/* Messages logging. Copyright (C) 2005 Free Software Foundation, Inc. This file is part of GNU Wget. GNU Wget is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. GNU Wget is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with Wget; if not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. In addition, as a special exception, the Free Software Foundation gives permission to link the code of its release of Wget with the OpenSSL project's "OpenSSL" library (or with modified versions of it that use the same license as the "OpenSSL" library), and distribute the linked executables. You must obey the GNU General Public License in all respects for all of the code used other than "OpenSSL". If you modify this file, you may extend this exception to your version of the file, but you are not obligated to do so. If you do not wish to do so, delete this exception statement from your version. */ #include #include #ifdef HAVE_STRING_H # include #else # include #endif #include #ifdef WGET_USE_STDARG # include #else # include #endif #ifdef HAVE_UNISTD_H # include #endif #include #include #include "wget.h" #include "utils.h" #include "log.h" #ifndef errno extern int errno; #endif /* This file impplement support for "logging". Logging means printing output, plus several additional features: - Cataloguing output by importance. You can specify that a log message is "verbose" or "debug", and it will not be printed unless in verbose or debug mode, respectively. - Redirecting the log to the file. When Wget's output goes to the terminal, and Wget receives SIGHUP, all further output is redirected to a log file. When this is the case, Wget can also print the last several lines of "context" to the log file so that it does not begin in the middle of a line. For this to work, the logging code stores the last several lines of context. Callers may request for certain output not to be stored. - Inhibiting output. When Wget receives SIGHUP, but redirecting the output fails, logging is inhibited. */ /* The file descriptor used for logging. This is NULL before log_init is called; logging functions log to stderr then. log_init sets it either to stderr or to a file pointer obtained from fopen(). If logging is inhibited, logfp is set back to NULL. */ static FILE *logfp; /* If non-zero, it means logging is inhibited, i.e. nothing is printed or stored. */ static int inhibit_logging; /* Whether the last output lines are stored for use as context. */ static int save_context_p; /* Whether the log is flushed after each command. */ static int flush_log_p = 1; /* Whether any output has been received while flush_log_p was 0. */ static int needs_flushing; /* In the event of a hang-up, and if its output was on a TTY, Wget redirects its output to `wget-log'. For the convenience of reading this newly-created log, we store the last several lines ("screenful", hence the choice of 24) of Wget output, and dump them as context when the time comes. */ #define SAVED_LOG_LINES 24 /* log_lines is a circular buffer that stores SAVED_LOG_LINES lines of output. log_line_current always points to the position in the buffer that will be written to next. When log_line_current reaches SAVED_LOG_LINES, it is reset to zero. The problem here is that we'd have to either (re)allocate and free strings all the time, or limit the lines to an arbitrary number of characters. Instead of settling for either of these, we do both: if the line is smaller than a certain "usual" line length (128 chars by default), a preallocated memory is used. The rare lines that are longer than 128 characters are malloc'ed and freed separately. This gives good performance with minimum memory consumption and fragmentation. */ #define STATIC_LENGTH 128 static struct log_ln { char static_line[STATIC_LENGTH + 1]; /* statically allocated line. */ char *malloced_line; /* malloc'ed line, for lines of output larger than 80 characters. */ char *content; /* this points either to malloced_line or to the appropriate static_line. If this is NULL, it means the line has not yet been used. */ } log_lines[SAVED_LOG_LINES]; /* The current position in the ring. */ static int log_line_current = -1; /* Whether the most recently written line was "trailing", i.e. did not finish with \n. This is an important piece of information because the code is always careful to append data to trailing lines, rather than create new ones. */ static int trailing_line; static void check_redirect_output PARAMS ((void)); #define ROT_ADVANCE(num) do { \ if (++num >= SAVED_LOG_LINES) \ num = 0; \ } while (0) /* Free the log line index with NUM. This calls free on ln->malloced_line if it's non-NULL, and it also resets ln->malloced_line and ln->content to NULL. */ static void free_log_line (int num) { struct log_ln *ln = log_lines + num; if (ln->malloced_line) { xfree (ln->malloced_line); ln->malloced_line = NULL; } ln->content = NULL; } /* Append bytes in the range [start, end) to one line in the log. The region is not supposed to contain newlines, except for the last character (at end[-1]). */ static void saved_append_1 (const char *start, const char *end) { int len = end - start; if (!len) return; /* First, check whether we need to append to an existing line or to create a new one. */ if (!trailing_line) { /* Create a new line. */ struct log_ln *ln; if (log_line_current == -1) log_line_current = 0; else free_log_line (log_line_current); ln = log_lines + log_line_current; if (len > STATIC_LENGTH) { ln->malloced_line = strdupdelim (start, end); ln->content = ln->malloced_line; } else { memcpy (ln->static_line, start, len); ln->static_line[len] = '\0'; ln->content = ln->static_line; } } else { /* Append to the last line. If the line is malloc'ed, we just call realloc and append the new string. If the line is static, we have to check whether appending the new string would make it exceed STATIC_LENGTH characters, and if so, convert it to malloc(). */ struct log_ln *ln = log_lines + log_line_current; if (ln->malloced_line) { /* Resize malloc'ed line and append. */ int old_len = strlen (ln->malloced_line); ln->malloced_line = xrealloc (ln->malloced_line, old_len + len + 1); memcpy (ln->malloced_line + old_len, start, len); ln->malloced_line[old_len + len] = '\0'; /* might have changed due to realloc */ ln->content = ln->malloced_line; } else { int old_len = strlen (ln->static_line); if (old_len + len > STATIC_LENGTH) { /* Allocate memory and concatenate the old and the new contents. */ ln->malloced_line = (char *)xmalloc (old_len + len + 1); memcpy (ln->malloced_line, ln->static_line, old_len); memcpy (ln->malloced_line + old_len, start, len); ln->malloced_line[old_len + len] = '\0'; ln->content = ln->malloced_line; } else { /* Just append to the old, statically allocated contents. */ memcpy (ln->static_line + old_len, start, len); ln->static_line[old_len + len] = '\0'; ln->content = ln->static_line; } } } trailing_line = !(end[-1] == '\n'); if (!trailing_line) ROT_ADVANCE (log_line_current); } /* Log the contents of S, as explained above. If S consists of multiple lines, they are logged separately. If S does not end with a newline, it will form a "trailing" line, to which things will get appended the next time this function is called. */ static void saved_append (const char *s) { while (*s) { const char *end = strchr (s, '\n'); if (!end) end = s + strlen (s); else ++end; saved_append_1 (s, end); s = end; } } /* Check X against opt.verbose and opt.quiet. The semantics is as follows: * LOG_ALWAYS - print the message unconditionally; * LOG_NOTQUIET - print the message if opt.quiet is non-zero; * LOG_NONVERBOSE - print the message if opt.verbose is zero; * LOG_VERBOSE - print the message if opt.verbose is non-zero. */ #define CHECK_VERBOSE(x) \ switch (x) \ { \ case LOG_ALWAYS: \ break; \ case LOG_NOTQUIET: \ if (opt.quiet) \ return; \ break; \ case LOG_NONVERBOSE: \ if (opt.verbose || opt.quiet) \ return; \ break; \ case LOG_VERBOSE: \ if (!opt.verbose) \ return; \ } /* Returns the file descriptor for logging. This is LOGFP, except if called before log_init, in which case it returns stderr. This is useful in case someone calls a logging function before log_init. If logging is inhibited, return NULL. */ static FILE * get_log_fp (void) { if (inhibit_logging) return NULL; if (logfp) return logfp; return stderr; } /* Log a literal string S. The string is logged as-is, without a newline appended. */ void logputs (enum log_options o, const char *s) { FILE *fp; check_redirect_output (); if ((fp = get_log_fp ()) == NULL) return; CHECK_VERBOSE (o); fputs (s, fp); if (save_context_p) saved_append (s); if (flush_log_p) logflush (); else needs_flushing = 1; } struct logvprintf_state { char *bigmsg; int expected_size; int allocated; }; /* Print a message to the log. A copy of message will be saved to saved_log, for later reusal by log_dump_context(). Normally we'd want this function to loop around vsnprintf until sufficient room is allocated, as the Linux man page recommends. However each call to vsnprintf() must be preceded by va_start and followed by va_end. Since calling va_start/va_end is possible only in the function that contains the `...' declaration, we cannot call vsnprintf more than once. Therefore this function saves its state to logvprintf_state and signals the parent to call it again. (An alternative approach would be to use va_copy, but that's not portable.) */ static int log_vprintf_internal (struct logvprintf_state *state, const char *fmt, va_list args) { char smallmsg[128]; char *write_ptr = smallmsg; int available_size = sizeof (smallmsg); int numwritten; FILE *fp = get_log_fp (); if (!save_context_p) { /* In the simple case just call vfprintf(), to avoid needless allocation and games with vsnprintf(). */ vfprintf (fp, fmt, args); goto flush; } if (state->allocated != 0) { write_ptr = state->bigmsg; available_size = state->allocated; } /* The GNU coding standards advise not to rely on the return value of sprintf(). However, vsnprintf() is a relatively new function missing from legacy systems. Therefore I consider it safe to assume that its return value is meaningful. On the systems where vsnprintf() is not available, we use the implementation from snprintf.c which does return the correct value. */ numwritten = vsnprintf (write_ptr, available_size, fmt, args); /* vsnprintf() will not step over the limit given by available_size. If it fails, it will return either -1 (POSIX?) or the number of characters that *would have* been written, if there had been enough room (C99). In the former case, we double the available_size and malloc to get a larger buffer, and try again. In the latter case, we use the returned information to build a buffer of the correct size. */ if (numwritten == -1) { /* Writing failed, and we don't know the needed size. Try again with doubled size. */ int newsize = available_size << 1; state->bigmsg = xrealloc (state->bigmsg, newsize); state->allocated = newsize; return 0; } else if (numwritten >= available_size) { /* Writing failed, but we know exactly how much space we need. */ int newsize = numwritten + 1; state->bigmsg = xrealloc (state->bigmsg, newsize); state->allocated = newsize; return 0; } /* Writing succeeded. */ saved_append (write_ptr); fputs (write_ptr, fp); if (state->bigmsg) xfree (state->bigmsg); flush: if (flush_log_p) logflush (); else needs_flushing = 1; return 1; } /* Flush LOGFP. Useful while flushing is disabled. */ void logflush (void) { FILE *fp = get_log_fp (); if (fp) fflush (fp); needs_flushing = 0; } /* Enable or disable log flushing. */ void log_set_flush (int flush) { if (flush == flush_log_p) return; if (flush == 0) { /* Disable flushing by setting flush_log_p to 0. */ flush_log_p = 0; } else { /* Reenable flushing. If anything was printed in no-flush mode, flush the log now. */ if (needs_flushing) logflush (); flush_log_p = 1; } } /* (Temporarily) disable storing log to memory. Returns the old status of storing, with which this function can be called again to reestablish storing. */ int log_set_save_context (int savep) { int old = save_context_p; save_context_p = savep; return old; } /* Handle difference in va_start between pre-ANSI and ANSI C. Note that we always use `...' in function definitions and let ansi2knr convert it for us. */ #ifdef WGET_USE_STDARG # define VA_START(args, arg1) va_start (args, arg1) #else # define VA_START(args, ignored) va_start (args) #endif /* Print a message to the screen or to the log. The first argument defines the verbosity of the message, and the rest are as in printf(3). */ void logprintf (enum log_options o, const char *fmt, ...) { va_list args; struct logvprintf_state lpstate; int done; check_redirect_output (); if (inhibit_logging) return; CHECK_VERBOSE (o); xzero (lpstate); do { VA_START (args, fmt); done = log_vprintf_internal (&lpstate, fmt, args); va_end (args); } while (!done); } #ifdef ENABLE_DEBUG /* The same as logprintf(), but does anything only if opt.debug is non-zero. */ void debug_logprintf (const char *fmt, ...) { if (opt.debug) { va_list args; struct logvprintf_state lpstate; int done; check_redirect_output (); if (inhibit_logging) return; xzero (lpstate); do { VA_START (args, fmt); done = log_vprintf_internal (&lpstate, fmt, args); va_end (args); } while (!done); } } #endif /* ENABLE_DEBUG */ /* Open FILE and set up a logging stream. If FILE cannot be opened, exit with status of 1. */ void log_init (const char *file, int appendp) { if (file) { logfp = fopen (file, appendp ? "a" : "w"); if (!logfp) { fprintf (stderr, "%s: %s: %s\n", exec_name, file, strerror (errno)); exit (1); } } else { /* The log goes to stderr to avoid collisions with the output if the user specifies `-O -'. #### Francois Pinard suggests that it's a better idea to print to stdout by default, and to stderr only if the user actually specifies `-O -'. He says this inconsistency is harder to document, but is overall easier on the user. */ logfp = stderr; if (1 #ifdef HAVE_ISATTY && isatty (fileno (logfp)) #endif ) { /* If the output is a TTY, enable save context, i.e. store the most recent several messages ("context") and dump them to a log file in case SIGHUP or SIGUSR1 is received (or Ctrl+Break is pressed under Windows). */ save_context_p = 1; } } } /* Close LOGFP, inhibit further logging and free the memory associated with it. */ void log_close (void) { int i; if (logfp) fclose (logfp); logfp = NULL; inhibit_logging = 1; save_context_p = 0; for (i = 0; i < SAVED_LOG_LINES; i++) free_log_line (i); log_line_current = -1; trailing_line = 0; } /* Dump saved lines to logfp. */ static void log_dump_context (void) { int num = log_line_current; FILE *fp = get_log_fp (); if (!fp) return; if (num == -1) return; if (trailing_line) ROT_ADVANCE (num); do { struct log_ln *ln = log_lines + num; if (ln->content) fputs (ln->content, fp); ROT_ADVANCE (num); } while (num != log_line_current); if (trailing_line) if (log_lines[log_line_current].content) fputs (log_lines[log_line_current].content, fp); fflush (fp); } /* String escape functions. */ /* Return the number of non-printable characters in SOURCE. Non-printable characters are determined as per safe-ctype.c. */ static int count_nonprint (const char *source) { const char *p; int cnt; for (p = source, cnt = 0; *p; p++) if (!ISPRINT (*p)) ++cnt; return cnt; } /* Copy SOURCE to DEST, escaping non-printable characters. Non-printable refers to anything outside the non-control ASCII range (32-126) which means that, for example, CR, LF, and TAB are considered non-printable along with ESC, BS, and other control chars. This is by design: it makes sure that messages from remote servers cannot be easily used to deceive the users by mimicking Wget's output. Disallowing non-ASCII characters is another necessary security measure, which makes sure that remote servers cannot garble the screen or guess the local charset and perform homographic attacks. Of course, the above mandates that escnonprint only be used in contexts expected to be ASCII, such as when printing host names, URL components, HTTP headers, FTP server messages, and the like. ESCAPE is the leading character of the escape sequence. BASE should be the base of the escape sequence, and must be either 8 for octal or 16 for hex. DEST must point to a location with sufficient room to store an encoded version of SOURCE. */ static void copy_and_escape (const char *source, char *dest, char escape, int base) { const char *from = source; char *to = dest; unsigned char c; /* Copy chars from SOURCE to DEST, escaping non-printable ones. */ switch (base) { case 8: while ((c = *from++) != '\0') if (ISPRINT (c)) *to++ = c; else { *to++ = escape; *to++ = '0' + (c >> 6); *to++ = '0' + ((c >> 3) & 7); *to++ = '0' + (c & 7); } break; case 16: while ((c = *from++) != '\0') if (ISPRINT (c)) *to++ = c; else { *to++ = escape; *to++ = XNUM_TO_DIGIT (c >> 4); *to++ = XNUM_TO_DIGIT (c & 0xf); } break; default: abort (); } *to = '\0'; } #define RING_SIZE 3 struct ringel { char *buffer; int size; }; static struct ringel ring[RING_SIZE]; /* ring data */ static const char * escnonprint_internal (const char *str, char escape, int base) { static int ringpos; /* current ring position */ int nprcnt; assert (base == 8 || base == 16); nprcnt = count_nonprint (str); if (nprcnt == 0) /* If there are no non-printable chars in STR, don't bother copying anything, just return STR. */ return str; { /* Set up a pointer to the current ring position, so we can write simply r->X instead of ring[ringpos].X. */ struct ringel *r = ring + ringpos; /* Every non-printable character is replaced with the escape char and three (or two, depending on BASE) *additional* chars. Size must also include the length of the original string and one additional char for the terminating \0. */ int needed_size = strlen (str) + 1 + (base == 8 ? 3 * nprcnt : 2 * nprcnt); /* If the current buffer is uninitialized or too small, (re)allocate it. */ if (r->buffer == NULL || r->size < needed_size) { r->buffer = xrealloc (r->buffer, needed_size); r->size = needed_size; } copy_and_escape (str, r->buffer, escape, base); ringpos = (ringpos + 1) % RING_SIZE; return r->buffer; } } /* Return a pointer to a static copy of STR with the non-printable characters escaped as \ooo. If there are no non-printable characters in STR, STR is returned. See copy_and_escape for more information on which characters are considered non-printable. DON'T call this function on translated strings because escaping will break them. Don't call it on literal strings from the source, which are by definition trusted. If newlines are allowed in the string, escape and print it line by line because escaping the whole string will convert newlines to \012. (This is so that expectedly single-line messages cannot use embedded newlines to mimic Wget's output and deceive the user.) escnonprint doesn't quote its escape character because it is notf meant as a general and reversible quoting mechanism, but as a quick way to defang binary junk sent by malicious or buggy servers. NOTE: since this function can return a pointer to static data, be careful to copy its result before calling it again. However, to be more useful with printf, it maintains an internal ring of static buffers to return. Currently the ring size is 3, which means you can print up to three values in the same printf; if more is needed, bump RING_SIZE. */ const char * escnonprint (const char *str) { return escnonprint_internal (str, '\\', 8); } /* Return a pointer to a static copy of STR with the non-printable characters escaped as %XX. If there are no non-printable characters in STR, STR is returned. See escnonprint for usage details. */ const char * escnonprint_uri (const char *str) { return escnonprint_internal (str, '%', 16); } void log_cleanup (void) { int i; for (i = 0; i < countof (ring); i++) xfree_null (ring[i].buffer); } /* When SIGHUP or SIGUSR1 are received, the output is redirected elsewhere. Such redirection is only allowed once. */ enum { RR_NONE, RR_REQUESTED, RR_DONE } redirect_request = RR_NONE; static const char *redirect_request_signal_name; /* Redirect output to `wget-log'. */ static void redirect_output (void) { char *logfile; logfp = unique_create (DEFAULT_LOGFILE, 0, &logfile); if (logfp) { fprintf (stderr, _("\n%s received, redirecting output to `%s'.\n"), redirect_request_signal_name, logfile); xfree (logfile); /* Dump the context output to the newly opened log. */ log_dump_context (); } else { /* Eek! Opening the alternate log file has failed. Nothing we can do but disable printing completely. */ fprintf (stderr, _("\n%s received.\n"), redirect_request_signal_name); fprintf (stderr, _("%s: %s; disabling logging.\n"), logfile, strerror (errno)); inhibit_logging = 1; } save_context_p = 0; } /* Check whether a signal handler requested the output to be redirected. */ static void check_redirect_output (void) { if (redirect_request == RR_REQUESTED) { redirect_request = RR_DONE; redirect_output (); } } /* Request redirection at a convenient time. This may be called from a signal handler. */ void log_request_redirect_output (const char *signal_name) { if (redirect_request == RR_NONE && save_context_p) /* Request output redirection. The request will be processed by check_redirect_output(), which is called from entry point log functions. */ redirect_request = RR_REQUESTED; redirect_request_signal_name = signal_name; }