[ALSA-OSS] Always initialize pointers before use

This patch makes sure that the initialize() is always called
before any pointer to function is used. Somehow it happens
that the __attribute__((constructor)) is not always sufficient -
other libs may have that attribute either, and may call fopen()
from within their constructors, which leads to a SIGSEGV, that
this patch fixes. Perhaps the __attribute__((constructor)) is no
longer needed with that patch at all.

Signed-off-by: Stas Sergeev <stsp@aknet.ru>

diff --git a/alsa/alsa-oss.c b/alsa/alsa-oss.c
index c8892bca86ef9a0f5c79989fdf471aede9e31b4f..a8a66252a3158a8ace3d414f6764b0c599a71ca4 100644 (file)
--- a/alsa/alsa-oss.c
+++ b/alsa/alsa-oss.c
@@ -99,6 +99,9 @@ typedef struct {
        void *mmap_area;
 } fd_t;
 
+static void initialize(void);
+static int initialized = 0;
+
 static int oss_wrapper_debug = 0;
 static int open_max;
 static int poll_fds_add = 0;
@@ -130,6 +133,9 @@ static int oss_pcm_fcntl(int fd, int cmd, ...)
        va_list args;
        long arg;
 
+       if (!initialized)
+               initialize();
+
        va_start(args, cmd);
        arg = va_arg(args, long);
        va_end(args);
@@ -232,6 +238,9 @@ int open(const char *file, int oflag, ...)
        mode_t mode = 0;
        int fd;
 
+       if (!initialized)
+               initialize();
+
        if (oflag & O_CREAT) {
                va_start(args, oflag);
                mode = va_arg(args, mode_t);
@@ -272,6 +281,9 @@ int open(const char *file, int oflag, ...)
 
 int close(int fd)
 {
+       if (!initialized)
+               initialize();
+
        if (fd < 0 || fd >= open_max || fds[fd] == NULL) {
                return _close(fd);
        } else {
@@ -288,6 +300,9 @@ int close(int fd)
 
 ssize_t write(int fd, const void *buf, size_t n)
 {
+       if (!initialized)
+               initialize();
+
        if (fd < 0 || fd >= open_max || fds[fd] == NULL)
                return _write(fd, buf, n);
        else
@@ -296,6 +311,9 @@ ssize_t write(int fd, const void *buf, size_t n)
 
 ssize_t read(int fd, void *buf, size_t n)
 {
+       if (!initialized)
+               initialize();
+
        if (fd < 0 || fd >= open_max || fds[fd] == NULL)
                return _read(fd, buf, n);
        else
@@ -307,6 +325,9 @@ int ioctl(int fd, unsigned long request, ...)
        va_list args;
        void *arg;
 
+       if (!initialized)
+               initialize();
+
        va_start(args, request);
        arg = va_arg(args, void *);
        va_end(args);
@@ -333,6 +354,10 @@ int fcntl(int fd, int cmd, ...)
 void *mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
 {
        void *result;
+
+       if (!initialized)
+               initialize();
+
        if (fd < 0 || fd >= open_max || fds[fd] == NULL)
                return _mmap(addr, len, prot, flags, fd, offset);
        result = ops[fds[fd]->class].mmap(addr, len, prot, flags, fd, offset);
@@ -344,6 +369,10 @@ void *mmap(void *addr, size_t len, int prot, int flags, int fd, off_t offset)
 int munmap(void *addr, size_t len)
 {
        int fd;
+
+       if (!initialized)
+               initialize();
+
        for (fd = 0; fd < open_max; ++fd) {
                if (fds[fd] && fds[fd]->mmap_area == addr)
                        break;
@@ -416,6 +445,10 @@ int poll(struct pollfd *pfds, unsigned long nfds, int timeout)
        int count, count1;
        int direct = 1;
        struct pollfd pfds1[nfds + poll_fds_add + 16];
+
+       if (!initialized)
+               initialize();
+
        nfds1 = 0;
        for (k = 0; k < nfds; ++k) {
                int fd = pfds[k].fd;
@@ -512,6 +545,9 @@ int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds,
        int fd;
        int direct = 1;
 
+       if (!initialized)
+               initialize();
+
        if (rfds) {
                _rfds1 = *rfds;
        } else {
@@ -654,6 +690,10 @@ int select(int nfds, fd_set *rfds, fd_set *wfds, fd_set *efds,
 #include "stdioemu.c"
 
 FILE *fopen(const char* path, const char *mode) {
+
+       if (!initialized)
+               initialize();
+
        if(!is_dsp_device(path)) 
                return _fopen (path, mode);
        
@@ -744,4 +784,5 @@ static void initialize()
        _select = dlsym(RTLD_NEXT, "select");
        _poll = dlsym(RTLD_NEXT, "poll");
        _fopen = dlsym(RTLD_NEXT, "fopen");
+       initialized = 1;
 }