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Init: Use the new pwd.h api for user parsing

This commit is contained in:
Bananymous 2023-07-13 12:01:41 +03:00
parent bba09a3cd0
commit e341a36287
1 changed files with 42 additions and 118 deletions
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118
userspace/init/main.cpp
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@ -4,82 +4,11 @@
#include <ctype.h> #include <ctype.h>
#include <fcntl.h> #include <fcntl.h>
#include <pwd.h>
#include <stdio.h> #include <stdio.h>
#include <stdlib.h> #include <stdlib.h>
#include <string.h> #include <string.h>
struct User
{
BAN::String name;
uid_t uid;
gid_t gid;
BAN::String home;
BAN::String shell;
};
BAN::Optional<id_t> parse_id(BAN::StringView value)
{
// NOTE: we only allow 10^9 uids
if (value.size() < 1 || value.size() > 9)
return {};
id_t id { 0 };
for (char c : value)
{
if (!isdigit(c))
return {};
id = (id * 10) + (c - '0');
}
return id;
}
BAN::Optional<User> parse_user(BAN::StringView line)
{
auto parts = MUST(line.split(':', true));
if (parts.size() != 7)
return {};
User user;
user.name = parts[0];
user.uid = ({ auto id = parse_id(parts[2]); if (!id.has_value()) return {}; id.value(); });
user.gid = ({ auto id = parse_id(parts[3]); if (!id.has_value()) return {}; id.value(); });
user.home = parts[5];
user.shell = parts[6];
return user;
}
BAN::Vector<User> parse_users()
{
FILE* fp = fopen("/etc/passwd", "r");
if (fp == nullptr)
{
fprintf(stderr, "could not open /etc/passwd\n");
perror("fopen");
}
BAN::Vector<User> users;
char buffer[1024];
while (fgets(buffer, sizeof(buffer), fp))
{
*strchrnul(buffer, '\n') = '\0';
auto user = parse_user(buffer);
if (user.has_value())
MUST(users.push_back(user.release_value()));
}
if (ferror(fp))
{
perror("fread");
fclose(fp);
return {};
}
fclose(fp);
return users;
}
void initialize_stdio() void initialize_stdio()
{ {
char tty[L_ctermid]; char tty[L_ctermid];
@ -97,18 +26,9 @@ int main()
while (true) while (true)
{ {
auto users = parse_users();
char name_buffer[128]; char name_buffer[128];
BAN::StringView name;
if (first) while (!first)
{
name = "user"sv;
first = false;
}
while (name.empty())
{ {
printf("username: "); printf("username: ");
fflush(stdout); fflush(stdout);
@ -123,36 +43,43 @@ int main()
} }
continue; continue;
} }
if (nread == 1) if (nread <= 1 || name_buffer[nread - 1] != '\n')
continue; continue;
name_buffer[nread - 1] = '\0';
name = BAN::StringView(name_buffer, nread - 1);
break; break;
} }
for (const User& user : users) if (first)
{
if (user.name == name)
{ {
strcpy(name_buffer, "user");
first = false;
}
auto* pwd = getpwnam(name_buffer);
if (pwd == nullptr)
continue;
pid_t pid = fork(); pid_t pid = fork();
if (pid == 0) if (pid == 0)
{ {
printf("Welcome back %s!\n", user.name.data()); printf("Welcome back %s!\n", pwd->pw_name);
if (setgid(user.gid) == -1) if (setgid(pwd->pw_gid) == -1)
perror("setgid"); perror("setgid");
if (setuid(user.uid) == -1) if (setuid(pwd->pw_uid) == -1)
perror("setuid"); perror("setuid");
setenv("HOME", user.home.data(), 1); setenv("HOME", pwd->pw_dir, 1);
chdir(user.home.data()); chdir(pwd->pw_dir);
execl(user.shell.data(), user.shell.data(), nullptr); execl(pwd->pw_shell, pwd->pw_shell, nullptr);
perror("execl"); perror("execl");
exit(1); exit(1);
} }
endpwent();
if (pid == -1) if (pid == -1)
{ {
perror("fork"); perror("fork");
@ -162,8 +89,5 @@ int main()
int status; int status;
waitpid(pid, &status, 0); waitpid(pid, &status, 0);
} }
}
}
} }