From 05edc813413e23afcd22cd6b01b1dac96c200507 Mon Sep 17 00:00:00 2001 From: Elliott Hughes Date: Mon, 28 Aug 2023 21:35:16 -0700 Subject: [PATCH] strace: various fixes and improvements. More system calls and better decoding of existing syscalls. --- toys/pending/strace.c | 220 ++++++++++++++++++++++++------------------ 1 file changed, 128 insertions(+), 92 deletions(-) diff --git a/toys/pending/strace.c b/toys/pending/strace.c index e340a4f7..49ac2b69 100644 --- a/toys/pending/strace.c +++ b/toys/pending/strace.c @@ -167,13 +167,6 @@ static void xptrace(int req, pid_t pid, void *addr, void *data) if (ptrace(req, pid, addr, data)) perror_exit("ptrace %d pid %d", req, pid); } -static void get_regs(void) -{ - struct iovec v = {.iov_base=&TT.regs, .iov_len=sizeof(TT.regs)}; - - xptrace(PTRACE_GETREGSET, TT.pid, (void *)1, &v); // NT_PRSTATUS -} - static void ptrace_struct(long addr, void *dst, size_t bytes) { int offset = 0, i; @@ -188,6 +181,53 @@ static void ptrace_struct(long addr, void *dst, size_t bytes) } } +#define C(n) n, #n + +static void print_bits(int bitmask, long v, char *zero, ...) +{ + va_list ap; + int first = 1; + + if (!v && zero) { + fprintf(stderr, "%s", zero); + return; + } + va_start(ap, zero); + for (;;) { + int this = va_arg(ap, int); + char *name; + + if (!this) break; + name = va_arg(ap, char*); + if (bitmask) { + if (v & this) { + fprintf(stderr, "%s%s", first?"":"|", name); + first = 0; + v &= ~this; + } + } else { + if (v == this) { + fprintf(stderr, "%s", name); + v = 0; + break; + } + } + } + va_end(ap); + if (v) fprintf(stderr, "%s%#lx", first?"":"|", v); +} + +static void print_mode(unsigned m) +{ + if (m & S_IFMT) { + print_bits(0, m & S_IFMT, "", C(S_IFREG), C(S_IFDIR), C(S_IFLNK), + C(S_IFBLK), C(S_IFCHR), C(S_IFIFO), C(S_IFSOCK), 0); + fputc('|', stderr); + m &= ~S_IFMT; + } + fprintf(stderr, "%#o", m); +} + // TODO: this all relies on having the libc structs match the kernel structs, // which isn't always true for glibc... static void print_struct(long addr) @@ -240,19 +280,20 @@ static void print_struct(long addr) struct stat sb; ptrace_struct(addr, &sb, sizeof(sb)); - // TODO: decode IFMT bits in st_mode if (FLAG(v)) { // TODO: full atime/mtime/ctime dump. - fprintf(stderr, "{st_dev=makedev(%#x, %#x), st_ino=%ld, st_mode=%o, " - "st_nlink=%ld, st_uid=%d, st_gid=%d, st_blksize=%ld, st_blocks=%ld, " - "st_size=%lld, st_atime=%ld, st_mtime=%ld, st_ctime=%ld}", - dev_major(sb.st_dev), dev_minor(sb.st_dev), sb.st_ino, sb.st_mode, - (long) sb.st_nlink, sb.st_uid, sb.st_gid, (long) sb.st_blksize, - sb.st_blocks, (long long)sb.st_size, sb.st_atime, sb.st_mtime, - sb.st_ctime); + fprintf(stderr, "{st_dev=makedev(%#x, %#x), st_ino=%ld, st_mode=", + dev_major(sb.st_dev), dev_minor(sb.st_dev), sb.st_ino); + print_mode(sb.st_mode); + fprintf(stderr, ", st_nlink=%ld, st_uid=%d, st_gid=%d, " + "st_blksize=%ld, st_blocks=%ld, st_size=%lld, st_atime=%ld, " + "st_mtime=%ld, st_ctime=%ld}", (long) sb.st_nlink, sb.st_uid, + sb.st_gid, (long) sb.st_blksize, sb.st_blocks, (long long)sb.st_size, + sb.st_atime, sb.st_mtime, sb.st_ctime); } else { - fprintf(stderr, "{st_mode=%o, st_size=%lld, ...}", sb.st_mode, - (long long)sb.st_size); + fprintf(stderr, "{st_mode="); + print_mode(sb.st_mode); + fprintf(stderr, ", st_size=%lld, ...}", (long long)sb.st_size); } } else if (strstart(&TT.fmt, "termios}")) { struct termios to; @@ -281,13 +322,13 @@ static void print_ptr(long addr) else fprintf(stderr, "0x%lx", addr); } -static void print_string(long addr) +static void print_string(long addr, long limit) { long offset = 0, total = 0; - int done = 0, i; + int i; fputc('"', stderr); - while (!done) { + for (;;) { errno = 0; long v = ptrace(PTRACE_PEEKDATA, TT.pid, addr + offset); if (errno) return; @@ -296,8 +337,8 @@ static void print_string(long addr) if (!toybuf[i]) { // TODO: handle the case of dumping n bytes (e.g. read()/write()), not // just NUL-terminated strings. - done = 1; - break; + fputc('"', stderr); + return; } if (isprint(toybuf[i])) fputc(toybuf[i], stderr); else { @@ -308,89 +349,65 @@ static void print_string(long addr) else if (toybuf[i] == '\t') fputc('t', stderr); else fprintf(stderr, "x%2.2x", toybuf[i]); } - if (++total >= TT.s) { - done = 1; - break; + if (++total >= limit) { + fprintf(stderr, "\"..."); + return; } } offset += sizeof(v); } - fputc('"', stderr); -} - -static void print_bitmask(int bitmask, long v, char *zero, ...) -{ - va_list ap; - int first = 1; - - if (!v && zero) { - fprintf(stderr, "%s", zero); - return; - } - - va_start(ap, zero); - for (;;) { - int this = va_arg(ap, int); - char *name; - - if (!this) break; - name = va_arg(ap, char*); - if (bitmask) { - if (v & this) { - fprintf(stderr, "%s%s", first?"":"|", name); - first = 0; - v &= ~this; - } - } else { - if (v == this) { - fprintf(stderr, "%s", name); - v = 0; - break; - } - } - } - va_end(ap); - if (v) fprintf(stderr, "%s%#lx", first?"":"|", v); } static void print_flags(long v) { -#define C(n) n, #n if (strstart(&TT.fmt, "access|")) { - print_bitmask(1, v, "F_OK", C(R_OK), C(W_OK), C(X_OK), 0); + print_bits(1, v, "F_OK", C(R_OK), C(W_OK), C(X_OK), 0); } else if (strstart(&TT.fmt, "mmap|")) { - print_bitmask(1, v, 0, C(MAP_SHARED), C(MAP_PRIVATE), + print_bits(1, v, 0, C(MAP_SHARED), C(MAP_PRIVATE), #if defined(MAP_32BIT) C(MAP_32BIT), #endif C(MAP_ANONYMOUS), C(MAP_FIXED), C(MAP_GROWSDOWN), C(MAP_HUGETLB), C(MAP_DENYWRITE), 0); } else if (strstart(&TT.fmt, "open|")) { - print_bitmask(1, v, "O_RDONLY", C(O_WRONLY), C(O_RDWR), C(O_CLOEXEC), + print_bits(1, v, "O_RDONLY", C(O_WRONLY), C(O_RDWR), C(O_CLOEXEC), C(O_CREAT), C(O_DIRECTORY), C(O_EXCL), C(O_NOCTTY), C(O_NOFOLLOW), C(O_TRUNC), C(O_ASYNC), C(O_APPEND), C(O_DSYNC), C(O_EXCL), C(O_NOATIME), C(O_NONBLOCK), C(O_PATH), C(O_SYNC), 0x4000, "O_DIRECT", 0x8000, "O_LARGEFILE", 0x410000, "O_TMPFILE", 0); } else if (strstart(&TT.fmt, "prot|")) { - print_bitmask(1,v,"PROT_NONE",C(PROT_READ),C(PROT_WRITE),C(PROT_EXEC),0); + print_bits(1,v,"PROT_NONE",C(PROT_READ),C(PROT_WRITE),C(PROT_EXEC), +#if defined(PROT_BTI) + C(PROT_BTI), +#endif +#if defined(PROT_MTE) + C(PROT_MTE), +#endif + 0); } else if (strstart(&TT.fmt, "grnd|")) { - print_bitmask(1,v,"0",C(GRND_RANDOM),C(GRND_NONBLOCK),0); + print_bits(1,v,"0",C(GRND_RANDOM),C(GRND_NONBLOCK),0); } else abort(); } static void print_alternatives(long v) { - if (strstart(&TT.fmt, "rlimit^")) { - print_bitmask(0, v, "RLIMIT_CPU", C(RLIMIT_FSIZE), C(RLIMIT_DATA), + if (strstart(&TT.fmt, "clockid^")) { + print_bits(0, v, "CLOCK_REALTIME", C(CLOCK_MONOTONIC), + C(CLOCK_PROCESS_CPUTIME_ID), C(CLOCK_THREAD_CPUTIME_ID), + C(CLOCK_MONOTONIC_RAW), C(CLOCK_REALTIME_COARSE), + C(CLOCK_MONOTONIC_COARSE), C(CLOCK_BOOTTIME), + C(CLOCK_REALTIME_ALARM), C(CLOCK_BOOTTIME_ALARM), 0); + } else if (strstart(&TT.fmt, "rlimit^")) { + print_bits(0, v, "RLIMIT_CPU", C(RLIMIT_FSIZE), C(RLIMIT_DATA), C(RLIMIT_STACK), C(RLIMIT_CORE), C(RLIMIT_RSS), C(RLIMIT_NPROC), C(RLIMIT_NOFILE), C(RLIMIT_MEMLOCK), C(RLIMIT_AS), C(RLIMIT_LOCKS), C(RLIMIT_SIGPENDING), C(RLIMIT_MSGQUEUE), C(RLIMIT_NICE), C(RLIMIT_RTPRIO), C(RLIMIT_RTTIME), 0); } else if (strstart(&TT.fmt, "seek^")) { - print_bitmask(0, v, "SEEK_SET", C(SEEK_CUR), C(SEEK_END), C(SEEK_DATA), + print_bits(0, v, "SEEK_SET", C(SEEK_CUR), C(SEEK_END), C(SEEK_DATA), C(SEEK_HOLE), 0); } else if (strstart(&TT.fmt, "sig^")) { - print_bitmask(0, v, "SIG_BLOCK", C(SIG_UNBLOCK), C(SIG_SETMASK), 0); + print_bits(0, v, "SIG_BLOCK", C(SIG_UNBLOCK), C(SIG_SETMASK), 0); } else abort(); } @@ -406,21 +423,22 @@ static void print_args() if (i) fprintf(stderr, ", "); switch (ch = *TT.fmt++) { case 'd': fprintf(stderr, "%ld", v); break; // decimal - case 'f': if ((int) v == AT_FDCWD) fprintf(stderr, "AT_FDCWD"); + case 'f': if ((int) v == AT_FDCWD) fprintf(stderr, "AT_FDCWD"); // fd else fprintf(stderr, "%ld", v); break; - case 'i': fprintf(stderr, "%s", strioctl(v)); break; // decimal - case 'm': fprintf(stderr, "%03o", (unsigned) v); break; // mode for open() + case 'F': print_string(v, LONG_MAX); break; + case 'i': fprintf(stderr, "%s", strioctl(v)); break; // ioctl name + case 'm': print_mode(v); break; case 'o': fprintf(stderr, "%ld", v); break; // off_t case 'p': print_ptr(v); break; - case 's': print_string(v); break; + case 's': print_string(v, TT.s); break; case 'S': // The libc-reserved signals aren't known to num_to_sig(). // TODO: use an strace-only routine for >= 32? if (!(s = num_to_sig(v))) fprintf(stderr, "%ld", v); else fprintf(stderr, "SIG%s", s); break; - case 'z': fprintf(stderr, "%ld", (long) v); break; // size_t - case 'x': fprintf(stderr, "%lx", v); break; // hex + case 'z': fprintf(stderr, "%lu", (unsigned long) v); break; // size_t + case 'x': fprintf(stderr, "%#lx", v); break; // hex case '{': print_struct(v); break; case '|': print_flags(v); break; @@ -428,16 +446,17 @@ static void print_args() case '/': return; // Separates "enter" and "exit" arguments. - default: fprintf(stderr, "?%c<0x%lx>", ch, v); break; + default: fprintf(stderr, "?%c<%#lx>", ch, v); break; } } } static void print_enter(void) { + struct iovec v = {.iov_base=&TT.regs, .iov_len=sizeof(TT.regs)}; char *name; - get_regs(); + xptrace(PTRACE_GETREGSET, TT.pid, (void *)1, &v); // NT_PRSTATUS TT.syscall = TT.regs[REG_ORDER[6]]; if (TT.syscall == __NR_ioctl) { name = "ioctl"; @@ -478,12 +497,13 @@ static void print_enter(void) } else switch (TT.syscall) { #define SC(n,f) case __NR_ ## n: name = #n; TT.fmt = f; break #if defined(__NR_access) - SC(access, "s|access|"); + SC(access, "F|access|"); #endif #if defined(__NR_arch_prctl) SC(arch_prctl, "dp"); #endif SC(brk, "p"); + SC(clock_nanosleep, "^clockid^d{timespec}/{timespec}"); SC(close, "d"); SC(connect, "fpd"); // TODO: sockaddr SC(dup, "f"); @@ -491,19 +511,22 @@ static void print_enter(void) SC(dup2, "ff"); #endif SC(dup3, "ff|open|"); - SC(execve, "spp"); + SC(execve, "Fpp"); SC(exit_group, "d"); - SC(faccessat, "fs|access|"); + SC(faccessat, "fF|access|"); SC(fcntl, "fdp"); // TODO: probably needs special case SC(fstat, "f/{stat}"); SC(futex, "pdxppx"); + SC(getcwd, "/Fz"); SC(getdents64, "dpz"); + SC(getegid, ""); SC(geteuid, ""); SC(getrandom, "pz|grnd|"); + SC(getgid, ""); SC(getuid, ""); - SC(getxattr, "sspz"); - SC(lgetxattr, "sspz"); + SC(getxattr, "Fspz"); + SC(lgetxattr, "Fspz"); SC(fgetxattr, "fspz"); SC(lseek, "fo^seek^"); @@ -516,27 +539,33 @@ static void print_enter(void) SC(munmap, "pz"); SC(nanosleep, "{timespec}/{timespec}"); #if defined(__NR_newfstatat) - SC(newfstatat, "fs/{stat}d"); + SC(newfstatat, "fF/{stat}d"); #endif #if defined(__NR_open) - SC(open, "sd|open|m"); + SC(open, "Fd|open|m"); #endif - SC(openat, "fs|open|m"); + SC(openat, "fF|open|m"); #if defined(__NR_poll) SC(poll, "pdd"); #endif SC(prlimit64, "d^rlimit^{rlimit}/{rlimit}"); SC(read, "d/sz"); - SC(readlinkat, "s/sz"); +#if defined(__NR_readlink) + SC(readlink, "F/sz"); +#endif + SC(readlinkat, "fF/sz"); +#if defined(__NR_rseq) + SC(rseq, "pzxx"); +#endif SC(rt_sigaction, "Sppz"); SC(rt_sigprocmask, "^sig^{sigset}/{sigset}z"); SC(set_robust_list, "pd"); SC(set_tid_address, "p"); SC(socket, "ddd"); // TODO: flags #if defined(__NR_stat) - SC(stat, "s/{stat}"); + SC(stat, "F/{stat}"); #endif - SC(statfs, "sp"); + SC(statfs, "Fp"); SC(sysinfo, "p"); SC(umask, "m"); SC(uname, "p"); @@ -554,12 +583,19 @@ static void print_enter(void) static void print_exit(void) { + long regs[256/sizeof(long)]; + struct iovec v = {.iov_base=®s, .iov_len=sizeof(regs)}; long result; - get_regs(); - result = TT.regs[REG_ORDER[7]]; + // We read the registers into a local because we only want the result, + // and don't want to clobber the argument that was in the same register + // earlier (the first argument of getcwd(2), for example, gets printed + // on exit rather than entry, and arm/riscv both reuse that register for + // the result). + xptrace(PTRACE_GETREGSET, TT.pid, (void *)1, &v); // NT_PRSTATUS if (*TT.fmt) print_args(); fprintf(stderr, ") = "); + result = regs[REG_ORDER[7]]; if (result >= -4095UL) fprintf(stderr, "-1 %s (%s)", strerrno(-result), strerror(-result)); else if (TT.syscall==__NR_mmap || TT.syscall==__NR_brk) print_ptr(result); -- 2.42.0.rc2.253.gd59a3bf2b4-goog