source: MondoRescue/branches/2.2.5/mindi-busybox/libbb/xfuncs.c@ 1765

/* vi: set sw=4 ts=4: */
/*
 * Utility routines.
 *
 * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
 * Copyright (C) 2006 Rob Landley
 * Copyright (C) 2006 Denis Vlasenko
 *
 * Licensed under GPL version 2, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

/* All the functions starting with "x" call bb_error_msg_and_die() if they
 * fail, so callers never need to check for errors.  If it returned, it
 * succeeded. */

#ifndef DMALLOC
/* dmalloc provides variants of these that do abort() on failure.
 * Since dmalloc's prototypes overwrite the impls here as they are
 * included after these prototypes in libbb.h, all is well.
 */
// Warn if we can't allocate size bytes of memory.
void *malloc_or_warn(size_t size)
{
    void *ptr = malloc(size);
    if (ptr == NULL && size != 0)
        bb_error_msg(bb_msg_memory_exhausted);
    return ptr;
}

// Die if we can't allocate size bytes of memory.
void *xmalloc(size_t size)
{
    void *ptr = malloc(size);
    if (ptr == NULL && size != 0)
        bb_error_msg_and_die(bb_msg_memory_exhausted);
    return ptr;
}

// Die if we can't resize previously allocated memory.  (This returns a pointer
// to the new memory, which may or may not be the same as the old memory.
// It'll copy the contents to a new chunk and free the old one if necessary.)
void *xrealloc(void *ptr, size_t size)
{
    ptr = realloc(ptr, size);
    if (ptr == NULL && size != 0)
        bb_error_msg_and_die(bb_msg_memory_exhausted);
    return ptr;
}
#endif /* DMALLOC */

// Die if we can't allocate and zero size bytes of memory.
void *xzalloc(size_t size)
{
    void *ptr = xmalloc(size);
    memset(ptr, 0, size);
    return ptr;
}

// Die if we can't copy a string to freshly allocated memory.
char * xstrdup(const char *s)
{
    char *t;

    if (s == NULL)
        return NULL;

    t = strdup(s);

    if (t == NULL)
        bb_error_msg_and_die(bb_msg_memory_exhausted);

    return t;
}

// Die if we can't allocate n+1 bytes (space for the null terminator) and copy
// the (possibly truncated to length n) string into it.
char * xstrndup(const char *s, int n)
{
    int m;
    char *t;

    if (ENABLE_DEBUG && s == NULL)
        bb_error_msg_and_die("xstrndup bug");

    /* We can just xmalloc(n+1) and strncpy into it, */
    /* but think about xstrndup("abc", 10000) wastage! */
    m = n;
    t = (char*) s;
    while (m) {
        if (!*t) break;
        m--;
        t++;
    }
    n -= m;
    t = xmalloc(n + 1);
    t[n] = '\0';

    return memcpy(t, s, n);
}

// Die if we can't open a file and return a FILE * to it.
// Notice we haven't got xfread(), This is for use with fscanf() and friends.
FILE *xfopen(const char *path, const char *mode)
{
    FILE *fp = fopen(path, mode);
    if (fp == NULL)
        bb_perror_msg_and_die("can't open '%s'", path);
    return fp;
}

// Die if we can't open a file and return a fd.
int xopen3(const char *pathname, int flags, int mode)
{
    int ret;

    ret = open(pathname, flags, mode);
    if (ret < 0) {
        bb_perror_msg_and_die("can't open '%s'", pathname);
    }
    return ret;
}

// Die if we can't open an existing file and return a fd.
int xopen(const char *pathname, int flags)
{
    return xopen3(pathname, flags, 0666);
}

// Warn if we can't open a file and return a fd.
int open3_or_warn(const char *pathname, int flags, int mode)
{
    int ret;

    ret = open(pathname, flags, mode);
    if (ret < 0) {
        bb_perror_msg("can't open '%s'", pathname);
    }
    return ret;
}

// Warn if we can't open a file and return a fd.
int open_or_warn(const char *pathname, int flags)
{
    return open3_or_warn(pathname, flags, 0666);
}

void xpipe(int filedes[2])
{
    if (pipe(filedes))
        bb_perror_msg_and_die("can't create pipe");
}

void xunlink(const char *pathname)
{
    if (unlink(pathname))
        bb_perror_msg_and_die("can't remove file '%s'", pathname);
}

// Turn on nonblocking I/O on a fd
int ndelay_on(int fd)
{
    return fcntl(fd, F_SETFL, fcntl(fd,F_GETFL) | O_NONBLOCK);
}

int ndelay_off(int fd)
{
    return fcntl(fd, F_SETFL, fcntl(fd,F_GETFL) & ~O_NONBLOCK);
}

void xdup2(int from, int to)
{
    if (dup2(from, to) != to)
        bb_perror_msg_and_die("can't duplicate file descriptor");
}

// "Renumber" opened fd
void xmove_fd(int from, int to)
{
    if (from == to)
        return;
    xdup2(from, to);
    close(from);
}

// Die with an error message if we can't write the entire buffer.
void xwrite(int fd, const void *buf, size_t count)
{
    if (count) {
        ssize_t size = full_write(fd, buf, count);
        if (size != count)
            bb_error_msg_and_die("short write");
    }
}

// Die with an error message if we can't lseek to the right spot.
off_t xlseek(int fd, off_t offset, int whence)
{
    off_t off = lseek(fd, offset, whence);
    if (off == (off_t)-1) {
        if (whence == SEEK_SET)
            bb_perror_msg_and_die("lseek(%"OFF_FMT"u)", offset);
        bb_perror_msg_and_die("lseek");
    }
    return off;
}

// Die with supplied filename if this FILE * has ferror set.
void die_if_ferror(FILE *fp, const char *fn)
{
    if (ferror(fp)) {
        /* ferror doesn't set useful errno */
        bb_error_msg_and_die("%s: I/O error", fn);
    }
}

// Die with an error message if stdout has ferror set.
void die_if_ferror_stdout(void)
{
    die_if_ferror(stdout, bb_msg_standard_output);
}

// Die with an error message if we have trouble flushing stdout.
void xfflush_stdout(void)
{
    if (fflush(stdout)) {
        bb_perror_msg_and_die(bb_msg_standard_output);
    }
}

void sig_block(int sig)
{
    sigset_t ss;
    sigemptyset(&ss);
    sigaddset(&ss, sig);
    sigprocmask(SIG_BLOCK, &ss, NULL);
}

void sig_unblock(int sig)
{
    sigset_t ss;
    sigemptyset(&ss);
    sigaddset(&ss, sig);
    sigprocmask(SIG_UNBLOCK, &ss, NULL);
}

#if 0
void sig_blocknone(void)
{
    sigset_t ss;
    sigemptyset(&ss);
    sigprocmask(SIG_SETMASK, &ss, NULL);
}
#endif

void sig_catch(int sig, void (*f)(int))
{
    struct sigaction sa;
    sa.sa_handler = f;
    sa.sa_flags = 0;
    sigemptyset(&sa.sa_mask);
    sigaction(sig, &sa, NULL);
}

void sig_pause(void)
{
    sigset_t ss;
    sigemptyset(&ss);
    sigsuspend(&ss);
}


void xsetenv(const char *key, const char *value)
{
    if (setenv(key, value, 1))
        bb_error_msg_and_die(bb_msg_memory_exhausted);
}

// Converts unsigned long long value into compact 4-char
// representation. Examples: "1234", "1.2k", " 27M", "123T"
// Fifth char is always '\0'
void smart_ulltoa5(unsigned long long ul, char buf[5])
{
    const char *fmt;
    char c;
    unsigned v,idx = 0;
    ul *= 10;
    if (ul > 9999*10) { // do not scale if 9999 or less
        while (ul >= 10000) {
            ul /= 1024;
            idx++;
        }
    }
    v = ul; // ullong divisions are expensive, avoid them

    fmt = " 123456789";
    if (!idx) {     // 9999 or less: use 1234 format
        c = buf[0] = " 123456789"[v/10000];
        if (c != ' ') fmt = "0123456789";
        c = buf[1] = fmt[v/1000%10];
        if (c != ' ') fmt = "0123456789";
        buf[2] = fmt[v/100%10];
        buf[3] = "0123456789"[v/10%10];
    } else {
        if (v >= 10*10) {   // scaled value is >=10: use 123M format
            c = buf[0] = " 123456789"[v/1000];
            if (c != ' ') fmt = "0123456789";
            buf[1] = fmt[v/100%10];
            buf[2] = "0123456789"[v/10%10];
        } else {    // scaled value is <10: use 1.2M format
            buf[0] = "0123456789"[v/10];
            buf[1] = '.';
            buf[2] = "0123456789"[v%10];
        }
        // see http://en.wikipedia.org/wiki/Tera
        buf[3] = " kMGTPEZY"[idx];
    }
    buf[4] = '\0';
}

// Convert unsigned integer to ascii, writing into supplied buffer.
// A truncated result contains the first few digits of the result ala strncpy.
// Returns a pointer past last generated digit, does _not_ store NUL.
void BUG_sizeof_unsigned_not_4(void);
char *utoa_to_buf(unsigned n, char *buf, unsigned buflen)
{
    unsigned i, out, res;
    if (sizeof(unsigned) != 4)
        BUG_sizeof_unsigned_not_4();
    if (buflen) {
        out = 0;
        for (i = 1000000000; i; i /= 10) {
            res = n / i;
            if (res || out || i == 1) {
                if (!--buflen) break;
                out++;
                n -= res*i;
                *buf++ = '0' + res;
            }
        }
    }
    return buf;
}

// Convert signed integer to ascii, like utoa_to_buf()
char *itoa_to_buf(int n, char *buf, unsigned buflen)
{
    if (buflen && n<0) {
        n = -n;
        *buf++ = '-';
        buflen--;
    }
    return utoa_to_buf((unsigned)n, buf, buflen);
}

// The following two functions use a static buffer, so calling either one a
// second time will overwrite previous results.
//
// The largest 32 bit integer is -2 billion plus null terminator, or 12 bytes.
// Int should always be 32 bits on any remotely Unix-like system, see
// http://www.unix.org/whitepapers/64bit.html for the reasons why.

static char local_buf[12];

// Convert unsigned integer to ascii using a static buffer (returned).
char *utoa(unsigned n)
{
    *(utoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';

    return local_buf;
}

// Convert signed integer to ascii using a static buffer (returned).
char *itoa(int n)
{
    *(itoa_to_buf(n, local_buf, sizeof(local_buf))) = '\0';

    return local_buf;
}

// Emit a string of hex representation of bytes
char *bin2hex(char *p, const char *cp, int count)
{
    while (count) {
        unsigned char c = *cp++;
        /* put lowercase hex digits */
        *p++ = 0x20 | bb_hexdigits_upcase[c >> 4];
        *p++ = 0x20 | bb_hexdigits_upcase[c & 0xf];
        count--;
    }
    return p;
}

// Die with an error message if we can't set gid.  (Because resource limits may
// limit this user to a given number of processes, and if that fills up the
// setgid() will fail and we'll _still_be_root_, which is bad.)
void xsetgid(gid_t gid)
{
    if (setgid(gid)) bb_perror_msg_and_die("setgid");
}

// Die with an error message if we can't set uid.  (See xsetgid() for why.)
void xsetuid(uid_t uid)
{
    if (setuid(uid)) bb_perror_msg_and_die("setuid");
}

// Return how long the file at fd is, if there's any way to determine it.
off_t fdlength(int fd)
{
    off_t bottom = 0, top = 0, pos;
    long size;

    // If the ioctl works for this, return it.

    if (ioctl(fd, BLKGETSIZE, &size) >= 0) return size*512;

    // FIXME: explain why lseek(SEEK_END) is not used here!

    // If not, do a binary search for the last location we can read.  (Some
    // block devices don't do BLKGETSIZE right.)

    do {
        char temp;

        pos = bottom + (top - bottom) / 2;

        // If we can read from the current location, it's bigger.

        if (lseek(fd, pos, SEEK_SET)>=0 && safe_read(fd, &temp, 1)==1) {
            if (bottom == top) bottom = top = (top+1) * 2;
            else bottom = pos;

        // If we can't, it's smaller.

        } else {
            if (bottom == top) {
                if (!top) return 0;
                bottom = top/2;
            }
            else top = pos;
        }
    } while (bottom + 1 != top);

    return pos + 1;
}

// Die with an error message if we can't malloc() enough space and do an
// sprintf() into that space.
char *xasprintf(const char *format, ...)
{
    va_list p;
    int r;
    char *string_ptr;

#if 1
    // GNU extension
    va_start(p, format);
    r = vasprintf(&string_ptr, format, p);
    va_end(p);
#else
    // Bloat for systems that haven't got the GNU extension.
    va_start(p, format);
    r = vsnprintf(NULL, 0, format, p);
    va_end(p);
    string_ptr = xmalloc(r+1);
    va_start(p, format);
    r = vsnprintf(string_ptr, r+1, format, p);
    va_end(p);
#endif

    if (r < 0) bb_error_msg_and_die(bb_msg_memory_exhausted);
    return string_ptr;
}

#if 0 /* If we will ever meet a libc which hasn't [f]dprintf... */
int fdprintf(int fd, const char *format, ...)
{
    va_list p;
    int r;
    char *string_ptr;

#if 1
    // GNU extension
    va_start(p, format);
    r = vasprintf(&string_ptr, format, p);
    va_end(p);
#else
    // Bloat for systems that haven't got the GNU extension.
    va_start(p, format);
    r = vsnprintf(NULL, 0, format, p) + 1;
    va_end(p);
    string_ptr = malloc(r);
    if (string_ptr) {
        va_start(p, format);
        r = vsnprintf(string_ptr, r, format, p);
        va_end(p);
    }
#endif

    if (r >= 0) {
        full_write(fd, string_ptr, r);
        free(string_ptr);
    }
    return r;
}
#endif

// Die with an error message if we can't copy an entire FILE * to stdout, then
// close that file.
void xprint_and_close_file(FILE *file)
{
    fflush(stdout);
    // copyfd outputs error messages for us.
    if (bb_copyfd_eof(fileno(file), 1) == -1)
        xfunc_die();

    fclose(file);
}

// Die if we can't chdir to a new path.
void xchdir(const char *path)
{
    if (chdir(path))
        bb_perror_msg_and_die("chdir(%s)", path);
}

// Print a warning message if opendir() fails, but don't die.
DIR *warn_opendir(const char *path)
{
    DIR *dp;

    dp = opendir(path);
    if (!dp)
        bb_perror_msg("can't open '%s'", path);
    return dp;
}

// Die with an error message if opendir() fails.
DIR *xopendir(const char *path)
{
    DIR *dp;

    dp = opendir(path);
    if (!dp)
        bb_perror_msg_and_die("can't open '%s'", path);
    return dp;
}

// Die with an error message if we can't open a new socket.
int xsocket(int domain, int type, int protocol)
{
    int r = socket(domain, type, protocol);

    if (r < 0) {
        /* Hijack vaguely related config option */
#if ENABLE_VERBOSE_RESOLUTION_ERRORS
        const char *s = "INET";
        if (domain == AF_PACKET) s = "PACKET";
        if (domain == AF_NETLINK) s = "NETLINK";
USE_FEATURE_IPV6(if (domain == AF_INET6) s = "INET6";)
        bb_perror_msg_and_die("socket(AF_%s)", s);
#else
        bb_perror_msg_and_die("socket");
#endif
    }

    return r;
}

// Die with an error message if we can't bind a socket to an address.
void xbind(int sockfd, struct sockaddr *my_addr, socklen_t addrlen)
{
    if (bind(sockfd, my_addr, addrlen)) bb_perror_msg_and_die("bind");
}

// Die with an error message if we can't listen for connections on a socket.
void xlisten(int s, int backlog)
{
    if (listen(s, backlog)) bb_perror_msg_and_die("listen");
}

/* Die with an error message if sendto failed.
 * Return bytes sent otherwise  */
ssize_t xsendto(int s, const  void *buf, size_t len, const struct sockaddr *to,
                socklen_t tolen)
{
    ssize_t ret = sendto(s, buf, len, 0, to, tolen);
    if (ret < 0) {
        if (ENABLE_FEATURE_CLEAN_UP)
            close(s);
        bb_perror_msg_and_die("sendto");
    }
    return ret;
}

// xstat() - a stat() which dies on failure with meaningful error message
void xstat(const char *name, struct stat *stat_buf)
{
    if (stat(name, stat_buf))
        bb_perror_msg_and_die("can't stat '%s'", name);
}

// selinux_or_die() - die if SELinux is disabled.
void selinux_or_die(void)
{
#if ENABLE_SELINUX
    int rc = is_selinux_enabled();
    if (rc == 0) {
        bb_error_msg_and_die("SELinux is disabled");
    } else if (rc < 0) {
        bb_error_msg_and_die("is_selinux_enabled() failed");
    }
#else
    bb_error_msg_and_die("SELinux support is disabled");
#endif
}

/* It is perfectly ok to pass in a NULL for either width or for
 * height, in which case that value will not be set.  */
int get_terminal_width_height(int fd, int *width, int *height)
{
    struct winsize win = { 0, 0, 0, 0 };
    int ret = ioctl(fd, TIOCGWINSZ, &win);

    if (height) {
        if (!win.ws_row) {
            char *s = getenv("LINES");
            if (s) win.ws_row = atoi(s);
        }
        if (win.ws_row <= 1 || win.ws_row >= 30000)
            win.ws_row = 24;
        *height = (int) win.ws_row;
    }

    if (width) {
        if (!win.ws_col) {
            char *s = getenv("COLUMNS");
            if (s) win.ws_col = atoi(s);
        }
        if (win.ws_col <= 1 || win.ws_col >= 30000)
            win.ws_col = 80;
        *width = (int) win.ws_col;
    }

    return ret;
}

void ioctl_or_perror_and_die(int fd, int request, void *argp, const char *fmt,...)
{
    va_list p;

    if (ioctl(fd, request, argp) < 0) {
        va_start(p, fmt);
        bb_verror_msg(fmt, p, strerror(errno));
        /* xfunc_die can actually longjmp, so be nice */
        va_end(p);
        xfunc_die();
    }
}

int ioctl_or_perror(int fd, int request, void *argp, const char *fmt,...)
{
    va_list p;
    int ret = ioctl(fd, request, argp);

    if (ret < 0) {
        va_start(p, fmt);
        bb_verror_msg(fmt, p, strerror(errno));
        va_end(p);
    }
    return ret;
}

#if ENABLE_IOCTL_HEX2STR_ERROR
int bb_ioctl_or_warn(int fd, int request, void *argp, const char *ioctl_name)
{
    int ret;

    ret = ioctl(fd, request, argp);
    if (ret < 0)
        bb_perror_msg("%s", ioctl_name);
    return ret;
}
void bb_xioctl(int fd, int request, void *argp, const char *ioctl_name)
{
    if (ioctl(fd, request, argp) < 0)
        bb_perror_msg_and_die("%s", ioctl_name);
}
#else
int bb_ioctl_or_warn(int fd, int request, void *argp)
{
    int ret;

    ret = ioctl(fd, request, argp);
    if (ret < 0)
        bb_perror_msg("ioctl %#x failed", request);
    return ret;
}
void bb_xioctl(int fd, int request, void *argp)
{
    if (ioctl(fd, request, argp) < 0)
        bb_perror_msg_and_die("ioctl %#x failed", request);
}
#endif