From d00a27c5addfb6b7350a39215b48f4aaffa5960c Mon Sep 17 00:00:00 2001 From: Paul Marechal Date: Fri, 21 Dec 2018 12:02:33 -0500 Subject: [PATCH] gdb: Fix "info os " command Running `info os someUnknownOsType` is crashing when gdb is built with -D_GLIBCXX_DEBUG: /usr/include/c++/5/debug/vector:439:error: attempt to access an element in an empty container. In target_read_stralloc from target.c, the call to target_read_alloc_1 can return an empty vector, we then call vector::back on this vector, which is invalid. This commit adds a check for emptiness before trying to call vector::back on it. It also adds test to check for `info os ` to return the proper error message. This is a regression in gdb 8.2 and this patch restores the behavior of previous versions. gdb/ChangeLog: PR gdb/23974 * target.c (target_read_stralloc): Check for empty vector. gdb/testsuite/ChangeLog: PR gdb/23974 * gdb.base/info-os.exp: Check return for unknown "info os" type. --- gdb/ChangeLog | 5 +++++ gdb/target.c | 2 +- gdb/testsuite/ChangeLog | 5 +++++ gdb/testsuite/gdb.base/info-os.exp | 3 +++ 4 files changed, 14 insertions(+), 1 deletion(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4ead538e674..db7a745a9cd 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2018-12-21 Paul Marechal + + PR gdb/23974 + * target.c (target_read_stralloc): Check for empty vector. + 2018-12-21 Дилян Палаузов * top.c (print_gdb_configuration): Print "--without-python" diff --git a/gdb/target.c b/gdb/target.c index 80b84531764..6c63255d03c 100644 --- a/gdb/target.c +++ b/gdb/target.c @@ -1793,7 +1793,7 @@ target_read_stralloc (struct target_ops *ops, enum target_object object, if (!buf) return {}; - if (buf->back () != '\0') + if (buf->empty () || buf->back () != '\0') buf->push_back ('\0'); /* Check for embedded NUL bytes; but allow trailing NULs. */ diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index c499d624dc4..f3224d4b4e4 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-12-21 Paul Marechal + + PR gdb/23974 + * gdb.base/info-os.exp: Check return for unknown "info os" type. + 2018-12-20 Philippe Waroquiers * gdb.ada/info_auto_lang.exp: Normalize some_c source file. diff --git a/gdb/testsuite/gdb.base/info-os.exp b/gdb/testsuite/gdb.base/info-os.exp index 8d7eab9c530..c44e6b27c38 100644 --- a/gdb/testsuite/gdb.base/info-os.exp +++ b/gdb/testsuite/gdb.base/info-os.exp @@ -175,6 +175,9 @@ expect_multiline "info os semaphores" "$semkey +$semid +666 +1 .*" "get semaphor # key msqid perm num used bytes num messages last msgsnd() command last msgrcv() command user group creator user creator group last msgsnd() time last msgrcv() time last msgctl() time expect_multiline "info os msg" "$msgkey +$msqid +666 .*" "get message queues" +gdb_test "info os unknown_entry" [multi_line \ + "warning: Empty data returned by target. Wrong osdata type\\\?" \ + "Can not fetch data now."] # The SysV IPC primitives linger on after the creating process is killed # unless they are destroyed explicitly, so allow the test program to tidy -- 2.30.2