66 lines
1.3 KiB
C
66 lines
1.3 KiB
C
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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static void usage (void);
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bool
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is_util (char *str)
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{
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char *utils[] = { "./bin/cat", "./bin/chmod", "./bin/cut", "./bin/env",
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"./bin/head", "./bin/ls", "./bin/repeat" };
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for (size_t i = 0; i < 7; i++)
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{
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if (strcmp (str, utils[i]) == 0)
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{
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return true;
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}
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}
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return false;
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}
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int
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main (int argc, char *argv[], char *envp[])
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{
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size_t envp_count = 0;
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while (envp[envp_count] != NULL) envp_count++;
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size_t env_args = 0;
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char* util = NULL;
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for (size_t i = 1; i < argc; i++)
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{
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if (is_util (argv[i])) {
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util = argv[i];
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break;
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}
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env_args++;
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}
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if (util == NULL) {
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usage();
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exit(EXIT_FAILURE);
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}
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char **combined_envp = calloc (envp_count + env_args + 1, sizeof (char *));
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memcpy (combined_envp, envp, envp_count * sizeof (char *));
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memcpy (combined_envp + envp_count, &argv[1], env_args * sizeof (char *));
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combined_envp[envp_count + env_args] = NULL;
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execve(util, &argv[env_args + 1], combined_envp);
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return EXIT_SUCCESS;
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}
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static void
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usage (void)
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{
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printf ("env, set environment variables and execute program\n");
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printf ("usage: env [name=value ...] PROG ARGS\n");
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}
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