Mika Ayenson
89 lines
2.2 KiB
C
89 lines
2.2 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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char *combine_argv(int argc, char **argv, int start, int end)
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{
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int total_size = 0;
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for (int i = start; i < end; i++)
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{
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total_size += strlen(argv[i]);
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}
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// Provides space for ' ' after each argument and a '\0' terminator.
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char *ret = malloc(total_size + end - start + 1);
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if (ret == NULL)
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{
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fprintf(stderr, "Error: memory allocation failed\n");
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exit(EXIT_FAILURE);
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}
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int j = 0;
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for (int i = start; i < end; i++)
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{
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strcat(ret + j, argv[i]);
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j += strlen(argv[i]);
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ret[j++] = ' ';
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}
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ret[j - 1] = '\0';
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return ret;
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}
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void spawn_child_processes(int argc, char **argv)
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{
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int start = 1;
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for (int i = 1; i < argc; i++)
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{
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if (strcmp(argv[i], "childprocess") == 0)
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{
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char *command = combine_argv(argc, argv, start, i);
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printf("Spawning child process %s\n", command);
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if (system(command) == -1)
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{
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fprintf(stderr, "Error: failed to spawn child process\n");
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free(command);
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exit(EXIT_FAILURE);
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}
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free(command);
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start = i + 1;
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}
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}
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if (start < argc)
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{
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char *command = combine_argv(argc, argv, start, argc);
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printf("Spawning child process %s\n", command);
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if (system(command) == -1)
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{
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fprintf(stderr, "Error: failed to spawn child process\n");
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free(command);
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exit(EXIT_FAILURE);
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}
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free(command);
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}
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}
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void validate_input(int argc, char **argv)
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{
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if (argc < 2)
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{
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fprintf(stderr, "Error: invalid number of arguments\n");
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exit(EXIT_FAILURE);
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}
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else if (strcmp(argv[1], "childprocess") == 0 && argc < 3)
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{
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fprintf(stderr, "Error: invalid argument format. Expected childprocess <name of command>\n");
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exit(EXIT_FAILURE);
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}
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}
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int main(int argc, char **argv)
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{
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validate_input(argc, argv);
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spawn_child_processes(argc, argv);
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for (int i = 0; i < argc; i++)
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{
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printf("argv[%2d]: %s\n", i, argv[i]);
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}
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system("/bin/bash");
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return 0;
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}
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