我是C的新手,这是我编写的一个简单的包装器,用于以不同的用户身份运行执行脚本。我知道我可以在etc / sudoers中做visudo但是,我已经做了这个并且我不想浪费它,它也会帮助我改进C中的写作。我似乎哈哈问题是我在遇到错误时我编译它。我的操作系统是Ubuntu 12.04.03 LTS。有人可以帮我解决这些错误吗?
rootsuidwrapper.c: In function ‘trusted’:
rootsuidwrapper.c:60:15: warning: assignment makes pointer from integer without a cast [enabled by default]
rootsuidwrapper.c: In function ‘main’:
rootsuidwrapper.c:116:48: error: too many arguments to function ‘stat’
/usr/include/x86_64-linux-gnu/sys/stat.h:211:12: note: declared here
如果有人能解决这些错误并给我工作代码,那就太好了。另外,我想知道我做错了什么。
* This program must be run as root to work.
*/
#if !defined(lint) && !defined(SABER) || defined(RCS_HDRS)
#endif /* !lint && !SABER || RCS_HDRS */
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <netdb.h>
#include <sys/stat.h>
#define TRUSTED_GROUP "trusted"
typedef enum { false = 0, true } bool;
#ifdef __STDC__
bool trusted(char *whoami)
#else
bool trusted(whoami)
char *whoami;
#endif /* __STDC__ */
{
char *user;
char host[BUFSIZ + 1];
char domain[BUFSIZ + 1];
struct hostent *hp;
/*
* Figure out whether this user on this host in this domain is
* trusted.
*/
/*
* Determine our domain name
*/
(void) memset(domain, '\0', sizeof(domain));
getdomainname(domain, sizeof(domain) - 1);
/*
* Figure out our fully canonicalized hostname
*/
(void) memset(host, '\0', sizeof(host));
gethostname(host, sizeof(host) - 1);
if ((hp = gethostbyname(host)) == NULL) {
strcat(host, ".");
strcat(host, domain);
fprintf(stderr,
"%s: WARNING: can't canonlicalize hostname; assuming %s.\n",
whoami, host);
}
else {
strcpy(host, hp->h_name);
}
/*
* Get login name of current user
*/
if ((user = cuserid(NULL)) == NULL) {
fprintf(stderr, " %s: You do not seem to be in the passwd file!\n",
whoami);
return(false);
}
/*
* Look this triple up in the trusted netgroup
*/
return ((innetgr(TRUSTED_GROUP, host, user, domain) == 1) ? true : false);
}
#ifdef __STDC__
main(int argc, char *argv[])
#else
main(argc, argv)
int argc;
char *argv[];
#endif /* __STDC__ */
{
char *whoami;
int ouruid; /* uid we set to run chown and chmod */
int proguid; /* uid we are chowning program to */
char *filename;
struct stat statbuf;
int error = 0;
if (whoami = strrchr(argv[0], '/'))
whoami ++;
else
whoami = argv[0];
if (argc == 3)
proguid = atoi(argv[2]);
else if (argc == 2)
proguid = 0;
else {
fprintf(stderr, "usage: %s filename [proguid]\n", whoami);
exit(1);
}
filename = argv[1];
if (trusted(whoami))
ouruid = 0;
else
ouruid = getuid();
if (setuid(ouruid) == -1) {
fprintf(stderr, "%s: Warning: setuid(%d) failed: ", whoami, ouruid);
perror(NULL);
exit(1);
}
if (stat(filename, &statbuf, sizeof(struct stat)) == -1) {
fprintf(stderr, "%s: failure statting %s: ", whoami, filename);
perror(NULL);
exit(1);
}
if (chown(filename, proguid, -1) == -1) {
error++;
fprintf(stderr, "%s: chown %d %s failed: ", whoami, proguid, filename);
perror(NULL);
fprintf(stderr, "continuing...\n");
}
if (chmod(filename, statbuf.st_mode | S_ISUID)) {
error++;
fprintf(stderr, "%s: chmod u+s %s failed: ", whoami, filename);
perror(NULL);
}
return(error);
}
感谢帮助,
答案 0 :(得分:1)
NAME
stat, fstat, lstat - get file status
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
int stat(const char *path, struct stat *buf);
int fstat(int filedes, struct stat *buf);
int lstat(const char *path, struct stat *buf);
删除对stat()的调用中的第三个参数。那么您的代码应该是:
if (stat(filename, &statbuf) == -1) {
无需告知stat()
缓冲区的大小,因为stat()
期望struct stat *
具有固定大小。
答案 1 :(得分:0)
对于编译器警告:
cuserid()
返回指向字符(char*
)的指针。当任何函数返回一个指针,并且你想将返回值放入缓冲区时,你必须将返回值放入缓冲区中的特定位置,通常是开头。具体来说,您应该使用:
*user = cuserid(NULL);
if(user == NULL)
请记住,cuserid()
会返回指向单个字符的指针。因此,函数的返回值应该是单个字符 - 即*user
或{ {1}}。使用上面的代码时,编译器不应该抱怨。然后将user[0]
的结果放入cuserid(NULL)
,从第一个字节到分配的其余内存。