62 lines
1.7 KiB
C
62 lines
1.7 KiB
C
// makeCWrapper /path/to/executable \
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--argv0 my-wrapper \
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--set-default MESSAGE HELLO \
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--prefix PATH : /usr/bin/ \
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--suffix PATH : /usr/local/bin/ \
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--add-flags "-x -y -z" \
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--set MESSAGE2 WORLD
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#define _GNU_SOURCE /* See feature_test_macros(7) */
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#include <unistd.h>
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#include <stdlib.h>
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#include <assert.h>
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#include <stdio.h>
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#define assert_success(e) do { if ((e) < 0) { perror(#e); abort(); } } while (0)
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void set_env_prefix(char *env, char *sep, char *prefix) {
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char *existing = getenv(env);
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if (existing) {
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char *val;
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assert_success(asprintf(&val, "%s%s%s", prefix, sep, existing));
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assert_success(setenv(env, val, 1));
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free(val);
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} else {
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assert_success(setenv(env, prefix, 1));
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}
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}
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void set_env_suffix(char *env, char *sep, char *suffix) {
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char *existing = getenv(env);
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if (existing) {
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char *val;
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assert_success(asprintf(&val, "%s%s%s", existing, sep, suffix));
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assert_success(setenv(env, val, 1));
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free(val);
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} else {
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assert_success(setenv(env, suffix, 1));
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}
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}
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int main(int argc, char **argv) {
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assert_success(setenv("MESSAGE", "HELLO", 0));
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set_env_prefix("PATH", ":", "/usr/bin/");
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set_env_suffix("PATH", ":", "/usr/local/bin/");
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putenv("MESSAGE2=WORLD");
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char **argv_tmp = calloc(4 + argc, sizeof(*argv_tmp));
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assert(argv_tmp != NULL);
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argv_tmp[0] = argv[0];
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argv_tmp[1] = "-x";
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argv_tmp[2] = "-y";
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argv_tmp[3] = "-z";
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for (int i = 1; i < argc; ++i) {
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argv_tmp[3 + i] = argv[i];
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}
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argv_tmp[3 + argc] = NULL;
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argv = argv_tmp;
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argv[0] = "my-wrapper";
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return execv("/path/to/executable", argv);
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}
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