[linux-2.6-block.git] / tools / lib / subcmd / run-command.c

// SPDX-License-Identifier: GPL-2.0
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <linux/string.h>
#include <errno.h>
#include <sys/wait.h>
#include "subcmd-util.h"
#include "run-command.h"
#include "exec-cmd.h"

#define STRERR_BUFSIZE 128

static inline void close_pair(int fd[2])
{
	close(fd[0]);
	close(fd[1]);
}

static inline void dup_devnull(int to)
{
	int fd = open("/dev/null", O_RDWR);
	dup2(fd, to);
	close(fd);
}

int start_command(struct child_process *cmd)
{
	int need_in, need_out, need_err;
	int fdin[2], fdout[2], fderr[2];
	char sbuf[STRERR_BUFSIZE];

	/*
	 * In case of errors we must keep the promise to close FDs
	 * that have been passed in via ->in and ->out.
	 */

	need_in = !cmd->no_stdin && cmd->in < 0;
	if (need_in) {
		if (pipe(fdin) < 0) {
			if (cmd->out > 0)
				close(cmd->out);
			return -ERR_RUN_COMMAND_PIPE;
		}
		cmd->in = fdin[1];
	}

	need_out = !cmd->no_stdout
		&& !cmd->stdout_to_stderr
		&& cmd->out < 0;
	if (need_out) {
		if (pipe(fdout) < 0) {
			if (need_in)
				close_pair(fdin);
			else if (cmd->in)
				close(cmd->in);
			return -ERR_RUN_COMMAND_PIPE;
		}
		cmd->out = fdout[0];
	}

	need_err = !cmd->no_stderr && cmd->err < 0;
	if (need_err) {
		if (pipe(fderr) < 0) {
			if (need_in)
				close_pair(fdin);
			else if (cmd->in)
				close(cmd->in);
			if (need_out)
				close_pair(fdout);
			else if (cmd->out)
				close(cmd->out);
			return -ERR_RUN_COMMAND_PIPE;
		}
		cmd->err = fderr[0];
	}

	fflush(NULL);
	cmd->pid = fork();
	if (!cmd->pid) {
		if (cmd->no_stdin)
			dup_devnull(0);
		else if (need_in) {
			dup2(fdin[0], 0);
			close_pair(fdin);
		} else if (cmd->in) {
			dup2(cmd->in, 0);
			close(cmd->in);
		}

		if (cmd->no_stderr)
			dup_devnull(2);
		else if (need_err) {
			dup2(fderr[1], 2);
			close_pair(fderr);
		}

		if (cmd->no_stdout)
			dup_devnull(1);
		else if (cmd->stdout_to_stderr)
			dup2(2, 1);
		else if (need_out) {
			dup2(fdout[1], 1);
			close_pair(fdout);
		} else if (cmd->out > 1) {
			dup2(cmd->out, 1);
			close(cmd->out);
		}

		if (cmd->dir && chdir(cmd->dir))
			die("exec %s: cd to %s failed (%s)", cmd->argv[0],
			    cmd->dir, str_error_r(errno, sbuf, sizeof(sbuf)));
		if (cmd->env) {
			for (; *cmd->env; cmd->env++) {
				if (strchr(*cmd->env, '='))
					putenv((char*)*cmd->env);
				else
					unsetenv(*cmd->env);
			}
		}
		if (cmd->preexec_cb)
			cmd->preexec_cb();
		if (cmd->exec_cmd) {
			execv_cmd(cmd->argv);
		} else {
			execvp(cmd->argv[0], (char *const*) cmd->argv);
		}
		exit(127);
	}

	if (cmd->pid < 0) {
		int err = errno;
		if (need_in)
			close_pair(fdin);
		else if (cmd->in)
			close(cmd->in);
		if (need_out)
			close_pair(fdout);
		else if (cmd->out)
			close(cmd->out);
		if (need_err)
			close_pair(fderr);
		return err == ENOENT ?
			-ERR_RUN_COMMAND_EXEC :
			-ERR_RUN_COMMAND_FORK;
	}

	if (need_in)
		close(fdin[0]);
	else if (cmd->in)
		close(cmd->in);

	if (need_out)
		close(fdout[1]);
	else if (cmd->out)
		close(cmd->out);

	if (need_err)
		close(fderr[1]);

	return 0;
}

static int wait_or_whine(pid_t pid)
{
	char sbuf[STRERR_BUFSIZE];

	for (;;) {
		int status, code;
		pid_t waiting = waitpid(pid, &status, 0);

		if (waiting < 0) {
			if (errno == EINTR)
				continue;
			fprintf(stderr, " Error: waitpid failed (%s)",
				str_error_r(errno, sbuf, sizeof(sbuf)));
			return -ERR_RUN_COMMAND_WAITPID;
		}
		if (waiting != pid)
			return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
		if (WIFSIGNALED(status))
			return -ERR_RUN_COMMAND_WAITPID_SIGNAL;

		if (!WIFEXITED(status))
			return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
		code = WEXITSTATUS(status);
		switch (code) {
		case 127:
			return -ERR_RUN_COMMAND_EXEC;
		case 0:
			return 0;
		default:
			return -code;
		}
	}
}

int finish_command(struct child_process *cmd)
{
	return wait_or_whine(cmd->pid);
}

int run_command(struct child_process *cmd)
{
	int code = start_command(cmd);
	if (code)
		return code;
	return finish_command(cmd);
}

static void prepare_run_command_v_opt(struct child_process *cmd,
				      const char **argv,
				      int opt)
{
	memset(cmd, 0, sizeof(*cmd));
	cmd->argv = argv;
	cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
	cmd->exec_cmd = opt & RUN_EXEC_CMD ? 1 : 0;
	cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
}

int run_command_v_opt(const char **argv, int opt)
{
	struct child_process cmd;
	prepare_run_command_v_opt(&cmd, argv, opt);
	return run_command(&cmd);
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
2f4ce5ec JP	2	#include <unistd.h>
	3	#include <sys/types.h>
	4	#include <sys/stat.h>
	5	#include <fcntl.h>
	6	#include <string.h>
07eebccb	7	#include <linux/string.h>
2f4ce5ec JP	8	#include <errno.h>
	9	#include <sys/wait.h>
	10	#include "subcmd-util.h"
07800601	11	#include "run-command.h"
4b6ab94e	12	#include "exec-cmd.h"
2f4ce5ec JP	13
2f4ce5ec JP	14	#define STRERR_BUFSIZE 128
07800601 IM	15
	16	static inline void close_pair(int fd[2])
	17	{
	18	close(fd[0]);
	19	close(fd[1]);
	20	}
	21
	22	static inline void dup_devnull(int to)
	23	{
	24	int fd = open("/dev/null", O_RDWR);
	25	dup2(fd, to);
	26	close(fd);
	27	}
	28
	29	int start_command(struct child_process *cmd)
	30	{
	31	int need_in, need_out, need_err;
	32	int fdin[2], fdout[2], fderr[2];
6e81c74c	33	char sbuf[STRERR_BUFSIZE];
07800601 IM	34
	35	/*
	36	* In case of errors we must keep the promise to close FDs
	37	* that have been passed in via ->in and ->out.
	38	*/
	39
	40	need_in = !cmd->no_stdin && cmd->in < 0;
	41	if (need_in) {
	42	if (pipe(fdin) < 0) {
	43	if (cmd->out > 0)
	44	close(cmd->out);
	45	return -ERR_RUN_COMMAND_PIPE;
	46	}
	47	cmd->in = fdin[1];
	48	}
	49
	50	need_out = !cmd->no_stdout
	51	&& !cmd->stdout_to_stderr
	52	&& cmd->out < 0;
	53	if (need_out) {
	54	if (pipe(fdout) < 0) {
	55	if (need_in)
	56	close_pair(fdin);
	57	else if (cmd->in)
	58	close(cmd->in);
	59	return -ERR_RUN_COMMAND_PIPE;
	60	}
	61	cmd->out = fdout[0];
	62	}
	63
	64	need_err = !cmd->no_stderr && cmd->err < 0;
	65	if (need_err) {
	66	if (pipe(fderr) < 0) {
	67	if (need_in)
	68	close_pair(fdin);
	69	else if (cmd->in)
	70	close(cmd->in);
	71	if (need_out)
	72	close_pair(fdout);
	73	else if (cmd->out)
	74	close(cmd->out);
	75	return -ERR_RUN_COMMAND_PIPE;
	76	}
	77	cmd->err = fderr[0];
	78	}
	79
07800601 IM	80	fflush(NULL);
	81	cmd->pid = fork();
	82	if (!cmd->pid) {
	83	if (cmd->no_stdin)
	84	dup_devnull(0);
	85	else if (need_in) {
	86	dup2(fdin[0], 0);
	87	close_pair(fdin);
	88	} else if (cmd->in) {
	89	dup2(cmd->in, 0);
	90	close(cmd->in);
	91	}
	92
	93	if (cmd->no_stderr)
	94	dup_devnull(2);
	95	else if (need_err) {
	96	dup2(fderr[1], 2);
	97	close_pair(fderr);
	98	}
	99
	100	if (cmd->no_stdout)
	101	dup_devnull(1);
	102	else if (cmd->stdout_to_stderr)
	103	dup2(2, 1);
	104	else if (need_out) {
	105	dup2(fdout[1], 1);
	106	close_pair(fdout);
	107	} else if (cmd->out > 1) {
	108	dup2(cmd->out, 1);
	109	close(cmd->out);
	110	}
	111
	112	if (cmd->dir && chdir(cmd->dir))
	113	die("exec %s: cd to %s failed (%s)", cmd->argv[0],
07eebccb	114	cmd->dir, str_error_r(errno, sbuf, sizeof(sbuf)));
07800601 IM	115	if (cmd->env) {
	116	for (; *cmd->env; cmd->env++) {
	117	if (strchr(*cmd->env, '='))
	118	putenv((char)cmd->env);
	119	else
	120	unsetenv(*cmd->env);
	121	}
	122	}
	123	if (cmd->preexec_cb)
	124	cmd->preexec_cb();
46113a54 JP	125	if (cmd->exec_cmd) {
46113a54 JP	126	execv_cmd(cmd->argv);
07800601 IM	127	} else {
	128	execvp(cmd->argv[0], (char const) cmd->argv);
	129	}
	130	exit(127);
	131	}
07800601 IM	132
	133	if (cmd->pid < 0) {
	134	int err = errno;
	135	if (need_in)
	136	close_pair(fdin);
	137	else if (cmd->in)
	138	close(cmd->in);
	139	if (need_out)
	140	close_pair(fdout);
	141	else if (cmd->out)
	142	close(cmd->out);
	143	if (need_err)
	144	close_pair(fderr);
	145	return err == ENOENT ?
	146	-ERR_RUN_COMMAND_EXEC :
	147	-ERR_RUN_COMMAND_FORK;
	148	}
	149
	150	if (need_in)
	151	close(fdin[0]);
	152	else if (cmd->in)
	153	close(cmd->in);
	154
	155	if (need_out)
	156	close(fdout[1]);
	157	else if (cmd->out)
	158	close(cmd->out);
	159
	160	if (need_err)
	161	close(fderr[1]);
	162
	163	return 0;
	164	}
	165
	166	static int wait_or_whine(pid_t pid)
	167	{
6e81c74c MH	168	char sbuf[STRERR_BUFSIZE];
6e81c74c MH	169
07800601 IM	170	for (;;) {
	171	int status, code;
	172	pid_t waiting = waitpid(pid, &status, 0);
	173
	174	if (waiting < 0) {
	175	if (errno == EINTR)
	176	continue;
2f4ce5ec	177	fprintf(stderr, " Error: waitpid failed (%s)",
07eebccb	178	str_error_r(errno, sbuf, sizeof(sbuf)));
07800601 IM	179	return -ERR_RUN_COMMAND_WAITPID;
	180	}
	181	if (waiting != pid)
	182	return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
	183	if (WIFSIGNALED(status))
	184	return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
	185
	186	if (!WIFEXITED(status))
	187	return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
	188	code = WEXITSTATUS(status);
	189	switch (code) {
	190	case 127:
	191	return -ERR_RUN_COMMAND_EXEC;
	192	case 0:
	193	return 0;
	194	default:
	195	return -code;
	196	}
	197	}
	198	}
	199
	200	int finish_command(struct child_process *cmd)
	201	{
	202	return wait_or_whine(cmd->pid);
	203	}
	204
	205	int run_command(struct child_process *cmd)
	206	{
	207	int code = start_command(cmd);
	208	if (code)
	209	return code;
	210	return finish_command(cmd);
	211	}
	212
	213	static void prepare_run_command_v_opt(struct child_process *cmd,
	214	const char **argv,
	215	int opt)
	216	{
	217	memset(cmd, 0, sizeof(*cmd));
	218	cmd->argv = argv;
	219	cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
46113a54	220	cmd->exec_cmd = opt & RUN_EXEC_CMD ? 1 : 0;
07800601 IM	221	cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
	222	}
	223
	224	int run_command_v_opt(const char **argv, int opt)
	225	{
	226	struct child_process cmd;
	227	prepare_run_command_v_opt(&cmd, argv, opt);
	228	return run_command(&cmd);
	229	}