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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <err.h>
struct context {
void *buf;
struct {
size_t offset, len;
bool has_offset, has_len;
struct {
FILE *src;
size_t size;
} wm;
enum {
MODE_MAP,
MODE_WRITE,
MODE_READ
} mode;
} op;
struct {
FILE *mem;
pid_t pid;
} proc;
};
static void
usage(const char *argv0)
{
fprintf(stderr, "usage: %s pid map file [offset] [len] < regions\n"
" %s pid write file [offset] [len] < regions\n"
" %s pid read [offset] [len] < regions\n"
" regions must be in /proc/<pid>/maps format", argv0, argv0, argv0);
exit(EXIT_FAILURE);
}
static void
context_init(struct context *ctx, size_t argc, const char *argv[])
{
if (argc < 3)
usage(argv[0]);
size_t arg = 1;
*ctx = (struct context){0};
ctx->proc.pid = strtoull(argv[arg++], NULL, 10);
{
bool m = false, w = false, r = false;
const char *mode = argv[arg++];
if (!(m = !strcmp(mode, "map")) && !(w = !strcmp(mode, "write")) && !(r = !strcmp(mode, "read")))
errx(EXIT_FAILURE, "mode must be write or read");
ctx->op.mode = (m ? MODE_MAP : (w ? MODE_WRITE : MODE_READ));
}
const char *wmname = NULL;
if (ctx->op.mode == MODE_MAP || ctx->op.mode == MODE_WRITE) {
if (argc < arg + 1)
usage(argv[0]);
wmname = argv[arg++];
}
if (argc >= arg + 1) {
ctx->op.offset = strtoull(argv[arg++], NULL, 10);
ctx->op.has_offset = true;
}
if (argc >= arg + 1) {
ctx->op.len = strtoull(argv[arg++], NULL, 10);
ctx->op.has_len = true;
}
if (wmname) {
if (!(ctx->op.wm.src = fopen(wmname, "rb")))
err(EXIT_FAILURE, "fopen(%s)", wmname);
if (fseek(ctx->op.wm.src, 0, SEEK_END) != 0)
err(EXIT_FAILURE, "fseek");
ctx->op.wm.size = ftell(ctx->op.wm.src);
}
char path[128];
snprintf(path, sizeof(path), "/proc/%u/mem", ctx->proc.pid);
if (!(ctx->proc.mem = fopen(path, "w+b")))
err(EXIT_FAILURE, "fopen(%s)", path);
}
static void
context_release(struct context *ctx)
{
if (ctx->op.wm.src)
fclose(ctx->op.wm.src);
fclose(ctx->proc.mem);
free(ctx->buf);
*ctx = (struct context){0};
}
static void
for_each_line_in_file(FILE *f, void (*cb)(const char *line, void *data), void *data)
{
char *buffer = NULL;
size_t step = 1024, allocated = 0, written = 0, read = 0;
do {
if (written + read >= allocated && !(buffer = realloc(buffer, (allocated += step) + 1)))
err(EXIT_FAILURE, "realloc");
buffer[(written += read)] = 0;
size_t ate = 0;
for (char *line = buffer, *nl; (nl = strchr(line, '\n')); line = nl + 1) {
*nl = 0;
cb(line, data);
ate += nl + 1 - line;
}
memmove(buffer, buffer + ate, (written = written - ate));
} while ((read = fread(buffer + written, 1, allocated - written, f)));
free(buffer);
}
static void
region_cb(const char *line, void *data)
{
struct context *ctx = data;
unsigned long start, end, region_offset;
if (sscanf(line, "%lx-%lx %*s %lx", &start, &end, ®ion_offset) < 3) {
warnx("failed to parse mapping:\n%s", line);
return;
}
warnx("%s", line);
start += ctx->op.offset;
if (start > end) {
warnx("write offset %lx is out of bounds", start);
return;
}
region_offset = (ctx->op.mode == MODE_MAP ? region_offset : 0);
const size_t rlen = (ctx->op.has_len ? ctx->op.len : (ctx->op.mode == MODE_READ ? end - start : ctx->op.wm.size));
const size_t len = (rlen > end - start ? end - start : rlen);
if (!len)
return;
if (!(ctx->buf = realloc(ctx->buf, len)))
err(EXIT_FAILURE, "realloc");
clearerr(ctx->proc.mem);
if (ctx->op.mode == MODE_MAP || ctx->op.mode == MODE_WRITE) {
if (fseek(ctx->op.wm.src, region_offset, SEEK_SET) != 0)
err(EXIT_FAILURE, "fseek");
const size_t rd = fread(ctx->buf, 1, len, ctx->op.wm.src);
if (fseek(ctx->proc.mem, start, SEEK_SET) != 0)
err(EXIT_FAILURE, "fseek");
const size_t wd = fwrite(ctx->buf, 1, rd, ctx->proc.mem);
if (ferror(ctx->proc.mem)) {
warn("fread(/proc/%u/mem)", ctx->proc.pid);
return;
}
if (ctx->op.mode == MODE_WRITE) {
if (rlen > wd) {
warnx("wrote %lu bytes (%lu bytes truncated) to offset 0x%lx", wd, rlen - wd, start);
} else {
warnx("wrote %lu bytes to offset 0x%lx", wd, start);
}
} else {
if (rlen > wd) {
warnx("mapped %lu bytes (%lu bytes truncated) from offset 0x%lx to offset 0x%lx", wd, rlen - wd, region_offset, start);
} else {
warnx("mapped %lu bytes from offset 0x%lx to offset 0x%lx", wd, region_offset, start);
}
}
} else {
if (fseek(ctx->proc.mem, start, SEEK_SET) != 0)
err(EXIT_FAILURE, "fseek");
const size_t rd = fread(ctx->buf, 1, len, ctx->proc.mem);
if (ferror(ctx->proc.mem))
warn("fread(/proc/%u/mem)", ctx->proc.pid);
if (fwrite(ctx->buf, 1, rd, stdout) != rd)
err(EXIT_FAILURE, "fwrite");
}
}
int
main(int argc, const char *argv[])
{
struct context ctx;
context_init(&ctx, argc, argv);
if (ptrace(PTRACE_ATTACH, ctx.proc.pid, NULL, NULL) == -1L)
err(EXIT_FAILURE, "ptrace(PTRACE_ATTACH, %u, NULL, NULL)", ctx.proc.pid);
{
int status;
if (waitpid(ctx.proc.pid, &status, 0) == -1 || !WIFSTOPPED(status))
err(EXIT_FAILURE, "waitpid");
}
for_each_line_in_file(stdin, region_cb, &ctx);
ptrace(PTRACE_DETACH, ctx.proc.pid, 1, 0);
context_release(&ctx);
return EXIT_SUCCESS;
}
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