Re: [PATCH] Implement "info proc mappings" for NetBSD

Kamil Rytarowski
2020-03-19T13:09:09Z

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Ping?

I depend on this patch with more feature in "info proc" and

This one is mostly resuing prior art from the FreeBSD code.

On 16.03.2020 18:34, Kamil Rytarowski wrote:
> Define nbsd_nat_target::find_memory_regions and
> nbsd_nat_target::info_proc. info_proc handles as of now only
> the "mappings" command.
>
> Define a local static function kinfo_get_vmmap() that reads
> the process memory layout of a specified process.
> kinfo_get_vmmap() wraps the sysctl(3) call.
>
> nbsd-tdep.c defines now utility functions for printing the
> process memory layout:
> * nbsd_info_proc_mappings_header()
> * nbsd_vm_map_entry_flags()
> * nbsd_info_proc_mappings_entry()
>
> This code is based on the FreeBSD implementation.
>
> gdb/ChangeLog:
>
> * nbsd-nat.c; Include "nbsd-tdep.h", "inferior.h" and "gdbarch.h".
> * nbsd-nat.c (nbsd_nat_target::find_memory_regions)
> (nbsd_nat_target::info_proc): New functions.
> * nbsd-nat.c (kinfo_get_vmmap): New function.
> * nbsd-nat.c (nbsd_nat_target::info_proc) Use
> nbsd_info_proc_mappings_header and nbsd_info_proc_mappings_entry.
> * nbsd-tdep.c (nbsd_info_proc_mappings_header)
> (nbsd_info_proc_mappings_entry, nbsd_vm_map_entry_flags): New
> functions.
> * nbsd-tdep.c (KINFO_VME_PROT_READ, KINFO_VME_PROT_WRITE)
> (KINFO_VME_PROT_EXEC, KINFO_VME_FLAG_COW)
> (KINFO_VME_FLAG_NEEDS_COPY, KINFO_VME_FLAG_NOCOREDUMP)
> (KINFO_VME_FLAG_PAGEABLE, KINFO_VME_FLAG_GROWS_UP)
> (KINFO_VME_FLAG_GROWS_DOWN): New.
> ---
> gdb/ChangeLog | 17 ++++++
> gdb/nbsd-nat.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++++
> gdb/nbsd-nat.h | 2 +
> gdb/nbsd-tdep.c | 91 +++++++++++++++++++++++++++++
> gdb/nbsd-tdep.h | 18 ++++++
> 5 files changed, 277 insertions(+)
>
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index a0d97584189..b690222068a 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,3 +1,20 @@
> +2020-03-16 Kamil Rytarowski <n54@gmx.com>
> +
> + * nbsd-nat.c; Include "nbsd-tdep.h", "inferior.h" and "gdbarch.h".
> + * nbsd-nat.c (nbsd_nat_target::find_memory_regions)
> + (nbsd_nat_target::info_proc): New functions.
> + * nbsd-nat.c (kinfo_get_vmmap): New function.
> + * nbsd-nat.c (nbsd_nat_target::info_proc) Use
> + nbsd_info_proc_mappings_header and nbsd_info_proc_mappings_entry.
> + * nbsd-tdep.c (nbsd_info_proc_mappings_header)
> + (nbsd_info_proc_mappings_entry, nbsd_vm_map_entry_flags): New
> + functions.
> + * nbsd-tdep.c (KINFO_VME_PROT_READ, KINFO_VME_PROT_WRITE)
> + (KINFO_VME_PROT_EXEC, KINFO_VME_FLAG_COW)
> + (KINFO_VME_FLAG_NEEDS_COPY, KINFO_VME_FLAG_NOCOREDUMP)
> + (KINFO_VME_FLAG_PAGEABLE, KINFO_VME_FLAG_GROWS_UP)
> + (KINFO_VME_FLAG_GROWS_DOWN): New.
> +
> 2020-03-14 Tom Tromey <tom@tromey.com>
>
> * c-typeprint.c (cp_type_print_method_args): Print "__restrict__"
> diff --git a/gdb/nbsd-nat.c b/gdb/nbsd-nat.c
> index e7f91bebb0d..3cafd24b1dc 100644
> --- a/gdb/nbsd-nat.c
> +++ b/gdb/nbsd-nat.c
> @@ -20,6 +20,9 @@
> #include "defs.h"
>
> #include "nbsd-nat.h"
> +#include "nbsd-tdep.h"
> +#include "inferior.h"
> +#include "gdbarch.h"
>
> /* Return the name of a file that can be opened to get the symbols for
> the child process identified by PID. */
> @@ -41,3 +44,149 @@ nbsd_nat_target::pid_to_exec_file (int pid)
>
> return NULL;
> }
> +
> +/* Retrieve all the memory regions in the specified process. */
> +
> +static struct kinfo_vmentry *
> +kinfo_get_vmmap(pid_t pid, size_t *size)
> +{
> + int mib[5] = {CTL_VM, VM_PROC, VM_PROC_MAP, pid, sizeof(struct kinfo_vmentry)};
> +
> + size_t length = 0;
> + if (sysctl(mib, ARRAY_SIZE (mib), NULL, &length, NULL, 0)) {
> + *size = 0;
> + return NULL;
> + }
> +
> + /* Prereserve more space. */
> + length = length * 5 / 3;
> +
> + struct kinfo_vmentry *kiv = (struct kinfo_vmentry *) calloc(length, 1);
> + if (kiv == NULL) {
> + *size = 0;
> + return NULL;
> + }
> +
> + if (sysctl(mib, ARRAY_SIZE (mib), kiv, &length, NULL, 0)) {
> + *size = 0;
> + free(kiv);
> + return NULL;
> + }
> +
> + *size = length / sizeof(*kiv);
> + return kiv;
> +}
> +
> +/* Iterate over all the memory regions in the current inferior,
> + calling FUNC for each memory region. OBFD is passed as the last
> + argument to FUNC. */
> +
> +int
> +nbsd_nat_target::find_memory_regions (find_memory_region_ftype func,
> + void *obfd)
> +{
> + pid_t pid = inferior_ptid.pid ();
> + struct kinfo_vmentry *kve;
> + uint64_t size;
> + int i;
> + size_t nitems;
> +
> + gdb::unique_xmalloc_ptr<struct kinfo_vmentry>
> + vmentl (kinfo_get_vmmap (pid, &nitems));
> + if (vmentl == NULL)
> + perror_with_name (_("Couldn't fetch VM map entries."));
> +
> + for (i = 0, kve = vmentl.get (); i < nitems; i++, kve++)
> + {
> + /* Skip unreadable segments and those where MAP_NOCORE has been set. */
> + if (!(kve->kve_protection & KVME_PROT_READ)
> + || kve->kve_flags & KVME_FLAG_NOCOREDUMP)
> + continue;
> +
> + /* Skip segments with an invalid type. */
> + switch (kve->kve_type) {
> + case KVME_TYPE_VNODE:
> + case KVME_TYPE_ANON:
> + case KVME_TYPE_SUBMAP:
> + case KVME_TYPE_OBJECT:
> + break;
> + default:
> + continue;
> + }
> +
> + size = kve->kve_end - kve->kve_start;
> + if (info_verbose)
> + {
> + fprintf_filtered (gdb_stdout,
> + "Save segment, %ld bytes at %s (%c%c%c)\n",
> + (long) size,
> + paddress (target_gdbarch (), kve->kve_start),
> + kve->kve_protection & KVME_PROT_READ ? 'r' : '-',
> + kve->kve_protection & KVME_PROT_WRITE ? 'w' : '-',
> + kve->kve_protection & KVME_PROT_EXEC ? 'x' : '-');
> + }
> +
> + /* Invoke the callback function to create the corefile segment.
> + Pass MODIFIED as true, we do not know the real modification state. */
> + func (kve->kve_start, size, kve->kve_protection & KVME_PROT_READ,
> + kve->kve_protection & KVME_PROT_WRITE,
> + kve->kve_protection & KVME_PROT_EXEC, 1, obfd);
> + }
> + return 0;
> +}
> +
> +/* Implement the "info_proc" target_ops method. */
> +
> +bool
> +nbsd_nat_target::info_proc (const char *args, enum info_proc_what what)
> +{
> + pid_t pid;
> + bool do_mappings = false;
> +
> + switch (what)
> + {
> + case IP_MAPPINGS:
> + do_mappings = true;
> + break;
> + default:
> + error (_("Not supported on this target."));
> + }
> +
> + gdb_argv built_argv (args);
> + if (built_argv.count () == 0)
> + {
> + pid = inferior_ptid.pid ();
> + if (pid == 0)
> + error (_("No current process: you must name one."));
> + }
> + else if (built_argv.count () == 1 && isdigit (built_argv[0][0]))
> + pid = strtol (built_argv[0], NULL, 10);
> + else
> + error (_("Invalid arguments."));
> +
> + printf_filtered (_("process %d\n"), pid);
> +
> + if (do_mappings)
> + {
> + size_t nvment;
> + gdb::unique_xmalloc_ptr<struct kinfo_vmentry>
> + vmentl (kinfo_get_vmmap (pid, &nvment));
> +
> + if (vmentl != nullptr)
> + {
> + int addr_bit = TARGET_CHAR_BIT * sizeof (void *);
> + nbsd_info_proc_mappings_header (addr_bit);
> +
> + struct kinfo_vmentry *kve = vmentl.get ();
> + for (int i = 0; i < nvment; i++, kve++)
> + nbsd_info_proc_mappings_entry (addr_bit, kve->kve_start,
> + kve->kve_end, kve->kve_offset,
> + kve->kve_flags, kve->kve_protection,
> + kve->kve_path);
> + }
> + else
> + warning (_("unable to fetch virtual memory map"));
> + }
> +
> + return true;
> +}
> diff --git a/gdb/nbsd-nat.h b/gdb/nbsd-nat.h
> index a752fbe572d..98af21d0bda 100644
> --- a/gdb/nbsd-nat.h
> +++ b/gdb/nbsd-nat.h
> @@ -27,6 +27,8 @@
> struct nbsd_nat_target : public inf_ptrace_target
> {
> char *pid_to_exec_file (int pid) override;
> + int find_memory_regions (find_memory_region_ftype func, void *data) override;
> + bool info_proc (const char *, enum info_proc_what) override;
> };
>
> #endif /* nbsd-nat.h */
> diff --git a/gdb/nbsd-tdep.c b/gdb/nbsd-tdep.c
> index 49bb2b706bd..23732854172 100644
> --- a/gdb/nbsd-tdep.c
> +++ b/gdb/nbsd-tdep.c
> @@ -23,6 +23,23 @@
> #include "solib-svr4.h"
> #include "nbsd-tdep.h"
>
> +/* Flags in the 'kve_protection' field in struct kinfo_vmentry. These
> + match the KVME_PROT_* constants in <sys/sysctl.h>. */
> +
> +#define KINFO_VME_PROT_READ 0x00000001
> +#define KINFO_VME_PROT_WRITE 0x00000002
> +#define KINFO_VME_PROT_EXEC 0x00000004
> +
> +/* Flags in the 'kve_flags' field in struct kinfo_vmentry. These
> + match the KVME_FLAG_* constants in <sys/sysctl.h>. */
> +
> +#define KINFO_VME_FLAG_COW 0x00000001
> +#define KINFO_VME_FLAG_NEEDS_COPY 0x00000002
> +#define KINFO_VME_FLAG_NOCOREDUMP 0x00000004
> +#define KINFO_VME_FLAG_PAGEABLE 0x00000008
> +#define KINFO_VME_FLAG_GROWS_UP 0x00000010
> +#define KINFO_VME_FLAG_GROWS_DOWN 0x00000020
> +
> /* FIXME: kettenis/20060115: We should really eliminate the next two
> functions completely. */
>
> @@ -47,3 +64,77 @@ nbsd_pc_in_sigtramp (CORE_ADDR pc, const char *func_name)
> return (func_name != NULL
> && startswith (func_name, "__sigtramp"));
> }
> +
> +/* See fbsd-tdep.h. */
> +
> +void
> +nbsd_info_proc_mappings_header (int addr_bit)
> +{
> + printf_filtered (_("Mapped address spaces:\n\n"));
> + if (addr_bit == 64)
> + {
> + printf_filtered (" %18s %18s %10s %10s %9s %s\n",
> + "Start Addr",
> + " End Addr",
> + " Size", " Offset", "Flags ", "File");
> + }
> + else
> + {
> + printf_filtered ("\t%10s %10s %10s %10s %9s %s\n",
> + "Start Addr",
> + " End Addr",
> + " Size", " Offset", "Flags ", "File");
> + }
> +}
> +
> +/* Helper function to generate mappings flags for a single VM map
> + entry in 'info proc mappings'. */
> +
> +static const char *
> +nbsd_vm_map_entry_flags (int kve_flags, int kve_protection)
> +{
> + static char vm_flags[9];
> +
> + vm_flags[0] = (kve_protection & KINFO_VME_PROT_READ) ? 'r' : '-';
> + vm_flags[1] = (kve_protection & KINFO_VME_PROT_WRITE) ? 'w' : '-';
> + vm_flags[2] = (kve_protection & KINFO_VME_PROT_EXEC) ? 'x' : '-';
> + vm_flags[3] = ' ';
> + vm_flags[4] = (kve_flags & KINFO_VME_FLAG_COW) ? 'C' : '-';
> + vm_flags[5] = (kve_flags & KINFO_VME_FLAG_NEEDS_COPY) ? 'N' : '-';
> + vm_flags[6] = (kve_flags & KINFO_VME_FLAG_PAGEABLE) ? 'P' : '-';
> + vm_flags[7] = (kve_flags & KINFO_VME_FLAG_GROWS_UP) ? 'U'
> + : (kve_flags & KINFO_VME_FLAG_GROWS_DOWN) ? 'D' : '-';
> + vm_flags[8] = '\0';
> +
> + return vm_flags;
> +}
> +
> +/* See nbsd-tdep.h. */
> +
> +void
> +nbsd_info_proc_mappings_entry (int addr_bit, ULONGEST kve_start,
> + ULONGEST kve_end, ULONGEST kve_offset,
> + int kve_flags, int kve_protection,
> + const void *kve_path)
> +{
> + if (addr_bit == 64)
> + {
> + printf_filtered (" %18s %18s %10s %10s %9s %s\n",
> + hex_string (kve_start),
> + hex_string (kve_end),
> + hex_string (kve_end - kve_start),
> + hex_string (kve_offset),
> + nbsd_vm_map_entry_flags (kve_flags, kve_protection),
> + reinterpret_cast<const char *> (kve_path));
> + }
> + else
> + {
> + printf_filtered ("\t%10s %10s %10s %10s %9s %s\n",
> + hex_string (kve_start),
> + hex_string (kve_end),
> + hex_string (kve_end - kve_start),
> + hex_string (kve_offset),
> + nbsd_vm_map_entry_flags (kve_flags, kve_protection),
> + reinterpret_cast<const char *> (kve_path));
> + }
> +}
> diff --git a/gdb/nbsd-tdep.h b/gdb/nbsd-tdep.h
> index c99a8b537b6..81bdb2510f5 100644
> --- a/gdb/nbsd-tdep.h
> +++ b/gdb/nbsd-tdep.h
> @@ -25,4 +25,22 @@ struct link_map_offsets *nbsd_lp64_solib_svr4_fetch_link_map_offsets (void);
>
> int nbsd_pc_in_sigtramp (CORE_ADDR, const char *);
>
> +/* Output the header for "info proc mappings". ADDR_BIT is the size
> + of a virtual address in bits. */
> +
> +extern void nbsd_info_proc_mappings_header (int addr_bit);
> +
> +/* Output description of a single memory range for "info proc
> + mappings". ADDR_BIT is the size of a virtual address in bits. The
> + KVE_START, KVE_END, KVE_OFFSET, KVE_FLAGS, and KVE_PROTECTION
> + parameters should contain the value of the corresponding fields in
> + a 'struct kinfo_vmentry'. The KVE_PATH parameter should contain a
> + pointer to the 'kve_path' field in a 'struct kinfo_vmentry'. */
> +
> +extern void nbsd_info_proc_mappings_entry (int addr_bit, ULONGEST kve_start,
> + ULONGEST kve_end,
> + ULONGEST kve_offset,
> + int kve_flags, int kve_protection,
> + const void *kve_path);
> +
> #endif /* NBSD_TDEP_H */
> --
> 2.25.0
>

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