Change in simtrace2[master]: stdio: fix detection of malformated format strings

[Kévin Redon]

Kévin Redon has uploaded this change for review. ( 
https://gerrit.osmocom.org/10671


Change subject: stdio: fix detection of malformated format strings
......................................................................

stdio: fix detection of malformated format strings

the error code returned by vsnprintf was ignored,
resulting in printing the string from a previous print.

Change-Id: I8506b05d56da55d1357a1234917adf341b46e1db
---
M firmware/libcommon/source/stdio.c
1 file changed, 21 insertions(+), 8 deletions(-)



  git pull ssh://gerrit.osmocom.org:29418/simtrace2 refs/changes/71/10671/1

diff --git a/firmware/libcommon/source/stdio.c 
b/firmware/libcommon/source/stdio.c
index 2bfaed7..78517de 100644
--- a/firmware/libcommon/source/stdio.c
+++ b/firmware/libcommon/source/stdio.c
@@ -401,6 +401,9 @@

        va_start(ap, pFormat);
        rc = vsnprintf(pString, length, pFormat, ap);
+       if (rc < 0) { // format string error
+               return rc;
+       }
        va_end(ap);

        return rc;
@@ -429,12 +432,17 @@
 signed int vfprintf(FILE *pStream, const char *pFormat, va_list ap)
 {
        char pStr[MAX_STRING_SIZE];
-       char pError[] = "stdio.c: increase MAX_STRING_SIZE\n\r";

        // Write formatted string in buffer
-       if (vsprintf(pStr, pFormat, ap) >= MAX_STRING_SIZE) {
-
-               fputs(pError, stderr);
+       int rc = vsprintf(pStr, pFormat, ap);
+       if (rc < 0) {
+               fputs("format string error in ", stderr);
+               fputs(pFormat, stderr);
+               return rc;
+       }
+       if (rc >= MAX_STRING_SIZE) {
+               fputs("stdio.c: increase MAX_STRING_SIZE\n\r", stderr);
+               return rc;
        }

        // Display string
@@ -454,12 +462,17 @@
 signed int vfprintf_sync(FILE *pStream, const char *pFormat, va_list ap)
 {
        char pStr[MAX_STRING_SIZE];
-       char pError[] = "stdio.c: increase MAX_STRING_SIZE\n\r";

        // Write formatted string in buffer
-       if (vsprintf(pStr, pFormat, ap) >= MAX_STRING_SIZE) {
-
-               fputs_sync(pError, stderr);
+       int rc = vsprintf(pStr, pFormat, ap);
+       if (rc < 0) {
+               fputs_sync("format string error in ", stderr);
+               fputs_sync(pFormat, stderr);
+               return rc;
+       }
+       if (rc >= MAX_STRING_SIZE) {
+               fputs_sync("stdio.c: increase MAX_STRING_SIZE\n\r", stderr);
+               return rc;
        }

        // Display string

--
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Gerrit-Project: simtrace2
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: I8506b05d56da55d1357a1234917adf341b46e1db
Gerrit-Change-Number: 10671
Gerrit-PatchSet: 1
Gerrit-Owner: Kévin Redon <kre...@sysmocom.de>