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LibC: Cleanup environment variable code

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Bananymous
2026-04-13 00:36:13 +03:00
parent 42964ad0b4
commit ad12bf3e1d
1 changed files with 37 additions and 58 deletions
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87
userspace/libraries/LibC/environ.cpp
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@@ -14,6 +14,19 @@ static bool s_environ_malloced = false;
static size_t s_environ_count = 0; // only valid when s_environ_malloced == true static size_t s_environ_count = 0; // only valid when s_environ_malloced == true
static uint8_t* s_environ_bitmap = nullptr; // if bit i is set, environ[i] has to be freed static uint8_t* s_environ_bitmap = nullptr; // if bit i is set, environ[i] has to be freed
static bool is_bitmap_bit_set(size_t index)
{
return !!(s_environ_bitmap[index / 8] & (1 << (index % 8)));
}
static void set_bitmap_bit(size_t index, bool value)
{
if (value)
s_environ_bitmap[index / 8] |= 1 << (index % 8);
else
s_environ_bitmap[index / 8] &= ~(1 << (index % 8));
}
static int malloc_environ() static int malloc_environ()
{ {
ASSERT(!s_environ_malloced); ASSERT(!s_environ_malloced);
@@ -28,7 +41,7 @@ static int malloc_environ()
return -1; return -1;
memset(new_bitmap, 0, bitmap_size); memset(new_bitmap, 0, bitmap_size);
char** new_environ = static_cast<char**>(malloc((environ_count + 1) * sizeof(char*))); auto** new_environ = static_cast<char**>(malloc((environ_count + 1) * sizeof(char*)));
if (new_environ == nullptr) if (new_environ == nullptr)
{ {
free(new_bitmap); free(new_bitmap);
@@ -60,53 +73,42 @@ static int putenv_impl(char* string, bool malloced)
} }
const size_t namelen = eq_addr - string; const size_t namelen = eq_addr - string;
for (int i = 0; environ[i]; i++) for (size_t i = 0; environ[i]; i++)
{ {
if (strncmp(environ[i], string, namelen + 1) == 0) if (strncmp(environ[i], string, namelen + 1) != 0)
{ continue;
const size_t byte = i / 8;
const uint8_t mask = 1 << (i % 8);
if (s_environ_bitmap[byte] & mask) if (is_bitmap_bit_set(i))
free(environ[i]); free(environ[i]);
set_bitmap_bit(i, malloced);
if (malloced)
s_environ_bitmap[byte] |= mask;
else
s_environ_bitmap[byte] &= ~mask;
environ[i] = string; environ[i] = string;
return 0; return 0;
} }
}
if (s_environ_count % 8 == 0) if (s_environ_count % 8 == 0)
{ {
const size_t bytes = s_environ_count / 8 + 1; const size_t bytes = s_environ_count / 8 + 1;
void* new_bitmap = realloc(s_environ_bitmap, bytes); auto* new_bitmap = static_cast<uint8_t*>(realloc(s_environ_bitmap, bytes));
if (new_bitmap == nullptr) if (new_bitmap == nullptr)
return -1; return -1;
s_environ_bitmap = static_cast<uint8_t*>(new_bitmap); s_environ_bitmap = new_bitmap;
s_environ_bitmap[bytes - 1] = 0; s_environ_bitmap[bytes - 1] = 0;
} }
void* new_environ = realloc(environ, sizeof(char*) * (s_environ_count + 2)); auto** new_environ = static_cast<char**>(realloc(environ, (s_environ_count + 2) * sizeof(char*)));
if (new_environ == nullptr) if (new_environ == nullptr)
return -1; return -1;
environ = static_cast<char**>(new_environ); environ = new_environ;
environ[s_environ_count] = string; environ[s_environ_count] = string;
environ[s_environ_count + 1] = nullptr; environ[s_environ_count + 1] = nullptr;
s_environ_count++;
if (malloced) set_bitmap_bit(s_environ_count, malloced);
{
const size_t byte = s_environ_count / 8; s_environ_count++;
const size_t mask = 1 << (s_environ_count % 8);
s_environ_bitmap[byte] |= mask;
}
return 0; return 0;
} }
@@ -116,15 +118,9 @@ int clearenv(void)
if (s_environ_malloced) if (s_environ_malloced)
{ {
ASSERT(environ); ASSERT(environ);
for (size_t i = 0; environ[i]; i++) for (size_t i = 0; environ[i]; i++)
{ if (is_bitmap_bit_set(i))
const size_t byte = i / 8;
const size_t mask = 1 << (i % 8);
if (s_environ_bitmap[byte] & mask)
free(environ[i]); free(environ[i]);
}
free(s_environ_bitmap); free(s_environ_bitmap);
free(environ); free(environ);
} }
@@ -142,8 +138,7 @@ char* getenv(const char* name)
return nullptr; return nullptr;
const size_t namelen = strlen(name); const size_t namelen = strlen(name);
for (size_t i = 0; environ[i]; i++) for (size_t i = 0; environ[i]; i++)
if (strncmp(name, environ[i], namelen) == 0) if (strncmp(name, environ[i], namelen) == 0 && environ[i][namelen] == '=')
if (environ[i][namelen] == '=')
return environ[i] + namelen + 1; return environ[i] + namelen + 1;
return nullptr; return nullptr;
} }
@@ -162,7 +157,7 @@ int setenv(const char* name, const char* val, int overwrite)
const size_t namelen = strlen(name); const size_t namelen = strlen(name);
const size_t vallen = strlen(val); const size_t vallen = strlen(val);
char* string = (char*)malloc(namelen + vallen + 2); auto* string = static_cast<char*>(malloc(namelen + vallen + 2));
memcpy(string, name, namelen); memcpy(string, name, namelen);
string[namelen] = '='; string[namelen] = '=';
memcpy(string + namelen + 1, val, vallen); memcpy(string + namelen + 1, val, vallen);
@@ -189,13 +184,8 @@ int unsetenv(const char* name)
{ {
if (strncmp(environ[i], name, namelen) || environ[i][namelen] != '=') if (strncmp(environ[i], name, namelen) || environ[i][namelen] != '=')
continue; continue;
if (!s_environ_malloced) if (s_environ_malloced && is_bitmap_bit_set(i))
break;
const size_t byte = i / 8;
const size_t mask = 1 << (i % 8);
if (s_environ_bitmap[byte] & mask)
free(environ[i]); free(environ[i]);
s_environ_count--;
break; break;
} }
@@ -204,17 +194,7 @@ int unsetenv(const char* name)
environ[i] = environ[i + 1]; environ[i] = environ[i + 1];
if (!s_environ_malloced) if (!s_environ_malloced)
continue; continue;
set_bitmap_bit(i, is_bitmap_bit_set(i + 1));
const size_t cbyte = i / 8;
const size_t cmask = 1 << (i % 8);
const size_t nbyte = (i + 1) / 8;
const size_t nmask = 1 << ((i + 1) % 8);
if (s_environ_bitmap[nbyte] & nmask)
s_environ_bitmap[cbyte] |= cmask;
else
s_environ_bitmap[cbyte] &= ~cmask;
} }
if (environ[i]) if (environ[i])
@@ -223,9 +203,8 @@ int unsetenv(const char* name)
if (s_environ_malloced) if (s_environ_malloced)
{ {
const size_t byte = i / 8; set_bitmap_bit(i, false);
const size_t mask = 1 << (i % 8); s_environ_count--;
s_environ_bitmap[byte] &= ~mask;
} }
} }