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 /* Get a trace file descriptor from GIT_TRACE env variable. */
  29 static int get_trace_fd(int *need_close)
  30 {
  31         char *trace = getenv("GIT_TRACE");
  32
  33         if (!trace || !strcmp(trace, "") ||
  34             !strcmp(trace, "0") || !strcasecmp(trace, "false"))
  35                 return 0;
  36         if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
  37                 return STDERR_FILENO;
  38         if (strlen(trace) == 1 && isdigit(*trace))
  39                 return atoi(trace);
  40         if (is_absolute_path(trace)) {
  41                 int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
  42                 if (fd == -1) {
  43                         fprintf(stderr,
  44                                 "Could not open '%s' for tracing: %s\n"
  45                                 "Defaulting to tracing on stderr...\n",
  46                                 trace, strerror(errno));
  47                         return STDERR_FILENO;
  48                 }
  49                 *need_close = 1;
  50                 return fd;
  51         }
  52
  53         fprintf(stderr, "What does '%s' for GIT_TRACE mean?\n", trace);
  54         fprintf(stderr, "If you want to trace into a file, "
  55                 "then please set GIT_TRACE to an absolute pathname "
  56                 "(starting with /).\n");
  57         fprintf(stderr, "Defaulting to tracing on stderr...\n");
  58
  59         return STDERR_FILENO;
  60 }
  61
  62 static const char err_msg[] = "Could not trace into fd given by "
  63         "GIT_TRACE environment variable";
  64
  65 void trace_printf(const char *fmt, ...)
  66 {
  67         struct strbuf buf;
  68         va_list ap;
  69         int fd, len, need_close = 0;
  70
  71         fd = get_trace_fd(&need_close);
  72         if (!fd)
  73                 return;
  74
  75         strbuf_init(&buf, 64);
  76         va_start(ap, fmt);
  77         len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
  78         va_end(ap);
  79         if (len >= strbuf_avail(&buf)) {
  80                 strbuf_grow(&buf, len - strbuf_avail(&buf) + 128);
  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                         die("broken vsnprintf");
  86         }
  87         strbuf_setlen(&buf, len);
  88
  89         write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
  90         strbuf_release(&buf);
  91
  92         if (need_close)
  93                 close(fd);
  94 }
  95
  96 void trace_argv_printf(const char **argv, const char *fmt, ...)
  97 {
  98         struct strbuf buf;
  99         va_list ap;
 100         int fd, len, need_close = 0;
 101
 102         fd = get_trace_fd(&need_close);
 103         if (!fd)
 104                 return;
 105
 106         strbuf_init(&buf, 64);
 107         va_start(ap, fmt);
 108         len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
 109         va_end(ap);
 110         if (len >= strbuf_avail(&buf)) {
 111                 strbuf_grow(&buf, len - strbuf_avail(&buf) + 128);
 112                 va_start(ap, fmt);
 113                 len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
 114                 va_end(ap);
 115                 if (len >= strbuf_avail(&buf))
 116                         die("broken vsnprintf");
 117         }
 118         strbuf_setlen(&buf, len);
 119
 120         sq_quote_argv(&buf, argv, 0);
 121         strbuf_addch(&buf, '\n');
 122         write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
 123         strbuf_release(&buf);
 124
 125         if (need_close)
 126                 close(fd);
 127 }