trace.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
   5  * Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
   6  * Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
   7  * Copyright (C) 2006 Mike McCormack
   8  * Copyright (C) 2006 Christian Couder
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #include "cache.h"
  26 #include "quote.h"
  27
  28 static void do_nothing(size_t unused)
  29 {
  30 }
  31
  32 /* Get a trace file descriptor from GIT_TRACE env variable. */
  33 static int get_trace_fd(int *need_close)
  34 {
  35         char *trace = getenv("GIT_TRACE");
  36
  37         if (!trace || !strcmp(trace, "") ||
  38             !strcmp(trace, "0") || !strcasecmp(trace, "false"))
  39                 return 0;
  40         if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
  41                 return STDERR_FILENO;
  42         if (strlen(trace) == 1 && isdigit(*trace))
  43                 return atoi(trace);
  44         if (is_absolute_path(trace)) {
  45                 int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
  46                 if (fd == -1) {
  47                         fprintf(stderr,
  48                                 "Could not open '%s' for tracing: %s\n"
  49                                 "Defaulting to tracing on stderr...\n",
  50                                 trace, strerror(errno));
  51                         return STDERR_FILENO;
  52                 }
  53                 *need_close = 1;
  54                 return fd;
  55         }
  56
  57         fprintf(stderr, "What does '%s' for GIT_TRACE mean?\n", trace);
  58         fprintf(stderr, "If you want to trace into a file, "
  59                 "then please set GIT_TRACE to an absolute pathname "
  60                 "(starting with /).\n");
  61         fprintf(stderr, "Defaulting to tracing on stderr...\n");
  62
  63         return STDERR_FILENO;
  64 }
  65
  66 static const char err_msg[] = "Could not trace into fd given by "
  67         "GIT_TRACE environment variable";
  68
  69 void trace_printf(const char *fmt, ...)
  70 {
  71         struct strbuf buf;
  72         va_list ap;
  73         int fd, len, need_close = 0;
  74
  75         fd = get_trace_fd(&need_close);
  76         if (!fd)
  77                 return;
  78
  79         set_try_to_free_routine(do_nothing);    /* is never reset */
  80         strbuf_init(&buf, 64);
  81         va_start(ap, fmt);
  82         len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
  83         va_end(ap);
  84         if (len >= strbuf_avail(&buf)) {
  85                 strbuf_grow(&buf, len - strbuf_avail(&buf) + 128);
  86                 va_start(ap, fmt);
  87                 len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
  88                 va_end(ap);
  89                 if (len >= strbuf_avail(&buf))
  90                         die("broken vsnprintf");
  91         }
  92         strbuf_setlen(&buf, len);
  93
  94         write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
  95         strbuf_release(&buf);
  96
  97         if (need_close)
  98                 close(fd);
  99 }
 100
 101 void trace_argv_printf(const char **argv, const char *fmt, ...)
 102 {
 103         struct strbuf buf;
 104         va_list ap;
 105         int fd, len, need_close = 0;
 106
 107         fd = get_trace_fd(&need_close);
 108         if (!fd)
 109                 return;
 110
 111         set_try_to_free_routine(do_nothing);    /* is never reset */
 112         strbuf_init(&buf, 64);
 113         va_start(ap, fmt);
 114         len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
 115         va_end(ap);
 116         if (len >= strbuf_avail(&buf)) {
 117                 strbuf_grow(&buf, len - strbuf_avail(&buf) + 128);
 118                 va_start(ap, fmt);
 119                 len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
 120                 va_end(ap);
 121                 if (len >= strbuf_avail(&buf))
 122                         die("broken vsnprintf");
 123         }
 124         strbuf_setlen(&buf, len);
 125
 126         sq_quote_argv(&buf, argv, 0);
 127         strbuf_addch(&buf, '\n');
 128         write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
 129         strbuf_release(&buf);
 130
 131         if (need_close)
 132                 close(fd);
 133 }