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Revision 56d7c27af1f8aa7519f165f6c022732e64db3716 authored by Jeff King on 26 May 2011, 16:30:27 UTC, committed by Junio C Hamano on 26 May 2011, 20:54:18 UTC 
read_in_full: always report errors
 
The read_in_full function repeatedly calls read() to fill a
buffer. If the first read() returns an error, we notify the
caller by returning the error. However, if we read some data
and then get an error on a subsequent read, we simply return
the amount of data that we did read, and the caller is
unaware of the error.

This makes the tradeoff that seeing the partial data is more
important than the fact that an error occurred. In practice,
this is generally not the case; we care more if an error
occurred, and should throw away any partial data.

I audited the current callers. In most cases, this will make
no difference at all, as they do:

  if (read_in_full(fd, buf, size) != size)
	  error("short read");

However, it will help in a few cases:

  1. In sha1_file.c:index_stream, we would fail to notice
     errors in the incoming stream.

  2. When reading symbolic refs in resolve_ref, we would
     fail to notice errors and potentially use a truncated
     ref name.

  3. In various places, we will get much better error
     messages. For example, callers of safe_read would
     erroneously print "the remote end hung up unexpectedly"
     instead of showing the read error.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 09ffc70
Raw File
usage.c 
/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#include "git-compat-util.h"

void vreportf(const char *prefix, const char *err, va_list params)
{
	char msg[4096];
	vsnprintf(msg, sizeof(msg), err, params);
	fprintf(stderr, "%s%s\n", prefix, msg);
}

static NORETURN void usage_builtin(const char *err, va_list params)
{
	vreportf("usage: ", err, params);
	exit(129);
}

static NORETURN void die_builtin(const char *err, va_list params)
{
	vreportf("fatal: ", err, params);
	exit(128);
}

static void error_builtin(const char *err, va_list params)
{
	vreportf("error: ", err, params);
}

static void warn_builtin(const char *warn, va_list params)
{
	vreportf("warning: ", warn, params);
}

/* If we are in a dlopen()ed .so write to a global variable would segfault
 * (ugh), so keep things static. */
static NORETURN_PTR void (*usage_routine)(const char *err, va_list params) = usage_builtin;
static NORETURN_PTR void (*die_routine)(const char *err, va_list params) = die_builtin;
static void (*error_routine)(const char *err, va_list params) = error_builtin;
static void (*warn_routine)(const char *err, va_list params) = warn_builtin;

void set_die_routine(NORETURN_PTR void (*routine)(const char *err, va_list params))
{
	die_routine = routine;
}

void NORETURN usagef(const char *err, ...)
{
	va_list params;

	va_start(params, err);
	usage_routine(err, params);
	va_end(params);
}

void NORETURN usage(const char *err)
{
	usagef("%s", err);
}

void NORETURN die(const char *err, ...)
{
	va_list params;

	va_start(params, err);
	die_routine(err, params);
	va_end(params);
}

void NORETURN die_errno(const char *fmt, ...)
{
	va_list params;
	char fmt_with_err[1024];
	char str_error[256], *err;
	int i, j;

	err = strerror(errno);
	for (i = j = 0; err[i] && j < sizeof(str_error) - 1; ) {
		if ((str_error[j++] = err[i++]) != '%')
			continue;
		if (j < sizeof(str_error) - 1) {
			str_error[j++] = '%';
		} else {
			/* No room to double the '%', so we overwrite it with
			 * '\0' below */
			j--;
			break;
		}
	}
	str_error[j] = 0;
	snprintf(fmt_with_err, sizeof(fmt_with_err), "%s: %s", fmt, str_error);

	va_start(params, fmt);
	die_routine(fmt_with_err, params);
	va_end(params);
}

int error(const char *err, ...)
{
	va_list params;

	va_start(params, err);
	error_routine(err, params);
	va_end(params);
	return -1;
}

void warning(const char *warn, ...)
{
	va_list params;

	va_start(params, warn);
	warn_routine(warn, params);
	va_end(params);
}
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