File size: 2,770 Bytes
4559903 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 | #include <stdio.h>
#include <sys/stat.h> //provides information about the system
#include <pwd.h> //provides information about the user
#include <string.h> //used by strcat
int main (int argc, char *argv[]) {
int i = 1;
while (argv[i] != NULL) {//argv[i] is the name of the file as a string.
int flag1 = 0, flag2 = 0, flag3= 0;
struct stat buf;
char *f = argv[i];
stat(f, &buf);
struct passwd *ptr;
ptr = getpwuid(getuid());
if (buf.st_uid == getuid()) {//if st_uid and getuid are the same,
//they have permission to access the file.
flag1 = 1;
flag2 = 1;
}
//compare read/write/execute permissions.
if (((buf.st_mode & S_IRUSR) > 200) && ((buf.st_mode & S_IRUSR) < 300) &&
(buf.st_mode & S_IWUSR > 100) && (buf.st_mode & S_IXUSR == 0)) {
flag1 = 1;
flag2 = 1;
flag3 = 0;
}
if (((buf.st_mode & S_IWUSR) > 200) && ((buf.st_mode & S_IWUSR) < 200)) {
flag2 = 1;
}
if ((buf.st_mode & S_IXUSR) > 0) {
flag3 = 1;
}
//Check Group ids
if (buf.st_gid == getgid()) {
flag1 = 1;
flag2 = 1;
}
//Check home directory of user.
//Concatenate path to user's home directory.
f = strcpy(argv[i], ptr->pw_dir);
stat(f, &buf);
//check permissions again with new f
if ((buf.st_mode & S_IRUSR) < 99) {
flag1 = 1;
}
if ((buf.st_mode & S_IWUSR) < 99) {
flag2 = 1;
}
if ((buf.st_mode & S_IXUSR) > 100) {
flag3 = 1;
}
//print according to flags
printf("User's Permissions: -");
if (flag1 == 1)
printf("r");
else
printf("-");
if (flag2 == 1)
printf("w");
else
printf("-");
if (flag3 == 1)
printf("x\t");
else
printf("-\t");
//print user name and file name
printf("%s\t", ptr->pw_name);
printf("%s\n", argv[i]);
i++;
}
return 0;
}
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