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Commit e3d0c968 authored by Mark Salyzyn's avatar Mark Salyzyn
Browse files

liblogcat: add simple stdout redirection 

Provide minimal redirection functionality, adding stdout redirection
to the existing stderr redirection parsing.

- stderr and stdout redirection do _not_ support append, will treat
  like write only.
- stderr redirection does _not_ support filename. Only 2>&1 to
  join stderr and stdout and 2>/dev/null to drop content on floor.
- stdout redirection supports filename only.
- stderr 2>&1 redirection must be last for shell compatibility.
- preserve 2>&1 through file rotation (bugfix)

Test: logcat-benchmarks --benchmark_filter='BM_logcat_popen*|BM_logcat_system*'
Bug: 35326290
Change-Id: Id36b59358167f21381bd1dbf0bd7a7e10e2a2ed9
parent 3e3aaca4

logcat/logcat.cpp

+49 −14
Original line number Diff line number Diff line
@@ -67,8 +67,8 @@ struct android_logcat_context_internal { 
    std::vector<const char*> argv_hold;

    std::vector<std::string> envs;

    std::vector<const char*> envp_hold;

    int output_fd;

    int error_fd;

    int output_fd; // duplication of fileno(output) (below)

    int error_fd;  // duplication of fileno(error) (below)



    // library

    int fds[2];    // From popen call
@@ -284,6 +284,15 @@ static void rotateLogs(android_logcat_context_internal* context) { 
        return;

    }

    context->output = fdopen(context->output_fd, "web");

    if (context->output == NULL) {

        logcat_panic(context, HELP_FALSE, "couldn't fdopen output file");

        return;

    }

    if (context->stderr_stdout) {

        close_error(context);

        context->error = context->output;

        context->error_fd = context->output_fd;

    }



    context->outByteCount = 0;

}
@@ -788,6 +797,7 @@ static int __logcat(android_logcat_context_internal* context) { 
        // Simulate shell stderr redirect parsing

        if ((argv[i][0] != '2') || (argv[i][1] != '>')) continue;



        // Append to file not implemented, just open file

        size_t skip = (argv[i][2] == '>') + 2;

        if (!strcmp(&argv[i][skip], "/dev/null")) {

            context->stderr_null = true;
@@ -799,16 +809,29 @@ static int __logcat(android_logcat_context_internal* context) { 
                    "stderr redirection to file %s unsupported, skipping\n",

                    &argv[i][skip]);

        }

        // Only the first one

        break;

    }



    const char* filename = NULL;

    for (int i = 0; i < argc; ++i) {

        // Simulate shell stdout redirect parsing

        if (argv[i][0] != '>') continue;



        // Append to file not implemented, just open file

        filename = &argv[i][(argv[i][1] == '>') + 1];

        // Only the first one

        break;

    }



    // Deal with setting up file descriptors and FILE pointers

    if (context->error_fd >= 0) {

    if (context->error_fd >= 0) { // Is an error file descriptor supplied?

        if (context->error_fd == context->output_fd) {

            context->stderr_stdout = true;

        } else if (context->stderr_null) {

        } else if (context->stderr_null) { // redirection told us to close it

            close(context->error_fd);

            context->error_fd = -1;

        } else {

        } else { // All Ok, convert error to a FILE pointer

            context->error = fdopen(context->error_fd, "web");

            if (!context->error) {

                context->retval = -errno;
@@ -819,22 +842,32 @@ static int __logcat(android_logcat_context_internal* context) { 
            }

        }

    }

    if (context->output_fd >= 0) {

    if (context->output_fd >= 0) { // Is an output file descriptor supplied?

        if (filename) { // redirect to file, close the supplied file descriptor.

            close(context->output_fd);

            context->output_fd = -1;

        } else { // All Ok, convert output to a FILE pointer

            context->output = fdopen(context->output_fd, "web");

            if (!context->output) {

                context->retval = -errno;

                fprintf(context->stderr_stdout ? stdout : context->error,

                    "Failed to fdopen(output_fd=%d) %s\n", context->output_fd,

                    strerror(errno));

                        "Failed to fdopen(output_fd=%d) %s\n",

                        context->output_fd, strerror(errno));

                goto exit;

            }

        }

    }

    if (filename) { // We supplied an output file redirected in command line

        context->output = fopen(filename, "web");

    }

    // Deal with 2>&1

    if (context->stderr_stdout) context->error = context->output;

    // Deal with 2>/dev/null

    if (context->stderr_null) {

        context->error_fd = -1;

        context->error = NULL;

    }

    // Only happens if output=stdout

    // Only happens if output=stdout or output=filename

    if ((context->output_fd < 0) && context->output) {

        context->output_fd = fileno(context->output);

    }
@@ -1351,6 +1384,8 @@ static int __logcat(android_logcat_context_internal* context) { 
        for (int i = optind ; i < argc ; i++) {

            // skip stderr redirections of _all_ kinds

            if ((argv[i][0] == '2') && (argv[i][1] == '>')) continue;

            // skip stdout redirections of _all_ kinds

            if (argv[i][0] == '>') continue;



            err = android_log_addFilterString(context->logformat, argv[i]);

            if (err < 0) {