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/*
* libexplain - Explain errno values returned by libc functions
* Copyright (C) 2008-2010, 2012, 2013 Peter Miller
* Written by Peter Miller <pmiller@opensource.org.au>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 3 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <libexplain/ac/assert.h>
#include <libexplain/ac/ctype.h>
#include <libexplain/ac/errno.h>
#include <libexplain/ac/limits.h> /* for PATH_MAX on Solaris */
#include <libexplain/ac/stdlib.h>
#include <libexplain/ac/string.h>
#include <libexplain/ac/sys/param.h> /* for PATH_MAX except Solaris */
#include <libexplain/ac/sys/wait.h>
#include <libexplain/ac/unistd.h>
#include <libexplain/buffer/errno/access.h>
#include <libexplain/buffer/errno/fork.h>
#include <libexplain/buffer/errno/system.h>
#include <libexplain/buffer/errno/wait.h>
#include <libexplain/buffer/wait_status.h>
#include <libexplain/common_message_buffer.h>
#include <libexplain/string_buffer.h>
#include <libexplain/system.h>
#include <libexplain/output.h>
static int
extract_command(const char *src, char *dst, size_t dst_size)
{
char *dst_end = dst + dst_size - 1;
char *dp;
for (;;)
{
if (!*src)
break;
if (isspace((unsigned char)*src))
{
++src;
continue;
}
dp = dst;
for (;;)
{
if (dp < dst_end)
*dp++ = *src;
++src;
if (!*src)
break;
if (isspace((unsigned char)*src) || strchr("<>^|", *src))
{
++src;
break;
}
}
*dp = '\0';
/*
* If there is an equals sign, it is probably an environment
* variable setting before the command word.
*/
if (strchr(dst, '='))
continue;
/*
* Probably found the command, so long as it contains no shell
* special characters.
*/
return !strpbrk(dst, "!\"#$&'()*:;<>?[\\]^`{|}");
}
return 0;
}
static int
command_on_path(const char *cmd)
{
char combo[PATH_MAX * 2 + 3];
explain_string_buffer_t combo_sb;
const char *path;
const char *start;
path = getenv("PATH");
if (!path)
path = ".";
for (;;)
{
start = path;
for (;;)
{
if (*path == '\0')
break;
if (*path == ':')
break;
++path;
}
explain_string_buffer_init(&combo_sb, combo, sizeof(combo));
if (start == path)
explain_string_buffer_putc(&combo_sb, '.');
else
explain_string_buffer_write(&combo_sb, start, path - start);
explain_string_buffer_path_join(&combo_sb, cmd);
if (access(combo, X_OK) >= 0)
return 1;
if (*path == '\0')
return 0;
assert(*path == ':');
++path;
}
}
int
explain_system_success(const char *command)
{
int status;
status = system(command);
if (status < 0)
{
explain_output_error("%s", explain_system(command));
}
else if (status != 0)
{
explain_string_buffer_t sb;
explain_string_buffer_init
(
&sb,
explain_common_message_buffer,
explain_common_message_buffer_size
);
explain_buffer_errno_system(&sb, 0, command);
if (!command)
command = "/bin/sh";
/* FIXME: i18n */
explain_string_buffer_puts(&sb, ", but ");
explain_buffer_wait_status(&sb, status);
if (WIFEXITED(status) && WEXITSTATUS(status) == 127)
{
char cmd[PATH_MAX + 1];
/*
* It is possible that execl(2) used by system(3) failed,
* and this could have caused the 127 exit status. On the
* other hand, the command itself could return this.
*/
if (extract_command(command, cmd, sizeof(cmd)))
{
if (strchr(cmd, '/'))
{
if (access(cmd, X_OK) < 0)
{
explain_string_buffer_puts(&sb, ", ");
explain_buffer_errno_access_explanation
(
&sb,
errno,
"system",
cmd,
X_OK
);
}
}
else if (!command_on_path(cmd))
{
explain_string_buffer_puts(&sb, ", ");
explain_string_buffer_puts_quoted(&sb, cmd);
explain_string_buffer_puts
(
&sb,
" command not found on $PATH"
);
}
}
}
explain_output_error("%s", explain_common_message_buffer);
}
return status;
}
void
explain_system_success_or_die(const char *command)
{
if (explain_system_success(command))
explain_output_exit_failure();
}
/* vim: set ts=8 sw=4 et : */
|
