Overview
| Comment: | Fix _start to properly find the environment. The arguments and environment are directly on the initial stack, which means that more work is needed to find the start of the environment properly. Also remove the hack in _boot that made it work if there were no arguments, as all of the math is being done in _start now. |
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| SHA3-256: |
62fd1bfe97dfd2f741f8c43d1c888577 |
| User & Date: | glowpelt on 2020-01-05 17:52:15 |
| Other Links: | manifest | tags |
Context
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2020-01-19
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| 04:12 | Partially fix shared library build by making sure that data_objects are linked in. This means that internal.ident.o is properly linked in, but internal.ident.o itself still references undefined symbols, so this is only a partial fix. check-in: 0d71b71cc8 user: glowpelt tags: trunk | |
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2020-01-05
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| 17:52 | Fix _start to properly find the environment. The arguments and environment are directly on the initial stack, which means that more work is needed to find the start of the environment properly. Also remove the hack in _boot that made it work if there were no arguments, as all of the math is being done in _start now. check-in: 62fd1bfe97 user: glowpelt tags: trunk | |
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2019-11-19
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| 05:34 | add freebsd signal numbers check-in: de2d78ff77 user: lexi tags: trunk | |
Changes
Modified mod/kcore/boot.rt.c from [a8282db34a] to [298efe4468].
7 7 unsigned long long 8 8 _boot(unsigned int argc, /* argument count */ 9 9 const char** argv, /* arguments */ 10 10 char** envp /* environment */ ) { 11 11 12 12 _k_internal_binary_name = argv[0]; 13 13 14 - envp ++; /* envp seems to point at a leading null; 15 - this is probably a sign of breakage but 16 - i don't know what else to do about it for 17 - the moment. */ 18 - 19 14 char** ep; 20 15 /* advance ep until it points at the last element */ 21 16 for (ep = envp; *ep != 0; ++ep); 22 17 23 18 /* allocate space for each environment variable */ 24 19 kvar variables [ep - envp]; 25 20
Modified mod/kcore/boot.rt.x86.lin.64.s from [a74c88489c] to [78d762a0b4].
19 19 mov edi, [rsp + 0] ; sizeof arguments 20 20 ; first argument to _boot(): argc 21 21 ; this is a 32-bit signed(??) integer 22 22 ; that is equal to the number of 23 23 ; elements in argv (see below). it is 24 24 ; not strictly necessary, because argv 25 25 ; is per spec always null-terminated, 26 - ; but we pass it just in case. 26 + ; but we pass it just in case. it is 27 + ; also used for finding the environment 28 + ; below. 27 29 28 30 lea rsi, [rsp + 8] ; &arguments 29 31 ; 2nd argument to _boot(): ptr to argv 30 32 ; this points to an array of strings 31 33 ; containing the program's command line 32 34 ; arguments. _boot() does not need to 33 35 ; parse this, but it does need to store 34 36 ; it in the structure passed to main() 37 + ; this exists on the stack, right above 38 + ; argc 35 39 36 - lea rdx, [rsp + 16] ; &environment 40 + lea rdx, [rsp + rdi * 8 + 16] ; &environment 37 41 ; third argument to _boot(): ptr to envp 38 42 ; this points to the list of environment 39 43 ; variables for the running program. it 40 44 ; is the responsibility of _boot to parse 41 45 ; this list and arrange it into a set of 42 - ; legible and useful C arrays. 46 + ; legible and useful C arrays. it exists 47 + ; above the argument list, the math is 48 + ; stack pointer + argc*pointers(8 bytes) 49 + ; + 16 bytes (argc itself and the 50 + ; terminating null from argv) 43 51 44 52 mov rax, 0 ; zero out %rax 45 53 ; this is required by the C ABI, and is 46 54 ; reputedly necessary for compatibility 47 55 ; with icc, intel's own proprietary C 48 56 ; compiler. 49 57