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env flag

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implemented -e flag:
it copies the elements of env that we want to keep, clears the environment and
sets it to only the saved and default elements.

also removed the code for copying the environment and allocating a new one
This commit is contained in:
Alessandro Mauri 2021-04-04 19:34:10 +02:00
parent 5412a3785e
commit fe9d88e7f9
1 changed files with 48 additions and 27 deletions
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75
us.c
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@ -42,6 +42,8 @@ static struct group* group_to_grp (const char *);
// our own pam module
static struct pam_conv conv = {misc_conv, NULL};
extern char **environ;
int main (int argc, char *argv[])
{
// TODO: Add arguments
@ -50,8 +52,8 @@ int main (int argc, char *argv[])
struct passwd *t_pw;
struct group *t_gr;
int opt, err;
int shellflag = 0;
while ((opt = getopt(argc, argv, "A:u:g:C:s")) != -1) {
int shellflag = 0, envflag = 0;
while ((opt = getopt(argc, argv, "A:u:g:C:se")) != -1) {
switch (opt) {
case 'A':
printf("-A is not yet implemented\n");
@ -70,6 +72,9 @@ int main (int argc, char *argv[])
case 's':
shellflag = 1;
break;
case 'e':
envflag = 1;
break;
case '?':
usage();
exit(EINVAL);
@ -139,33 +144,49 @@ int main (int argc, char *argv[])
if (authenticate(uname) != PAM_SUCCESS)
exit(EXIT_FAILURE);
// TODO: clean up env
/* copy and filter env */
/*
char **c_env;
extern char **environ;
int size = 0;
for (int i = 0; environ[i]; i++, size++);
c_env = malloc(sizeof(char *) * (size + 1));
if (!c_env) {
fprintf(stderr, "malloc: %s\n", strerror(errno));
exit(errno);
struct env_elem {
char *name;
char *value;
};
struct env_elem env_keep[] = {
{"PATH", NULL},
{"TERM", NULL},
{"EDITOR", NULL},
{"VISUAL", NULL},
{"DISPLAY", NULL},
{"XAUTHORITY", NULL},
{NULL, NULL}
};
struct env_elem env_mod[] = {
{"USER", t_pw->pw_name},
{"LOGNAME", t_pw->pw_name},
{"SHELL", t_pw->pw_shell},
{"HOME", t_pw->pw_dir},
{NULL, NULL}
};
if (envflag) { /* clear env */
for (int i = 0; env_keep[i].name; i++)
env_keep[i].value = strdup(getenv(env_keep[i].name));
environ = NULL; // in place of clearenv
}
for (int i = 0; environ[i]; i++) {
c_env[i] = strdup(environ[i]);
if (!c_env[i]) {
fprintf(stderr, "strdup: %s\n", strerror(errno));
exit(errno);
for (int i = 0; env_mod[i].name; i++) {
// TODO: check err value
err = setenv(env_mod[i].name, env_mod[i].value, 1);
}
if (envflag) {
for (int i = 0; env_keep[i].name; i++) {
// TODO: check err value
if (env_keep[i].value)
err = setenv(env_keep[i].name, env_keep[i].value, 1);
}
}
c_env[size] = NULL;
*/
// TODO: check err value
// TODO: add all this to list and loop over it
err = setenv("USER", t_pw->pw_name, 1);
err = setenv("LOGNAME", t_pw->pw_name, 1);
err = setenv("SHELL", t_pw->pw_shell, 1);
err = setenv("HOME", t_pw->pw_dir, 1);
// do not override, we might be under more levels of 'us'
err = setenv("US_USER", my_pw->pw_name, 0);
errno = 0;
/* Set permissions */
@ -198,7 +219,7 @@ static inline void usage (void)
// -c [file]: manually select config file
// something about environment
// something about non interactiveness
printf("usage: us [-s] [-u user] [-g group] command [args]\n");
printf("usage: us [-se] [-u user] [-g group] command [args]\n");
}
static int perm_set (struct passwd *pw, struct group *gr)