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/*
* This file is part of ltrace.
* Copyright (C) 2011,2012 Petr Machata, Red Hat Inc.
* Copyright (C) 2010 Joe Damato
* Copyright (C) 1998,1999,2003,2008,2009 Juan Cespedes
* Copyright (C) 2006 Ian Wienand
*
* 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., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*/
#include "config.h"
#if defined(HAVE_LIBUNWIND)
#include <libunwind-ptrace.h>
#endif /* defined(HAVE_LIBUNWIND) */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include "backend.h"
#include "options.h"
#include "debug.h"
static void
change_uid(const char * command)
{
uid_t run_uid, run_euid;
gid_t run_gid, run_egid;
if (options.user) {
struct passwd *pent;
if (getuid() != 0 || geteuid() != 0) {
fprintf(stderr,
"you must be root to use the -u option\n");
exit(1);
}
if ((pent = getpwnam(options.user)) == NULL) {
fprintf(stderr, "cannot find user `%s'\n", options.user);
exit(1);
}
run_uid = pent->pw_uid;
run_gid = pent->pw_gid;
if (initgroups(options.user, run_gid) < 0) {
perror("ltrace: initgroups");
exit(1);
}
} else {
run_uid = getuid();
run_gid = getgid();
}
if (options.user || !geteuid()) {
struct stat statbuf;
run_euid = run_uid;
run_egid = run_gid;
if (!stat(command, &statbuf)) {
if (statbuf.st_mode & S_ISUID) {
run_euid = statbuf.st_uid;
}
if (statbuf.st_mode & S_ISGID) {
run_egid = statbuf.st_gid;
}
}
if (setregid(run_gid, run_egid) < 0) {
perror("ltrace: setregid");
exit(1);
}
if (setreuid(run_uid, run_euid) < 0) {
perror("ltrace: setreuid");
exit(1);
}
}
}
pid_t
execute_program(const char * command, char **argv)
{
pid_t pid;
debug(1, "Executing `%s'...", command);
pid = fork();
if (pid < 0) {
fail:
perror("ltrace: fork");
exit(1);
} else if (!pid) { /* child */
change_uid(command);
trace_me();
execvp(command, argv);
fprintf(stderr, "Can't execute `%s': %s\n", command,
strerror(errno));
_exit(1);
}
if (wait_for_proc(pid) < 0)
goto fail;
debug(1, "PID=%d", pid);
return pid;
}
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