execute_program.c revision 8d1b92ba755f6d6229f5e230fc43d958b13836f8 
1#if HAVE_CONFIG_H
2#include "config.h"
3#endif
4
5#include <stdio.h>
6#include <stdlib.h>
7#include <sys/types.h>
8#include <sys/stat.h>
9#include <unistd.h>
10#include <errno.h>
11#include <string.h>
12#include <pwd.h>
13#include <grp.h>
14
15#include "common.h"
16
17static void
18change_uid(Process *proc) {
19	uid_t run_uid, run_euid;
20	gid_t run_gid, run_egid;
21
22	if (options.user) {
23		struct passwd *pent;
24
25		if (getuid() != 0 || geteuid() != 0) {
26			fprintf(stderr,
27				"you must be root to use the -u option\n");
28			exit(1);
29		}
30		if ((pent = getpwnam(options.user)) == NULL) {
31			fprintf(stderr, "cannot find user `%s'\n", options.user);
32			exit(1);
33		}
34		run_uid = pent->pw_uid;
35		run_gid = pent->pw_gid;
36
37		if (initgroups(options.user, run_gid) < 0) {
38			perror("ltrace: initgroups");
39			exit(1);
40		}
41	} else {
42		run_uid = getuid();
43		run_gid = getgid();
44	}
45	if (options.user || !geteuid()) {
46		struct stat statbuf;
47		run_euid = run_uid;
48		run_egid = run_gid;
49
50		if (!stat(proc->filename, &statbuf)) {
51			if (statbuf.st_mode & S_ISUID) {
52				run_euid = statbuf.st_uid;
53			}
54			if (statbuf.st_mode & S_ISGID) {
55				run_egid = statbuf.st_gid;
56			}
57		}
58		if (setregid(run_gid, run_egid) < 0) {
59			perror("ltrace: setregid");
60			exit(1);
61		}
62		if (setreuid(run_uid, run_euid) < 0) {
63			perror("ltrace: setreuid");
64			exit(1);
65		}
66	}
67}
68
69void
70execute_program(Process *sp, char **argv) {
71	pid_t pid;
72
73	debug(1, "Executing `%s'...", sp->filename);
74
75	pid = fork();
76	if (pid < 0) {
77		perror("ltrace: fork");
78		exit(1);
79	} else if (!pid) {	/* child */
80		change_uid(sp);
81		trace_me();
82		execvp(sp->filename, argv);
83		fprintf(stderr, "Can't execute `%s': %s\n", sp->filename,
84			strerror(errno));
85		_exit(1);
86	}
87
88	debug(1, "PID=%d", pid);
89
90	sp->pid = pid;
91
92	return;
93}
94