250
 251         if (tag_files.tcpgid != -1) {
 252                 tc_pgid = tcgetpgrp(tag_files.ofd);
 253                 if (tc_pgid == tag_files.pager_pid ||
 254                     tc_pgid == getpgid(0) ||
 255                     getpgid(tc_pgid) == -1)
 256                         (void)tcsetpgrp(tag_files.ofd, tag_files.tcpgid);
 257         }
 258         if (*tag_files.ofn != '\0')
 259                 unlink(tag_files.ofn);
 260         if (*tag_files.tfn != '\0')
 261                 unlink(tag_files.tfn);
 262 }
 263
 264 static void
 265 tag_signal(int signum)
 266 {
 267         struct sigaction         sa;
 268
 269         tag_unlink();
 270         memset(&sa, 0, sizeof(sa));
 271         sigemptyset(&sa.sa_mask);
 272         sa.sa_handler = SIG_DFL;
 273         sigaction(signum, &sa, NULL);
 274         kill(getpid(), signum);
 275         /* NOTREACHED */
 276         _exit(1);
 277 }