* [PATCH v2] gdb: Fix "target file /proc/.../cmdline contained unexpected null characters"
@ 2023-07-19 11:27 Ilya Leoshkevich
2023-07-19 16:07 ` Bruno Larsen
0 siblings, 1 reply; 2+ messages in thread
From: Ilya Leoshkevich @ 2023-07-19 11:27 UTC (permalink / raw)
To: Tom Tromey, Bruno Larsen; +Cc: gdb-patches, Ilya Leoshkevich
When using the gcore command, GDB prints the following warning:
(gdb) gcore
warning: target file /proc/.../cmdline contained unexpected null characters
The reason is that cmdline is read with target_fileio_read_stralloc(),
which warns on seeing null characters. However, it's perfectly valid
for cmdline to contain \0s, so switch to target_fileio_read_alloc().
---
v1: https://sourceware.org/pipermail/gdb-patches/2023-June/200436.html
https://sourceware.org/pipermail/gdb-patches/2023-July/200993.html
v1 -> v2: Improve the commit message (Bruno).
Handle the missing trailing '\0' (Bruno).
gdb/linux-tdep.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index b5eee5e108c..90ad02310b3 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -1902,15 +1902,23 @@ linux_fill_prpsinfo (struct elf_internal_linux_prpsinfo *p)
pid = inferior_ptid.pid ();
xsnprintf (filename, sizeof (filename), "/proc/%d/cmdline", (int) pid);
/* The full name of the program which generated the corefile. */
- gdb::unique_xmalloc_ptr<char> fname
- = target_fileio_read_stralloc (NULL, filename);
+ gdb_byte *buf = NULL;
+ size_t buf_len = target_fileio_read_alloc (NULL, filename, &buf);
+ gdb::unique_xmalloc_ptr<char> fname ((char *)buf);
- if (fname == NULL || fname.get ()[0] == '\0')
+ if (buf_len < 1 || fname.get ()[0] == '\0')
{
/* No program name was read, so we won't be able to retrieve more
information about the process. */
return 0;
}
+ if (fname.get ()[buf_len - 1] != '\0')
+ {
+ warning (_("target file %s "
+ "does not contain a trailing null character"),
+ filename);
+ return 0;
+ }
memset (p, 0, sizeof (*p));
--
2.41.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v2] gdb: Fix "target file /proc/.../cmdline contained unexpected null characters"
2023-07-19 11:27 [PATCH v2] gdb: Fix "target file /proc/.../cmdline contained unexpected null characters" Ilya Leoshkevich
@ 2023-07-19 16:07 ` Bruno Larsen
0 siblings, 0 replies; 2+ messages in thread
From: Bruno Larsen @ 2023-07-19 16:07 UTC (permalink / raw)
To: Ilya Leoshkevich, Tom Tromey; +Cc: gdb-patches
On 19/07/2023 13:27, Ilya Leoshkevich wrote:
> When using the gcore command, GDB prints the following warning:
>
> (gdb) gcore
> warning: target file /proc/.../cmdline contained unexpected null characters
>
> The reason is that cmdline is read with target_fileio_read_stralloc(),
> which warns on seeing null characters. However, it's perfectly valid
> for cmdline to contain \0s, so switch to target_fileio_read_alloc().
> ---
Looks good to me now :)
Reviewed-By: Bruno Larsen <blarsen@redhat.com>
I hope a maintainer can approve this soon!
--
Cheers,
Bruno
> v1: https://sourceware.org/pipermail/gdb-patches/2023-June/200436.html
> https://sourceware.org/pipermail/gdb-patches/2023-July/200993.html
>
> v1 -> v2: Improve the commit message (Bruno).
> Handle the missing trailing '\0' (Bruno).
>
> gdb/linux-tdep.c | 14 +++++++++++---
> 1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
> index b5eee5e108c..90ad02310b3 100644
> --- a/gdb/linux-tdep.c
> +++ b/gdb/linux-tdep.c
> @@ -1902,15 +1902,23 @@ linux_fill_prpsinfo (struct elf_internal_linux_prpsinfo *p)
> pid = inferior_ptid.pid ();
> xsnprintf (filename, sizeof (filename), "/proc/%d/cmdline", (int) pid);
> /* The full name of the program which generated the corefile. */
> - gdb::unique_xmalloc_ptr<char> fname
> - = target_fileio_read_stralloc (NULL, filename);
> + gdb_byte *buf = NULL;
> + size_t buf_len = target_fileio_read_alloc (NULL, filename, &buf);
> + gdb::unique_xmalloc_ptr<char> fname ((char *)buf);
>
> - if (fname == NULL || fname.get ()[0] == '\0')
> + if (buf_len < 1 || fname.get ()[0] == '\0')
> {
> /* No program name was read, so we won't be able to retrieve more
> information about the process. */
> return 0;
> }
> + if (fname.get ()[buf_len - 1] != '\0')
> + {
> + warning (_("target file %s "
> + "does not contain a trailing null character"),
> + filename);
> + return 0;
> + }
>
> memset (p, 0, sizeof (*p));
>
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2023-07-19 16:07 ` Bruno Larsen
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