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/*
* lxc: linux Container library
*
* (C) Copyright IBM Corp. 2007, 2008
*
* Authors:
* Daniel Lezcano <daniel.lezcano at free.fr>
*
* This library 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 2.1 of the License, or (at your option) any later version.
*
* This library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#ifdef __linux__
#include <sys/prctl.h>
#include <sys/syscall.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include "config.h"
#define prctl_arg(x) ((unsigned long)x)
static char *setproctitle_argv;
int setproctitle(const char *fmt, ...)
{
const char *progname;
char title[1024], *tp;
size_t tl, n;
va_list args;
int ret;
#if 0
progname = getprogname();
#else
progname = "dhcpcd";
#endif
tp = title;
tl = sizeof(title);
n = strlcpy(tp, progname, tl);
tp += n;
tl -= n;
n = strlcpy(tp, ": ", tl);
tp += n;
tl -= n;
va_start(args, fmt);
vsnprintf(tp, tl, fmt, args);
va_end(args);
#if defined(__linux__) && defined(PR_SET_MM_MAP)
int fd, i;
char *buf_ptr, *tmp_proctitle;
char buf[BUFSIZ];
ssize_t bytes_read;
size_t len;
/*
* We don't really need to know all of this stuff, but unfortunately
* PR_SET_MM_MAP requires us to set it all at once, so we have to
* figure it out anyway.
*/
unsigned long start_data, end_data, start_brk, start_code, end_code,
start_stack, arg_start, arg_end, env_start, env_end;
long brk_val;
struct prctl_mm_map prctl_map;
fd = open("/proc/self/stat", O_RDONLY);
if (fd == -1)
return -1;
bytes_read = read(fd, buf, sizeof(buf) - 1);
close(fd);
if (bytes_read == -1)
return -1;
buf[bytes_read] = '\0';
/* Skip the first 25 fields, column 26-28 are start_code, end_code,
* and start_stack */
buf_ptr = strchr(buf, ' ');
for (i = 0; i < 24; i++) {
if (!buf_ptr)
return -1;
buf_ptr = strchr(buf_ptr + 1, ' ');
}
if (!buf_ptr)
return -1;
i = sscanf(buf_ptr, "%lu %lu %lu", &start_code, &end_code, &start_stack);
if (i != 3)
return -1;
/* Skip the next 19 fields, column 45-51 are start_data to arg_end */
for (i = 0; i < 19; i++) {
if (!buf_ptr)
return -1;
buf_ptr = strchr(buf_ptr + 1, ' ');
}
if (!buf_ptr)
return -1;
i = sscanf(buf_ptr, "%lu %lu %lu %*u %*u %lu %lu", &start_data,
&end_data, &start_brk, &env_start, &env_end);
if (i != 5)
return -1;
/* Include the null byte here, because in the calculations below we
* want to have room for it. */
len = strlen(title) + 1;
tmp_proctitle = realloc(setproctitle_argv, len);
if (!tmp_proctitle)
return -1;
setproctitle_argv = tmp_proctitle;
arg_start = (unsigned long)setproctitle_argv;
arg_end = arg_start + len;
brk_val = syscall(__NR_brk, 0);
prctl_map = (struct prctl_mm_map){
.start_code = start_code,
.end_code = end_code,
.start_stack = start_stack,
.start_data = start_data,
.end_data = end_data,
.start_brk = start_brk,
.brk = (unsigned long long)brk_val,
.arg_start = arg_start,
.arg_end = arg_end,
.env_start = env_start,
.env_end = env_end,
.auxv = NULL,
.auxv_size = 0,
.exe_fd = (unsigned int)-1,
};
ret = prctl(PR_SET_MM, prctl_arg(PR_SET_MM_MAP), prctl_arg(&prctl_map),
prctl_arg(sizeof(prctl_map)), prctl_arg(0));
if (ret == 0)
(void)strlcpy((char *)arg_start, title, len);
#else
/* Solaris doesn't work with the ARGV stamping approach.
* Is there any other way? */
ret = -1;
errno = ENOTSUP;
#endif
return ret;
}
void
setproctitle_free(void)
{
free(setproctitle_argv);
}
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