Merge "run-as: use mmap to read package list file"

#include <fcntl.h>

#include <fcntl.h>

#include <unistd.h>

#include <unistd.h>

#include <sys/stat.h>

#include <sys/stat.h>

#include <sys/mman.h>

#include <private/android_filesystem_config.h>

#include <private/android_filesystem_config.h>

#include "package.h"

#include "package.h"

/* The file containing the list of installed packages on the system */

/* The file containing the list of installed packages on the system */

#define PACKAGES_LIST_FILE  "/data/system/packages.list"

#define PACKAGES_LIST_FILE  "/data/system/packages.list"

/* This should be large enough to hold the content of the package database file */

#define PACKAGES_LIST_BUFFER_SIZE  65536

/* Copy 'srclen' string bytes from 'src' into buffer 'dst' of size 'dstlen'

/* Copy 'srclen' string bytes from 'src' into buffer 'dst' of size 'dstlen'

 * This function always zero-terminate the destination buffer unless

 * This function always zero-terminate the destination buffer unless

 * 'dstlen' is 0, even in case of overflow.

 * 'dstlen' is 0, even in case of overflow.

    *dst = '\0'; /* zero-terminate result */

    *dst = '\0'; /* zero-terminate result */

}

}

/* Read up to 'buffsize' bytes into 'buff' from the file

/* Open 'filename' and map it into our address-space.

 * named 'filename'. Return byte length on success, or -1

 * Returns buffer address, or NULL on error

 * on error.

 * On exit, *filesize will be set to the file's size, or 0 on error

 */

 */

static int

static void*

read_file(const char* filename, char* buff, size_t buffsize)

map_file(const char* filename, size_t* filesize)

{

{

    int  fd, len, old_errno;

    int  fd, ret, old_errno;

    struct stat  st;

    size_t  length = 0;

    void*   address = NULL;

    /* check the input buffer size */

    *filesize = 0;

    if (buffsize >= INT_MAX) {

        errno = EINVAL;

        return -1;

    }

    /* open the file for reading */

    /* open the file for reading */

    do {

    fd = TEMP_FAILURE_RETRY(open(filename, O_RDONLY));

        fd = open(filename, O_RDONLY);

    } while (fd < 0 && errno == EINTR);

    if (fd < 0)

    if (fd < 0)

        return -1;

        return NULL;

    /* read the content */

    /* get its size */

    do {

    ret = TEMP_FAILURE_RETRY(fstat(fd, &st));

        len = read(fd, buff, buffsize);

    if (ret < 0)

    } while (len < 0 && errno == EINTR);

        goto EXIT;

    /* Ensure that the size is not ridiculously large */

    length = (size_t)st.st_size;

    if ((off_t)length != st.st_size) {

        errno = ENOMEM;

        goto EXIT;

    }

    /* Memory-map the file now */

    address = TEMP_FAILURE_RETRY(mmap(NULL, length, PROT_READ, MAP_PRIVATE, fd, 0));

    if (address == MAP_FAILED) {

        address = NULL;

        goto EXIT;

    }

    /* We're good, return size */

    *filesize = length;

EXIT:

    /* close the file, preserve old errno for better diagnostics */

    /* close the file, preserve old errno for better diagnostics */

    old_errno = errno;

    old_errno = errno;

    close(fd);

    close(fd);

    errno = old_errno;

    errno = old_errno;

    return len;

    return address;

}

/* unmap the file, but preserve errno */

static void

unmap_file(void*  address, size_t  size)

{

    int old_errno = errno;

    TEMP_FAILURE_RETRY(munmap(address, size));

    errno = old_errno;

}

}

/* Check that a given directory:

/* Check that a given directory:

int

int

get_package_info(const char* pkgName, PackageInfo *info)

get_package_info(const char* pkgName, PackageInfo *info)

{

{

    static char  buffer[PACKAGES_LIST_BUFFER_SIZE];

    char*        buffer;

    int          buffer_len;

    size_t       buffer_len;

    const char*  p;

    const char*  p;

    const char*  buffer_end;

    const char*  buffer_end;

    int          result;

    int          result = -1;

    info->uid          = 0;

    info->uid          = 0;

    info->isDebuggable = 0;

    info->isDebuggable = 0;

    info->dataDir[0]   = '\0';

    info->dataDir[0]   = '\0';

    buffer_len = read_file(PACKAGES_LIST_FILE, buffer, sizeof buffer);

    buffer = map_file(PACKAGES_LIST_FILE, &buffer_len);

    if (buffer_len < 0)

    if (buffer == NULL)

        return -1;

        return -1;

    p          = buffer;

    p          = buffer;

        string_copy(info->dataDir, sizeof info->dataDir, p, q - p);

        string_copy(info->dataDir, sizeof info->dataDir, p, q - p);

        /* Ignore the rest */

        /* Ignore the rest */

        return 0;

        result = 0;

        goto EXIT;

    NEXT_LINE:

    NEXT_LINE:

        p = next;

        p = next;

    /* the package is unknown */

    /* the package is unknown */

    errno = ENOENT;

    errno = ENOENT;

    return -1;

    result = -1;

    goto EXIT;

BAD_FORMAT:

BAD_FORMAT:

    errno = EINVAL;

    errno = EINVAL;

    return -1;

    result = -1;

EXIT:

    unmap_file(buffer, buffer_len);

    return result;

}

}