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LibC: Rewrite environ handling

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environ is only allocated on heap when you insert new variables.

environment variables are only `free`'d if they are `malloc`'d by libc
This commit is contained in:
Bananymous
2025-04-16 21:08:01 +03:00
parent ee9e941a56
commit bdbde25784
3 changed files with 217 additions and 131 deletions
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131
userspace/libraries/LibC/stdlib.cpp
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@@ -14,15 +14,10 @@
#include <strings.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/weak_alias.h>
#include <unistd.h>
#include <icxxabi.h>
char** __environ;
weak_alias(__environ, environ);
static bool s_environ_malloced = false;
void abort(void)
{
sigset_t set;
@@ -365,18 +360,6 @@ unsigned long long strtoull(const char* __restrict str, char** __restrict endp,
return strtoT<unsigned long long>(str, endp, base, errno);
}
char* getenv(const char* name)
{
if (environ == nullptr)
return nullptr;
size_t len = strlen(name);
for (int i = 0; environ[i]; i++)
if (strncmp(name, environ[i], len) == 0)
if (environ[i][len] == '=')
return environ[i] + len + 1;
return nullptr;
}
char* realpath(const char* __restrict file_name, char* __restrict resolved_name)
{
char buffer[PATH_MAX] {};
@@ -450,120 +433,6 @@ int system(const char* command)
return stat_val;
}
int setenv(const char* name, const char* val, int overwrite)
{
if (name == nullptr || !name[0] || strchr(name, '='))
{
errno = EINVAL;
return -1;
}
if (!overwrite && getenv(name))
return 0;
size_t namelen = strlen(name);
size_t vallen = strlen(val);
char* string = (char*)malloc(namelen + vallen + 2);
memcpy(string, name, namelen);
string[namelen] = '=';
memcpy(string + namelen + 1, val, vallen);
string[namelen + vallen + 1] = '\0';
return putenv(string);
}
int unsetenv(const char* name)
{
if (name == nullptr || !name[0] || strchr(name, '='))
{
errno = EINVAL;
return -1;
}
size_t len = strlen(name);
bool found = false;
for (int i = 0; environ[i]; i++)
{
if (!found && strncmp(environ[i], name, len) == 0 && environ[i][len] == '=')
{
free(environ[i]);
found = true;
}
if (found)
environ[i] = environ[i + 1];
}
return 0;
}
int putenv(char* string)
{
if (string == nullptr || !string[0])
{
errno = EINVAL;
return -1;
}
if (!s_environ_malloced)
{
size_t env_count = 0;
while (environ[env_count])
env_count++;
char** new_environ = static_cast<char**>(malloc((env_count + 1) * sizeof(char*)));
if (new_environ == nullptr)
return -1;
for (size_t i = 0; i < env_count; i++)
{
const size_t bytes = strlen(environ[i]) + 1;
new_environ[i] = (char*)malloc(bytes);
memcpy(new_environ[i], environ[i], bytes);
}
new_environ[env_count] = nullptr;
environ = new_environ;
s_environ_malloced = true;
}
const char* eq_addr = strchr(string, '=');
if (eq_addr == nullptr)
{
errno = EINVAL;
return -1;
}
size_t namelen = eq_addr - string;
for (int i = 0; environ[i]; i++)
{
if (strncmp(environ[i], string, namelen + 1) == 0)
{
free(environ[i]);
environ[i] = string;
return 0;
}
}
size_t env_count = 0;
while (environ[env_count])
env_count++;
char** new_envp = static_cast<char**>(malloc(sizeof(char*) * (env_count + 2)));
if (new_envp == nullptr)
return -1;
for (size_t i = 0; i < env_count; i++)
new_envp[i] = environ[i];
new_envp[env_count] = string;
new_envp[env_count + 1] = nullptr;
free(environ);
environ = new_envp;
return 0;
}
static size_t temp_template_count_x(const char* _template)
{
const size_t len = strlen(_template);