Answer:
/*
Student: Hugo Meza
Date: February 15, 2019
Description: This program mimic the cat command from Linux. Checks whether the source file
has the right permissions, and then writes in the console its content.
*/
#include <stdio.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
int hasPermission(char *filepath){
int returnval;
// Check file existence
returnval = access (filepath, F_OK);
if(errno == ENOENT){
printf ("%s does not exist\n", filepath);
return 0;
}
else if (errno == EACCES){
printf ("%s is not accessible\n", filepath);
return 0;
}
// Check read access
returnval = access (filepath, R_OK);
if(errno == ENOENT){
printf ("%s does not have read access\n", filepath);
return 0;
}
else if (errno == EACCES){
printf ("%s is not accessible\n",filepath);
return 0;
}
// Check write access
returnval = access (filepath, W_OK);
if(errno == ENOENT){
printf ("%s does not have read access\n", filepath);
return 0;
}
else if (errno == EACCES){
printf ("%s is not accessible\n",filepath);
return 0;
}
return 1;
}
int main(int argc, char* argv[]){
if(!argv[1]){
printf("Error. Specify file to open\n");
return 0;
}
int fd;
char *fp = argv[1], content[fd];
if(hasPermission(fp) == 0)
return 1;
fd = open(fp, O_RDONLY);
int bytes = read(fd,content,sizeof(content)-1);
write(1, content, bytes);
close(fd);
return 0;
}
Explanation:
