git/trace.c
Shawn O. Pearce f141bd804d Handle broken vsnprintf implementations in strbuf
Solaris 9's vsnprintf implementation returns -1 if we pass it a
buffer of length 0.  The only way to get it to give us the actual
length necessary for the formatted string is to grow the buffer
out to have at least 1 byte available in the strbuf and then ask
it to compute the length.

If the available space is 0 I'm growing it out by 64 to ensure
we will get an accurate length estimate from all implementations.
Some callers may need to grow the strbuf again but 64 should be a
reasonable enough initial growth.

We also no longer silently fail to append to the string when we are
faced with a broken vsnprintf implementation.  On Solaris 9 this
silent failure caused me to no longer be able to execute "git clone"
as we tried to exec the empty string rather than "git-clone".

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-11-14 02:00:13 -08:00

128 lines
3.5 KiB
C

/*
* GIT - The information manager from hell
*
* Copyright (C) 2000-2002 Michael R. Elkins <me@mutt.org>
* Copyright (C) 2002-2004 Oswald Buddenhagen <ossi@users.sf.net>
* Copyright (C) 2004 Theodore Y. Ts'o <tytso@mit.edu>
* Copyright (C) 2006 Mike McCormack
* Copyright (C) 2006 Christian Couder
*
* This program 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.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "cache.h"
#include "quote.h"
/* Get a trace file descriptor from GIT_TRACE env variable. */
static int get_trace_fd(int *need_close)
{
char *trace = getenv("GIT_TRACE");
if (!trace || !strcmp(trace, "") ||
!strcmp(trace, "0") || !strcasecmp(trace, "false"))
return 0;
if (!strcmp(trace, "1") || !strcasecmp(trace, "true"))
return STDERR_FILENO;
if (strlen(trace) == 1 && isdigit(*trace))
return atoi(trace);
if (*trace == '/') {
int fd = open(trace, O_WRONLY | O_APPEND | O_CREAT, 0666);
if (fd == -1) {
fprintf(stderr,
"Could not open '%s' for tracing: %s\n"
"Defaulting to tracing on stderr...\n",
trace, strerror(errno));
return STDERR_FILENO;
}
*need_close = 1;
return fd;
}
fprintf(stderr, "What does '%s' for GIT_TRACE means ?\n", trace);
fprintf(stderr, "If you want to trace into a file, "
"then please set GIT_TRACE to an absolute pathname "
"(starting with /).\n");
fprintf(stderr, "Defaulting to tracing on stderr...\n");
return STDERR_FILENO;
}
static const char err_msg[] = "Could not trace into fd given by "
"GIT_TRACE environment variable";
void trace_printf(const char *fmt, ...)
{
struct strbuf buf;
va_list ap;
int fd, len, need_close = 0;
fd = get_trace_fd(&need_close);
if (!fd)
return;
strbuf_init(&buf, 64);
va_start(ap, fmt);
len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
va_end(ap);
if (len >= strbuf_avail(&buf)) {
strbuf_grow(&buf, len - strbuf_avail(&buf) + 128);
va_start(ap, fmt);
len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
va_end(ap);
if (len >= strbuf_avail(&buf))
die("broken vsnprintf");
}
strbuf_setlen(&buf, len);
write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
strbuf_release(&buf);
if (need_close)
close(fd);
}
void trace_argv_printf(const char **argv, int count, const char *fmt, ...)
{
struct strbuf buf;
va_list ap;
int fd, len, need_close = 0;
fd = get_trace_fd(&need_close);
if (!fd)
return;
strbuf_init(&buf, 64);
va_start(ap, fmt);
len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
va_end(ap);
if (len >= strbuf_avail(&buf)) {
strbuf_grow(&buf, len - strbuf_avail(&buf) + 128);
va_start(ap, fmt);
len = vsnprintf(buf.buf, strbuf_avail(&buf), fmt, ap);
va_end(ap);
if (len >= strbuf_avail(&buf))
die("broken vsnprintf");
}
strbuf_setlen(&buf, len);
sq_quote_argv(&buf, argv, count, 0);
strbuf_addch(&buf, '\n');
write_or_whine_pipe(fd, buf.buf, buf.len, err_msg);
strbuf_release(&buf);
if (need_close)
close(fd);
}