support "sideload over ADB" mode

Rather than depending on the existence of some place to store a file
that is accessible to users on an an unbootable device (eg, a physical
sdcard, external USB drive, etc.), add support for sideloading
packages sent to the device with adb.

This change adds a "minimal adbd" which supports nothing but receiving
a package over adb (with the "adb sideload" command) and storing it to
a fixed filename in the /tmp ramdisk, from where it can be verified
and sideloaded in the usual way.  This should be leave available even
on locked user-build devices.

The user can select "apply package from ADB" from the recovery menu,
which starts minimal-adb mode (shutting down any real adbd that may be
running).  Once minimal-adb has received a package it exits
(restarting real adbd if appropriate) and then verification and
installation of the received package proceeds.

Change-Id: I6fe13161ca064a98d06fa32104e1f432826582f5
diff --git a/minadbd/fdevent.c b/minadbd/fdevent.c
new file mode 100644
index 0000000..5c374a7
--- /dev/null
+++ b/minadbd/fdevent.c
@@ -0,0 +1,695 @@
+/* http://frotznet.googlecode.com/svn/trunk/utils/fdevent.c
+**
+** Copyright 2006, Brian Swetland <swetland@frotz.net>
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+
+#include <sys/ioctl.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <fcntl.h>
+
+#include <stdarg.h>
+#include <stddef.h>
+
+#include "fdevent.h"
+#include "transport.h"
+#include "sysdeps.h"
+
+
+/* !!! Do not enable DEBUG for the adb that will run as the server:
+** both stdout and stderr are used to communicate between the client
+** and server. Any extra output will cause failures.
+*/
+#define DEBUG 0   /* non-0 will break adb server */
+
+// This socket is used when a subproc shell service exists.
+// It wakes up the fdevent_loop() and cause the correct handling
+// of the shell's pseudo-tty master. I.e. force close it.
+int SHELL_EXIT_NOTIFY_FD = -1;
+
+static void fatal(const char *fn, const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    fprintf(stderr, "%s:", fn);
+    vfprintf(stderr, fmt, ap);
+    va_end(ap);
+    abort();
+}
+
+#define FATAL(x...) fatal(__FUNCTION__, x)
+
+#if DEBUG
+#define D(...) \
+    do { \
+        adb_mutex_lock(&D_lock);               \
+        int save_errno = errno;                \
+        fprintf(stderr, "%s::%s():", __FILE__, __FUNCTION__);  \
+        errno = save_errno;                    \
+        fprintf(stderr, __VA_ARGS__);          \
+        adb_mutex_unlock(&D_lock);             \
+        errno = save_errno;                    \
+    } while(0)
+static void dump_fde(fdevent *fde, const char *info)
+{
+    adb_mutex_lock(&D_lock);
+    fprintf(stderr,"FDE #%03d %c%c%c %s\n", fde->fd,
+            fde->state & FDE_READ ? 'R' : ' ',
+            fde->state & FDE_WRITE ? 'W' : ' ',
+            fde->state & FDE_ERROR ? 'E' : ' ',
+            info);
+    adb_mutex_unlock(&D_lock);
+}
+#else
+#define D(...) ((void)0)
+#define dump_fde(fde, info) do { } while(0)
+#endif
+
+#define FDE_EVENTMASK  0x00ff
+#define FDE_STATEMASK  0xff00
+
+#define FDE_ACTIVE     0x0100
+#define FDE_PENDING    0x0200
+#define FDE_CREATED    0x0400
+
+static void fdevent_plist_enqueue(fdevent *node);
+static void fdevent_plist_remove(fdevent *node);
+static fdevent *fdevent_plist_dequeue(void);
+static void fdevent_subproc_event_func(int fd, unsigned events, void *userdata);
+
+static fdevent list_pending = {
+    .next = &list_pending,
+    .prev = &list_pending,
+};
+
+static fdevent **fd_table = 0;
+static int fd_table_max = 0;
+
+#ifdef CRAPTASTIC
+//HAVE_EPOLL
+
+#include <sys/epoll.h>
+
+static int epoll_fd = -1;
+
+static void fdevent_init()
+{
+        /* XXX: what's a good size for the passed in hint? */
+    epoll_fd = epoll_create(256);
+
+    if(epoll_fd < 0) {
+        perror("epoll_create() failed");
+        exit(1);
+    }
+
+        /* mark for close-on-exec */
+    fcntl(epoll_fd, F_SETFD, FD_CLOEXEC);
+}
+
+static void fdevent_connect(fdevent *fde)
+{
+    struct epoll_event ev;
+
+    memset(&ev, 0, sizeof(ev));
+    ev.events = 0;
+    ev.data.ptr = fde;
+
+#if 0
+    if(epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fde->fd, &ev)) {
+        perror("epoll_ctl() failed\n");
+        exit(1);
+    }
+#endif
+}
+
+static void fdevent_disconnect(fdevent *fde)
+{
+    struct epoll_event ev;
+
+    memset(&ev, 0, sizeof(ev));
+    ev.events = 0;
+    ev.data.ptr = fde;
+
+        /* technically we only need to delete if we
+        ** were actively monitoring events, but let's
+        ** be aggressive and do it anyway, just in case
+        ** something's out of sync
+        */
+    epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fde->fd, &ev);
+}
+
+static void fdevent_update(fdevent *fde, unsigned events)
+{
+    struct epoll_event ev;
+    int active;
+
+    active = (fde->state & FDE_EVENTMASK) != 0;
+
+    memset(&ev, 0, sizeof(ev));
+    ev.events = 0;
+    ev.data.ptr = fde;
+
+    if(events & FDE_READ) ev.events |= EPOLLIN;
+    if(events & FDE_WRITE) ev.events |= EPOLLOUT;
+    if(events & FDE_ERROR) ev.events |= (EPOLLERR | EPOLLHUP);
+
+    fde->state = (fde->state & FDE_STATEMASK) | events;
+
+    if(active) {
+            /* we're already active. if we're changing to *no*
+            ** events being monitored, we need to delete, otherwise
+            ** we need to just modify
+            */
+        if(ev.events) {
+            if(epoll_ctl(epoll_fd, EPOLL_CTL_MOD, fde->fd, &ev)) {
+                perror("epoll_ctl() failed\n");
+                exit(1);
+            }
+        } else {
+            if(epoll_ctl(epoll_fd, EPOLL_CTL_DEL, fde->fd, &ev)) {
+                perror("epoll_ctl() failed\n");
+                exit(1);
+            }
+        }
+    } else {
+            /* we're not active.  if we're watching events, we need
+            ** to add, otherwise we can just do nothing
+            */
+        if(ev.events) {
+            if(epoll_ctl(epoll_fd, EPOLL_CTL_ADD, fde->fd, &ev)) {
+                perror("epoll_ctl() failed\n");
+                exit(1);
+            }
+        }
+    }
+}
+
+static void fdevent_process()
+{
+    struct epoll_event events[256];
+    fdevent *fde;
+    int i, n;
+
+    n = epoll_wait(epoll_fd, events, 256, -1);
+
+    if(n < 0) {
+        if(errno == EINTR) return;
+        perror("epoll_wait");
+        exit(1);
+    }
+
+    for(i = 0; i < n; i++) {
+        struct epoll_event *ev = events + i;
+        fde = ev->data.ptr;
+
+        if(ev->events & EPOLLIN) {
+            fde->events |= FDE_READ;
+        }
+        if(ev->events & EPOLLOUT) {
+            fde->events |= FDE_WRITE;
+        }
+        if(ev->events & (EPOLLERR | EPOLLHUP)) {
+            fde->events |= FDE_ERROR;
+        }
+        if(fde->events) {
+            if(fde->state & FDE_PENDING) continue;
+            fde->state |= FDE_PENDING;
+            fdevent_plist_enqueue(fde);
+        }
+    }
+}
+
+#else /* USE_SELECT */
+
+#ifdef HAVE_WINSOCK
+#include <winsock2.h>
+#else
+#include <sys/select.h>
+#endif
+
+static fd_set read_fds;
+static fd_set write_fds;
+static fd_set error_fds;
+
+static int select_n = 0;
+
+static void fdevent_init(void)
+{
+    FD_ZERO(&read_fds);
+    FD_ZERO(&write_fds);
+    FD_ZERO(&error_fds);
+}
+
+static void fdevent_connect(fdevent *fde)
+{
+    if(fde->fd >= select_n) {
+        select_n = fde->fd + 1;
+    }
+}
+
+static void fdevent_disconnect(fdevent *fde)
+{
+    int i, n;
+
+    FD_CLR(fde->fd, &read_fds);
+    FD_CLR(fde->fd, &write_fds);
+    FD_CLR(fde->fd, &error_fds);
+
+    for(n = 0, i = 0; i < select_n; i++) {
+        if(fd_table[i] != 0) n = i;
+    }
+    select_n = n + 1;
+}
+
+static void fdevent_update(fdevent *fde, unsigned events)
+{
+    if(events & FDE_READ) {
+        FD_SET(fde->fd, &read_fds);
+    } else {
+        FD_CLR(fde->fd, &read_fds);
+    }
+    if(events & FDE_WRITE) {
+        FD_SET(fde->fd, &write_fds);
+    } else {
+        FD_CLR(fde->fd, &write_fds);
+    }
+    if(events & FDE_ERROR) {
+        FD_SET(fde->fd, &error_fds);
+    } else {
+        FD_CLR(fde->fd, &error_fds);
+    }
+
+    fde->state = (fde->state & FDE_STATEMASK) | events;
+}
+
+/* Looks at fd_table[] for bad FDs and sets bit in fds.
+** Returns the number of bad FDs.
+*/
+static int fdevent_fd_check(fd_set *fds)
+{
+    int i, n = 0;
+    fdevent *fde;
+
+    for(i = 0; i < select_n; i++) {
+        fde = fd_table[i];
+        if(fde == 0) continue;
+        if(fcntl(i, F_GETFL, NULL) < 0) {
+            FD_SET(i, fds);
+            n++;
+            // fde->state |= FDE_DONT_CLOSE;
+
+        }
+    }
+    return n;
+}
+
+#if !DEBUG
+static inline void dump_all_fds(const char *extra_msg) {}
+#else
+static void dump_all_fds(const char *extra_msg)
+{
+int i;
+    fdevent *fde;
+    // per fd: 4 digits (but really: log10(FD_SETSIZE)), 1 staus, 1 blank
+    char msg_buff[FD_SETSIZE*6 + 1], *pb=msg_buff;
+    size_t max_chars = FD_SETSIZE * 6 + 1;
+    int printed_out;
+#define SAFE_SPRINTF(...)                                                    \
+    do {                                                                     \
+        printed_out = snprintf(pb, max_chars, __VA_ARGS__);                  \
+        if (printed_out <= 0) {                                              \
+            D("... snprintf failed.\n");                                     \
+            return;                                                          \
+        }                                                                    \
+        if (max_chars < (unsigned int)printed_out) {                         \
+            D("... snprintf out of space.\n");                               \
+            return;                                                          \
+        }                                                                    \
+        pb += printed_out;                                                   \
+        max_chars -= printed_out;                                            \
+    } while(0)
+
+    for(i = 0; i < select_n; i++) {
+        fde = fd_table[i];
+        SAFE_SPRINTF("%d", i);
+        if(fde == 0) {
+            SAFE_SPRINTF("? ");
+            continue;
+        }
+        if(fcntl(i, F_GETFL, NULL) < 0) {
+            SAFE_SPRINTF("b");
+        }
+        SAFE_SPRINTF(" ");
+    }
+    D("%s fd_table[]->fd = {%s}\n", extra_msg, msg_buff);
+}
+#endif
+
+static void fdevent_process()
+{
+    int i, n;
+    fdevent *fde;
+    unsigned events;
+    fd_set rfd, wfd, efd;
+
+    memcpy(&rfd, &read_fds, sizeof(fd_set));
+    memcpy(&wfd, &write_fds, sizeof(fd_set));
+    memcpy(&efd, &error_fds, sizeof(fd_set));
+
+    dump_all_fds("pre select()");
+
+    n = select(select_n, &rfd, &wfd, &efd, NULL);
+    int saved_errno = errno;
+    D("select() returned n=%d, errno=%d\n", n, n<0?saved_errno:0);
+
+    dump_all_fds("post select()");
+
+    if(n < 0) {
+        switch(saved_errno) {
+        case EINTR: return;
+        case EBADF:
+            // Can't trust the FD sets after an error.
+            FD_ZERO(&wfd);
+            FD_ZERO(&efd);
+            FD_ZERO(&rfd);
+            break;
+        default:
+            D("Unexpected select() error=%d\n", saved_errno);
+            return;
+        }
+    }
+    if(n <= 0) {
+        // We fake a read, as the rest of the code assumes
+        // that errors will be detected at that point.
+        n = fdevent_fd_check(&rfd);
+    }
+
+    for(i = 0; (i < select_n) && (n > 0); i++) {
+        events = 0;
+        if(FD_ISSET(i, &rfd)) { events |= FDE_READ; n--; }
+        if(FD_ISSET(i, &wfd)) { events |= FDE_WRITE; n--; }
+        if(FD_ISSET(i, &efd)) { events |= FDE_ERROR; n--; }
+
+        if(events) {
+            fde = fd_table[i];
+            if(fde == 0)
+              FATAL("missing fde for fd %d\n", i);
+
+            fde->events |= events;
+
+            D("got events fde->fd=%d events=%04x, state=%04x\n",
+                fde->fd, fde->events, fde->state);
+            if(fde->state & FDE_PENDING) continue;
+            fde->state |= FDE_PENDING;
+            fdevent_plist_enqueue(fde);
+        }
+    }
+}
+
+#endif
+
+static void fdevent_register(fdevent *fde)
+{
+    if(fde->fd < 0) {
+        FATAL("bogus negative fd (%d)\n", fde->fd);
+    }
+
+    if(fde->fd >= fd_table_max) {
+        int oldmax = fd_table_max;
+        if(fde->fd > 32000) {
+            FATAL("bogus huuuuge fd (%d)\n", fde->fd);
+        }
+        if(fd_table_max == 0) {
+            fdevent_init();
+            fd_table_max = 256;
+        }
+        while(fd_table_max <= fde->fd) {
+            fd_table_max *= 2;
+        }
+        fd_table = realloc(fd_table, sizeof(fdevent*) * fd_table_max);
+        if(fd_table == 0) {
+            FATAL("could not expand fd_table to %d entries\n", fd_table_max);
+        }
+        memset(fd_table + oldmax, 0, sizeof(int) * (fd_table_max - oldmax));
+    }
+
+    fd_table[fde->fd] = fde;
+}
+
+static void fdevent_unregister(fdevent *fde)
+{
+    if((fde->fd < 0) || (fde->fd >= fd_table_max)) {
+        FATAL("fd out of range (%d)\n", fde->fd);
+    }
+
+    if(fd_table[fde->fd] != fde) {
+        FATAL("fd_table out of sync [%d]\n", fde->fd);
+    }
+
+    fd_table[fde->fd] = 0;
+
+    if(!(fde->state & FDE_DONT_CLOSE)) {
+        dump_fde(fde, "close");
+        adb_close(fde->fd);
+    }
+}
+
+static void fdevent_plist_enqueue(fdevent *node)
+{
+    fdevent *list = &list_pending;
+
+    node->next = list;
+    node->prev = list->prev;
+    node->prev->next = node;
+    list->prev = node;
+}
+
+static void fdevent_plist_remove(fdevent *node)
+{
+    node->prev->next = node->next;
+    node->next->prev = node->prev;
+    node->next = 0;
+    node->prev = 0;
+}
+
+static fdevent *fdevent_plist_dequeue(void)
+{
+    fdevent *list = &list_pending;
+    fdevent *node = list->next;
+
+    if(node == list) return 0;
+
+    list->next = node->next;
+    list->next->prev = list;
+    node->next = 0;
+    node->prev = 0;
+
+    return node;
+}
+
+static void fdevent_call_fdfunc(fdevent* fde)
+{
+    unsigned events = fde->events;
+    fde->events = 0;
+    if(!(fde->state & FDE_PENDING)) return;
+    fde->state &= (~FDE_PENDING);
+    dump_fde(fde, "callback");
+    fde->func(fde->fd, events, fde->arg);
+}
+
+static void fdevent_subproc_event_func(int fd, unsigned ev, void *userdata)
+{
+
+    D("subproc handling on fd=%d ev=%04x\n", fd, ev);
+
+    // Hook oneself back into the fde's suitable for select() on read.
+    if((fd < 0) || (fd >= fd_table_max)) {
+        FATAL("fd %d out of range for fd_table \n", fd);
+    }
+    fdevent *fde = fd_table[fd];
+    fdevent_add(fde, FDE_READ);
+
+    if(ev & FDE_READ){
+      int subproc_fd;
+
+      if(readx(fd, &subproc_fd, sizeof(subproc_fd))) {
+          FATAL("Failed to read the subproc's fd from fd=%d\n", fd);
+      }
+      if((subproc_fd < 0) || (subproc_fd >= fd_table_max)) {
+          D("subproc_fd %d out of range 0, fd_table_max=%d\n",
+            subproc_fd, fd_table_max);
+          return;
+      }
+      fdevent *subproc_fde = fd_table[subproc_fd];
+      if(!subproc_fde) {
+          D("subproc_fd %d cleared from fd_table\n", subproc_fd);
+          return;
+      }
+      if(subproc_fde->fd != subproc_fd) {
+          // Already reallocated?
+          D("subproc_fd %d != fd_table[].fd %d\n", subproc_fd, subproc_fde->fd);
+          return;
+      }
+
+      subproc_fde->force_eof = 1;
+
+      int rcount = 0;
+      ioctl(subproc_fd, FIONREAD, &rcount);
+      D("subproc with fd=%d  has rcount=%d err=%d\n",
+        subproc_fd, rcount, errno);
+
+      if(rcount) {
+        // If there is data left, it will show up in the select().
+        // This works because there is no other thread reading that
+        // data when in this fd_func().
+        return;
+      }
+
+      D("subproc_fde.state=%04x\n", subproc_fde->state);
+      subproc_fde->events |= FDE_READ;
+      if(subproc_fde->state & FDE_PENDING) {
+        return;
+      }
+      subproc_fde->state |= FDE_PENDING;
+      fdevent_call_fdfunc(subproc_fde);
+    }
+}
+
+fdevent *fdevent_create(int fd, fd_func func, void *arg)
+{
+    fdevent *fde = (fdevent*) malloc(sizeof(fdevent));
+    if(fde == 0) return 0;
+    fdevent_install(fde, fd, func, arg);
+    fde->state |= FDE_CREATED;
+    return fde;
+}
+
+void fdevent_destroy(fdevent *fde)
+{
+    if(fde == 0) return;
+    if(!(fde->state & FDE_CREATED)) {
+        FATAL("fde %p not created by fdevent_create()\n", fde);
+    }
+    fdevent_remove(fde);
+}
+
+void fdevent_install(fdevent *fde, int fd, fd_func func, void *arg)
+{
+    memset(fde, 0, sizeof(fdevent));
+    fde->state = FDE_ACTIVE;
+    fde->fd = fd;
+    fde->force_eof = 0;
+    fde->func = func;
+    fde->arg = arg;
+
+#ifndef HAVE_WINSOCK
+    fcntl(fd, F_SETFL, O_NONBLOCK);
+#endif
+    fdevent_register(fde);
+    dump_fde(fde, "connect");
+    fdevent_connect(fde);
+    fde->state |= FDE_ACTIVE;
+}
+
+void fdevent_remove(fdevent *fde)
+{
+    if(fde->state & FDE_PENDING) {
+        fdevent_plist_remove(fde);
+    }
+
+    if(fde->state & FDE_ACTIVE) {
+        fdevent_disconnect(fde);
+        dump_fde(fde, "disconnect");
+        fdevent_unregister(fde);
+    }
+
+    fde->state = 0;
+    fde->events = 0;
+}
+
+
+void fdevent_set(fdevent *fde, unsigned events)
+{
+    events &= FDE_EVENTMASK;
+
+    if((fde->state & FDE_EVENTMASK) == events) return;
+
+    if(fde->state & FDE_ACTIVE) {
+        fdevent_update(fde, events);
+        dump_fde(fde, "update");
+    }
+
+    fde->state = (fde->state & FDE_STATEMASK) | events;
+
+    if(fde->state & FDE_PENDING) {
+            /* if we're pending, make sure
+            ** we don't signal an event that
+            ** is no longer wanted.
+            */
+        fde->events &= (~events);
+        if(fde->events == 0) {
+            fdevent_plist_remove(fde);
+            fde->state &= (~FDE_PENDING);
+        }
+    }
+}
+
+void fdevent_add(fdevent *fde, unsigned events)
+{
+    fdevent_set(
+        fde, (fde->state & FDE_EVENTMASK) | (events & FDE_EVENTMASK));
+}
+
+void fdevent_del(fdevent *fde, unsigned events)
+{
+    fdevent_set(
+        fde, (fde->state & FDE_EVENTMASK) & (~(events & FDE_EVENTMASK)));
+}
+
+void fdevent_subproc_setup()
+{
+    int s[2];
+
+    if(adb_socketpair(s)) {
+        FATAL("cannot create shell-exit socket-pair\n");
+    }
+    SHELL_EXIT_NOTIFY_FD = s[0];
+    fdevent *fde;
+    fde = fdevent_create(s[1], fdevent_subproc_event_func, NULL);
+    if(!fde)
+      FATAL("cannot create fdevent for shell-exit handler\n");
+    fdevent_add(fde, FDE_READ);
+}
+
+void fdevent_loop()
+{
+    fdevent *fde;
+    fdevent_subproc_setup();
+
+    for(;;) {
+        D("--- ---- waiting for events\n");
+
+        fdevent_process();
+
+        while((fde = fdevent_plist_dequeue())) {
+            fdevent_call_fdfunc(fde);
+        }
+    }
+}