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wget/src/log.c
2001-05-27 12:35:15 -07:00

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/* Messages logging.
Copyright (C) 1998, 2000 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. */
#include <config.h>
#include <stdio.h>
#ifdef HAVE_STRING_H
# include <string.h>
#else
# include <strings.h>
#endif
#include <stdlib.h>
#ifdef HAVE_STDARG_H
# define WGET_USE_STDARG
# include <stdarg.h>
#else
# include <varargs.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif
#include <assert.h>
#include <errno.h>
#include "wget.h"
#include "utils.h"
#ifndef errno
extern int errno;
#endif
/* The file descriptor used for logging. */
static FILE *logfp;
/* Whether logging is saved at all. */
int save_log_p;
/* 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 (80 chars
by default), a preallocated memory is used. The rare lines that
are longer than 80 characters are malloc'ed and freed separately.
This gives good performance with minimum memory consumption and
fragmentation. */
#define STATIC_LENGTH 80
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;
#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 = 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; \
}
#define CANONICALIZE_LOGFP_OR_RETURN do { \
if (logfp == stdin) \
return; \
else if (!logfp) \
/* This might happen if somebody calls a */ \
/* log* function before log_init(). */ \
logfp = stderr; \
} while (0)
/* Log a literal string S. The string is logged as-is, without a
newline appended. */
void
logputs (enum log_options o, const char *s)
{
CHECK_VERBOSE (o);
CANONICALIZE_LOGFP_OR_RETURN;
fputs (s, logfp);
if (!opt.no_flush)
fflush (logfp);
if (save_log_p)
saved_append (s);
}
/* Print a message to the log. A copy of message will be saved to
saved_log, for later reusal by log_dump(). */
static void
logvprintf (enum log_options o, const char *fmt, va_list args)
{
CHECK_VERBOSE (o);
CANONICALIZE_LOGFP_OR_RETURN;
/* Originally, we first used vfprintf(), and then checked whether
the message needs to be stored with vsprintf(). However, Watcom
C didn't like ARGS being used twice, so now we first vsprintf()
the message, and then fwrite() it to LOGFP. */
if (!save_log_p)
{
/* In the simple case just call vfprintf(), to avoid needless
allocation and games with vsnprintf(). */
vfprintf (logfp, fmt, args);
}
else
{
char smallmsg[128];
char *bigmsg = NULL;
int available_size = sizeof (smallmsg);
char *write_ptr = smallmsg;
while (1)
{
/* 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 it's
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. */
int 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. 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. */
available_size <<= 1;
bigmsg = xrealloc (bigmsg, available_size);
write_ptr = bigmsg;
}
else if (numwritten >= available_size)
{
/* Writing failed, but we know exactly how much space we
need. */
available_size = numwritten + 1;
bigmsg = xrealloc (bigmsg, available_size);
write_ptr = bigmsg;
}
else
{
/* Writing succeeded. */
break;
}
}
saved_append (write_ptr);
fputs (write_ptr, logfp);
if (bigmsg)
xfree (bigmsg);
}
if (!opt.no_flush)
fflush (logfp);
}
/* Flush LOGFP. */
void
logflush (void)
{
CANONICALIZE_LOGFP_OR_RETURN;
fflush (logfp);
}
/* Portability with pre-ANSI compilers makes these two functions look
like @#%#@$@#$. */
#ifdef WGET_USE_STDARG
void
logprintf (enum log_options o, const char *fmt, ...)
#else /* not WGET_USE_STDARG */
void
logprintf (va_alist)
va_dcl
#endif /* not WGET_USE_STDARG */
{
va_list args;
#ifndef WGET_USE_STDARG
enum log_options o;
const char *fmt;
#endif
#ifdef WGET_USE_STDARG
va_start (args, fmt);
#else
va_start (args);
o = va_arg (args, enum log_options);
fmt = va_arg (args, char *);
#endif
logvprintf (o, fmt, args);
va_end (args);
}
#ifdef DEBUG
/* The same as logprintf(), but does anything only if opt.debug is
non-zero. */
#ifdef WGET_USE_STDARG
void
debug_logprintf (const char *fmt, ...)
#else /* not WGET_USE_STDARG */
void
debug_logprintf (va_alist)
va_dcl
#endif /* not WGET_USE_STDARG */
{
if (opt.debug)
{
va_list args;
#ifndef WGET_USE_STDARG
const char *fmt;
#endif
#ifdef WGET_USE_STDARG
va_start (args, fmt);
#else
va_start (args);
fmt = va_arg (args, char *);
#endif
logvprintf (LOG_ALWAYS, fmt, args);
va_end (args);
}
}
#endif /* 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)
{
perror (opt.lfilename);
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 the output is a TTY, enable logging, which will make Wget
remember all the printed messages, to be able to dump them to
a log file in case SIGHUP or SIGUSR1 is received (or
Ctrl+Break is pressed under Windows). */
if (1
#ifdef HAVE_ISATTY
&& isatty (fileno (logfp))
#endif
)
{
save_log_p = 1;
}
}
}
/* Close LOGFP, inhibit further logging and free the memory associated
with it. */
void
log_close (void)
{
int i;
if (logfp != stdin)
fclose (logfp);
save_log_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 (void)
{
int num = log_line_current;
FILE *fp = logfp;
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);
}
/* Redirect output to `wget-log'. MESSIJ is printed on stdout, and
should contain *exactly one* `%s', which will be replaced by the
log file name.
If logging was not enabled, MESSIJ will not be printed. */
void
redirect_output (const char *messij)
{
char *logfile;
if (!save_log_p)
return;
logfile = unique_name (DEFAULT_LOGFILE);
logfp = fopen (logfile, "w");
if (!logfp)
{
/* Eek! Opening the alternate log file has failed. Nothing we
can do but disable printing completely. */
fprintf (stderr, "%s: %s: %s\n", exec_name, logfile, strerror (errno));
/* `stdin' is magic to not print anything, ever. */
logfp = stdin;
}
fprintf (stderr, messij, logfile);
xfree (logfile);
/* Dump the previous screenful of output to LOGFILE. */
log_dump ();
save_log_p = 0;
}