diff options
Diffstat (limited to 'host/lib/subprocess.c')
| -rw-r--r-- | host/lib/subprocess.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/host/lib/subprocess.c b/host/lib/subprocess.c new file mode 100644 index 00000000..5721a576 --- /dev/null +++ b/host/lib/subprocess.c @@ -0,0 +1,239 @@ +/* Copyright 2019 The Chromium OS Authors. All rights reserved. + * Use of this source code is governed by a BSD-style license that can be + * found in the LICENSE file. + */ + +#include <fcntl.h> +#include <stdlib.h> +#include <string.h> +#include <sys/wait.h> +#include <unistd.h> + +#include "subprocess.h" + +static char *program_name; + +__attribute__((constructor, used)) +static int libinit(int argc, char **argv) +{ + program_name = *argv; + return 0; +} + +static int init_target_private(struct subprocess_target *target) +{ + switch (target->type) { + case TARGET_BUFFER: + case TARGET_BUFFER_NULL_TERMINATED: + return pipe(target->buffer._pipefd); + default: + return 0; + } +} + +static int flags_for_fd(int fd) +{ + switch (fd) { + case STDIN_FILENO: + return O_RDONLY; + case STDOUT_FILENO: + case STDERR_FILENO: + return O_WRONLY; + default: + return -1; + } +} + +static int connect_process_target(struct subprocess_target *target, int fd) +{ + int target_fd; + + switch (target->type) { + case TARGET_NULL: + target_fd = open("/dev/null", flags_for_fd(fd)); + break; + case TARGET_FD: + target_fd = target->fd; + break; + case TARGET_FILE: + target_fd = fileno(target->file); + break; + case TARGET_BUFFER: + case TARGET_BUFFER_NULL_TERMINATED: + switch (fd) { + case STDIN_FILENO: + target_fd = target->buffer._pipefd[0]; + close(target->buffer._pipefd[1]); + break; + case STDOUT_FILENO: + case STDERR_FILENO: + target_fd = target->buffer._pipefd[1]; + close(target->buffer._pipefd[0]); + break; + default: + return -1; + } + break; + } + + return dup2(target_fd, fd); +} + +static int process_target_input(struct subprocess_target *target) +{ + int rv = 0; + ssize_t write_rv; + size_t bytes_to_write; + char *buf; + + switch (target->type) { + case TARGET_BUFFER: + bytes_to_write = target->buffer.size; + break; + case TARGET_BUFFER_NULL_TERMINATED: + bytes_to_write = strlen(target->buffer.buf); + break; + default: + return 0; + } + + close(target->buffer._pipefd[0]); + buf = target->buffer.buf; + while (bytes_to_write) { + write_rv = + write(target->buffer._pipefd[1], buf, bytes_to_write); + if (write_rv <= 0) { + rv = -1; + goto cleanup; + } + buf += write_rv; + bytes_to_write -= write_rv; + } + +cleanup: + close(target->buffer._pipefd[1]); + return rv; +} + +static int process_target_output(struct subprocess_target *target) +{ + int rv = 0; + ssize_t read_rv; + size_t bytes_remaining; + + switch (target->type) { + case TARGET_BUFFER: + bytes_remaining = target->buffer.size; + break; + case TARGET_BUFFER_NULL_TERMINATED: + if (target->buffer.size == 0) + return -1; + bytes_remaining = target->buffer.size - 1; + break; + default: + return 0; + } + + close(target->buffer._pipefd[1]); + target->buffer.bytes_consumed = 0; + while (bytes_remaining) { + read_rv = read( + target->buffer._pipefd[0], + target->buffer.buf + target->buffer.bytes_consumed, + bytes_remaining); + if (read_rv < 0) { + rv = -1; + goto cleanup; + } + if (read_rv == 0) + break; + target->buffer.bytes_consumed += read_rv; + bytes_remaining -= read_rv; + } + + if (target->type == TARGET_BUFFER_NULL_TERMINATED) + target->buffer.buf[target->buffer.bytes_consumed] = '\0'; + +cleanup: + close(target->buffer._pipefd[0]); + return rv; +} + +struct subprocess_target subprocess_null = { + .type = TARGET_NULL, +}; + +struct subprocess_target subprocess_stdin = { + .type = TARGET_FD, + .fd = STDIN_FILENO, +}; + +struct subprocess_target subprocess_stdout = { + .type = TARGET_FD, + .fd = STDOUT_FILENO, +}; + +struct subprocess_target subprocess_stderr = { + .type = TARGET_FD, + .fd = STDERR_FILENO, +}; + +int subprocess_run(const char *const argv[], + struct subprocess_target *input, + struct subprocess_target *output, + struct subprocess_target *error) +{ + int status; + pid_t pid = -1; + + if (!input) + input = &subprocess_stdin; + if (!output) + output = &subprocess_stdout; + if (!error) + error = &subprocess_stderr; + + if (init_target_private(input) < 0) + goto fail; + if (init_target_private(output) < 0) + goto fail; + if (init_target_private(error) < 0) + goto fail; + + if ((pid = fork()) < 0) + goto fail; + if (pid == 0) { + /* Child process */ + if (connect_process_target(input, STDIN_FILENO) < 0) + goto fail; + if (connect_process_target(output, STDOUT_FILENO) < 0) + goto fail; + if (connect_process_target(error, STDERR_FILENO) < 0) + goto fail; + execvp(*argv, (char *const *)argv); + goto fail; + } + + /* Parent process */ + if (process_target_input(input) < 0) + goto fail; + if (process_target_output(output) < 0) + goto fail; + if (process_target_output(error) < 0) + goto fail; + + if (waitpid(pid, &status, 0) < 0) + goto fail; + + if (WIFEXITED(status)) + return WEXITSTATUS(status); + +fail: + if (program_name) + perror(program_name); + else + perror("subprocess"); + if (pid == 0) + exit(127); + return -1; +} |