diff options
Diffstat (limited to 'proc-region-rw.c')
| -rw-r--r-- | proc-region-rw.c | 225 |
1 files changed, 0 insertions, 225 deletions
diff --git a/proc-region-rw.c b/proc-region-rw.c deleted file mode 100644 index f25fe2b..0000000 --- a/proc-region-rw.c +++ /dev/null @@ -1,225 +0,0 @@ -#include <stdio.h> -#include <stdlib.h> -#include <stdbool.h> -#include <string.h> -#include <sys/ptrace.h> -#include <sys/wait.h> -#include <err.h> - -// It's recommended to `setcap cap_sys_ptrace=eip proc-region-rw` to run this tool without sudo - -struct context { - void *buf; - - struct { - size_t offset, len; - bool has_offset, has_len; - - struct { - FILE *src; - size_t size; - } wm; // write/map - - 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); - - // requested write/read - const size_t rlen = (ctx->op.has_len ? ctx->op.len : (ctx->op.mode == MODE_READ ? end - start : ctx->op.wm.size)); - - // actual write/read - 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; -} |