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io: POSIX implementation tries to get status information on short reads/writes.

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Fixes #13413.
This commit is contained in:
Ryan C. Gordon
2025-09-11 09:32:32 -04:00
parent 4d6e0e0087
commit 8d5b82be2e
1 changed files with 44 additions and 7 deletions
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51
src/io/SDL_iostream.c
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@@ -421,18 +421,36 @@ static size_t SDLCALL fd_read(void *userdata, void *ptr, size_t size, SDL_IOStat
ssize_t bytes;
do {
bytes = read(iodata->fd, ptr, size);
} while (bytes < 0 && errno == EINTR);
} while ((bytes < 0) && (errno == EINTR));
if (bytes < 0) {
ssize_t result = bytes;
if ((bytes > 0) && (bytes < size)) { // was it a short read, EOF, or error?
// try to read the difference, so we can rule out a short read.
do {
result = read(iodata->fd, ((Uint8 *) ptr) + bytes, size - bytes);
} while ((result < 0) && (errno == EINTR));
if (result > 0) {
bytes += result;
result = bytes;
SDL_assert(bytes <= size);
}
}
if (result < 0) {
if (errno == EAGAIN) {
*status = SDL_IO_STATUS_NOT_READY;
} else {
*status = SDL_IO_STATUS_ERROR;
SDL_SetError("Error reading from datastream: %s", strerror(errno));
}
bytes = 0;
} else if (bytes == 0) {
if (bytes < 0) {
bytes = 0;
}
} else if (result == 0) {
*status = SDL_IO_STATUS_EOF;
} else if (result < size) {
*status = SDL_IO_STATUS_NOT_READY;;
}
return (size_t)bytes;
}
@@ -443,17 +461,36 @@ static size_t SDLCALL fd_write(void *userdata, const void *ptr, size_t size, SDL
ssize_t bytes;
do {
bytes = write(iodata->fd, ptr, size);
} while (bytes < 0 && errno == EINTR);
} while ((bytes < 0) && (errno == EINTR));
if (bytes < 0) {
ssize_t result = bytes;
if ((bytes > 0) && (bytes < size)) { // was it a short write, or error?
// try to write the difference, so we can rule out a short read.
do {
result = write(iodata->fd, ((Uint8 *) ptr) + bytes, size - bytes);
} while ((result < 0) && (errno == EINTR));
if (result > 0) {
bytes += result;
result = bytes;
SDL_assert(bytes <= size);
}
}
if (result < 0) {
if (errno == EAGAIN) {
*status = SDL_IO_STATUS_NOT_READY;
} else {
*status = SDL_IO_STATUS_ERROR;
SDL_SetError("Error writing to datastream: %s", strerror(errno));
}
bytes = 0;
if (bytes < 0) {
bytes = 0;
}
} else if (result < size) {
*status = SDL_IO_STATUS_NOT_READY;;
}
return (size_t)bytes;
}