tag.c

   1 /*      $Id: tag.c,v 1.25 2019/07/27 13:40:57 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(char *tagname)
  57 {
  58         struct sigaction         sa;
  59         int                      ofd;
  60
  61         ofd = -1;
  62         tag_files.tfd = -1;
  63         tag_files.tcpgid = -1;
  64         tag_files.tagname = tagname;
  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                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
  88                 goto fail;
  89         }
  90
  91         /* Create both temporary output files. */
  92
  93         (void)strlcpy(tag_files.ofn, "/tmp/man.XXXXXXXXXX",
  94             sizeof(tag_files.ofn));
  95         (void)strlcpy(tag_files.tfn, "/tmp/man.XXXXXXXXXX",
  96             sizeof(tag_files.tfn));
  97         if ((ofd = mkstemp(tag_files.ofn)) == -1) {
  98                 mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
  99                     "%s: %s", tag_files.ofn, strerror(errno));
 100                 goto fail;
 101         }
 102         if ((tag_files.tfd = mkstemp(tag_files.tfn)) == -1) {
 103                 mandoc_msg(MANDOCERR_MKSTEMP, 0, 0,
 104                     "%s: %s", tag_files.tfn, strerror(errno));
 105                 goto fail;
 106         }
 107         if (dup2(ofd, STDOUT_FILENO) == -1) {
 108                 mandoc_msg(MANDOCERR_DUP, 0, 0, "%s", strerror(errno));
 109                 goto fail;
 110         }
 111         close(ofd);
 112
 113         /*
 114          * Set up the ohash table to collect output line numbers
 115          * where various marked-up terms are documented.
 116          */
 117
 118         mandoc_ohash_init(&tag_data, 4, offsetof(struct tag_entry, s));
 119         return &tag_files;
 120
 121 fail:
 122         tag_unlink();
 123         if (ofd != -1)
 124                 close(ofd);
 125         if (tag_files.ofd != -1)
 126                 close(tag_files.ofd);
 127         if (tag_files.tfd != -1)
 128                 close(tag_files.tfd);
 129         *tag_files.ofn = '\0';
 130         *tag_files.tfn = '\0';
 131         tag_files.ofd = -1;
 132         tag_files.tfd = -1;
 133         tag_files.tagname = NULL;
 134         return NULL;
 135 }
 136
 137 /*
 138  * Set the line number where a term is defined,
 139  * unless it is already defined at a lower priority.
 140  */
 141 void
 142 tag_put(const char *s, int prio, size_t line)
 143 {
 144         struct tag_entry        *entry;
 145         const char              *se;
 146         size_t                   len;
 147         unsigned int             slot;
 148
 149         if (tag_files.tfd <= 0)
 150                 return;
 151
 152         if (s[0] == '\\' && (s[1] == '&' || s[1] == 'e'))
 153                 s += 2;
 154
 155         /*
 156          * Skip whitespace and escapes and whatever follows,
 157          * and if there is any, downgrade the priority.
 158          */
 159
 160         len = strcspn(s, " \t\\");
 161         if (len == 0)
 162                 return;
 163
 164         se = s + len;
 165         if (*se != '\0')
 166                 prio = INT_MAX;
 167
 168         slot = ohash_qlookupi(&tag_data, s, &se);
 169         entry = ohash_find(&tag_data, slot);
 170
 171         if (entry == NULL) {
 172
 173                 /* Build a new entry. */
 174
 175                 entry = mandoc_malloc(sizeof(*entry) + len + 1);
 176                 memcpy(entry->s, s, len);
 177                 entry->s[len] = '\0';
 178                 entry->lines = NULL;
 179                 entry->maxlines = entry->nlines = 0;
 180                 ohash_insert(&tag_data, slot, entry);
 181
 182         } else {
 183
 184                 /*
 185                  * Lower priority numbers take precedence,
 186                  * but 0 is special.
 187                  * A tag with priority 0 is only used
 188                  * if the tag occurs exactly once.
 189                  */
 190
 191                 if (prio == 0) {
 192                         if (entry->prio == 0)
 193                                 entry->prio = -1;
 194                         return;
 195                 }
 196
 197                 /* A better entry is already present, ignore the new one. */
 198
 199                 if (entry->prio > 0 && entry->prio < prio)
 200                         return;
 201
 202                 /* The existing entry is worse, clear it. */
 203
 204                 if (entry->prio < 1 || entry->prio > prio)
 205                         entry->nlines = 0;
 206         }
 207
 208         /* Remember the new line. */
 209
 210         if (entry->maxlines == entry->nlines) {
 211                 entry->maxlines += 4;
 212                 entry->lines = mandoc_reallocarray(entry->lines,
 213                     entry->maxlines, sizeof(*entry->lines));
 214         }
 215         entry->lines[entry->nlines++] = line;
 216         entry->prio = prio;
 217 }
 218
 219 /*
 220  * Write out the tags file using the previously collected
 221  * information and clear the ohash table while going along.
 222  */
 223 void
 224 tag_write(void)
 225 {
 226         FILE                    *stream;
 227         struct tag_entry        *entry;
 228         size_t                   i;
 229         unsigned int             slot;
 230         int                      empty;
 231
 232         if (tag_files.tfd <= 0)
 233                 return;
 234         if (tag_files.tagname != NULL && ohash_find(&tag_data,
 235             ohash_qlookup(&tag_data, tag_files.tagname)) == NULL) {
 236                 mandoc_msg(MANDOCERR_TAG, 0, 0, "%s", tag_files.tagname);
 237                 tag_files.tagname = NULL;
 238         }
 239         if ((stream = fdopen(tag_files.tfd, "w")) == NULL)
 240                 mandoc_msg(MANDOCERR_FDOPEN, 0, 0, "%s", strerror(errno));
 241         empty = 1;
 242         entry = ohash_first(&tag_data, &slot);
 243         while (entry != NULL) {
 244                 if (stream != NULL && entry->prio >= 0) {
 245                         for (i = 0; i < entry->nlines; i++) {
 246                                 fprintf(stream, "%s %s %zu\n",
 247                                     entry->s, tag_files.ofn, entry->lines[i]);
 248                                 empty = 0;
 249                         }
 250                 }
 251                 free(entry->lines);
 252                 free(entry);
 253                 entry = ohash_next(&tag_data, &slot);
 254         }
 255         ohash_delete(&tag_data);
 256         if (stream != NULL)
 257                 fclose(stream);
 258         else
 259                 close(tag_files.tfd);
 260         tag_files.tfd = -1;
 261         if (empty) {
 262                 unlink(tag_files.tfn);
 263                 *tag_files.tfn = '\0';
 264         }
 265 }
 266
 267 void
 268 tag_unlink(void)
 269 {
 270         pid_t    tc_pgid;
 271
 272         if (tag_files.tcpgid != -1) {
 273                 tc_pgid = tcgetpgrp(tag_files.ofd);
 274                 if (tc_pgid == tag_files.pager_pid ||
 275                     tc_pgid == getpgid(0) ||
 276                     getpgid(tc_pgid) == -1)
 277                         (void)tcsetpgrp(tag_files.ofd, tag_files.tcpgid);
 278         }
 279         if (*tag_files.ofn != '\0')
 280                 unlink(tag_files.ofn);
 281         if (*tag_files.tfn != '\0')
 282                 unlink(tag_files.tfn);
 283 }
 284
 285 static void
 286 tag_signal(int signum)
 287 {
 288         struct sigaction         sa;
 289
 290         tag_unlink();
 291         memset(&sa, 0, sizeof(sa));
 292         sigemptyset(&sa.sa_mask);
 293         sa.sa_handler = SIG_DFL;
 294         sigaction(signum, &sa, NULL);
 295         kill(getpid(), signum);
 296         /* NOTREACHED */
 297         _exit(1);
 298 }