Module: ngircd.git Branch: master Commit: 5d88030bd1a197041f84530a88c2590e6bb1bbb1 URL: http://ngircd.barton.de/cgi-bin/gitweb.cgi?p=ngircd.git&a=commit;h=5d880...
Author: Alexander Barton alex@barton.de Date: Sat Jan 4 23:57:05 2014 +0100
Support non-standard vsnprintf() return code
C99 states that vsnprintf() "returns the number of characters that would have been printed if the n were unlimited"; but according to the Linux manual page "glibc until 2.0.6 would return -1 when the output was truncated" -- so we have to handle both cases ...
---
src/ngircd/conn.c | 13 +++++++++++-- src/portab/portabtest.c | 25 ++++++++++++++++++++++--- 2 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/src/ngircd/conn.c b/src/ngircd/conn.c index 3f447c6..fef568e 100644 --- a/src/ngircd/conn.c +++ b/src/ngircd/conn.c @@ -1,6 +1,6 @@ /* * ngIRCd -- The Next Generation IRC Daemon - * Copyright (c)2001-2013 Alexander Barton (alex@barton.de) and Contributors. + * Copyright (c)2001-2014 Alexander Barton (alex@barton.de) and Contributors. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -984,6 +984,7 @@ va_dcl size_t len; bool ok; va_list ap; + int r;
assert( Idx > NONE ); assert( Format != NULL ); @@ -993,7 +994,8 @@ va_dcl #else va_start( ap ); #endif - if (vsnprintf( buffer, COMMAND_LEN - 2, Format, ap ) >= COMMAND_LEN - 2 ) { + r = vsnprintf(buffer, COMMAND_LEN - 2, Format, ap); + if (r >= COMMAND_LEN - 2 || r == -1) { /* * The string that should be written to the socket is longer * than the allowed size of COMMAND_LEN bytes (including both @@ -1014,6 +1016,13 @@ va_dcl * an other server only routing the message!), so the only * option left is to shorten the string and to hope that the * result is still somewhat useful ... + * + * Note: + * C99 states that vsnprintf() "returns the number of characters + * that would have been printed if the n were unlimited"; but + * according to the Linux manual page "glibc until 2.0.6 would + * return -1 when the output was truncated" -- so we have to + * handle both cases ... * -alex- */
diff --git a/src/portab/portabtest.c b/src/portab/portabtest.c index 9e6bd22..b104739 100644 --- a/src/portab/portabtest.c +++ b/src/portab/portabtest.c @@ -139,16 +139,35 @@ va_dcl { char str[5]; va_list ap; + int r;
#ifdef PROTOTYPES va_start(ap, Format); #else va_start(ap); #endif - if (vsnprintf(str, sizeof(str), Format, ap) != Len) - Panic("vsnprintf return code"); + r = vsnprintf(str, sizeof(str), Format, ap); va_end(ap); - + if (r != Len) { + /* C99 states that vsnprintf() "returns the number of + * characters that would have been printed if the n were + * unlimited", but according to the Linux manual page "glibc + * until 2.0.6 would return -1 when the output was truncated", + * and other implementations (libUTIL on A/UX) even return the + * number of characters processed ... so we only test our own + * implementation and warn on errors otherwise :-/ */ +#ifdef HAVE_VSNPRINTF + fprintf(stderr, + "\n ** WARNING: The vsnprintf() function of this system isn't standard\n"); + fprintf(stderr, + " ** conformant and returns a WRONG result: %d (should be %d)! The test\n", + r, Len); + fprintf(stderr, + " ** result has been ignored but may lead to errors during execution!\n\n"); +#else + Panic("vsnprintf return code"); +#endif + } if (str[4] != '\0') Panic("vsnprintf NULL byte"); if (strlen(str) != 4)