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/**
* mds — A micro-display server
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* 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 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "mds-server.h"
#include "config.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <limits.h>
#include <unistd.h>
/**
* Number of elements in `argv`
*/
static int argc;
/**
* Command line arguments
*/
static char** argv;
/**
* Entry point of the server
*
* @param argc_ Number of elements in `argv_`
* @param argv_ Command line arguments
* @return Non-zero on error
*/
int main(int argc_, char** argv_)
{
char* unparsed_args[ARGC_LIMIT + LIBEXEC_ARGC_EXTRA_LIMIT + 1];
int i;
int is_respawn = -1;
int socket_fd = -1;
int unparsed_args_ptr = 0;
argc = argc_;
argv = argv_;
/* Drop privileges like it's hot. */
if ((geteuid() == getuid() ? 0 : seteuid(getuid())) ||
(getegid() == getgid() ? 0 : setegid(getgid())))
{
perror(*argv);
return 1;
}
/* Sanity check the number of command line arguments. */
if (argc > ARGC_LIMIT + LIBEXEC_ARGC_EXTRA_LIMIT)
{
fprintf(stderr,
"%s: that number of arguments is ridiculous, I will not allow it.\n",
*argv);
return 1;
}
/* Parse command line arguments. */
for (i = 1; i < argc; i++)
{
char* arg = argv[i];
if (!strcmp(arg, "--initial-spawn")) /* Initial spawn? */
if (is_respawn == 1)
{
fprintf(stderr,
"%s: conflicting arguments %s and %s cannot be combined.\n",
*argv, "--initial-spawn", "--respawn");
return 1;
}
else
is_respawn = 0;
else if (!strcmp(arg, "--respawn")) /* Respawning after crash? */
if (is_respawn == 0)
{
fprintf(stderr,
"%s: conflicting arguments %s and %s cannot be combined.\n",
*argv, "--initial-spawn", "--respawn");
return 1;
}
else
is_respawn = 1;
else if (strstr(arg, "--socket-fd=") == arg) /* Socket file descriptor. */
{
long int r;
char* endptr;
if (socket_fd != -1)
{
fprintf(stderr, "%s: duplicate declaration of %s.\n", *argv, "--socket-fd");
return -1;
}
arg += strlen("--socket-fd=");
r = strtol(arg, &endptr, 10);
if ((*argv == '\0') || isspace(*argv) ||
(endptr - arg != (ssize_t)strlen(arg))
|| (r < 0) || (r > INT_MAX))
{
fprintf(stderr, "%s: invalid value for %s: %s.\n", *argv, "--socket-fd", arg);
return 1;
}
socket_fd = (int)r;
}
else
/* Not recognised, it is probably for another server. */
unparsed_args[unparsed_args_ptr++] = arg;
}
unparsed_args[unparsed_args_ptr] = NULL;
/* Check that manditory arguments have been specified. */
if (is_respawn < 0)
{
fprintf(stderr,
"%s: missing state argument, require either %s or %s.\n",
*argv, "--initial-spawn", "--respawn");
return 1;
}
if (socket_fd < 0)
{
fprintf(stderr, "%s: missing socket file descriptor argument.\n", *argv);
return 1;
}
return 0;
}
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