The problem here was that we alway added the base address, and we
assumed that all addresses we access are relative but this is not the
case in case of non pie binaries. The issue is that all addresses were
base+offset. so if we added the base again it will ofcourse generate
wrong address.
This was triggered by gcc for some reason It included sys/types.h and
assumed sys/select.h to be there. And that seams to be the case in musl.
The problem with relibc here is that sys/types.h is are part of relibc
"include/*.h" files, while sys/select.h is generated by cbindgen. That
makes it impossible to #include select.h in types.h epsecially that
there are files like fcntl.c that uses types.h. They would complain
about missing headers. I fixed this by renaming sys/types.h to
sys/types_internal.h and then generating types.h using cbindgen as well
except for that. however fcntl and dlmalloc can include types_internal
instead of types.h
The problem here is that _Bool type is not defined in C++ yet this file
is using it. That leads to issues when compiling gcc. I borrowed the
same techniques used in other stdbool.h
This reverts commit b0dde81c75.
The main issue was not with "access" being used, it was with errno being
accessed. This patch accesses errno as well
LD_LIBRARY_PATH="/folder/with/no/libc" ./a.out
gives segfault with the following stack trace
0x00000000004d1cae in relibc::platform::sys::e (sys=18446744073709551614) at src/platform/linux/mod.rs:54
54 errno = -(sys as isize) as c_int;
(gdb) bt
#0 0x00000000004d1cae in relibc::platform::sys::e (sys=18446744073709551614) at src/platform/linux/mod.rs:54
#1 0x00000000004d361e in <relibc::platform::sys::Sys as relibc::platform::pal::Pal>::open (path=0x5555555634c0, oflag=524288, mode=0) at src/platform/linux/mod.rs:330
#2 0x000000000049a2ad in relibc::fs::File::open (path=0x5555555634c0, oflag=524288) at src/fs.rs:28
#3 0x0000000000482b49 in relibc::ld_so::linker::Linker::load_recursive (self=0x7fffffffdd30, name=..., path=...) at src/ld_so/linker.rs:119
#4 0x0000000000484963 in relibc::ld_so::linker::Linker::load_library (self=0x7fffffffdd30, name=...) at src/ld_so/linker.rs:184
#5 0x0000000000483b53 in relibc::ld_so::linker::Linker::load_data (self=0x7fffffffdd30, name=..., data=...) at src/ld_so/linker.rs:152
#6 0x00000000004831fe in relibc::ld_so::linker::Linker::load_recursive (self=0x7fffffffdd30, name=..., path=...) at src/ld_so/linker.rs:140
#7 0x000000000048228a in relibc::ld_so::linker::Linker::load (self=0x7fffffffdd30, name=..., path=...) at src/ld_so/linker.rs:97
#8 0x0000000000414a3b in relibc_ld_so_start (sp=0x7fffffffe310, ld_entry=4198896) at src/ld_so/start.rs:182
#9 0x0000000000401209 in _start () at src/ld_so/src/lib.rs:10
#10 0x0000000000000001 in ?? ()
#11 0x00007fffffffe592 in ?? ()
#12 0x0000000000000000 in ?? ()
The LookAheadReader api works similar to read but it has 2 methods,
lookahead: it will read 1 byte (with internal ftell) without modifying
the file's own ftell() and commit() which saves the current file ftell
LookAheadReader can wrap both buffers and files
During early parts of ld.so, errno and other thread local variables are
not yet initialized so we cannot use function (such as unistd::access)
that depends on such thread local variables (errno). For this reason
this patch creates small wrapper around the syscall that doesn't not
touch the errno
Current LD_LIBRARY_PATH implementation overwrites the original search
path, which is not the best idea, instead this patch would check
LD_LIBRARY_PATH first and if it didn't find the libraries it is looking
for, then it will search the original search path
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