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#include <stdio.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 "ltrace.h"
#include "options.h"
#include "output.h"
#include "sysdep.h"
static void change_uid(struct process * proc);
void execute_program(struct process * sp, char **argv)
{
int pid;
if (opt_d) {
output_line(0, "Executing `%s'...", sp->filename);
}
pid = fork();
if (pid<0) {
perror("fork");
exit(1);
} else if (!pid) { /* child */
change_uid(sp);
trace_me();
execvp(sp->filename, argv);
fprintf(stderr, "Can't execute `%s': %s\n", sp->filename, strerror(errno));
exit(1);
}
if (opt_d) {
output_line(0, "PID=%d", pid);
}
sp->pid = pid;
return;
}
static void change_uid(struct process * proc)
{
uid_t run_uid, run_euid;
gid_t run_gid, run_egid;
if (opt_u) {
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(opt_u)) == NULL) {
fprintf(stderr, "cannot find user `%s'\n", opt_u);
exit(1);
}
run_uid = pent->pw_uid;
run_gid = pent->pw_gid;
if (initgroups(opt_u, run_gid) < 0) {
perror("initgroups");
exit(1);
}
} else {
run_uid = getuid();
run_gid = getgid();
}
if (opt_u || !geteuid()) {
struct stat statbuf;
run_euid = run_uid;
run_egid = run_gid;
if (!stat(proc->filename, &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("setregid");
exit(1);
}
if (setreuid(run_uid, run_euid) < 0) {
perror("setreuid");
exit(1);
}
}
}
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