banan-os/userspace/libraries/LibC/pwd.cpp

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#include <BAN/Assert.h>
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
static FILE* s_pwent_fp = nullptr;
static passwd s_pwent_struct;
static bool open_pwent()
{
if (s_pwent_fp)
return true;
s_pwent_fp = fopen("/etc/passwd", "r");
return s_pwent_fp;
}
static void clear_pwent(passwd& passwd)
{
if (passwd.pw_name)
free(passwd.pw_name);
passwd.pw_name = nullptr;
if (passwd.pw_dir)
free(passwd.pw_dir);
passwd.pw_dir = nullptr;
if (passwd.pw_shell)
free(passwd.pw_shell);
passwd.pw_shell = nullptr;
}
void endpwent(void)
{
if (!s_pwent_fp)
return;
fclose(s_pwent_fp);
s_pwent_fp = nullptr;
clear_pwent(s_pwent_struct);
}
struct passwd* getpwent(void)
{
if (!s_pwent_fp)
if (!open_pwent())
return nullptr;
clear_pwent(s_pwent_struct);
static char buffer[4096];
if (!fgets(buffer, sizeof(buffer), s_pwent_fp))
return nullptr;
size_t buffer_len = strlen(buffer);
ASSERT(buffer[buffer_len - 1] == '\n');
buffer[buffer_len - 1] = '\0';
buffer_len--;
const char* ptr = buffer;
for (int i = 0; i < 7; i++)
{
char* end = strchr(ptr, ':');
ASSERT((i < 6) ? end != nullptr : end == nullptr);
if (!end)
end = buffer + buffer_len;
*end = '\0';
const size_t field_len = end - ptr;
switch (i)
{
case 0:
s_pwent_struct.pw_name = (char*)malloc(field_len + 1);
if (!s_pwent_struct.pw_name)
return nullptr;
strcpy(s_pwent_struct.pw_name, ptr);
break;
case 1:
break;
case 2:
ASSERT(1 <= field_len && field_len <= 9);
for (size_t j = 0; j < field_len; j++)
ASSERT(isdigit(ptr[j]));
s_pwent_struct.pw_uid = atoi(ptr);
break;
case 3:
ASSERT(1 <= field_len && field_len <= 9);
for (size_t j = 0; j < field_len; j++)
ASSERT(isdigit(ptr[j]));
s_pwent_struct.pw_uid = atoi(ptr);
break;
case 4:
break;
case 5:
s_pwent_struct.pw_dir = (char*)malloc(field_len + 1);
if (!s_pwent_struct.pw_dir)
return nullptr;
strcpy(s_pwent_struct.pw_dir, ptr);
break;
case 6:
s_pwent_struct.pw_shell = (char*)malloc(field_len + 1);
if (!s_pwent_struct.pw_shell)
return nullptr;
strcpy(s_pwent_struct.pw_shell, ptr);
break;
}
ptr = end + 1;
}
return &s_pwent_struct;
}
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struct passwd* getpwnam(const char* name)
{
passwd* pwd;
setpwent();
while ((pwd = getpwent()))
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if (strcmp(pwd->pw_name, name) == 0)
return pwd;
return nullptr;
}
struct passwd* getpwuid(uid_t uid)
{
passwd* pwd;
setpwent();
while ((pwd = getpwent()))
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if (pwd->pw_uid == uid)
return pwd;
return nullptr;
}
void setpwent(void)
{
if (!s_pwent_fp)
return;
fseek(s_pwent_fp, 0, SEEK_SET);
}