2 Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
3 2007, 2008 Free Software Foundation, Inc.
5 This file is part of GNU Wget.
7 GNU Wget is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 GNU Wget is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with Wget. If not, see <http://www.gnu.org/licenses/>.
20 Additional permission under GNU GPL version 3 section 7
22 If you modify this program, or any covered work, by linking or
23 combining it with the OpenSSL project's OpenSSL library (or a
24 modified version of that library), containing parts covered by the
25 terms of the OpenSSL or SSLeay licenses, the Free Software Foundation
26 grants you additional permission to convey the resulting work.
27 Corresponding Source for a non-source form of such a combination
28 shall include the source code for the parts of OpenSSL used as well
29 as that of the covered work. */
46 /* This file impplement support for "logging". Logging means printing
47 output, plus several additional features:
49 - Cataloguing output by importance. You can specify that a log
50 message is "verbose" or "debug", and it will not be printed unless
51 in verbose or debug mode, respectively.
53 - Redirecting the log to the file. When Wget's output goes to the
54 terminal, and Wget receives SIGHUP, all further output is
55 redirected to a log file. When this is the case, Wget can also
56 print the last several lines of "context" to the log file so that
57 it does not begin in the middle of a line. For this to work, the
58 logging code stores the last several lines of context. Callers may
59 request for certain output not to be stored.
61 - Inhibiting output. When Wget receives SIGHUP, but redirecting
62 the output fails, logging is inhibited. */
65 /* The file descriptor used for logging. This is NULL before log_init
66 is called; logging functions log to stderr then. log_init sets it
67 either to stderr or to a file pointer obtained from fopen(). If
68 logging is inhibited, logfp is set back to NULL. */
71 /* If true, it means logging is inhibited, i.e. nothing is printed or
73 static bool inhibit_logging;
75 /* Whether the last output lines are stored for use as context. */
76 static bool save_context_p;
78 /* Whether the log is flushed after each command. */
79 static bool flush_log_p = true;
81 /* Whether any output has been received while flush_log_p was 0. */
82 static bool needs_flushing;
84 /* In the event of a hang-up, and if its output was on a TTY, Wget
85 redirects its output to `wget-log'.
87 For the convenience of reading this newly-created log, we store the
88 last several lines ("screenful", hence the choice of 24) of Wget
89 output, and dump them as context when the time comes. */
90 #define SAVED_LOG_LINES 24
92 /* log_lines is a circular buffer that stores SAVED_LOG_LINES lines of
93 output. log_line_current always points to the position in the
94 buffer that will be written to next. When log_line_current reaches
95 SAVED_LOG_LINES, it is reset to zero.
97 The problem here is that we'd have to either (re)allocate and free
98 strings all the time, or limit the lines to an arbitrary number of
99 characters. Instead of settling for either of these, we do both:
100 if the line is smaller than a certain "usual" line length (128
101 chars by default), a preallocated memory is used. The rare lines
102 that are longer than 128 characters are malloc'ed and freed
103 separately. This gives good performance with minimum memory
104 consumption and fragmentation. */
106 #define STATIC_LENGTH 128
108 static struct log_ln {
109 char static_line[STATIC_LENGTH + 1]; /* statically allocated
111 char *malloced_line; /* malloc'ed line, for lines of output
112 larger than 80 characters. */
113 char *content; /* this points either to malloced_line
114 or to the appropriate static_line.
115 If this is NULL, it means the line
116 has not yet been used. */
117 } log_lines[SAVED_LOG_LINES];
119 /* The current position in the ring. */
120 static int log_line_current = -1;
122 /* Whether the most recently written line was "trailing", i.e. did not
123 finish with \n. This is an important piece of information because
124 the code is always careful to append data to trailing lines, rather
125 than create new ones. */
126 static bool trailing_line;
128 static void check_redirect_output (void);
130 #define ROT_ADVANCE(num) do { \
131 if (++num >= SAVED_LOG_LINES) \
135 /* Free the log line index with NUM. This calls free on
136 ln->malloced_line if it's non-NULL, and it also resets
137 ln->malloced_line and ln->content to NULL. */
140 free_log_line (int num)
142 struct log_ln *ln = log_lines + num;
143 if (ln->malloced_line)
145 xfree (ln->malloced_line);
146 ln->malloced_line = NULL;
151 /* Append bytes in the range [start, end) to one line in the log. The
152 region is not supposed to contain newlines, except for the last
153 character (at end[-1]). */
156 saved_append_1 (const char *start, const char *end)
158 int len = end - start;
162 /* First, check whether we need to append to an existing line or to
166 /* Create a new line. */
169 if (log_line_current == -1)
170 log_line_current = 0;
172 free_log_line (log_line_current);
173 ln = log_lines + log_line_current;
174 if (len > STATIC_LENGTH)
176 ln->malloced_line = strdupdelim (start, end);
177 ln->content = ln->malloced_line;
181 memcpy (ln->static_line, start, len);
182 ln->static_line[len] = '\0';
183 ln->content = ln->static_line;
188 /* Append to the last line. If the line is malloc'ed, we just
189 call realloc and append the new string. If the line is
190 static, we have to check whether appending the new string
191 would make it exceed STATIC_LENGTH characters, and if so,
192 convert it to malloc(). */
193 struct log_ln *ln = log_lines + log_line_current;
194 if (ln->malloced_line)
196 /* Resize malloc'ed line and append. */
197 int old_len = strlen (ln->malloced_line);
198 ln->malloced_line = xrealloc (ln->malloced_line, old_len + len + 1);
199 memcpy (ln->malloced_line + old_len, start, len);
200 ln->malloced_line[old_len + len] = '\0';
201 /* might have changed due to realloc */
202 ln->content = ln->malloced_line;
206 int old_len = strlen (ln->static_line);
207 if (old_len + len > STATIC_LENGTH)
209 /* Allocate memory and concatenate the old and the new
211 ln->malloced_line = xmalloc (old_len + len + 1);
212 memcpy (ln->malloced_line, ln->static_line,
214 memcpy (ln->malloced_line + old_len, start, len);
215 ln->malloced_line[old_len + len] = '\0';
216 ln->content = ln->malloced_line;
220 /* Just append to the old, statically allocated
222 memcpy (ln->static_line + old_len, start, len);
223 ln->static_line[old_len + len] = '\0';
224 ln->content = ln->static_line;
228 trailing_line = !(end[-1] == '\n');
230 ROT_ADVANCE (log_line_current);
233 /* Log the contents of S, as explained above. If S consists of
234 multiple lines, they are logged separately. If S does not end with
235 a newline, it will form a "trailing" line, to which things will get
236 appended the next time this function is called. */
239 saved_append (const char *s)
243 const char *end = strchr (s, '\n');
245 end = s + strlen (s);
248 saved_append_1 (s, end);
253 /* Check X against opt.verbose and opt.quiet. The semantics is as
256 * LOG_ALWAYS - print the message unconditionally;
258 * LOG_NOTQUIET - print the message if opt.quiet is non-zero;
260 * LOG_NONVERBOSE - print the message if opt.verbose is zero;
262 * LOG_VERBOSE - print the message if opt.verbose is non-zero. */
263 #define CHECK_VERBOSE(x) \
272 case LOG_NONVERBOSE: \
273 if (opt.verbose || opt.quiet) \
281 /* Returns the file descriptor for logging. This is LOGFP, except if
282 called before log_init, in which case it returns stderr. This is
283 useful in case someone calls a logging function before log_init.
285 If logging is inhibited, return NULL. */
297 /* Log a literal string S. The string is logged as-is, without a
301 logputs (enum log_options o, const char *s)
305 check_redirect_output ();
306 if ((fp = get_log_fp ()) == NULL)
316 needs_flushing = true;
319 struct logvprintf_state {
325 /* Print a message to the log. A copy of message will be saved to
326 saved_log, for later reusal by log_dump_context().
328 Normally we'd want this function to loop around vsnprintf until
329 sufficient room is allocated, as the Linux man page recommends.
330 However each call to vsnprintf() must be preceded by va_start and
331 followed by va_end. Since calling va_start/va_end is possible only
332 in the function that contains the `...' declaration, we cannot call
333 vsnprintf more than once. Therefore this function saves its state
334 to logvprintf_state and signals the parent to call it again.
336 (An alternative approach would be to use va_copy, but that's not
340 log_vprintf_internal (struct logvprintf_state *state, const char *fmt,
344 char *write_ptr = smallmsg;
345 int available_size = sizeof (smallmsg);
347 FILE *fp = get_log_fp ();
351 /* In the simple case just call vfprintf(), to avoid needless
352 allocation and games with vsnprintf(). */
353 vfprintf (fp, fmt, args);
357 if (state->allocated != 0)
359 write_ptr = state->bigmsg;
360 available_size = state->allocated;
363 /* The GNU coding standards advise not to rely on the return value
364 of sprintf(). However, vsnprintf() is a relatively new function
365 missing from legacy systems. Therefore I consider it safe to
366 assume that its return value is meaningful. On the systems where
367 vsnprintf() is not available, we use the implementation from
368 snprintf.c which does return the correct value. */
369 numwritten = vsnprintf (write_ptr, available_size, fmt, args);
371 /* vsnprintf() will not step over the limit given by available_size.
372 If it fails, it returns either -1 (older implementations) or the
373 number of characters (not counting the terminating \0) that
374 *would have* been written if there had been enough room (C99).
375 In the former case, we double available_size and malloc to get a
376 larger buffer, and try again. In the latter case, we use the
377 returned information to build a buffer of the correct size. */
379 if (numwritten == -1)
381 /* Writing failed, and we don't know the needed size. Try
382 again with doubled size. */
383 int newsize = available_size << 1;
384 state->bigmsg = xrealloc (state->bigmsg, newsize);
385 state->allocated = newsize;
388 else if (numwritten >= available_size)
390 /* Writing failed, but we know exactly how much space we
392 int newsize = numwritten + 1;
393 state->bigmsg = xrealloc (state->bigmsg, newsize);
394 state->allocated = newsize;
398 /* Writing succeeded. */
399 saved_append (write_ptr);
400 fputs (write_ptr, fp);
402 xfree (state->bigmsg);
408 needs_flushing = true;
413 /* Flush LOGFP. Useful while flushing is disabled. */
417 FILE *fp = get_log_fp ();
420 needs_flushing = false;
423 /* Enable or disable log flushing. */
425 log_set_flush (bool flush)
427 if (flush == flush_log_p)
432 /* Disable flushing by setting flush_log_p to 0. */
437 /* Reenable flushing. If anything was printed in no-flush mode,
438 flush the log now. */
445 /* (Temporarily) disable storing log to memory. Returns the old
446 status of storing, with which this function can be called again to
447 reestablish storing. */
450 log_set_save_context (bool savep)
452 bool old = save_context_p;
453 save_context_p = savep;
457 /* Print a message to the screen or to the log. The first argument
458 defines the verbosity of the message, and the rest are as in
462 logprintf (enum log_options o, const char *fmt, ...)
465 struct logvprintf_state lpstate;
468 check_redirect_output ();
476 va_start (args, fmt);
477 done = log_vprintf_internal (&lpstate, fmt, args);
484 /* The same as logprintf(), but does anything only if opt.debug is
487 debug_logprintf (const char *fmt, ...)
492 struct logvprintf_state lpstate;
495 check_redirect_output ();
502 va_start (args, fmt);
503 done = log_vprintf_internal (&lpstate, fmt, args);
509 #endif /* ENABLE_DEBUG */
511 /* Open FILE and set up a logging stream. If FILE cannot be opened,
512 exit with status of 1. */
514 log_init (const char *file, bool appendp)
518 logfp = fopen (file, appendp ? "a" : "w");
521 fprintf (stderr, "%s: %s: %s\n", exec_name, file, strerror (errno));
527 /* The log goes to stderr to avoid collisions with the output if
528 the user specifies `-O -'. #### Francois Pinard suggests
529 that it's a better idea to print to stdout by default, and to
530 stderr only if the user actually specifies `-O -'. He says
531 this inconsistency is harder to document, but is overall
532 easier on the user. */
537 && isatty (fileno (logfp))
541 /* If the output is a TTY, enable save context, i.e. store
542 the most recent several messages ("context") and dump
543 them to a log file in case SIGHUP or SIGUSR1 is received
544 (or Ctrl+Break is pressed under Windows). */
545 save_context_p = true;
550 /* Close LOGFP, inhibit further logging and free the memory associated
560 inhibit_logging = true;
561 save_context_p = false;
563 for (i = 0; i < SAVED_LOG_LINES; i++)
565 log_line_current = -1;
566 trailing_line = false;
569 /* Dump saved lines to logfp. */
571 log_dump_context (void)
573 int num = log_line_current;
574 FILE *fp = get_log_fp ();
584 struct log_ln *ln = log_lines + num;
586 fputs (ln->content, fp);
589 while (num != log_line_current);
591 if (log_lines[log_line_current].content)
592 fputs (log_lines[log_line_current].content, fp);
596 /* String escape functions. */
598 /* Return the number of non-printable characters in SOURCE.
599 Non-printable characters are determined as per c-ctype.c. */
602 count_nonprint (const char *source)
606 for (p = source, cnt = 0; *p; p++)
612 /* Copy SOURCE to DEST, escaping non-printable characters.
614 Non-printable refers to anything outside the non-control ASCII
615 range (32-126) which means that, for example, CR, LF, and TAB are
616 considered non-printable along with ESC, BS, and other control
617 chars. This is by design: it makes sure that messages from remote
618 servers cannot be easily used to deceive the users by mimicking
619 Wget's output. Disallowing non-ASCII characters is another
620 necessary security measure, which makes sure that remote servers
621 cannot garble the screen or guess the local charset and perform
624 Of course, the above mandates that escnonprint only be used in
625 contexts expected to be ASCII, such as when printing host names,
626 URL components, HTTP headers, FTP server messages, and the like.
628 ESCAPE is the leading character of the escape sequence. BASE
629 should be the base of the escape sequence, and must be either 8 for
632 DEST must point to a location with sufficient room to store an
633 encoded version of SOURCE. */
636 copy_and_escape (const char *source, char *dest, char escape, int base)
638 const char *from = source;
642 /* Copy chars from SOURCE to DEST, escaping non-printable ones. */
646 while ((c = *from++) != '\0')
652 *to++ = '0' + (c >> 6);
653 *to++ = '0' + ((c >> 3) & 7);
654 *to++ = '0' + (c & 7);
658 while ((c = *from++) != '\0')
664 *to++ = XNUM_TO_DIGIT (c >> 4);
665 *to++ = XNUM_TO_DIGIT (c & 0xf);
679 static struct ringel ring[RING_SIZE]; /* ring data */
682 escnonprint_internal (const char *str, char escape, int base)
684 static int ringpos; /* current ring position */
687 assert (base == 8 || base == 16);
689 nprcnt = count_nonprint (str);
691 /* If there are no non-printable chars in STR, don't bother
692 copying anything, just return STR. */
696 /* Set up a pointer to the current ring position, so we can write
697 simply r->X instead of ring[ringpos].X. */
698 struct ringel *r = ring + ringpos;
700 /* Every non-printable character is replaced with the escape char
701 and three (or two, depending on BASE) *additional* chars. Size
702 must also include the length of the original string and one
703 additional char for the terminating \0. */
704 int needed_size = strlen (str) + 1 + (base == 8 ? 3 * nprcnt : 2 * nprcnt);
706 /* If the current buffer is uninitialized or too small,
708 if (r->buffer == NULL || r->size < needed_size)
710 r->buffer = xrealloc (r->buffer, needed_size);
711 r->size = needed_size;
714 copy_and_escape (str, r->buffer, escape, base);
715 ringpos = (ringpos + 1) % RING_SIZE;
720 /* Return a pointer to a static copy of STR with the non-printable
721 characters escaped as \ooo. If there are no non-printable
722 characters in STR, STR is returned. See copy_and_escape for more
723 information on which characters are considered non-printable.
725 DON'T call this function on translated strings because escaping
726 will break them. Don't call it on literal strings from the source,
727 which are by definition trusted. If newlines are allowed in the
728 string, escape and print it line by line because escaping the whole
729 string will convert newlines to \012. (This is so that expectedly
730 single-line messages cannot use embedded newlines to mimic Wget's
731 output and deceive the user.)
733 escnonprint doesn't quote its escape character because it is notf
734 meant as a general and reversible quoting mechanism, but as a quick
735 way to defang binary junk sent by malicious or buggy servers.
737 NOTE: since this function can return a pointer to static data, be
738 careful to copy its result before calling it again. However, to be
739 more useful with printf, it maintains an internal ring of static
740 buffers to return. Currently the ring size is 3, which means you
741 can print up to three values in the same printf; if more is needed,
745 escnonprint (const char *str)
747 return escnonprint_internal (str, '\\', 8);
750 /* Return a pointer to a static copy of STR with the non-printable
751 characters escaped as %XX. If there are no non-printable
752 characters in STR, STR is returned.
754 See escnonprint for usage details. */
757 escnonprint_uri (const char *str)
759 return escnonprint_internal (str, '%', 16);
766 for (i = 0; i < countof (ring); i++)
767 xfree_null (ring[i].buffer);
770 /* When SIGHUP or SIGUSR1 are received, the output is redirected
771 elsewhere. Such redirection is only allowed once. */
772 static enum { RR_NONE, RR_REQUESTED, RR_DONE } redirect_request = RR_NONE;
773 static const char *redirect_request_signal_name;
775 /* Redirect output to `wget-log'. */
778 redirect_output (void)
781 logfp = unique_create (DEFAULT_LOGFILE, false, &logfile);
784 fprintf (stderr, _("\n%s received, redirecting output to `%s'.\n"),
785 redirect_request_signal_name, logfile);
787 /* Dump the context output to the newly opened log. */
792 /* Eek! Opening the alternate log file has failed. Nothing we
793 can do but disable printing completely. */
794 fprintf (stderr, _("\n%s received.\n"), redirect_request_signal_name);
795 fprintf (stderr, _("%s: %s; disabling logging.\n"),
796 logfile, strerror (errno));
797 inhibit_logging = true;
799 save_context_p = false;
802 /* Check whether a signal handler requested the output to be
806 check_redirect_output (void)
808 if (redirect_request == RR_REQUESTED)
810 redirect_request = RR_DONE;
815 /* Request redirection at a convenient time. This may be called from
819 log_request_redirect_output (const char *signal_name)
821 if (redirect_request == RR_NONE && save_context_p)
822 /* Request output redirection. The request will be processed by
823 check_redirect_output(), which is called from entry point log
825 redirect_request = RR_REQUESTED;
826 redirect_request_signal_name = signal_name;