I hope I am not overusing assert calls

You do. assert is a debugging instrument. If NDEBUG macro is defined, the calls to assert are removed at the compile time. This is a usual practice for the production code.

• #define whaterror strerror(errno)

  I advise against it. The macro adds no value, and only obfuscates the code.

• memset(malloc

  Keep in mind that malloc may fail.

• memset(bytes == -1 ? chunk : chunk + bytes, 0, BUFFSIZE);

  Setting BUFFSIZE bytes to 0 writes beyond the allocated space. You need BUFFSIZE - bytes.

  On the other hand, clearing the entire tail of the chunk is not necessary. chunk[bytes] = 0; is enough.

• !errno ?, besides being another obfuscation, is quite wrong. errno is a way to inspect errors, not to detect them. In fact, quoting man errno,

  Successful calls never set errno; once set, it remains until another error occurs.

  recv returning -1 is one and only indication of error.

• Since the socket is not marked nonblocking, it may never return EAGAIN. On the other hand, some errors are irrecoverable, and should break the loop.

I hope I am not overusing assert calls

You do. assert is a debugging instrument. If NDEBUG macro is defined, the calls to assert are removed at the compile time. This is a usual practice for the production code.

• #define whaterror strerror(errno)

  I advise against it. The macro adds no value, and only obfuscates the code.

• memset(malloc

  Keep in mind that malloc may fail.

• memset(bytes == -1 ? chunk : chunk + bytes, 0, BUFFSIZE);

  Setting BUFFSIZE bytes to 0 writes beyond the allocated space. You need BUFFSIZE - bytes.

  On the other hand, clearing the entire tail of the chunk is not necessary. chunk[bytes] = 0; is enough.

• !errno ?, besides being another obfuscation, is quite wrong. errno is a way to inspect errors, not to detect them. In fact, quoting man errno,

  Successful calls never set errno; once set, it remains until another error occurs.

  recv returning -1 is one and only indication of error.

• Since the socket is not marked nonblocking, it may never return EAGAIN. On the other hand, some errors are transient, and should not break the loop.

I hope I am not overusing assert calls

You do. assert is a debugging instrument. If NDEBUG macro is defined, the calls to assert are removed at the compile time. This is a usual practice for the production code.

• #define whaterror strerror(errno)

  I advise against it. The macro adds no value, and only obfuscates the code.

• memset(malloc

  Keep in mind that malloc may fail.

• memset(bytes == -1 ? chunk : chunk + bytes, 0, BUFFSIZE);

  Setting BUFFSIZE bytes to 0 writes beyond the allocated space. You need BUFFSIZE - bytes.

  On the other hand, clearing the entire tail of the chunk is not necessary. chunk[bytes] = 0; is enough.

• !errno ?, besides being another obfuscation, is quite wrong. errno is a way to report errors, not to detect them. In fact, quoting man errno,

  Successful calls never set errno; once set, it remains until another error occurs.

  recv returning -1 is one and only indication of error.

• Since the socket is not marked nonblocking, it may never return EAGAIN. On the other hand, there are other transient errors, which do not necessarily require exit. For example, a system may recover from ENOBUFS; EINTR also should not unconditionally stop the server.

I hope I am not overusing assert calls

You do. assert is a debugging instrument. If NDEBUG macro is defined, the calls to assert are removed at the compile time. This is a usual practice for the production code.

• #define whaterror strerror(errno)

  I advise against it. The macro adds no value, and only obfuscates the code.

• memset(malloc

  Keep in mind that malloc may fail.

• memset(bytes == -1 ? chunk : chunk + bytes, 0, BUFFSIZE);

  Setting BUFFSIZE bytes to 0 writes beyond the allocated space. You need BUFFSIZE - bytes.

  On the other hand, clearing the entire tail of the chunk is not necessary. chunk[bytes] = 0; is enough.

• !errno ?, besides being another obfuscation, is quite wrong. errno is a way to inspect errors, not to detect them. In fact, quoting man errno,

  Successful calls never set errno; once set, it remains until another error occurs.

  recv returning -1 is one and only indication of error.

• Since the socket is not marked nonblocking, it may never return EAGAIN. On the other hand, some errors are irrecoverable, and should break the loop.