libpwdgrp/pwd_grp.c: allocate local storage on first call, not in bss. -1k bss

function                                             old     new   delta
get_S                                                  -      31     +31
bb_internal_getpwnam                                  38      44      +6
bb_internal_getgrnam                                  38      44      +6
bb_internal_getgrgid                                  38      44      +6
ptr_to_statics                                         -       4      +4
static.resultbuf                                      88       -     -88
static.buffer                                       1024       -   -1024
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 3/0 up/down: 53/-1112)        Total: -1059 bytes

1 files changed, 96 insertions, 27 deletions

diff --git a/libpwdgrp/pwd_grp.c b/libpwdgrp/pwd_grp.c
index d59fd50..4e476f2 100644
--- a/libpwdgrp/pwd_grp.c
+++ b/libpwdgrp/pwd_grp.c
@@ -53,6 +53,66 @@ static int bb__parsespent(void *sp, char *line);
 #endif
 
 /**********************************************************************/
+/* We avoid having big global data. */
+
+struct statics {
+	/* Smaller things first */
+	struct passwd getpwuid_resultbuf;
+	struct group getgrgid_resultbuf;
+	struct passwd getpwnam_resultbuf;
+	struct group getgrnam_resultbuf;
+
+	char getpwuid_buffer[PWD_BUFFER_SIZE];
+	char getgrgid_buffer[GRP_BUFFER_SIZE];
+	char getpwnam_buffer[PWD_BUFFER_SIZE];
+	char getgrnam_buffer[GRP_BUFFER_SIZE];
+#if 0
+	struct passwd fgetpwent_resultbuf;
+	struct group fgetgrent_resultbuf;
+	struct spwd fgetspent_resultbuf;
+	char fgetpwent_buffer[PWD_BUFFER_SIZE];
+	char fgetgrent_buffer[GRP_BUFFER_SIZE];
+	char fgetspent_buffer[PWD_BUFFER_SIZE];
+#endif
+#if 0 //ENABLE_USE_BB_SHADOW
+	struct spwd getspuid_resultbuf;
+	struct spwd getspnam_resultbuf;
+	char getspuid_buffer[PWD_BUFFER_SIZE];
+	char getspnam_buffer[PWD_BUFFER_SIZE];
+#endif
+// Not converted - too small to bother
+//pthread_mutex_t mylock = PTHREAD_MUTEX_INITIALIZER;
+//FILE *pwf /*= NULL*/;
+//FILE *grf /*= NULL*/;
+//FILE *spf /*= NULL*/;
+#if 0
+	struct passwd getpwent_pwd;
+	struct group getgrent_gr;
+	char getpwent_line_buff[PWD_BUFFER_SIZE];
+	char getgrent_line_buff[GRP_BUFFER_SIZE];
+#endif
+#if 0 //ENABLE_USE_BB_SHADOW
+	struct spwd getspent_spwd;
+	struct spwd sgetspent_spwd;
+	char getspent_line_buff[PWD_BUFFER_SIZE];
+	char sgetspent_line_buff[PWD_BUFFER_SIZE];
+#endif
+};
+
+static struct statics *ptr_to_statics;
+
+static struct statics *get_S(void)
+{
+	if (!ptr_to_statics)
+		ptr_to_statics = xzalloc(sizeof(*ptr_to_statics));
+	return ptr_to_statics;
+}
+
+/* Always use in this order, get_S() must be called first */
+#define RESULTBUF(name) &((S = get_S())->name##_resultbuf)
+#define BUFFER(name)    (S->name##_buffer)
+
+/**********************************************************************/
 /* For the various fget??ent_r funcs, return
  *
  *  0: success
@@ -127,21 +187,23 @@ int fgetspent_r(FILE *__restrict stream, struct spwd *__restrict resultbuf,
 #if 0
 struct passwd *fgetpwent(FILE *stream)
 {
-	static char buffer[PWD_BUFFER_SIZE];
-	static struct passwd resultbuf;
+	struct statics *S;
+	struct passwd *resultbuf = RESULTBUF(fgetpwent);
+	char *buffer = BUFFER(fgetpwent);
 	struct passwd *result;
 
-	fgetpwent_r(stream, &resultbuf, buffer, sizeof(buffer), &result);
+	fgetpwent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetpwent)), &result);
 	return result;
 }
 
 struct group *fgetgrent(FILE *stream)
 {
-	static char buffer[GRP_BUFFER_SIZE];
-	static struct group resultbuf;
+	struct statics *S;
+	struct group *resultbuf = RESULTBUF(fgetgrent);
+	char *buffer = BUFFER(fgetgrent);
 	struct group *result;
 
-	fgetgrent_r(stream, &resultbuf, buffer, sizeof(buffer), &result);
+	fgetgrent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetgrent)), &result);
 	return result;
 }
 #endif
@@ -150,11 +212,12 @@ struct group *fgetgrent(FILE *stream)
 #if 0
 struct spwd *fgetspent(FILE *stream)
 {
-	static char buffer[PWD_BUFFER_SIZE];
-	static struct spwd resultbuf;
+	struct statics *S;
+	struct spwd *resultbuf = RESULTBUF(fgetspent);
+	char *buffer = BUFFER(fgetspent);
 	struct spwd *result;
 
-	fgetspent_r(stream, &resultbuf, buffer, sizeof(buffer), &result);
+	fgetspent_r(stream, resultbuf, buffer, sizeof(BUFFER(fgetspent)), &result);
 	return result;
 }
 #endif
@@ -239,22 +302,24 @@ int sgetspent_r(const char *string, struct spwd *result_buf,
 /* This one has many users */
 struct passwd *getpwuid(uid_t uid)
 {
-	static char buffer[PWD_BUFFER_SIZE];
-	static struct passwd resultbuf;
+	struct statics *S;
+	struct passwd *resultbuf = RESULTBUF(getpwuid);
+	char *buffer = BUFFER(getpwuid);
 	struct passwd *result;
 
-	getpwuid_r(uid, &resultbuf, buffer, sizeof(buffer), &result);
+	getpwuid_r(uid, resultbuf, buffer, sizeof(BUFFER(getpwuid)), &result);
 	return result;
 }
 
 /* This one has many users */
 struct group *getgrgid(gid_t gid)
 {
-	static char buffer[GRP_BUFFER_SIZE];
-	static struct group resultbuf;
+	struct statics *S;
+	struct group *resultbuf = RESULTBUF(getgrgid);
+	char *buffer = BUFFER(getgrgid);
 	struct group *result;
 
-	getgrgid_r(gid, &resultbuf, buffer, sizeof(buffer), &result);
+	getgrgid_r(gid, resultbuf, buffer, sizeof(BUFFER(getgrgid)), &result);
 	return result;
 }
 
@@ -284,11 +349,12 @@ int getspuid_r(uid_t uid, struct spwd *__restrict resultbuf,
  * Why it was added, I do not know. */
 struct spwd *getspuid(uid_t uid)
 {
-	static char buffer[PWD_BUFFER_SIZE];
-	static struct spwd resultbuf;
+	struct statics *S;
+	struct spwd *resultbuf = RESULTBUF(getspuid);
+	char *buffer = BUFFER(getspuid);
 	struct spwd *result;
 
-	getspuid_r(uid, &resultbuf, buffer, sizeof(buffer), &result);
+	getspuid_r(uid, resultbuf, buffer, sizeof(BUFFER(getspuid)), &result);
 	return result;
 }
 #endif
@@ -296,33 +362,36 @@ struct spwd *getspuid(uid_t uid)
 /* This one has many users */
 struct passwd *getpwnam(const char *name)
 {
-	static char buffer[PWD_BUFFER_SIZE];
-	static struct passwd resultbuf;
+	struct statics *S;
+	struct passwd *resultbuf = RESULTBUF(getpwnam);
+	char *buffer = BUFFER(getpwnam);
 	struct passwd *result;
 
-	getpwnam_r(name, &resultbuf, buffer, sizeof(buffer), &result);
+	getpwnam_r(name, resultbuf, buffer, sizeof(BUFFER(getpwnam)), &result);
 	return result;
 }
 
 /* This one has many users */
 struct group *getgrnam(const char *name)
 {
-	static char buffer[GRP_BUFFER_SIZE];
-	static struct group resultbuf;
+	struct statics *S;
+	struct group *resultbuf = RESULTBUF(getgrnam);
+	char *buffer = BUFFER(getgrnam);
 	struct group *result;
 
-	getgrnam_r(name, &resultbuf, buffer, sizeof(buffer), &result);
+	getgrnam_r(name, resultbuf, buffer, sizeof(BUFFER(getgrnam)), &result);
 	return result;
 }
 
 #if 0 //ENABLE_USE_BB_SHADOW
 struct spwd *getspnam(const char *name)
 {
-	static char buffer[PWD_BUFFER_SIZE];
-	static struct spwd resultbuf;
+	struct statics *S;
+	struct spwd *resultbuf = RESULTBUF(getspnam);
+	char *buffer = BUFFER(getspnam);
 	struct spwd *result;
 
-	getspnam_r(name, &resultbuf, buffer, sizeof(buffer), &result);
+	getspnam_r(name, resultbuf, buffer, sizeof(BUFFER(getspnam)), &result);
 	return result;
 }
 #endif