* Off-by-one error in windows-nat.c causes abort at startup @ 2016-04-30 11:08 Eli Zaretskii 2016-05-02 11:50 ` Pedro Alves 0 siblings, 1 reply; 4+ messages in thread From: Eli Zaretskii @ 2016-04-30 11:08 UTC (permalink / raw) To: gdb-patches I created a gdb.ini file in my home directory, and suddenly found that almost all my GDB binaries stopped working. Even "gdb --version" would crash at startup thusly: ./common/common-utils.c:141: internal-error: xsnprintf: Assertion `ret < size' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) [answered Y; input not from terminal] This is a bug, please report it. For instructions, see: <http://www.gnu.org/software/gdb/bugs/>. ./common/common-utils.c:141: internal-error: xsnprintf: Assertion `ret < size' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Create a core file of GDB? (y or n) [answered Y; input not from terminal] This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. Luckily, I still had GDB 7.5, which did work. Using it, I found the off-by-one gotcha below (".gdbinit" is one character longer than "gdb.ini"). I guess no one tested this feature when we switched from using snprintf to xsnprintf... OK to commit (with a suitable ChangeLog entry, of course)? --- gdb/windows-nat.c~ 2016-02-10 05:19:39.000000000 +0200 +++ gdb/windows-nat.c 2016-04-30 11:57:08.500000000 +0300 @@ -2711,9 +2711,9 @@ _initialize_check_for_gdb_ini (void) if (access (oldini, 0) == 0) { int len = strlen (oldini); - char *newini = (char *) alloca (len + 1); + char *newini = (char *) alloca (len + 2); - xsnprintf (newini, len + 1, "%.*s.gdbinit", + xsnprintf (newini, len + 2, "%.*s.gdbinit", (int) (len - (sizeof ("gdb.ini") - 1)), oldini); warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini); } ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Off-by-one error in windows-nat.c causes abort at startup 2016-04-30 11:08 Off-by-one error in windows-nat.c causes abort at startup Eli Zaretskii @ 2016-05-02 11:50 ` Pedro Alves 2016-05-02 16:40 ` Eli Zaretskii 0 siblings, 1 reply; 4+ messages in thread From: Pedro Alves @ 2016-05-02 11:50 UTC (permalink / raw) To: Eli Zaretskii, gdb-patches On 04/30/2016 12:07 PM, Eli Zaretskii wrote: > Luckily, I still had GDB 7.5, which did work. Using it, I found the > off-by-one gotcha below (".gdbinit" is one character longer than > "gdb.ini"). I guess no one tested this feature when we switched from > using snprintf to xsnprintf... Sounds like gdb would corrupt memory before we switched to xsnprintf then. I'd say the problem is that the feature was added without a corresponding test case. > OK to commit (with a suitable ChangeLog entry, of course)? Sure. > > --- gdb/windows-nat.c~ 2016-02-10 05:19:39.000000000 +0200 > +++ gdb/windows-nat.c 2016-04-30 11:57:08.500000000 +0300 > @@ -2711,9 +2711,9 @@ _initialize_check_for_gdb_ini (void) > if (access (oldini, 0) == 0) > { > int len = strlen (oldini); > - char *newini = (char *) alloca (len + 1); > + char *newini = (char *) alloca (len + 2); > > - xsnprintf (newini, len + 1, "%.*s.gdbinit", > + xsnprintf (newini, len + 2, "%.*s.gdbinit", > (int) (len - (sizeof ("gdb.ini") - 1)), oldini); > warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini); (I suspect this whole function could be rewritten in a clearer form...) Thanks, Pedro Alves ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Off-by-one error in windows-nat.c causes abort at startup 2016-05-02 11:50 ` Pedro Alves @ 2016-05-02 16:40 ` Eli Zaretskii 2016-05-02 18:01 ` Pedro Alves 0 siblings, 1 reply; 4+ messages in thread From: Eli Zaretskii @ 2016-05-02 16:40 UTC (permalink / raw) To: Pedro Alves; +Cc: gdb-patches > From: Pedro Alves <palves@redhat.com> > Date: Mon, 2 May 2016 12:50:05 +0100 > > On 04/30/2016 12:07 PM, Eli Zaretskii wrote: > > > Luckily, I still had GDB 7.5, which did work. Using it, I found the > > off-by-one gotcha below (".gdbinit" is one character longer than > > "gdb.ini"). I guess no one tested this feature when we switched from > > using snprintf to xsnprintf... > > Sounds like gdb would corrupt memory before we switched to xsnprintf > then. I'd say the problem is that the feature was added without a > corresponding test case. > > > OK to commit (with a suitable ChangeLog entry, of course)? > > Sure. Thanks, pushed. > > --- gdb/windows-nat.c~ 2016-02-10 05:19:39.000000000 +0200 > > +++ gdb/windows-nat.c 2016-04-30 11:57:08.500000000 +0300 > > @@ -2711,9 +2711,9 @@ _initialize_check_for_gdb_ini (void) > > if (access (oldini, 0) == 0) > > { > > int len = strlen (oldini); > > - char *newini = (char *) alloca (len + 1); > > + char *newini = (char *) alloca (len + 2); > > > > - xsnprintf (newini, len + 1, "%.*s.gdbinit", > > + xsnprintf (newini, len + 2, "%.*s.gdbinit", > > (int) (len - (sizeof ("gdb.ini") - 1)), oldini); > > warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini); > > (I suspect this whole function could be rewritten in a clearer form...) Like not use xsnprintf at all, and instead use strcpy/strcat, perhaps? ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Off-by-one error in windows-nat.c causes abort at startup 2016-05-02 16:40 ` Eli Zaretskii @ 2016-05-02 18:01 ` Pedro Alves 0 siblings, 0 replies; 4+ messages in thread From: Pedro Alves @ 2016-05-02 18:01 UTC (permalink / raw) To: Eli Zaretskii; +Cc: gdb-patches On 05/02/2016 05:39 PM, Eli Zaretskii wrote: >> From: Pedro Alves <palves@redhat.com> >>> --- gdb/windows-nat.c~ 2016-02-10 05:19:39.000000000 +0200 >>> +++ gdb/windows-nat.c 2016-04-30 11:57:08.500000000 +0300 >>> @@ -2711,9 +2711,9 @@ _initialize_check_for_gdb_ini (void) >>> if (access (oldini, 0) == 0) >>> { >>> int len = strlen (oldini); >>> - char *newini = (char *) alloca (len + 1); >>> + char *newini = (char *) alloca (len + 2); >>> >>> - xsnprintf (newini, len + 1, "%.*s.gdbinit", >>> + xsnprintf (newini, len + 2, "%.*s.gdbinit", >>> (int) (len - (sizeof ("gdb.ini") - 1)), oldini); >>> warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini); >> >> (I suspect this whole function could be rewritten in a clearer form...) > > Like not use xsnprintf at all, and instead use strcpy/strcat, perhaps? > Yeah, something like this (untested). From 33738f6c5bf7f76d6cb6853aecf880c5570f7d74 Mon Sep 17 00:00:00 2001 From: Pedro Alves <palves@redhat.com> Date: Mon, 2 May 2016 18:57:50 +0100 Subject: [PATCH] Rewrite/simplify old gdb.ini warning --- gdb/windows-nat.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c index 2e8a777..161e887 100644 --- a/gdb/windows-nat.c +++ b/gdb/windows-nat.c @@ -2694,27 +2694,28 @@ void _initialize_check_for_gdb_ini (void) { char *homedir; + if (inhibit_gdbinit) return; homedir = getenv ("HOME"); - if (homedir) + if (homedir != NULL) { - char *p; - char *oldini = (char *) alloca (strlen (homedir) + - sizeof ("gdb.ini") + 1); - strcpy (oldini, homedir); - p = strchr (oldini, '\0'); - if (p > oldini && !IS_DIR_SEPARATOR (p[-1])) - *p++ = '/'; - strcpy (p, "gdb.ini"); + size_t homedir_len = strlen (homedir); + char *oldini; + + while (homedir_len > 0 && IS_DIR_SEPARATOR (homedir[homedir_len - 1])) + homedir_len--; + + oldini = (char *) alloca (homedir_len + sizeof ("/gdb.ini")); + memcpy (oldini, homedir, homedir_len); + strcpy (oldini + homedir_len, "/gdb.ini"); if (access (oldini, 0) == 0) { - int len = strlen (oldini); - char *newini = (char *) alloca (len + 2); + char *newini = (char *) alloca (homedir_len + sizeof ("/.gdbinit")); - xsnprintf (newini, len + 2, "%.*s.gdbinit", - (int) (len - (sizeof ("gdb.ini") - 1)), oldini); + memcpy (newini, homedir, homedir_len); + strcpy (newini + homedir_len, "/.gdbinit"); warning (_("obsolete '%s' found. Rename to '%s'."), oldini, newini); } } -- 2.5.5 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2016-05-02 18:01 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2016-04-30 11:08 Off-by-one error in windows-nat.c causes abort at startup Eli Zaretskii 2016-05-02 11:50 ` Pedro Alves 2016-05-02 16:40 ` Eli Zaretskii 2016-05-02 18:01 ` Pedro Alves
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