/*
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* mini shell, pseudo terminal
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* refers to adb(android debug bridge)
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* author: clarkyy
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* date: 20160803
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* http://www.allwinnertech.com
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include "mini_shell.h"
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#ifndef TEMP_FAILURE_RETRY
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#define TEMP_FAILURE_RETRY(exp) ({ \
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typeof (exp) _rc; \
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do { \
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_rc = (exp); \
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} while (_rc == -1 && errno == EINTR); \
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_rc; })
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#endif
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#define MINI_SHELL_DEBUG_EN 0
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#if MINI_SHELL_DEBUG_EN
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char g_dbg_buffer[1024];
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#define D(format, ...) \
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sprintf(g_dbg_buffer, format, ##__VA_ARGS__); \
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mini_shell_stdout(g_dbg_buffer);
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#else
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#define D(format, ...)
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#endif
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typedef pthread_t adb_thread_t;
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typedef void* (*adb_thread_func_t)( void* arg );
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typedef struct stinfo {
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void (*func)(int fd, void *cookie);
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int fd;
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void *cookie;
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} stinfo;
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static __inline__ void close_on_exec(int fd)
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{
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fcntl( fd, F_SETFD, FD_CLOEXEC );
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}
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static int unix_open(const char* path, int options,...)
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{
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if ((options & O_CREAT) == 0)
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return TEMP_FAILURE_RETRY( open(path, options) );
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else {
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int mode;
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va_list args;
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va_start( args, options );
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mode = va_arg( args, int );
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va_end( args );
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return TEMP_FAILURE_RETRY( open( path, options, mode ) );
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}
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}
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int adb_open( const char* pathname, int options )
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{
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int fd = TEMP_FAILURE_RETRY( open( pathname, options ) );
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if (fd < 0)
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return -1;
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close_on_exec( fd );
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return fd;
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}
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int adb_read(int fd, void* buf, size_t len)
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{
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return TEMP_FAILURE_RETRY( read( fd, buf, len ) );
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}
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int adb_write(int fd, const void* buf, size_t len)
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{
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return TEMP_FAILURE_RETRY( write( fd, buf, len ) );
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}
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__inline__ int adb_close(int fd)
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{
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return close(fd);
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}
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static void init_subproc_child()
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{
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D("init_subproc_child\n");
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setsid();
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// Set OOM score adjustment to prevent killing
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int fd = adb_open("/proc/self/oom_score_adj", O_WRONLY | O_CLOEXEC);
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if (fd >= 0) {
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adb_write(fd, "0", 1);
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adb_close(fd);
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} else
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D("adb: unable to update oom_score_adj\n");
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}
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static void subproc_waiter_service(int fd, void *cookie)
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{
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pid_t pid = (pid_t) (uintptr_t) cookie;
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D("entered. fd=%d of pid=%d\n", fd, pid);
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for (;;) {
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int status;
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pid_t p = waitpid(pid, &status, 0);
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if (p == pid) {
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D("fd=%d, post waitpid(pid=%d) status=%04x\n", fd, p, status);
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if (WIFSIGNALED(status)) {
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D("*** Killed by signal %d\n", WTERMSIG(status));
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break;
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} else if (!WIFEXITED(status)) {
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D("*** Didn't exit!!. status %d\n", status);
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break;
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} else if (WEXITSTATUS(status) >= 0) {
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D("*** Exit code %d\n", WEXITSTATUS(status));
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break;
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}
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}
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}
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D("shell exited fd=%d of pid=%d err=%d\n", fd, pid, errno);
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//if (SHELL_EXIT_NOTIFY_FD >=0) {
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// int res;
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// res = writex(SHELL_EXIT_NOTIFY_FD, &fd, sizeof(fd));
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// D("notified shell exit via fd=%d for pid=%d res=%d errno=%d\n",
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// SHELL_EXIT_NOTIFY_FD, pid, res, errno);
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//}
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}
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static int create_subproc_pty(const char *cmd, const char *arg0, const char *arg1, pid_t *pid)
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{
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int ptm = 0, pts = 0;
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D("create_subproc_pty(cmd=%s, arg0=%s, arg1=%s)\n", cmd, arg0, arg1);
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ptm = unix_open("/dev/ptmx", O_RDWR | O_CLOEXEC); // | O_NOCTTY);
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if (ptm < 0) {
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D("[ cannot open /dev/ptmx - %s ]\n",strerror(errno));
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return -1;
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}
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D("%s: %d\n", __FUNCTION__, __LINE__);
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char devname[64];
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if (grantpt(ptm) || unlockpt(ptm) || ptsname_r(ptm, devname, sizeof(devname)) != 0) {
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D("[trouble with /dev/ptmx - %s ]\n", strerror(errno));
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adb_close(ptm);
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return -1;
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}
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D("devname: %s\n", devname);
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D("%s: %d\n", __FUNCTION__, __LINE__);
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*pid = fork();
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if (*pid < 0) {
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D("- fork failed: %s -\n", strerror(errno));
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adb_close(ptm);
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return -1;
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}
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D("%s: %d\n", __FUNCTION__, __LINE__);
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if (*pid == 0) {
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D("%s: %d\n", __FUNCTION__, __LINE__);
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init_subproc_child();
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D("%s: %d\n", __FUNCTION__, __LINE__);
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pts = unix_open(devname, O_RDWR | O_CLOEXEC);
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if (pts < 0) {
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adb_close(ptm);
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D("child failed to open pseudo-term slave: %s\n", devname);
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exit(-1);
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}
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D("%s: %d\n", __FUNCTION__, __LINE__);
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dup2(pts, STDIN_FILENO);
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dup2(pts, STDOUT_FILENO);
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dup2(pts, STDERR_FILENO);
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D("%s: %d\n", __FUNCTION__, __LINE__);
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adb_close(pts);
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adb_close(ptm);
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D("%s: %d\n", __FUNCTION__, __LINE__);
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execl(cmd, cmd, arg0, arg1, NULL);
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D("- exec '%s' failed: %s (%d) -\n",
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cmd, strerror(errno), errno);
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exit(-1);
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} else {
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return ptm;
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}
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}
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static void *service_bootstrap_func(void *x)
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{
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stinfo *sti = x;
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D("%s: %d\n", __FUNCTION__, __LINE__);
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sti->func(sti->fd, sti->cookie);
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free(sti);
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return 0;
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}
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static int adb_thread_create( adb_thread_t *pthread, adb_thread_func_t start, void* arg )
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{
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pthread_attr_t attr;
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pthread_attr_init (&attr);
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pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED);
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return pthread_create( pthread, &attr, start, arg );
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}
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#if 0
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/*
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* compare current pts output to last pts output,
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* the real output saved in cur_output
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* returns length of cur_output, NOT includes '\0'
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*/
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static int calc_pts_output(const char *cur_output, const char *last_output)
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{
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int cur_len = 0, last_len = 0;
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const char *cur_ptr = NULL, *last_ptr = NULL;
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if (cur_output && last_output) {
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cur_len = strlen(cur_output);
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last_len = strlen(last_output);
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if (cur_len > 0 && cur_len == last_len) {
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cur_ptr = cur_output + cur_len - 1; // skip '\0'
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last_ptr = last_output + last_len - 1; // skip '\0'
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while (cur_len-- > 0 && *cur_ptr-- == *last_ptr--);
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if (cur_len == 0) {
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cur_len = last_len;
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} else {
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cur_len++;
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}
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}
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}
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return cur_len;
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}
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#endif
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// for pc, ADB_HOST = 1; for android, ADB_HOST = 0
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#define ADB_HOST 1
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#if ADB_HOST
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#define SHELL_COMMAND "/bin/sh"
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#else
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#define SHELL_COMMAND "/system/bin/sh"
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#endif
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static int fd_log_file = -1;
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static int fd_ptmx = -1;
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static int stdin_copy = -1;
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static int stdout_copy = -1;
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static int stderr_copy = -1;
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static char cmd_reply[1024] = { 0 };
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int init_mini_shell(const char *log_file)
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{
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stinfo *sti;
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adb_thread_t t;
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pid_t pid;
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//exit_mini_shell();
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stdin_copy = dup(STDIN_FILENO);
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stdout_copy = dup(STDOUT_FILENO);
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stderr_copy = dup(STDERR_FILENO);
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D("%s: %d %d %d\n", __FUNCTION__, stdin_copy, stdout_copy, stderr_copy);
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fd_ptmx = create_subproc_pty(SHELL_COMMAND, "-", NULL, &pid);
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if (fd_ptmx < 0) {
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D("cannot create subproc pty\n");
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return -1;
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}
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D("create_subprocess() ret_fd=%d pid=%d\n", fd_ptmx, pid);
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sti = malloc(sizeof(stinfo));
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if (sti == 0) {
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D("cannot allocate stinfo\n");
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return -1;
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}
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sti->func = subproc_waiter_service;
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sti->cookie = (void*)(intptr_t)pid;
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sti->fd = fd_ptmx;
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if (adb_thread_create( &t, service_bootstrap_func, sti)) {
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free(sti);
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adb_close(fd_ptmx);
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D("cannot create service thread\n");
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return -1;
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}
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D("service thread started, fd=%d pid=%d\n", fd_ptmx, pid);
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if (log_file)
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fd_log_file = open(log_file, O_CREAT|O_APPEND|O_RDWR, 0777);
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adb_write(fd_log_file, "mini_shell init\n", strlen("mini_shell init\n"));
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return 0;
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}
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void exit_mini_shell()
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{
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D("%s: ready to exit\n", __FUNCTION__);
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if (fd_ptmx >= 0) {
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adb_write(fd_ptmx, "exit\n", strlen("exit\n"));
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usleep(500000);
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adb_close(fd_ptmx);
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fd_ptmx = -1;
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}
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if (fd_log_file >= 0) {
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adb_close(fd_log_file);
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fd_log_file = -1;
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}
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if (stdin_copy >= 0) {
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dup2(stdin_copy, STDIN_FILENO);
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stdin_copy = -1;
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}
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if (stdout_copy >= 0) {
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dup2(stdout_copy, STDOUT_FILENO);
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stdout_copy = -1;
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}
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if (stderr_copy >= 0) {
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dup2(stderr_copy, STDERR_FILENO);
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stderr_copy = -1;
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}
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D("%s: exits\n", __FUNCTION__);
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}
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int mini_shell_exec(const char *command, char *reply)
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{
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if (fd_ptmx >= 0 && command) {
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adb_write(fd_ptmx, command, strlen(command));
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usleep(500000); // wait for pts write
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memset(cmd_reply, 0, sizeof(cmd_reply));
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adb_read(fd_ptmx, cmd_reply, sizeof(cmd_reply));
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D("%s: %s\n", __FUNCTION__, cmd_reply);
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if (reply)
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strncpy(reply, cmd_reply, sizeof(cmd_reply));
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if (fd_log_file >= 0) {
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D("%s: %s\n", __FUNCTION__, reply);
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adb_write(fd_log_file, cmd_reply, sizeof(cmd_reply));
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}
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return 0;
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}
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return -1;
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}
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int mini_shell_stdin(char *inputs, int len)
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{
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if (stdin_copy >= 0) {
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memset(inputs, 0, len);
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return adb_read(stdin_copy, inputs, len);
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}
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return -1;
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}
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int mini_shell_stdout(const char *outputs)
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{
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if (stdout_copy >= 0)
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return adb_write(stdout_copy, outputs, strlen(outputs));
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printf(outputs);
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return -1;
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}
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int mini_shell_stderr(const char *error)
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{
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if (stderr_copy >= 0)
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return adb_write(stderr_copy, error, strlen(error));
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printf(error);
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return -1;
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}
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