diff options
Diffstat (limited to 'src/tee.c')
| -rw-r--r-- | src/tee.c | 98 |
1 files changed, 85 insertions, 13 deletions
@@ -28,6 +28,7 @@ #include "fadvise.h" #include "stdio--.h" #include "xbinary-io.h" +#include "iopoll.h" /* The official name of this program (e.g., no 'g' prefix). */ #define PROGRAM_NAME "tee" @@ -45,6 +46,9 @@ static bool append; /* If true, ignore interrupts. */ static bool ignore_interrupts; +/* If true, detect if next output becomes broken while waiting for input. */ +static bool pipe_check; + enum output_error { output_error_sigpipe, /* traditional behavior, sigpipe enabled. */ @@ -149,6 +153,12 @@ main (int argc, char **argv) output_error_args, output_error_types); else output_error = output_error_warn_nopipe; + + /* Detect and close a broken pipe output when ignoring EPIPE. */ + if (output_error == output_error_warn_nopipe + || output_error == output_error_exit_nopipe) + pipe_check = true; + break; case_GETOPT_HELP_CHAR; @@ -166,6 +176,10 @@ main (int argc, char **argv) if (output_error != output_error_sigpipe) signal (SIGPIPE, SIG_IGN); + /* No need to poll outputs if input is always ready for reading. */ + if (pipe_check && !iopoll_input_ok (STDIN_FILENO)) + pipe_check = false; + /* Do *not* warn if tee is given no file arguments. POSIX requires that it work when given no arguments. */ @@ -176,6 +190,42 @@ main (int argc, char **argv) return ok ? EXIT_SUCCESS : EXIT_FAILURE; } + +/* Return the index of the first non-NULL descriptor after idx, + or -1 if all are NULL. */ + +static int +get_next_out (FILE **descriptors, int nfiles, int idx) +{ + for (idx++; idx <= nfiles; idx++) + if (descriptors[idx]) + return idx; + return -1; /* no outputs remaining */ +} + +/* Remove descriptors[i] due to write failure or broken pipe. + Return true if this indicates a reportable error. */ + +static bool +fail_output (FILE **descriptors, char **files, int i) +{ + int w_errno = errno; + bool fail = errno != EPIPE + || output_error == output_error_exit + || output_error == output_error_warn; + if (descriptors[i] == stdout) + clearerr (stdout); /* Avoid redundant close_stdout diagnostic. */ + if (fail) + { + error (output_error == output_error_exit + || output_error == output_error_exit_nopipe, + w_errno, "%s", quotef (files[i])); + } + descriptors[i] = NULL; + return fail; +} + + /* Copy the standard input into each of the NFILES files in FILES and into the standard output. As a side effect, modify FILES[-1]. Return true if successful. */ @@ -185,9 +235,11 @@ tee_files (int nfiles, char **files) { size_t n_outputs = 0; FILE **descriptors; + bool *out_pollable; char buffer[BUFSIZ]; ssize_t bytes_read = 0; int i; + int first_out = 0; /* idx of first non-NULL output in descriptors */ bool ok = true; char const *mode_string = (O_BINARY @@ -202,8 +254,12 @@ tee_files (int nfiles, char **files) In both arrays, entry 0 corresponds to standard output. */ descriptors = xnmalloc (nfiles + 1, sizeof *descriptors); + if (pipe_check) + out_pollable = xnmalloc (nfiles + 1, sizeof *out_pollable); files--; descriptors[0] = stdout; + if (pipe_check) + out_pollable[0] = iopoll_output_ok (fileno (descriptors[0])); files[0] = bad_cast (_("standard output")); setvbuf (stdout, NULL, _IONBF, 0); n_outputs++; @@ -212,6 +268,8 @@ tee_files (int nfiles, char **files) { /* Do not treat "-" specially - as mandated by POSIX. */ descriptors[i] = fopen (files[i], mode_string); + if (pipe_check) + out_pollable[i] = iopoll_output_ok (fileno (descriptors[i])); if (descriptors[i] == NULL) { error (output_error == output_error_exit @@ -228,6 +286,28 @@ tee_files (int nfiles, char **files) while (n_outputs) { + if (pipe_check && out_pollable[first_out]) + { + /* Monitor for input, or errors on first valid output. */ + int err = iopoll (STDIN_FILENO, fileno (descriptors[first_out])); + + /* Close the output if it became a broken pipe. */ + if (err == IOPOLL_BROKEN_OUTPUT) + { + errno = EPIPE; /* behave like write produced EPIPE */ + if (fail_output (descriptors, files, first_out)) + ok = false; + n_outputs--; + first_out = get_next_out (descriptors, nfiles, first_out); + continue; + } + else if (err == IOPOLL_ERROR) + { + error (0, errno, _("iopoll error")); + ok = false; + } + } + bytes_read = read (STDIN_FILENO, buffer, sizeof buffer); if (bytes_read < 0 && errno == EINTR) continue; @@ -240,21 +320,11 @@ tee_files (int nfiles, char **files) if (descriptors[i] && fwrite (buffer, bytes_read, 1, descriptors[i]) != 1) { - int w_errno = errno; - bool fail = errno != EPIPE || (output_error == output_error_exit - || output_error == output_error_warn); - if (descriptors[i] == stdout) - clearerr (stdout); /* Avoid redundant close_stdout diagnostic. */ - if (fail) - { - error (output_error == output_error_exit - || output_error == output_error_exit_nopipe, - w_errno, "%s", quotef (files[i])); - } - descriptors[i] = NULL; - if (fail) + if (fail_output (descriptors, files, i)) ok = false; n_outputs--; + if (i == first_out) + first_out = get_next_out (descriptors, nfiles, first_out); } } @@ -273,6 +343,8 @@ tee_files (int nfiles, char **files) } free (descriptors); + if (pipe_check) + free (out_pollable); return ok; } |