mirror of
https://git.proxmox.com/git/wasi-libc
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410c66070a
* Use constructor functions for optional init routines. Instead of using weak symbols, use constructor function attributes for the environment and preopen initialization routines. This is simpler, uses less code, and is more LTO-friendly. * Change the constructor priorities to start at 50. We don't currently have specific plans for other levels in the reserved range (0-100), so leave room for both lower and higher priorities.
67 lines
2.2 KiB
C
67 lines
2.2 KiB
C
#include <unistd.h>
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#include <stdlib.h>
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#include <sysexits.h>
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#include <wasi/api.h>
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#include <wasi/libc.h>
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static char *empty_environ[1] = { NULL };
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char **__environ = empty_environ;
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extern __typeof(__environ) _environ __attribute__((weak, alias("__environ")));
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extern __typeof(__environ) environ __attribute__((weak, alias("__environ")));
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// We define this function here in the same source file as __environ, so that
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// this function is called in iff environment variable support is used.
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// Concerning the 50 -- levels up to 100 are reserved for the implementation,
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// so we an arbitrary number in the middle of the range to allow other
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// reserved things to go before or after.
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__attribute__((constructor(50)))
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static void __wasilibc_populate_environ(void) {
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__wasi_errno_t err;
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// Get the sizes of the arrays we'll have to create to copy in the environment.
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size_t environ_count;
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size_t environ_buf_size;
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err = __wasi_environ_sizes_get(&environ_count, &environ_buf_size);
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if (err != __WASI_ERRNO_SUCCESS) {
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goto oserr;
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}
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if (environ_count == 0) {
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return;
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}
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// Add 1 for the NULL pointer to mark the end, and check for overflow.
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size_t num_ptrs = environ_count + 1;
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if (num_ptrs == 0) {
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goto software;
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}
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// Allocate memory for storing the environment chars.
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char *environ_buf = malloc(environ_buf_size);
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if (environ_buf == NULL) {
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goto software;
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}
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// Allocate memory for the array of pointers. This uses `calloc` both to
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// handle overflow and to initialize the NULL pointer at the end.
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char **environ_ptrs = calloc(num_ptrs, sizeof(char *));
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if (environ_ptrs == NULL) {
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free(environ_buf);
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goto software;
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}
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// Fill the environment chars, and the __environ array with pointers into those chars.
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// TODO: Remove the casts on `environ_ptrs` and `environ_buf` once the witx is updated with char8 support.
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err = __wasi_environ_get((uint8_t **)environ_ptrs, (uint8_t *)environ_buf);
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if (err != __WASI_ERRNO_SUCCESS) {
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free(environ_buf);
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free(environ_ptrs);
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goto oserr;
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}
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__environ = environ_ptrs;
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oserr:
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_Exit(EX_OSERR);
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software:
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_Exit(EX_SOFTWARE);
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}
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