From b005d2cbe00924ddfcb8766d49201e4044abfc21 Mon Sep 17 00:00:00 2001
From: oetiker <oetiker@a5681a0c-68f1-0310-ab6d-d61299d08faa>
Date: Sun, 1 Jun 2008 20:44:01 +0000
Subject: [PATCH] Patch for rrd_context system by sebastian harl, making it
 simpler and less error prone. Removing one buffer overflow in the process.

git-svn-id: svn://svn.oetiker.ch/rrdtool/trunk/program@1392 a5681a0c-68f1-0310-ab6d-d61299d08faa
---
 src/rrd.h                 |  6 ++----
 src/rrd_error.c           | 36 +++++++++++-------------------------
 src/rrd_not_thread_safe.c | 15 ++-------------
 src/rrd_thread_safe.c     |  6 +++---
 src/rrd_thread_safe_nt.c  |  4 ++--
 5 files changed, 20 insertions(+), 47 deletions(-)

diff --git a/src/rrd.h b/src/rrd.h
index cb9914c..5f4145b 100644
--- a/src/rrd.h
+++ b/src/rrd.h
@@ -231,10 +231,8 @@ extern    "C" {
 /* END parsetime.h */
 
     struct rrd_context {
-        int       len;
-        int       errlen;
-        char     *lib_errstr;
-        char     *rrd_error;
+        char     lib_errstr[256];
+        char     rrd_error[4096];
     };
 
 /* returns the current per-thread rrd_context */
diff --git a/src/rrd_error.c b/src/rrd_error.c
index ebc51f4..e64e2df 100644
--- a/src/rrd_error.c
+++ b/src/rrd_error.c
@@ -46,7 +46,7 @@ void rrd_set_error(
     rrd_clear_error();
     va_start(argp, fmt);
 #ifdef HAVE_VSNPRINTF
-    vsnprintf(CTX->rrd_error, CTX->len, fmt, argp);
+    vsnprintf(CTX->rrd_error, sizeof(CTX->rrd_error), fmt, argp);
 #else
     vsprintf(CTX->rrd_error, fmt, argp);
 #endif
@@ -87,10 +87,10 @@ void rrd_set_error_r(
     rrd_clear_error_r(rrd_ctx);
     va_start(argp, fmt);
 #ifdef HAVE_VSNPRINTF
-    vsnprintf((char *) rrd_ctx->rrd_error, rrd_ctx->len, fmt, argp);
-    rrd_ctx->rrd_error[rrd_ctx->len] = '\0';
+    vsnprintf(rrd_ctx->rrd_error, sizeof(rrd_ctx->rrd_error), fmt, argp);
+    rrd_ctx->rrd_error[sizeof(rrd_ctx->rrd_error) - 1] = '\0';
 #else
-    vsprintf((char *) rrd_ctx->rrd_error, fmt, argp);
+    vsprintf(rrd_ctx->rrd_error, fmt, argp);
 #endif
     va_end(argp);
 }
@@ -110,7 +110,7 @@ void rrd_clear_error_r(
 char     *rrd_get_error_r(
     struct rrd_context *rrd_ctx)
 {
-    return (char *) rrd_ctx->rrd_error;
+    return rrd_ctx->rrd_error;
 }
 #endif
 
@@ -122,33 +122,19 @@ struct rrd_context *rrd_new_context(
     struct rrd_context *rrd_ctx =
         (struct rrd_context *) malloc(sizeof(struct rrd_context));
 
-    if (rrd_ctx) {
-        rrd_ctx->rrd_error = malloc(MAXLEN + 10);
-        rrd_ctx->lib_errstr = malloc(ERRBUFLEN + 10);
-        if (rrd_ctx->rrd_error && rrd_ctx->lib_errstr) {
-            *rrd_ctx->rrd_error = 0;
-            *rrd_ctx->lib_errstr = 0;
-            rrd_ctx->len = MAXLEN;
-            rrd_ctx->errlen = ERRBUFLEN;
-            return rrd_ctx;
-        }
-        if (rrd_ctx->rrd_error)
-            free(rrd_ctx->rrd_error);
-        if (rrd_ctx->lib_errstr)
-            free(rrd_ctx->lib_errstr);
-        free(rrd_ctx);
+    if (! rrd_ctx) {
+        return NULL;
     }
-    return NULL;
+
+    rrd_ctx->rrd_error[0] = '\0';
+    rrd_ctx->lib_errstr[0] = '\0';
+    return rrd_ctx;
 }
 
 void rrd_free_context(
     struct rrd_context *rrd_ctx)
 {
     if (rrd_ctx) {
-        if (rrd_ctx->rrd_error)
-            free(rrd_ctx->rrd_error);
-        if (rrd_ctx->lib_errstr)
-            free(rrd_ctx->lib_errstr);
         free(rrd_ctx);
     }
 }
diff --git a/src/rrd_not_thread_safe.c b/src/rrd_not_thread_safe.c
index c68a161..b05ee1a 100644
--- a/src/rrd_not_thread_safe.c
+++ b/src/rrd_not_thread_safe.c
@@ -14,18 +14,12 @@
 #define MAXLEN 4096
 #define ERRBUFLEN 256
 
-static char rrd_error[MAXLEN + 10];
-static char rrd_liberror[ERRBUFLEN + 10];
-static int rrd_context_init = 0;
-
 /* The global context is very useful in the transition period to even
    more thread-safe stuff, it can be used whereever we need a context
    and do not need to worry about concurrency. */
 static struct rrd_context global_ctx = {
-    MAXLEN,
-    ERRBUFLEN,
-    rrd_error,
-    rrd_liberror
+    "",
+    ""
 };
 
 /* #include <stdarg.h> */
@@ -33,11 +27,6 @@ static struct rrd_context global_ctx = {
 struct rrd_context *rrd_get_context(
     void)
 {
-    if (!rrd_context_init) {
-        rrd_context_init = 1;
-        global_ctx.rrd_error[0] = '\0';
-        global_ctx.lib_errstr[0] = '\0';
-    }
     return &global_ctx;
 }
 
diff --git a/src/rrd_thread_safe.c b/src/rrd_thread_safe.c
index 5ef978b..3138cc8 100644
--- a/src/rrd_thread_safe.c
+++ b/src/rrd_thread_safe.c
@@ -60,7 +60,7 @@ const char *rrd_strerror(
 {
     struct rrd_context *ctx = rrd_get_context();
 
-    if (strerror_r(err, ctx->lib_errstr, ctx->errlen))
+    if (strerror_r(err, ctx->lib_errstr, sizeof(ctx->lib_errstr)))
         return "strerror_r failed. sorry!";
     else
         return ctx->lib_errstr;
@@ -75,8 +75,8 @@ const char *rrd_strerror(
 
     ctx = rrd_get_context();
     pthread_mutex_lock(&mtx);
-    strncpy(ctx->lib_errstr, strerror(err), ctx->errlen);
-    ctx->lib_errstr[ctx->errlen] = '\0';
+    strncpy(ctx->lib_errstr, strerror(err), sizeof(ctx->lib_errstr));
+    ctx->lib_errstr[sizeof(ctx->lib_errstr) - 1] = '\0';
     pthread_mutex_unlock(&mtx);
     return ctx->lib_errstr;
 }
diff --git a/src/rrd_thread_safe_nt.c b/src/rrd_thread_safe_nt.c
index dba1c3e..899fe93 100644
--- a/src/rrd_thread_safe_nt.c
+++ b/src/rrd_thread_safe_nt.c
@@ -70,8 +70,8 @@ const char *rrd_strerror(
     ctx = rrd_get_context();
 
     EnterCriticalSection(&CriticalSection);
-    strncpy(ctx->lib_errstr, strerror(err), ctx->errlen);
-    ctx->lib_errstr[ctx->errlen] = '\0';
+    strncpy(ctx->lib_errstr, strerror(err), sizeof(ctx->lib_errstr));
+    ctx->lib_errstr[sizeof(ctx->lib_errstr) - 1] = '\0';
     LeaveCriticalSection(&CriticalSection);
 
     return ctx->lib_errstr;
-- 
2.11.0