stdlib: Implement most LSB functions plus more

* Fix prototype of __realpath_chk.
* Add all strto* functions from LSB, plus the ones thata were previously
  incorrectly in string.c

The main missing LSB functions are the reentrant random functions, which
should not be used anyway.

Signed-off-by: Samuel Holland <samuel@sholland.org>

2 files changed, 107 insertions, 18 deletions

diff --git a/libgcompat/stdlib.c b/libgcompat/stdlib.c
index 6783615..c1eaa92 100644
--- a/libgcompat/stdlib.c
+++ b/libgcompat/stdlib.c
@@ -1,14 +1,116 @@
 #include <assert.h> /* assert */
-#include <stdlib.h> /* strtod */
+#include <limits.h> /* PATH_MAX */
+#include <locale.h> /* locale_t */
+#include <stddef.h> /* NULL, size_t */
+#include <stdlib.h> /* getenv, realpath, strto* */
+#include <unistd.h> /* get*id */
 
-char *__realpath_chk(const char *path, char *resolved_path)
+/**
+ * Resolve a pathname, with buffer overflow checking.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---realpath-chk-1.html
+ */
+char *__realpath_chk(const char *path, char *resolved_path, size_t resolved_len)
 {
 	assert(path != NULL);
+	assert(resolved_path != NULL);
+	assert(resolved_len >= PATH_MAX);
+
 	return realpath(path, resolved_path);
 }
 
-double __strtod_internal(const char *__nptr, char **__endptr, int __group)
+/**
+ * Get an environment variable.
+ */
+char *__secure_getenv(const char *name)
+{
+	if (geteuid() != getuid() || getegid() != getgid()) {
+		return NULL;
+	}
+
+	return getenv(name);
+}
+
+/**
+ * Underlying function for strtod.
+ *
+ * "__group shall be 0 or the behavior of __strtod_internal() is undefined."
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---strtod-internal-1.html
+ */
+double __strtod_internal(const char *nptr, char **endptr, int group)
+{
+	assert(group == 0);
+
+	return strtod(nptr, endptr);
+}
+
+/**
+ * Underlying function for strtof.
+ *
+ * "__group shall be 0 or the behavior of __strtof_internal() is undefined."
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---strtof-internal.html
+ */
+float __strtof_internal(const char *nptr, char **endptr, int group)
+{
+	assert(group == 0);
+
+	return strtof(nptr, endptr);
+}
+
+/**
+ * Underlying function for strtold.
+ *
+ * "__group shall be 0 or the behavior of __strtold_internal() is undefined."
+ *
+ * LSB 5.0: LSB-Core-generic/baselib---strtold-internal-1.html
+ */
+long double __strtold_internal(const char *nptr, char **endptr, int group)
+{
+	assert(group == 0);
+
+	return strtold(nptr, endptr);
+}
+
+/**
+ * Convert string value to a long long integer.
+ *
+ * Some day, when musl supports LC_NUMERIC, we can probably remove this.
+ */
+long long int strtoll_l(const char *nptr, char **endptr, int base,
+                        locale_t locale)
+{
+	return strtoll(nptr, endptr, base);
+}
+
+/**
+ * Convert string value to a long long integer.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-strtoq-3.html
+ */
+long long strtoq(const char *nptr, char **endptr, int base)
+{
+	return strtoll(nptr, endptr, base);
+}
+
+/**
+ * Convert a string to an unsigned long long.
+ *
+ * Some day, when musl supports LC_NUMERIC, we can probably remove this.
+ */
+unsigned long long int strtoull_l(const char *nptr, char **endptr, int base,
+                                  locale_t locale)
+{
+	return strtoull(nptr, endptr, base);
+}
+
+/**
+ * Convert a string to an unsigned long long.
+ *
+ * LSB 5.0: LSB-Core-generic/baselib-strtouq-3.html
+ */
+unsigned long long strtouq(const char *nptr, char **endptr, int base)
 {
-	assert(__group == 0);
-	return strtod(__nptr, __endptr);
+	return strtoull(nptr, endptr, base);
 }
diff --git a/libgcompat/string.c b/libgcompat/string.c
index 7ca0bf6..2c05caf 100644
--- a/libgcompat/string.c
+++ b/libgcompat/string.c
@@ -84,16 +84,3 @@ char *__strsep_g(char **stringp, const char *delim)
 {
 	return strsep(stringp, delim);
 }
-
-/* Some day, when musl supports LC_NUMERIC, we can probably remove these */
-long long int strtoll_l(const char *nptr, char **endptr, int base,
-                        locale_t locale)
-{
-	return strtoll(nptr, endptr, base);
-}
-
-unsigned long long int strtoull_l(const char *nptr, char **endptr, int base,
-                                  locale_t locale)
-{
-	return strtoull(nptr, endptr, base);
-}