X-Git-Url: https://ruderich.org/simon/gitweb/?p=coloredstderr%2Fcoloredstderr.git;a=blobdiff_plain;f=src%2Fcoloredstderr.c;h=9161fc34f3deff694dba52eb07923fdde19bc4c2;hp=eb9d92cc3c1148d6160e87c4aade4171d8fd2c91;hb=f78c0377c1fc1862aaa4103fc6de6cfbe3fd0725;hpb=1068648718dad86471451266fcdf4248bb79f3fe diff --git a/src/coloredstderr.c b/src/coloredstderr.c index eb9d92c..9161fc3 100644 --- a/src/coloredstderr.c +++ b/src/coloredstderr.c @@ -2,7 +2,7 @@ * Hook output functions (like printf(3)) with LD_PRELOAD to color stderr (or * other file descriptors). * - * Copyright (C) 2013 Simon Ruderich + * Copyright (C) 2013-2018 Simon Ruderich * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by @@ -30,14 +30,22 @@ # define NDEBUG #endif +#ifndef TLS +# define TLS +#endif + #include #include #include #include #include #include +#include #include +#ifdef HAVE_ERR_H +# include +#endif #ifdef HAVE_ERROR_H # include #endif @@ -45,13 +53,23 @@ # include #endif -/* Conflicting declaration in glibc. */ -#undef fwrite_unlocked -/* These functions may be macros when compiling with hardening flags (fortify) - * which cause build failures when used in our hook macros below. Observed - * with Clang on Debian Wheezy. */ +/* The following functions may be macros. Undefine them or they cause build + * failures when used in our hook macros below. */ + +/* In glibc, real fwrite_unlocked() is called in macro. */ +#ifdef HAVE_FWRITE_UNLOCKED +# undef fwrite_unlocked +#endif +/* In Clang when compiling with hardening flags (fortify) on Debian Wheezy. */ #undef printf #undef fprintf +/* On FreeBSD (9.1), __swbuf() is used instead of these macros. */ +#ifdef HAVE___SWBUF +# undef putc +# undef putc_unlocked +# undef putchar +# undef putchar_unlocked +#endif /* Used by various functions, including debug(). */ @@ -64,6 +82,15 @@ static size_t (*real_fwrite)(void const *, size_t, size_t, FILE *); static int initialized; /* Force hooked writes even when not writing to a tty. Used for tests. */ static int force_write_to_non_tty; +/* Was ENV_NAME_FDS found and used when init_from_environment() was called? + * This is not true if the process set it manually after initialization. */ +static int used_fds_set_by_user; +/* Was any of our handle_*_pre()/handle_*_post() functions called recursively? + * If so don't print the pre/post string for the recursive calls. This is + * necessary on some systems (e.g. FreeBSD 9.1) which call multiple hooked + * functions while printing a string (e.g. a FILE * and a fd hook function is + * called). This is not thread-safe if TLS is not available. */ +static TLS int handle_recursive; #include "constants.h" @@ -164,9 +191,13 @@ static void handle_file_pre(FILE *stream) noinline; static void handle_file_post(FILE *stream) noinline; static void handle_fd_pre(int fd) { + if (handle_recursive++ > 0) { + return; + } + int saved_errno = errno; - if (unlikely(!pre_string || !post_string)) { + if (unlikely(!pre_string)) { init_pre_post_string(); } @@ -176,6 +207,10 @@ static void handle_fd_pre(int fd) { errno = saved_errno; } static void handle_fd_post(int fd) { + if (--handle_recursive > 0) { + return; + } + int saved_errno = errno; /* write() already loaded above in handle_fd_pre(). */ @@ -185,9 +220,13 @@ static void handle_fd_post(int fd) { } static void handle_file_pre(FILE *stream) { + if (handle_recursive++ > 0) { + return; + } + int saved_errno = errno; - if (unlikely(!pre_string || !post_string)) { + if (unlikely(!pre_string)) { init_pre_post_string(); } @@ -197,6 +236,10 @@ static void handle_file_pre(FILE *stream) { errno = saved_errno; } static void handle_file_post(FILE *stream) { + if (--handle_recursive > 0) { + return; + } + int saved_errno = errno; /* fwrite() already loaded above in handle_file_pre(). */ @@ -221,6 +264,14 @@ HOOK_FILE2(int, fputc, stream, int, c, FILE *, stream) HOOK_FILE2(int, putc, stream, int, c, FILE *, stream) +/* The glibc uses a macro for putc() which expands to _IO_putc(). However + * sometimes the raw putc() is used as well, not sure why. Make sure to hook + * it too. */ +#ifdef putc +# undef putc +HOOK_FILE2(int, putc, stream, + int, c, FILE *, stream) +#endif HOOK_FILE1(int, putchar, stdout, int, c) HOOK_FILE1(int, puts, stdout, @@ -246,25 +297,71 @@ HOOK_FILE4(int, __vfprintf_chk, stream, FILE *, stream, int, flag, char const *, format, va_list, ap) /* unlocked_stdio(3), only functions from above are hooked */ +#ifdef HAVE_FWRITE_UNLOCKED HOOK_FILE4(size_t, fwrite_unlocked, stream, void const *, ptr, size_t, size, size_t, nmemb, FILE *, stream) +#endif +#ifdef HAVE_FPUTS_UNLOCKED HOOK_FILE2(int, fputs_unlocked, stream, char const *, s, FILE *, stream) +#endif +#ifdef HAVE_FPUTC_UNLOCKED HOOK_FILE2(int, fputc_unlocked, stream, int, c, FILE *, stream) +#endif HOOK_FILE2(int, putc_unlocked, stream, int, c, FILE *, stream) HOOK_FILE1(int, putchar_unlocked, stdout, int, c) -/* glibc defines (_IO_)putc_unlocked() to __overflow() in some cases. */ -#ifdef HAVE_STRUCT__IO_FILE__FILENO -HOOK_FD2(int, __overflow, f->_fileno, _IO_FILE *, f, int, ch) +/* glibc defines (_IO_)putc_unlocked() to a macro which either updates the + * output buffer or calls __overflow(). As this code is inlined we can't + * handle the first case, but if __overflow() is called we can color that + * part. As writes to stderr are never buffered, __overflow() is always called + * and everything works fine. This is only a problem if stdout is dupped to + * stderr (which shouldn't be the case too often). */ +#if defined(HAVE_STRUCT__IO_FILE__FILENO) && defined(HAVE___OVERFLOW) +/* _IO_FILE is glibc's representation of FILE. */ +HOOK_FILE2(int, __overflow, f, _IO_FILE *, f, int, ch) +#endif +/* Same for FreeBSD's libc. However it's more aggressive: The inline writing + * and __swbuf() are also used for normal output (e.g. putc()). Writing to + * stderr is still fine; it always calls __swbuf() as stderr is always + * unbuffered. */ +#ifdef HAVE___SWBUF +HOOK_FILE2(int, __swbuf, f, int, c, FILE *, f) #endif /* perror(3) */ HOOK_VOID1(void, perror, STDERR_FILENO, char const *, s) +/* err(3), non standard BSD extension */ +#ifdef HAVE_ERR_H +HOOK_VAR_VOID2(void, err, STDERR_FILENO, verr, + int, eval, char const *, fmt) +HOOK_VAR_VOID2(void, errx, STDERR_FILENO, verrx, + int, eval, char const *, fmt) +HOOK_VAR_VOID1(void, warn, STDERR_FILENO, vwarn, + char const *, fmt) +HOOK_VAR_VOID1(void, warnx, STDERR_FILENO, vwarnx, + char const *, fmt) +HOOK_FUNC_SIMPLE3(void, verr, int, eval, const char *, fmt, va_list, args) { + /* Can't use verr() directly as it terminates the process which prevents + * the post string from being printed. */ + vwarn(fmt, args); + exit(eval); +} +HOOK_FUNC_SIMPLE3(void, verrx, int, eval, const char *, fmt, va_list, args) { + /* See verr(). */ + vwarnx(fmt, args); + exit(eval); +} +HOOK_VOID2(void, vwarn, STDERR_FILENO, + char const *, fmt, va_list, args) +HOOK_VOID2(void, vwarnx, STDERR_FILENO, + char const *, fmt, va_list, args) +#endif + /* error(3), non-standard GNU extension */ #ifdef HAVE_ERROR_H static void error_vararg(int status, int errnum, @@ -278,7 +375,7 @@ static void error_vararg(int status, int errnum, if (error_one_per_line && filename != NULL && linenum != 0 && filename == last_filename && linenum == last_linenum) { - return; + goto out; } last_filename = filename; last_linenum = linenum; @@ -311,6 +408,7 @@ static void error_vararg(int status, int errnum, fprintf(stderr, "\n"); +out: if (status != 0) { exit(status); } @@ -343,7 +441,7 @@ HOOK_FUNC_DEF1(int, dup, int, oldfd) { DLSYM_FUNCTION(real_dup, "dup"); newfd = real_dup(oldfd); - if (newfd != -1) { + if (newfd > -1) { dup_fd(oldfd, newfd); } @@ -354,7 +452,7 @@ HOOK_FUNC_DEF2(int, dup2, int, oldfd, int, newfd) { DLSYM_FUNCTION(real_dup2, "dup2"); newfd = real_dup2(oldfd, newfd); - if (newfd != -1) { + if (newfd > -1) { dup_fd(oldfd, newfd); } @@ -365,7 +463,7 @@ HOOK_FUNC_DEF3(int, dup3, int, oldfd, int, newfd, int, flags) { DLSYM_FUNCTION(real_dup3, "dup3"); newfd = real_dup3(oldfd, newfd, flags); - if (newfd != -1) { + if (newfd > -1) { dup_fd(oldfd, newfd); } @@ -397,7 +495,7 @@ HOOK_FUNC_VAR_DEF2(int, fcntl, int, fd, int, cmd /*, ... */) { va_end(ap); /* We only care about duping fds. */ - if (cmd == F_DUPFD && result != -1) { + if (cmd == F_DUPFD && result > -1) { dup_fd(fd, result); } @@ -436,11 +534,12 @@ pid_t vfork(void) { * isn't allowed to perform any memory-modifications before the exec() * (except the pid_t result variable of vfork()). * - * As some programs don't adhere to the standard (e.g. the "child" closes - * or dups a descriptor before the exec()) and this breaks our tracking of - * file descriptors (e.g. it gets closed in the parent as well), we just - * fork() instead. This is in compliance with the POSIX standard and as - * most systems use copy-on-write anyway not a performance issue. */ + * As we have to store changes to the file descriptors in memory (e.g. the + * "child" closes or dups a descriptor before the exec()) and this + * modifies the parent as well due to the semantics of vfork() - thus + * breaking the requirements of vfork(), we just use fork instead(). This + * is in compliance with the POSIX standard and as most systems use + * copy-on-write anyway not a performance issue. */ return fork(); } #endif @@ -448,34 +547,28 @@ pid_t vfork(void) { /* Hook execve() and the other exec*() functions. Some shells use exec*() with * a custom environment which doesn't necessarily contain our updates to - * ENV_NAME_FDS. It's also faster to update the environment only when - * necessary, right before the exec() to pass it to the new process. */ + * ENV_NAME_PRIVATE_FDS. It's also faster to update the environment only when + * necessary, right before the exec(), to pass it to the new program. */ /* int execve(char const *, char * const [], char * const []) */ HOOK_FUNC_DEF3(int, execve, char const *, filename, char * const *, argv, char * const *, env) { DLSYM_FUNCTION(real_execve, "execve"); - int found = 0; - size_t index = 0; + char * const fake_env[] = {NULL}; + if (env == NULL) { + env = fake_env; + } - /* Count arguments and search for existing ENV_NAME_FDS environment - * variable. */ + /* Count environment variables. */ size_t count = 0; char * const *x = env; - while (*x) { - if (!strncmp(*x, ENV_NAME_FDS "=", strlen(ENV_NAME_FDS) + 1)) { - found = 1; - index = count; - } - - x++; + while (*x++) { count++; } /* Terminating NULL. */ count++; char *env_copy[count + 1 /* space for our new entry if necessary */]; - memcpy(env_copy, env, count * sizeof(char *)); /* Make sure the information from the environment is loaded. We can't just * do nothing (like update_environment()) because the caller might pass a @@ -484,17 +577,40 @@ HOOK_FUNC_DEF3(int, execve, char const *, filename, char * const *, argv, char * init_from_environment(); } - char fds_env[strlen(ENV_NAME_FDS) + 1 + update_environment_buffer_size()]; - strcpy(fds_env, ENV_NAME_FDS "="); - update_environment_buffer(fds_env + strlen(ENV_NAME_FDS) + 1); + char fds_env[strlen(ENV_NAME_PRIVATE_FDS) + + 1 + update_environment_buffer_size()]; + strcpy(fds_env, ENV_NAME_PRIVATE_FDS "="); + update_environment_buffer(fds_env + strlen(ENV_NAME_PRIVATE_FDS) + 1); - if (found) { - env_copy[index] = fds_env; - } else { - /* If the process removed ENV_NAME_FDS from the environment, re-add - * it. */ - env_copy[count-1] = fds_env; - env_copy[count] = NULL; + int found = 0; + char **x_copy = env_copy; + + /* Copy the environment manually; allows skipping elements. */ + x = env; + while ((*x_copy = *x)) { + /* Remove ENV_NAME_FDS if we've already used its value. The new + * program must use the updated list from ENV_NAME_PRIVATE_FDS. */ + if (used_fds_set_by_user + && !strncmp(*x, ENV_NAME_FDS "=", strlen(ENV_NAME_FDS) + 1)) { + x++; + continue; + /* Update ENV_NAME_PRIVATE_FDS. */ + } else if (!strncmp(*x, ENV_NAME_PRIVATE_FDS "=", + strlen(ENV_NAME_PRIVATE_FDS) + 1)) { + *x_copy = fds_env; + found = 1; + } + + x++; + x_copy++; + } + /* The loop "condition" NULL-terminates env_copy. */ + + if (!found) { + /* If the process removed ENV_NAME_PRIVATE_FDS from the environment, + * re-add it. */ + *x_copy++ = fds_env; + *x_copy++ = NULL; } return real_execve(filename, argv, env_copy); @@ -571,10 +687,16 @@ HOOK_FUNC_DEF2(int, execvp, char const *, file, char * const *, argv) { #ifdef HAVE_EXECVPE extern char **environ; int execvpe(char const *file, char * const argv[], char * const envp[]) { + int result; + char **old_environ = environ; + /* Fake the environment so we can reuse execvp(). */ environ = (char **)envp; /* execvp() updates the environment. */ - return execvp(file, argv); + result = execvp(file, argv); + + environ = old_environ; + return result; } #endif