diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/atomic.h | 33 | ||||
| -rw-r--r-- | src/bar.c | 137 | ||||
| -rw-r--r-- | src/bfstd.c | 31 | ||||
| -rw-r--r-- | src/bfstd.h | 5 | ||||
| -rw-r--r-- | src/bftw.c | 6 | ||||
| -rw-r--r-- | src/color.c | 50 | ||||
| -rw-r--r-- | src/color.h | 7 | ||||
| -rw-r--r-- | src/ctx.c | 104 | ||||
| -rw-r--r-- | src/diag.c | 4 | ||||
| -rw-r--r-- | src/diag.h | 43 | ||||
| -rw-r--r-- | src/dir.c | 16 | ||||
| -rw-r--r-- | src/dir.h | 8 | ||||
| -rw-r--r-- | src/dstring.c | 4 | ||||
| -rw-r--r-- | src/dstring.h | 4 | ||||
| -rw-r--r-- | src/eval.c | 2 | ||||
| -rw-r--r-- | src/exec.c | 6 | ||||
| -rw-r--r-- | src/fsade.c | 2 | ||||
| -rw-r--r-- | src/main.c | 1 | ||||
| -rw-r--r-- | src/mtab.c | 9 | ||||
| -rw-r--r-- | src/prelude.h | 15 | ||||
| -rw-r--r-- | src/printf.c | 2 | ||||
| -rw-r--r-- | src/sighook.c | 600 | ||||
| -rw-r--r-- | src/sighook.h | 73 | ||||
| -rw-r--r-- | src/stat.c | 37 | ||||
| -rw-r--r-- | src/xspawn.c | 37 | ||||
| -rw-r--r-- | src/xtime.c | 40 |
26 files changed, 1065 insertions, 211 deletions
diff --git a/src/atomic.h b/src/atomic.h index f1a6bea..360de20 100644 --- a/src/atomic.h +++ b/src/atomic.h @@ -8,6 +8,8 @@ #ifndef BFS_ATOMIC_H #define BFS_ATOMIC_H +#include "prelude.h" +#include "sanity.h" #include <stdatomic.h> /** @@ -82,4 +84,35 @@ #define fetch_and(obj, arg, order) \ atomic_fetch_and_explicit(obj, arg, memory_order_##order) +/** + * Shorthand for atomic_thread_fence(). + */ +#if SANITIZE_THREAD +// TSan doesn't support fences: https://github.com/google/sanitizers/issues/1415 +# define thread_fence(obj, order) \ + fetch_add(obj, 0, order) +#else +# define thread_fence(obj, order) \ + atomic_thread_fence(memory_order_##order) +#endif + +/** + * Shorthand for atomic_signal_fence(). + */ +#define signal_fence(order) \ + atomic_signal_fence(memory_order_##order) + +/** + * A hint to the CPU to relax while it spins. + */ +#if __has_builtin(__builtin_ia32_pause) +# define spin_loop() __builtin_ia32_pause() +#elif __has_builtin(__builtin_arm_yield) +# define spin_loop() __builtin_arm_yield() +#elif __has_builtin(__builtin_riscv_pause) +# define spin_loop() __builtin_riscv_pause() +#else +# define spin_loop() ((void)0) +#endif + #endif // BFS_ATOMIC_H @@ -3,10 +3,12 @@ #include "prelude.h" #include "bar.h" +#include "alloc.h" #include "atomic.h" #include "bfstd.h" #include "bit.h" #include "dstring.h" +#include "sighook.h" #include <errno.h> #include <fcntl.h> #include <signal.h> @@ -19,11 +21,9 @@ struct bfs_bar { int fd; atomic unsigned int width; atomic unsigned int height; -}; -/** The global status bar instance. */ -static struct bfs_bar the_bar = { - .fd = -1, + struct sighook *exit_hook; + struct sighook *winch_hook; }; /** Get the terminal size, if possible. */ @@ -43,10 +43,14 @@ static int bfs_bar_getsize(struct bfs_bar *bar) { #endif } -/** Async Signal Safe puts(). */ -static int ass_puts(int fd, const char *str) { - size_t len = strlen(str); - return xwrite(fd, str, len) == len ? 0 : -1; +/** Write a string to the status bar (async-signal-safe). */ +static int bfs_bar_write(struct bfs_bar *bar, const char *str, size_t len) { + return xwrite(bar->fd, str, len) == len ? 0 : -1; +} + +/** Write a string to the status bar (async-signal-safe). */ +static int bfs_bar_puts(struct bfs_bar *bar, const char *str) { + return bfs_bar_write(bar, str, strlen(str)); } /** Number of decimal digits needed for terminal sizes. */ @@ -70,39 +74,40 @@ static char *ass_itoa(char *str, unsigned int n) { /** Update the size of the scrollable region. */ static int bfs_bar_resize(struct bfs_bar *bar) { - char esc_seq[12 + ITOA_DIGITS] = + static const char PREFIX[] = + "\033D" // IND: Line feed, possibly scrolling + "\033[1A" // CUU: Move cursor up 1 row "\0337" // DECSC: Save cursor "\033[;"; // DECSTBM: Set scrollable region + static const char SUFFIX[] = + "r" // (end of DECSTBM) + "\0338" // DECRC: Restore the cursor + "\033[J"; // ED: Erase display from cursor to end + + char esc_seq[sizeof(PREFIX) + ITOA_DIGITS + sizeof(SUFFIX)]; // DECSTBM takes the height as the second argument - unsigned int height = load(&bar->height, relaxed); - char *ptr = esc_seq + strlen(esc_seq); - ptr = ass_itoa(ptr, height - 1); + unsigned int height = load(&bar->height, relaxed) - 1; - strcpy(ptr, - "r" // DECSTBM - "\0338" // DECRC: Restore the cursor - "\033[J" // ED: Erase display from cursor to end - ); + char *cur = stpcpy(esc_seq, PREFIX); + cur = ass_itoa(cur, height); + cur = stpcpy(cur, SUFFIX); - return ass_puts(bar->fd, esc_seq); + return bfs_bar_write(bar, esc_seq, cur - esc_seq); } #ifdef SIGWINCH /** SIGWINCH handler. */ -static void sighand_winch(int sig) { - int error = errno; - - bfs_bar_getsize(&the_bar); - bfs_bar_resize(&the_bar); - - errno = error; +static void bfs_bar_sigwinch(int sig, siginfo_t *info, void *arg) { + struct bfs_bar *bar = arg; + bfs_bar_getsize(bar); + bfs_bar_resize(bar); } #endif /** Reset the scrollable region and hide the bar. */ static int bfs_bar_reset(struct bfs_bar *bar) { - return ass_puts(bar->fd, + return bfs_bar_puts(bar, "\0337" // DECSC: Save cursor "\033[r" // DECSTBM: Reset scrollable region "\0338" // DECRC: Restore cursor @@ -111,19 +116,9 @@ static int bfs_bar_reset(struct bfs_bar *bar) { } /** Signal handler for process-terminating signals. */ -static void sighand_reset(int sig) { - bfs_bar_reset(&the_bar); - raise(sig); -} - -/** Register sighand_reset() for a signal. */ -static void reset_before_death_by(int sig) { - struct sigaction sa = { - .sa_handler = sighand_reset, - .sa_flags = SA_RESETHAND, - }; - sigemptyset(&sa.sa_mask); - sigaction(sig, &sa, NULL); +static void bfs_bar_sigexit(int sig, siginfo_t *info, void *arg) { + struct bfs_bar *bar = arg; + bfs_bar_reset(bar); } /** printf() to the status bar with a single write(). */ @@ -138,15 +133,15 @@ static int bfs_bar_printf(struct bfs_bar *bar, const char *format, ...) { return -1; } - int ret = ass_puts(bar->fd, str); + int ret = bfs_bar_write(bar, str, dstrlen(str)); dstrfree(str); return ret; } struct bfs_bar *bfs_bar_show(void) { - if (the_bar.fd >= 0) { - errno = EBUSY; - goto fail; + struct bfs_bar *bar = ALLOC(struct bfs_bar); + if (!bar) { + return NULL; } char term[L_ctermid]; @@ -156,46 +151,36 @@ struct bfs_bar *bfs_bar_show(void) { goto fail; } - the_bar.fd = open(term, O_RDWR | O_CLOEXEC); - if (the_bar.fd < 0) { + bar->fd = open(term, O_RDWR | O_CLOEXEC); + if (bar->fd < 0) { goto fail; } - if (bfs_bar_getsize(&the_bar) != 0) { + if (bfs_bar_getsize(bar) != 0) { goto fail_close; } - reset_before_death_by(SIGABRT); - reset_before_death_by(SIGINT); - reset_before_death_by(SIGPIPE); - reset_before_death_by(SIGQUIT); - reset_before_death_by(SIGTERM); + bar->exit_hook = atsigexit(bfs_bar_sigexit, bar); + if (!bar->exit_hook) { + goto fail_close; + } #ifdef SIGWINCH - struct sigaction sa = { - .sa_handler = sighand_winch, - .sa_flags = SA_RESTART, - }; - sigemptyset(&sa.sa_mask); - sigaction(SIGWINCH, &sa, NULL); + bar->winch_hook = sighook(SIGWINCH, bfs_bar_sigwinch, bar, 0); + if (!bar->winch_hook) { + goto fail_hook; + } #endif - unsigned int height = load(&the_bar.height, relaxed); - bfs_bar_printf(&the_bar, - "\n" // Make space for the bar - "\0337" // DECSC: Save cursor - "\033[;%ur" // DECSTBM: Set scrollable region - "\0338" // DECRC: Restore cursor - "\033[1A", // CUU: Move cursor up 1 row - height - 1 - ); - - return &the_bar; + bfs_bar_resize(bar); + return bar; +fail_hook: + sigunhook(bar->exit_hook); fail_close: - close_quietly(the_bar.fd); - the_bar.fd = -1; + close_quietly(bar->fd); fail: + free(bar); return NULL; } @@ -223,17 +208,11 @@ void bfs_bar_hide(struct bfs_bar *bar) { return; } - signal(SIGABRT, SIG_DFL); - signal(SIGINT, SIG_DFL); - signal(SIGPIPE, SIG_DFL); - signal(SIGQUIT, SIG_DFL); - signal(SIGTERM, SIG_DFL); -#ifdef SIGWINCH - signal(SIGWINCH, SIG_DFL); -#endif + sigunhook(bar->winch_hook); + sigunhook(bar->exit_hook); bfs_bar_reset(bar); xclose(bar->fd); - bar->fd = -1; + free(bar); } diff --git a/src/bfstd.c b/src/bfstd.c index f8ce871..7680f17 100644 --- a/src/bfstd.c +++ b/src/bfstd.c @@ -637,8 +637,14 @@ error: return NULL; } +#if BFS_HAS_STRTOFFLAGS +# define BFS_STRTOFFLAGS strtofflags +#elif BFS_HAS_STRING_TO_FLAGS +# define BFS_STRTOFFLAGS string_to_flags +#endif + int xstrtofflags(const char **str, unsigned long long *set, unsigned long long *clear) { -#if BSD && !__GNU__ +#ifdef BFS_STRTOFFLAGS char *str_arg = (char *)*str; #if __OpenBSD__ @@ -649,11 +655,7 @@ int xstrtofflags(const char **str, unsigned long long *set, unsigned long long * bfs_fflags_t set_arg = 0; bfs_fflags_t clear_arg = 0; -#if __NetBSD__ - int ret = string_to_flags(&str_arg, &set_arg, &clear_arg); -#else - int ret = strtofflags(&str_arg, &set_arg, &clear_arg); -#endif + int ret = BFS_STRTOFFLAGS(&str_arg, &set_arg, &clear_arg); *str = str_arg; *set = set_arg; @@ -663,12 +665,27 @@ int xstrtofflags(const char **str, unsigned long long *set, unsigned long long * errno = EINVAL; } return ret; -#else // !BSD +#else // !BFS_STRTOFFLAGS errno = ENOTSUP; return -1; #endif } +long xsysconf(int name) { +#if __FreeBSD__ && SANITIZE_MEMORY + // Work around https://github.com/llvm/llvm-project/issues/88163 + __msan_scoped_disable_interceptor_checks(); +#endif + + long ret = sysconf(name); + +#if __FreeBSD__ && SANITIZE_MEMORY + __msan_scoped_enable_interceptor_checks(); +#endif + + return ret; +} + size_t asciilen(const char *str) { return asciinlen(str, strlen(str)); } diff --git a/src/bfstd.h b/src/bfstd.h index f91e380..d06bbd9 100644 --- a/src/bfstd.h +++ b/src/bfstd.h @@ -410,6 +410,11 @@ char *xconfstr(int name); */ int xstrtofflags(const char **str, unsigned long long *set, unsigned long long *clear); +/** + * Wrapper for sysconf() that works around an MSan bug. + */ +long xsysconf(int name); + #include <wchar.h> /** @@ -1281,7 +1281,7 @@ static int bftw_pin_parent(struct bftw_state *state, struct bftw_file *file) { int fd = parent->fd; if (fd < 0) { - bfs_static_assert(AT_FDCWD != -1); + bfs_static_assert((int)AT_FDCWD != -1); return -1; } @@ -1298,7 +1298,7 @@ static int bftw_ioq_opendir(struct bftw_state *state, struct bftw_file *file) { } int dfd = bftw_pin_parent(state, file); - if (dfd < 0 && dfd != AT_FDCWD) { + if (dfd < 0 && dfd != (int)AT_FDCWD) { goto fail; } @@ -1450,7 +1450,7 @@ static int bftw_ioq_stat(struct bftw_state *state, struct bftw_file *file) { } int dfd = bftw_pin_parent(state, file); - if (dfd < 0 && dfd != AT_FDCWD) { + if (dfd < 0 && dfd != (int)AT_FDCWD) { goto fail; } diff --git a/src/color.c b/src/color.c index f004bf2..a0e553f 100644 --- a/src/color.c +++ b/src/color.c @@ -161,8 +161,13 @@ static struct esc_seq **get_esc(const struct colors *colors, const char *name) { return leaf ? leaf->value : NULL; } +/** Append an escape sequence to a string. */ +static int cat_esc(dchar **dstr, const struct esc_seq *seq) { + return dstrxcat(dstr, seq->seq, seq->len); +} + /** Set a named escape sequence. */ -static int set_esc(struct colors *colors, const char *name, char *value) { +static int set_esc(struct colors *colors, const char *name, dchar *value) { struct esc_seq **field = get_esc(colors, name); if (!field) { return 0; @@ -587,8 +592,8 @@ static int parse_gnu_ls_colors(struct colors *colors, const char *ls_colors) { // All-zero values should be treated like NULL, to fall // back on any other relevant coloring for that file - char *esc = value; - if (strspn(value, "0") == strlen(value) + dchar *esc = value; + if (strspn(value, "0") == dstrlen(value) && strcmp(key, "rs") != 0 && strcmp(key, "lc") != 0 && strcmp(key, "rc") != 0 @@ -693,6 +698,20 @@ struct colors *parse_colors(void) { colors->link->len = 0; } + // Pre-compute the reset escape sequence + if (!colors->endcode) { + dchar *ec = dstralloc(0); + if (!ec + || cat_esc(&ec, colors->leftcode) != 0 + || cat_esc(&ec, colors->reset) != 0 + || cat_esc(&ec, colors->rightcode) != 0 + || set_esc(colors, "ec", ec) != 0) { + dstrfree(ec); + goto fail; + } + dstrfree(ec); + } + return colors; fail: @@ -727,10 +746,11 @@ CFILE *cfwrap(FILE *file, const struct colors *colors, bool close) { } cfile->file = file; + cfile->fd = fileno(file); cfile->need_reset = false; cfile->close = close; - if (isatty(fileno(file))) { + if (isatty(cfile->fd)) { cfile->colors = colors; } else { cfile->colors = NULL; @@ -874,7 +894,7 @@ error: /** Print an escape sequence chunk. */ static int print_esc_chunk(CFILE *cfile, const struct esc_seq *esc) { - return dstrxcat(&cfile->buffer, esc->seq, esc->len); + return cat_esc(&cfile->buffer, esc); } /** Print an ANSI escape sequence. */ @@ -908,12 +928,7 @@ static int print_reset(CFILE *cfile) { } cfile->need_reset = false; - const struct colors *colors = cfile->colors; - if (colors->endcode) { - return print_esc_chunk(cfile, colors->endcode); - } else { - return print_esc(cfile, colors->reset); - } + return print_esc_chunk(cfile, cfile->colors->endcode); } /** Print a shell-escaped string. */ @@ -961,7 +976,7 @@ static ssize_t first_broken_offset(const char *path, const struct BFTW *ftwbuf, } else { // We're in print_link_target(), so resolve relative to the link's parent directory at_fd = ftwbuf->at_fd; - if (at_fd == AT_FDCWD && path[0] != '/') { + if (at_fd == (int)AT_FDCWD && path[0] != '/') { at_path = dstrndup(ftwbuf->path, ftwbuf->nameoff); if (at_path && dstrncat(&at_path, path, max) != 0) { ret = -1; @@ -1390,3 +1405,14 @@ int cfprintf(CFILE *cfile, const char *format, ...) { va_end(args); return ret; } + +int cfreset(CFILE *cfile) { + const struct colors *colors = cfile->colors; + if (!colors) { + return 0; + } + + const struct esc_seq *esc = colors->endcode; + size_t ret = xwrite(cfile->fd, esc->seq, esc->len); + return ret == esc->len ? 0 : -1; +} diff --git a/src/color.h b/src/color.h index 3278cd6..3550888 100644 --- a/src/color.h +++ b/src/color.h @@ -42,6 +42,8 @@ typedef struct CFILE { const struct colors *colors; /** A buffer for colored formatting. */ dchar *buffer; + /** Cached file descriptor number. */ + int fd; /** Whether the next ${rs} is actually necessary. */ bool need_reset; /** Whether to close the underlying stream. */ @@ -108,4 +110,9 @@ int cfprintf(CFILE *cfile, const char *format, ...); attr(printf(2, 0)) int cvfprintf(CFILE *cfile, const char *format, va_list args); +/** + * Reset the TTY state when terminating abnormally (async-signal-safe). + */ +int cfreset(CFILE *cfile); + #endif // BFS_COLOR_H @@ -3,24 +3,27 @@ #include "ctx.h" #include "alloc.h" +#include "bfstd.h" #include "color.h" #include "diag.h" #include "expr.h" #include "list.h" #include "mtab.h" #include "pwcache.h" +#include "sighook.h" #include "stat.h" #include "trie.h" #include "xtime.h" #include <errno.h> #include <limits.h> +#include <signal.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> /** Get the initial value for ctx->threads (-j). */ static int bfs_nproc(void) { - long nproc = sysconf(_SC_NPROCESSORS_ONLN); + long nproc = xsysconf(_SC_NPROCESSORS_ONLN); if (nproc < 1) { nproc = 1; @@ -98,13 +101,20 @@ struct bfs_ctx_file { CFILE *cfile; /** The path to the file (for diagnostics). */ const char *path; + /** Signal hook to send a reset escape sequence. */ + struct sighook *hook; /** Remembers I/O errors, to propagate them to the exit status. */ int error; }; +/** Call cfreset() on a tracked file. */ +static void cfreset_hook(int sig, siginfo_t *info, void *arg) { + cfreset(arg); +} + CFILE *bfs_ctx_dedup(struct bfs_ctx *ctx, CFILE *cfile, const char *path) { struct bfs_stat sb; - if (bfs_stat(fileno(cfile->file), NULL, 0, &sb) != 0) { + if (bfs_stat(cfile->fd, NULL, 0, &sb) != 0) { return NULL; } @@ -124,19 +134,31 @@ CFILE *bfs_ctx_dedup(struct bfs_ctx *ctx, CFILE *cfile, const char *path) { leaf->value = ctx_file = ALLOC(struct bfs_ctx_file); if (!ctx_file) { - trie_remove(&ctx->files, leaf); - return NULL; + goto fail; } ctx_file->cfile = cfile; ctx_file->path = path; ctx_file->error = 0; + ctx_file->hook = NULL; + + if (cfile->colors) { + ctx_file->hook = atsigexit(cfreset_hook, cfile); + if (!ctx_file->hook) { + goto fail; + } + } if (cfile != ctx->cout && cfile != ctx->cerr) { ++ctx->nfiles; } return cfile; + +fail: + trie_remove(&ctx->files, leaf); + free(ctx_file); + return NULL; } void bfs_ctx_flush(const struct bfs_ctx *ctx) { @@ -156,7 +178,7 @@ void bfs_ctx_flush(const struct bfs_ctx *ctx) { const char *path = ctx_file->path; if (path) { - bfs_error(ctx, "'%s': %m.\n", path); + bfs_error(ctx, "%pq: %m.\n", path); } else if (cfile == ctx->cout) { bfs_error(ctx, "(standard output): %m.\n"); } @@ -188,30 +210,49 @@ static int bfs_ctx_fflush(CFILE *cfile) { static int bfs_ctx_fclose(struct bfs_ctx *ctx, struct bfs_ctx_file *ctx_file) { CFILE *cfile = ctx_file->cfile; - if (cfile == ctx->cout) { - // Will be checked later - return 0; - } else if (cfile == ctx->cerr) { - // Writes to stderr are allowed to fail silently, unless the same file was used by - // -fprint, -fls, etc. - if (ctx_file->path) { - return bfs_ctx_fflush(cfile); - } else { - return 0; - } - } - + // Writes to stderr are allowed to fail silently, unless the same file + // was used by -fprint, -fls, etc. + bool silent = cfile == ctx->cerr && !ctx_file->path; int ret = 0, error = 0; - if (ferror(cfile->file)) { + + if (ctx_file->error) { + // An error was previously reported during bfs_ctx_flush() ret = -1; - error = EIO; + error = ctx_file->error; } - if (cfclose(cfile) != 0) { + + // Flush the file just before we remove the hook, to maximize the chance + // we leave the TTY in a good state + if (bfs_ctx_fflush(cfile) != 0) { ret = -1; error = errno; } - errno = error; + if (ctx_file->hook) { + sigunhook(ctx_file->hook); + } + + // Close the CFILE, except for stdio streams, which are closed later + if (cfile != ctx->cout && cfile != ctx->cerr) { + if (cfclose(cfile) != 0) { + ret = -1; + error = errno; + } + } + + if (silent) { + ret = 0; + } + + if (ret != 0 && ctx->cerr) { + if (ctx_file->path) { + bfs_error(ctx, "%pq: %s.\n", ctx_file->path, xstrerror(error)); + } else if (cfile == ctx->cout) { + bfs_error(ctx, "(standard output): %s.\n", xstrerror(error)); + } + } + + free(ctx_file); return ret; } @@ -229,33 +270,14 @@ int bfs_ctx_free(struct bfs_ctx *ctx) { for_trie (leaf, &ctx->files) { struct bfs_ctx_file *ctx_file = leaf->value; - - if (ctx_file->error) { - // An error was previously reported during bfs_ctx_flush() - ret = -1; - } - if (bfs_ctx_fclose(ctx, ctx_file) != 0) { - if (cerr) { - bfs_error(ctx, "%pq: %m.\n", ctx_file->path); - } ret = -1; } - - free(ctx_file); } trie_destroy(&ctx->files); - if (cout && bfs_ctx_fflush(cout) != 0) { - if (cerr) { - bfs_error(ctx, "(standard output): %m.\n"); - } - ret = -1; - } - cfclose(cout); cfclose(cerr); - free_colors(ctx->colors); for_slist (struct bfs_expr, expr, &ctx->expr_list, freelist) { @@ -38,6 +38,10 @@ noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...) { abort(); } +const char *bfs_errstr(void) { + return xstrerror(errno); +} + const char *debug_flag_name(enum debug_flags flag) { switch (flag) { case DEBUG_COST: @@ -55,6 +55,20 @@ void bfs_diagf(const struct bfs_loc *loc, const char *format, ...); #define bfs_diag(...) bfs_diagf(bfs_location(), __VA_ARGS__) /** + * Get the last error message. + */ +const char *bfs_errstr(void); + +/** + * Print a diagnostic message including the last error. + */ +#define bfs_ediag(...) \ + bfs_ediag_("" __VA_ARGS__, bfs_errstr()) + +#define bfs_ediag_(format, ...) \ + bfs_diag(sizeof(format) > 1 ? format ": %s" : "%s", __VA_ARGS__) + +/** * Print a message to standard error and abort. */ attr(cold, printf(2, 3)) @@ -63,15 +77,27 @@ noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...); /** * Unconditional abort with a message. */ -#define bfs_abort(...) bfs_abortf(bfs_location(), __VA_ARGS__) +#define bfs_abort(...) \ + bfs_abortf(bfs_location(), __VA_ARGS__) + +/** + * Abort with a message including the last error. + */ +#define bfs_eabort(...) \ + bfs_eabort_("" __VA_ARGS__, bfs_errstr()) + +#define bfs_eabort_(format, ...) \ + bfs_abort(sizeof(format) > 1 ? format ": %s" : "%s", __VA_ARGS__) /** * Abort in debug builds; no-op in release builds. */ #ifdef NDEBUG # define bfs_bug(...) ((void)0) +# define bfs_ebug(...) ((void)0) #else # define bfs_bug bfs_abort +# define bfs_ebug bfs_eabort #endif /** @@ -88,12 +114,27 @@ noreturn void bfs_abortf(const struct bfs_loc *loc, const char *format, ...); str, __VA_ARGS__)) /** + * Unconditional assert, including the last error. + */ +#define bfs_everify(...) \ + bfs_everify_(#__VA_ARGS__, __VA_ARGS__, "", bfs_errstr()) + +#define bfs_everify_(str, cond, format, ...) \ + ((cond) ? (void)0 : bfs_abort( \ + sizeof(format) > 1 \ + ? "%.0s" format "%s: %s" \ + : "Assertion failed: `%s`: %s", \ + str, __VA_ARGS__)) + +/** * Assert in debug builds; no-op in release builds. */ #ifdef NDEBUG # define bfs_assert(...) ((void)0) +# define bfs_eassert(...) ((void)0) #else # define bfs_assert bfs_verify +# define bfs_eassert bfs_everify #endif struct bfs_ctx; @@ -25,7 +25,13 @@ static ssize_t bfs_getdents(int fd, void *buf, size_t size) { sanitize_uninit(buf, size); -#if BFS_HAS_GETDENTS +#if BFS_HAS_POSIX_GETDENTS + int flags = 0; +# ifdef DT_FORCE_TYPE + flags |= DT_FORCE_TYPE; +# endif + ssize_t ret = posix_getdents(fd, buf, size, flags); +#elif BFS_HAS_GETDENTS ssize_t ret = getdents(fd, buf, size); #elif BFS_HAS_GETDENTS64 ssize_t ret = getdents64(fd, buf, size); @@ -44,11 +50,13 @@ static ssize_t bfs_getdents(int fd, void *buf, size_t size) { #endif // BFS_USE_GETDENTS -#if BFS_USE_GETDENTS && !BFS_HAS_GETDENTS /** Directory entry type for bfs_getdents() */ -typedef struct dirent64 sys_dirent; -#else +#if !BFS_USE_GETDENTS || BFS_HAS_GETDENTS typedef struct dirent sys_dirent; +#elif BFS_HAS_POSIX_GETDENTS +typedef struct posix_dent sys_dirent; +#else +typedef struct dirent64 sys_dirent; #endif enum bfs_type bfs_mode_to_type(mode_t mode) { @@ -15,8 +15,12 @@ * Whether the implementation uses the getdents() syscall directly, rather than * libc's readdir(). */ -#if !defined(BFS_USE_GETDENTS) && (__linux__ || __FreeBSD__) -# define BFS_USE_GETDENTS (BFS_HAS_GETDENTS || BFS_HAS_GETDENTS64 | BFS_HAS_GETDENTS64_SYSCALL) +#ifndef BFS_USE_GETDENTS +# if BFS_HAS_POSIX_GETDENTS +# define BFS_USE_GETDENTS true +# elif __linux__ || __FreeBSD__ +# define BFS_USE_GETDENTS (BFS_HAS_GETDENTS || BFS_HAS_GETDENTS64 | BFS_HAS_GETDENTS64_SYSCALL) +# endif #endif /** diff --git a/src/dstring.c b/src/dstring.c index b5bf3d3..86ab646 100644 --- a/src/dstring.c +++ b/src/dstring.c @@ -174,7 +174,7 @@ int dstrxcpy(dchar **dest, const char *src, size_t len) { return 0; } -char *dstrprintf(const char *format, ...) { +dchar *dstrprintf(const char *format, ...) { va_list args; va_start(args, format); @@ -184,7 +184,7 @@ char *dstrprintf(const char *format, ...) { return str; } -char *dstrvprintf(const char *format, va_list args) { +dchar *dstrvprintf(const char *format, va_list args) { // Guess a capacity to try to avoid reallocating dchar *str = dstralloc(2 * strlen(format)); if (!str) { diff --git a/src/dstring.h b/src/dstring.h index 9ea7eb9..14e1d3e 100644 --- a/src/dstring.h +++ b/src/dstring.h @@ -244,7 +244,7 @@ int dstrxcpy(dchar **dest, const char *str, size_t len); * The created string, or NULL on failure. */ attr(printf(1, 2)) -char *dstrprintf(const char *format, ...); +dchar *dstrprintf(const char *format, ...); /** * Create a dynamic string from a format string and a va_list. @@ -257,7 +257,7 @@ char *dstrprintf(const char *format, ...); * The created string, or NULL on failure. */ attr(printf(1, 0)) -char *dstrvprintf(const char *format, va_list args); +dchar *dstrvprintf(const char *format, va_list args); /** * Format some text onto the end of a dynamic string. @@ -1270,7 +1270,7 @@ static void debug_stat(const struct bfs_ctx *ctx, const struct BFTW *ftwbuf, enu bfs_debug_prefix(ctx, DEBUG_STAT); fprintf(stderr, "bfs_stat("); - if (ftwbuf->at_fd == AT_FDCWD) { + if (ftwbuf->at_fd == (int)AT_FDCWD) { fprintf(stderr, "AT_FDCWD"); } else { size_t baselen = strlen(ftwbuf->path) - strlen(ftwbuf->at_path); @@ -56,7 +56,7 @@ static size_t bfs_exec_arg_size(const char *arg) { /** Determine the maximum argv size. */ static size_t bfs_exec_arg_max(const struct bfs_exec *execbuf) { - long arg_max = sysconf(_SC_ARG_MAX); + long arg_max = xsysconf(_SC_ARG_MAX); bfs_exec_debug(execbuf, "ARG_MAX: %ld according to sysconf()\n", arg_max); if (arg_max < 0) { arg_max = BFS_EXEC_ARG_MAX; @@ -82,7 +82,7 @@ static size_t bfs_exec_arg_max(const struct bfs_exec *execbuf) { // Assume arguments are counted with the granularity of a single page, // so allow a one page cushion to account for rounding up - long page_size = sysconf(_SC_PAGESIZE); + long page_size = xsysconf(_SC_PAGESIZE); if (page_size < 4096) { page_size = 4096; } @@ -268,7 +268,7 @@ static int bfs_exec_openwd(struct bfs_exec *execbuf, const struct BFTW *ftwbuf) bfs_assert(execbuf->wd_fd < 0); bfs_assert(!execbuf->wd_path); - if (ftwbuf->at_fd != AT_FDCWD) { + if (ftwbuf->at_fd != (int)AT_FDCWD) { // Rely on at_fd being the immediate parent bfs_assert(xbaseoff(ftwbuf->at_path) == 0); diff --git a/src/fsade.c b/src/fsade.c index d56fb07..7310141 100644 --- a/src/fsade.c +++ b/src/fsade.c @@ -41,7 +41,7 @@ static const char *fake_at(const struct BFTW *ftwbuf) { static atomic int proc_works = -1; dchar *path = NULL; - if (ftwbuf->at_fd == AT_FDCWD || load(&proc_works, relaxed) == 0) { + if (ftwbuf->at_fd == (int)AT_FDCWD || load(&proc_works, relaxed) == 0) { goto fail; } @@ -36,6 +36,7 @@ * - mtab.[ch] (parses the system's mount table) * - pwcache.[ch] (a cache for the user/group tables) * - sanity.h (sanitizer interfaces) + * - sighook.[ch] (signal hooks) * - stat.[ch] (wraps stat(), or statx() on Linux) * - thread.h (multi-threading) * - trie.[ch] (a trie set/map implementation) @@ -13,11 +13,11 @@ #include <string.h> #include <sys/types.h> -#if !defined(BFS_USE_MNTENT) && BFS_USE_MNTENT_H +#if !defined(BFS_USE_MNTENT) && BFS_HAS_GETMNTENT_1 # define BFS_USE_MNTENT true -#elif !defined(BFS_USE_MNTINFO) && BSD +#elif !defined(BFS_USE_MNTINFO) && BFS_HAS_GETMNTINFO # define BFS_USE_MNTINFO true -#elif !defined(BFS_USE_MNTTAB) && __SVR4 +#elif !defined(BFS_USE_MNTTAB) && BFS_HAS_GETMNTENT_2 # define BFS_USE_MNTTAB true #endif @@ -27,7 +27,6 @@ # include <stdio.h> #elif BFS_USE_MNTINFO # include <sys/mount.h> -# include <sys/ucred.h> #elif BFS_USE_MNTTAB # include <stdio.h> # include <sys/mnttab.h> @@ -148,7 +147,7 @@ struct bfs_mtab *bfs_mtab_parse(void) { bfs_statfs *mntbuf; int size = getmntinfo(&mntbuf, MNT_WAIT); - if (size < 0) { + if (size <= 0) { error = errno; goto fail; } diff --git a/src/prelude.h b/src/prelude.h index ddeacbd..72f88b0 100644 --- a/src/prelude.h +++ b/src/prelude.h @@ -127,21 +127,6 @@ extern const char bfs_version[]; # define __has_attribute(attr) false #endif -// Platform detection - -// Get the definition of BSD if available -#if BFS_USE_SYS_PARAM_H -# include <sys/param.h> -#endif - -#ifndef __GLIBC_PREREQ -# define __GLIBC_PREREQ(maj, min) false -#endif - -#ifndef __NetBSD_Prereq__ -# define __NetBSD_Prereq__(maj, min, patch) false -#endif - // Fundamental utilities /** diff --git a/src/printf.c b/src/printf.c index f8428f7..be09ebd 100644 --- a/src/printf.c +++ b/src/printf.c @@ -709,9 +709,9 @@ int bfs_printf_parse(const struct bfs_ctx *ctx, struct bfs_expr *expr, const cha case '#': case '0': case '+': + case ' ': must_be_numeric = true; fallthru; - case ' ': case '-': if (strchr(fmt.str, c)) { bfs_expr_error(ctx, expr); diff --git a/src/sighook.c b/src/sighook.c new file mode 100644 index 0000000..ff5b96f --- /dev/null +++ b/src/sighook.c @@ -0,0 +1,600 @@ +// Copyright © Tavian Barnes <tavianator@tavianator.com> +// SPDX-License-Identifier: 0BSD + +/** + * Dynamic (un)registration of signal handlers. + * + * Because signal handlers can interrupt any thread at an arbitrary point, they + * must be lock-free or risk deadlock. Therefore, we implement the global table + * of signal "hooks" with a simple read-copy-update (RCU) scheme. Readers get a + * reference-counted pointer (struct arc) to the table in a lock-free way, and + * release the reference count when finished. + * + * Updates are managed by struct rcu, which has two slots: one active and one + * inactive. Readers acquire a reference to the active slot. A single writer + * can safely update it by initializing the inactive slot, atomically swapping + * the slots, and waiting for the reference count of the newly inactive slot to + * drop to zero. Once it does, the old pointer can be safely freed. + */ + +#include "prelude.h" +#include "sighook.h" +#include "alloc.h" +#include "atomic.h" +#include "bfstd.h" +#include "diag.h" +#include "thread.h" +#include <errno.h> +#include <signal.h> +#include <stdlib.h> +#include <unistd.h> + +#if _POSIX_SEMAPHORES > 0 +# include <semaphore.h> +#endif + +/** + * An atomically reference-counted pointer. + */ +struct arc { + /** The current reference count (0 means empty). */ + atomic size_t refs; + /** The reference itself. */ + void *ptr; + +#if _POSIX_SEMAPHORES > 0 + /** A semaphore for arc_wake(). */ + sem_t sem; + /** sem_init() result. */ + int sem_status; +#endif +}; + +/** Initialize an arc. */ +static void arc_init(struct arc *arc) { + atomic_init(&arc->refs, 0); + arc->ptr = NULL; + +#if _POSIX_SEMAPHORES > 0 + arc->sem_status = sem_init(&arc->sem, false, 0); +#endif +} + +/** Get the current refcount. */ +static size_t arc_refs(const struct arc *arc) { + return load(&arc->refs, relaxed); +} + +/** Set the pointer in an empty arc. */ +static void arc_set(struct arc *arc, void *ptr) { + bfs_assert(arc_refs(arc) == 0); + bfs_assert(ptr); + + arc->ptr = ptr; + store(&arc->refs, 1, release); +} + +/** Acquire a reference. */ +static void *arc_get(struct arc *arc) { + size_t refs = arc_refs(arc); + do { + if (refs < 1) { + return NULL; + } + } while (!compare_exchange_weak(&arc->refs, &refs, refs + 1, acquire, relaxed)); + + return arc->ptr; +} + +/** Release a reference. */ +static void arc_put(struct arc *arc) { + size_t refs = fetch_sub(&arc->refs, 1, release); + + if (refs == 1) { +#if _POSIX_SEMAPHORES > 0 + if (arc->sem_status == 0 && sem_post(&arc->sem) != 0) { + abort(); + } +#endif + } +} + +/** Wait on the semaphore. */ +static int arc_sem_wait(struct arc *arc) { +#if _POSIX_SEMAPHORES > 0 + if (arc->sem_status == 0) { + while (sem_wait(&arc->sem) != 0) { + bfs_everify(errno == EINTR, "sem_wait()"); + } + return 0; + } +#endif + + return -1; +} + +/** Wait for all references to be released. */ +static void *arc_wait(struct arc *arc) { + size_t refs = fetch_sub(&arc->refs, 1, relaxed); + bfs_assert(refs > 0); + + --refs; + while (refs > 0) { + if (arc_sem_wait(arc) == 0) { + bfs_assert(arc_refs(arc) == 0); + // sem_wait() provides enough ordering, so we can skip the fence + goto done; + } + + // Some platforms (like macOS) don't support unnamed semaphores, + // but we can always busy-wait + spin_loop(); + refs = arc_refs(arc); + } + + thread_fence(&arc->refs, acquire); + +done:; + void *ptr = arc->ptr; + arc->ptr = NULL; + return ptr; +} + +/** Destroy an arc. */ +static void arc_destroy(struct arc *arc) { + bfs_assert(arc_refs(arc) <= 1); + +#if _POSIX_SEMAPHORES > 0 + if (arc->sem_status == 0) { + bfs_everify(sem_destroy(&arc->sem) == 0, "sem_destroy()"); + } +#endif +} + +/** + * A simple read-copy-update memory reclamation scheme. + */ +struct rcu { + /** The currently active slot. */ + atomic size_t active; + /** The two slots. */ + struct arc slots[2]; +}; + +/** Sentinel value for RCU, since arc uses NULL already. */ +static void *RCU_NULL = &RCU_NULL; + +/** Initialize an RCU block. */ +static void rcu_init(struct rcu *rcu) { + atomic_init(&rcu->active, 0); + arc_init(&rcu->slots[0]); + arc_init(&rcu->slots[1]); + arc_set(&rcu->slots[0], RCU_NULL); +} + +/** Get the active slot. */ +static struct arc *rcu_active(struct rcu *rcu) { + size_t i = load(&rcu->active, relaxed); + return &rcu->slots[i]; +} + +/** Read an RCU-protected pointer. */ +static void *rcu_read(struct rcu *rcu, struct arc **slot) { + while (true) { + *slot = rcu_active(rcu); + void *ptr = arc_get(*slot); + if (ptr == RCU_NULL) { + return NULL; + } else if (ptr) { + return ptr; + } + // Otherwise, the other slot became active; retry + } +} + +/** Get the RCU-protected pointer without acquiring a reference. */ +static void *rcu_peek(struct rcu *rcu) { + struct arc *arc = rcu_active(rcu); + void *ptr = arc->ptr; + if (ptr == RCU_NULL) { + return NULL; + } else { + return ptr; + } +} + +/** Update an RCU-protected pointer, and return the old one. */ +static void *rcu_update(struct rcu *rcu, void *ptr) { + size_t i = load(&rcu->active, relaxed); + struct arc *prev = &rcu->slots[i]; + + size_t j = i ^ 1; + struct arc *next = &rcu->slots[j]; + + arc_set(next, ptr ? ptr : RCU_NULL); + store(&rcu->active, j, relaxed); + return arc_wait(prev); +} + +struct sighook { + int sig; + sighook_fn *fn; + void *arg; + enum sigflags flags; +}; + +/** + * A table of signal hooks. + */ +struct sigtable { + /** The number of filled slots. */ + size_t filled; + /** The length of the array. */ + size_t size; + /** An array of signal hooks. */ + struct arc hooks[]; +}; + +/** Add a hook to a table. */ +static int sigtable_add(struct sigtable *table, struct sighook *hook) { + if (!table || table->filled == table->size) { + return -1; + } + + for (size_t i = 0; i < table->size; ++i) { + struct arc *arc = &table->hooks[i]; + if (arc_refs(arc) == 0) { + arc_set(arc, hook); + ++table->filled; + return 0; + } + } + + return -1; +} + +/** Delete a hook from a table. */ +static int sigtable_del(struct sigtable *table, struct sighook *hook) { + for (size_t i = 0; i < table->size; ++i) { + struct arc *arc = &table->hooks[i]; + if (arc->ptr == hook) { + arc_wait(arc); + --table->filled; + return 0; + } + } + + return -1; +} + +/** Create a bigger copy of a signal table. */ +static struct sigtable *sigtable_grow(struct sigtable *prev) { + size_t old_size = prev ? prev->size : 0; + size_t new_size = old_size ? 2 * old_size : 1; + struct sigtable *table = ALLOC_FLEX(struct sigtable, hooks, new_size); + if (!table) { + return NULL; + } + + table->filled = 0; + table->size = new_size; + for (size_t i = 0; i < new_size; ++i) { + arc_init(&table->hooks[i]); + } + + for (size_t i = 0; i < old_size; ++i) { + struct sighook *hook = prev->hooks[i].ptr; + if (hook) { + bfs_verify(sigtable_add(table, hook) == 0); + } + } + + return table; +} + +/** Free a signal table. */ +static void sigtable_free(struct sigtable *table) { + if (!table) { + return; + } + + for (size_t i = 0; i < table->size; ++i) { + struct arc *arc = &table->hooks[i]; + arc_destroy(arc); + } + free(table); +} + +/** Add a hook to a signal table, growing it if necessary. */ +static int rcu_sigtable_add(struct rcu *rcu, struct sighook *hook) { + struct sigtable *prev = rcu_peek(rcu); + if (sigtable_add(prev, hook) == 0) { + return 0; + } + + struct sigtable *next = sigtable_grow(prev); + if (!next) { + return -1; + } + + bfs_verify(sigtable_add(next, hook) == 0); + rcu_update(rcu, next); + sigtable_free(prev); + return 0; +} + +/** The global table of signal hooks. */ +static struct rcu rcu_sighooks; +/** The global table of atsigexit() hooks. */ +static struct rcu rcu_exithooks; + +/** Mutex for initialization and RCU writer exclusion. */ +static pthread_mutex_t sigmutex = PTHREAD_MUTEX_INITIALIZER; + +/** Check if a signal was generated by userspace. */ +static bool is_user_generated(const siginfo_t *info) { + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03 + // + // If si_code is SI_USER or SI_QUEUE, or any value less than or + // equal to 0, then the signal was generated by a process ... + int code = info->si_code; + return code == SI_USER || code == SI_QUEUE || code <= 0; +} + +/** Check if a signal is caused by a fault. */ +static bool is_fault(const siginfo_t *info) { + int sig = info->si_signo; + if (sig == SIGBUS || sig == SIGFPE || sig == SIGILL || sig == SIGSEGV) { + return !is_user_generated(info); + } else { + return false; + } +} + +// https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/signal.h.html +static const int FATAL_SIGNALS[] = { + SIGABRT, + SIGALRM, + SIGBUS, + SIGFPE, + SIGHUP, + SIGILL, + SIGINT, + SIGPIPE, + SIGQUIT, + SIGSEGV, + SIGTERM, + SIGUSR1, + SIGUSR2, +#ifdef SIGPOLL + SIGPOLL, +#endif +#ifdef SIGPROF + SIGPROF, +#endif +#ifdef SIGSYS + SIGSYS, +#endif + SIGTRAP, +#ifdef SIGVTALRM + SIGVTALRM, +#endif + SIGXCPU, + SIGXFSZ, +}; + +/** Check if a signal's default action is to terminate the process. */ +static bool is_fatal(int sig) { + for (size_t i = 0; i < countof(FATAL_SIGNALS); ++i) { + if (sig == FATAL_SIGNALS[i]) { + return true; + } + } + +#ifdef SIGRTMIN + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03 + // + // The default actions for the realtime signals in the range + // SIGRTMIN to SIGRTMAX shall be to terminate the process + // abnormally. + if (sig >= SIGRTMIN && sig <= SIGRTMAX) { + return true; + } +#endif + + return false; +} + +/** Reraise a fatal signal. */ +static noreturn void reraise(int sig) { + // Restore the default signal action + if (signal(sig, SIG_DFL) == SIG_ERR) { + goto fail; + } + + // Unblock the signal, since we didn't set SA_NODEFER + sigset_t mask; + if (sigemptyset(&mask) != 0 + || sigaddset(&mask, sig) != 0 + || pthread_sigmask(SIG_UNBLOCK, &mask, NULL) != 0) { + goto fail; + } + + raise(sig); +fail: + abort(); +} + +/** Find any matching hooks and run them. */ +static enum sigflags run_hooks(struct rcu *rcu, int sig, siginfo_t *info) { + enum sigflags ret = 0; + struct arc *slot; + struct sigtable *table = rcu_read(rcu, &slot); + if (!table) { + goto done; + } + + for (size_t i = 0; i < table->size; ++i) { + struct arc *arc = &table->hooks[i]; + struct sighook *hook = arc_get(arc); + if (!hook) { + continue; + } + + if (hook->sig == sig || hook->sig == 0) { + hook->fn(sig, info, hook->arg); + ret |= hook->flags; + } + arc_put(arc); + } + +done: + arc_put(slot); + return ret; +} + +/** Dispatches a signal to the registered handlers. */ +static void sigdispatch(int sig, siginfo_t *info, void *context) { + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03 + // + // The behavior of a process is undefined after it returns normally + // from a signal-catching function for a SIGBUS, SIGFPE, SIGILL, or + // SIGSEGV signal that was not generated by kill(), sigqueue(), or + // raise(). + if (is_fault(info)) { + reraise(sig); + } + + // https://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_04_03 + // + // After returning from a signal-catching function, the value of + // errno is unspecified if the signal-catching function or any + // function it called assigned a value to errno and the signal- + // catching function did not save and restore the original value of + // errno. + int error = errno; + + // Run the normal hooks + enum sigflags flags = run_hooks(&rcu_sighooks, sig, info); + + // Run the atsigexit() hooks, if we're exiting + if (!(flags & SH_CONTINUE) && is_fatal(sig)) { + run_hooks(&rcu_exithooks, sig, info); + reraise(sig); + } + + errno = error; +} + +/** Make sure our signal handler is installed for a given signal. */ +static int siginit(int sig) { + static struct sigaction action = { + .sa_sigaction = sigdispatch, + .sa_flags = SA_RESTART | SA_SIGINFO, + }; + + static sigset_t signals; + static bool initialized = false; + + if (!initialized) { + if (sigemptyset(&signals) != 0 + || sigemptyset(&action.sa_mask) != 0) { + return -1; + } + rcu_init(&rcu_sighooks); + rcu_init(&rcu_exithooks); + initialized = true; + } + + int installed = sigismember(&signals, sig); + if (installed < 0) { + return -1; + } else if (installed) { + return 0; + } + + if (sigaction(sig, &action, NULL) != 0) { + return -1; + } + + if (sigaddset(&signals, sig) != 0) { + return -1; + } + + return 0; +} + +/** Shared sighook()/atsigexit() implementation. */ +static struct sighook *sighook_impl(struct rcu *rcu, int sig, sighook_fn *fn, void *arg, enum sigflags flags) { + struct sighook *hook = ALLOC(struct sighook); + if (!hook) { + return NULL; + } + + hook->sig = sig; + hook->fn = fn; + hook->arg = arg; + hook->flags = flags; + + if (rcu_sigtable_add(rcu, hook) != 0) { + free(hook); + return NULL; + } + + return hook; +} + +struct sighook *sighook(int sig, sighook_fn *fn, void *arg, enum sigflags flags) { + mutex_lock(&sigmutex); + + struct sighook *ret = NULL; + if (siginit(sig) != 0) { + goto done; + } + + ret = sighook_impl(&rcu_sighooks, sig, fn, arg, flags); +done: + mutex_unlock(&sigmutex); + return ret; +} + +struct sighook *atsigexit(sighook_fn *fn, void *arg) { + mutex_lock(&sigmutex); + + struct sighook *ret = NULL; + + for (size_t i = 0; i < countof(FATAL_SIGNALS); ++i) { + if (siginit(FATAL_SIGNALS[i]) != 0) { + goto done; + } + } + +#ifdef SIGRTMIN + for (int i = SIGRTMIN; i <= SIGRTMAX; ++i) { + if (siginit(i) != 0) { + goto done; + } + } +#endif + + ret = sighook_impl(&rcu_exithooks, 0, fn, arg, 0); +done: + mutex_unlock(&sigmutex); + return ret; +} + +void sigunhook(struct sighook *hook) { + mutex_lock(&sigmutex); + + struct rcu *rcu = hook->sig ? &rcu_sighooks : &rcu_exithooks; + struct sigtable *table = rcu_peek(rcu); + bfs_verify(sigtable_del(table, hook) == 0); + + if (table->filled == 0) { + rcu_update(rcu, NULL); + sigtable_free(table); + } + + mutex_unlock(&sigmutex); + free(hook); +} diff --git a/src/sighook.h b/src/sighook.h new file mode 100644 index 0000000..74d18c0 --- /dev/null +++ b/src/sighook.h @@ -0,0 +1,73 @@ +// Copyright © Tavian Barnes <tavianator@tavianator.com> +// SPDX-License-Identifier: 0BSD + +/** + * Signal hooks. + */ + +#ifndef BFS_SIGHOOK_H +#define BFS_SIGHOOK_H + +#include <signal.h> + +/** + * A dynamic signal hook. + */ +struct sighook; + +/** + * Signal hook flags. + */ +enum sigflags { + /** Suppress the default action for this signal. */ + SH_CONTINUE = 1 << 0, +}; + +/** + * A signal hook callback. Hooks are executed from a signal handler, so must + * only call async-signal-safe functions. + * + * @param sig + * The signal number. + * @param info + * Additional information about the signal. + * @param arg + * An arbitrary pointer passed to the hook. + */ +typedef void sighook_fn(int sig, siginfo_t *info, void *arg); + +/** + * Install a hook for a signal. + * + * @param sig + * The signal to hook. + * @param fn + * The function to call. + * @param arg + * An argument passed to the function. + * @param flags + * Flags for the new hook. + * @return + * The installed hook, or NULL on failure. + */ +struct sighook *sighook(int sig, sighook_fn *fn, void *arg, enum sigflags flags); + +/** + * On a best-effort basis, invoke the given hook just before the program is + * abnormally terminated by a signal. + * + * @param fn + * The function to call. + * @param arg + * An argument passed to the function. + * @return + * The installed hook, or NULL on failure. + */ +struct sighook *atsigexit(sighook_fn *fn, void *arg); + +/** + * Remove a signal hook. + */ +void sigunhook(struct sighook *hook); + +#endif // BFS_SIGHOOK_H @@ -62,7 +62,7 @@ int bfs_fstatat_flags(enum bfs_stat_flags flags) { ret |= AT_SYMLINK_NOFOLLOW; } -#if defined(AT_NO_AUTOMOUNT) && (!__GNU__ || __GLIBC_PREREQ(2, 35)) +#ifdef AT_NO_AUTOMOUNT ret |= AT_NO_AUTOMOUNT; #endif @@ -116,6 +116,9 @@ void bfs_stat_convert(struct bfs_stat *dest, const struct stat *src) { #if BFS_HAS_ST_BIRTHTIM dest->btime = src->st_birthtim; dest->mask |= BFS_STAT_BTIME; +#elif BFS_HAS___ST_BIRTHTIM + dest->btime = src->__st_birthtim; + dest->mask |= BFS_STAT_BTIME; #elif BFS_HAS_ST_BIRTHTIMESPEC dest->btime = src->st_birthtimespec; dest->mask |= BFS_STAT_BTIME; @@ -297,27 +300,21 @@ int bfs_stat(int at_fd, const char *at_path, enum bfs_stat_flags flags, struct b return bfs_stat_tryfollow(at_fd, at_path, at_flags, flags, buf); } - // Check __GNU__ to work around https://lists.gnu.org/archive/html/bug-hurd/2021-12/msg00001.html -#if defined(AT_EMPTY_PATH) && !__GNU__ - static atomic bool has_at_ep = true; - if (load(&has_at_ep, relaxed)) { - at_flags |= AT_EMPTY_PATH; - int ret = bfs_stat_explicit(at_fd, "", at_flags, buf); - if (ret != 0 && errno == EINVAL) { - store(&has_at_ep, false, relaxed); - } else { - return ret; - } - } -#endif - - struct stat statbuf; - if (fstat(at_fd, &statbuf) == 0) { - bfs_stat_convert(buf, &statbuf); - return 0; - } else { +#if BFS_USE_STATX + // If we have statx(), use it with AT_EMPTY_PATH for its extra features + at_flags |= AT_EMPTY_PATH; + return bfs_stat_explicit(at_fd, "", at_flags, buf); +#else + // Otherwise, just use fstat() rather than fstatat(at_fd, ""), to save + // the kernel the trouble of copying in the empty string + struct stat sb; + if (fstat(at_fd, &sb) != 0) { return -1; } + + bfs_stat_convert(buf, &sb); + return 0; +#endif } const struct timespec *bfs_stat_time(const struct bfs_stat *buf, enum bfs_stat_field field) { diff --git a/src/xspawn.c b/src/xspawn.c index 0b0cea4..33e5a4a 100644 --- a/src/xspawn.c +++ b/src/xspawn.c @@ -5,9 +5,11 @@ #include "xspawn.h" #include "alloc.h" #include "bfstd.h" +#include "diag.h" #include "list.h" #include <errno.h> #include <fcntl.h> +#include <signal.h> #include <stdlib.h> #include <string.h> #include <sys/resource.h> @@ -590,30 +592,49 @@ static pid_t bfs_fork_spawn(struct bfs_resolver *res, const struct bfs_spawn *ct return -1; } + // Block signals before fork() so handlers don't run in the child + sigset_t new_mask; + if (sigfillset(&new_mask) != 0) { + goto fail; + } + sigset_t old_mask; + errno = pthread_sigmask(SIG_BLOCK, &new_mask, &old_mask); + if (errno != 0) { + goto fail; + } + pid_t pid = fork(); - if (pid < 0) { - close_quietly(pipefd[1]); - close_quietly(pipefd[0]); - return -1; - } else if (pid == 0) { + if (pid == 0) { // Child bfs_spawn_exec(res, ctx, argv, envp, pipefd); } - // Parent + // Restore the original signal mask + int ret = pthread_sigmask(SIG_SETMASK, &old_mask, NULL); + bfs_everify(ret == 0, "pthread_sigmask()"); + + if (pid < 0) { + // fork() failed + goto fail; + } + xclose(pipefd[1]); int error; ssize_t nbytes = xread(pipefd[0], &error, sizeof(error)); xclose(pipefd[0]); if (nbytes == sizeof(error)) { - int wstatus; - xwaitpid(pid, &wstatus, 0); + xwaitpid(pid, NULL, 0); errno = error; return -1; } return pid; + +fail: + close_quietly(pipefd[1]); + close_quietly(pipefd[0]); + return -1; } /** Call the right bfs_spawn() implementation. */ diff --git a/src/xtime.c b/src/xtime.c index 91ed915..2808455 100644 --- a/src/xtime.c +++ b/src/xtime.c @@ -5,6 +5,7 @@ #include "xtime.h" #include "bfstd.h" #include "diag.h" +#include "sanity.h" #include <errno.h> #include <limits.h> #include <sys/time.h> @@ -12,14 +13,14 @@ #include <unistd.h> int xmktime(struct tm *tm, time_t *timep) { - *timep = mktime(tm); + time_t time = mktime(tm); - if (*timep == -1) { + if (time == -1) { int error = errno; struct tm tmp; - if (!localtime_r(timep, &tmp)) { - bfs_bug("localtime_r(-1): %s", xstrerror(errno)); + if (!localtime_r(&time, &tmp)) { + bfs_ebug("localtime_r(-1)"); return -1; } @@ -30,9 +31,38 @@ int xmktime(struct tm *tm, time_t *timep) { } } + *timep = time; + return 0; +} + +// FreeBSD is missing an interceptor +#if BFS_HAS_TIMEGM && !(__FreeBSD__ && SANITIZE_MEMORY) + +int xtimegm(struct tm *tm, time_t *timep) { + time_t time = timegm(tm); + + if (time == -1) { + int error = errno; + + struct tm tmp; + if (!gmtime_r(&time, &tmp)) { + bfs_ebug("gmtime_r(-1)"); + return -1; + } + + if (tm->tm_year != tmp.tm_year || tm->tm_yday != tmp.tm_yday + || tm->tm_hour != tmp.tm_hour || tm->tm_min != tmp.tm_min || tm->tm_sec != tmp.tm_sec) { + errno = error; + return -1; + } + } + + *timep = time; return 0; } +#else + static int safe_add(int *value, int delta) { if (*value >= 0) { if (delta > INT_MAX - *value) { @@ -147,6 +177,8 @@ overflow: return -1; } +#endif // !BFS_HAS_TIMEGM + /** Parse a decimal digit. */ static int xgetdigit(char c) { int ret = c - '0'; |