On 8/15/24 19:39, Sami Tolvanen wrote:
> Add a basic DWARF parser, which uses libdw to traverse the debugging
> information in an object file and looks for functions and variables.
> In follow-up patches, this will be expanded to produce symbol versions
> for CONFIG_MODVERSIONS from DWARF.
>
> Signed-off-by: Sami Tolvanen <samitolva...@google.com>
> ---
> kernel/module/Kconfig | 8 ++
> scripts/Makefile | 1 +
> scripts/gendwarfksyms/.gitignore | 2 +
> scripts/gendwarfksyms/Makefile | 7 ++
> scripts/gendwarfksyms/dwarf.c | 87 +++++++++++++++
> scripts/gendwarfksyms/gendwarfksyms.c | 146 ++++++++++++++++++++++++++
> scripts/gendwarfksyms/gendwarfksyms.h | 78 ++++++++++++++
> 7 files changed, 329 insertions(+)
> create mode 100644 scripts/gendwarfksyms/.gitignore
> create mode 100644 scripts/gendwarfksyms/Makefile
> create mode 100644 scripts/gendwarfksyms/dwarf.c
> create mode 100644 scripts/gendwarfksyms/gendwarfksyms.c
> create mode 100644 scripts/gendwarfksyms/gendwarfksyms.h
>
> [...]
> +static int parse_options(int argc, const char **argv)
> +{
> + for (int i = 1; i < argc; i++) {
> + bool flag = false;
> +
> + for (int j = 0; j < ARRAY_SIZE(options); j++) {
> + if (strcmp(argv[i], options[j].arg))
> + continue;
> +
> + *options[j].flag = true;
> +
> + if (options[j].param) {
> + if (++i >= argc) {
> + error("%s needs an argument",
> + options[j].arg);
> + return -1;
> + }
> +
> + *options[j].param = argv[i];
> + }
> +
> + flag = true;
> + break;
> + }
> +
> + if (!flag)
> + object_files[object_count++] = argv[i];
I would rather add a check that this doesn't produce an out-of-bounds
access.
> [...]
> +int main(int argc, const char **argv)
> +{
> + unsigned int n;
> +
> + if (parse_options(argc, argv) < 0)
> + return usage();
> +
> + for (n = 0; n < object_count; n++) {
> + Dwfl *dwfl;
> + int fd;
> +
> + fd = open(object_files[n], O_RDONLY);
> + if (fd == -1) {
> + error("open failed for '%s': %s", object_files[n],
> + strerror(errno));
> + return -1;
> + }
> +
> + dwfl = dwfl_begin(&callbacks);
> + if (!dwfl) {
> + error("dwfl_begin failed for '%s': %s", object_files[n],
> + dwarf_errmsg(-1));
> + return -1;
> + }
> +
> + if (!dwfl_report_offline(dwfl, object_files[n], object_files[n],
> + fd)) {
> + error("dwfl_report_offline failed for '%s': %s",
> + object_files[n], dwarf_errmsg(-1));
> + return -1;
> + }
> +
> + dwfl_report_end(dwfl, NULL, NULL);
> +
> + if (dwfl_getmodules(dwfl, &process_modules, NULL, 0)) {
> + error("dwfl_getmodules failed for '%s'",
> + object_files[n]);
> + return -1;
> + }
I see that libdwfl has also directly function dwfl_nextcu(). Would it
make sense to use it to simplify the code?
> +
> + dwfl_end(dwfl);
> + close(fd);
Isn't fd consumed by dwfl_report_offline() on success? I'm seeing EBADF
from this close() call.
> + }
> +
> + return 0;
> +}
--
Thanks,
Petr
