d1bf69ce0d
Sysfs: - New VFS driver mounted at /sys that lets kernel drivers expose virtual text files via namespace registration - Drivers call sysfs_register(name, ops, ctx) with list/read/write callbacks for their namespace - IDE driver registers 'ide' namespace exposing per-device attributes: model, type, channel, drive, sectors, sector_size - Tested: ls /sys -> ide, ls /sys/ide -> hdd1 cd1, cat /sys/ide/hdd1/model -> QEMU HARDDISK Syscalls: - Added SYS_OPEN (11) and SYS_CLOSE (12) for file I/O from userspace - Extended SYS_READ/SYS_WRITE to handle VFS file descriptors (fd >= 3) - Updated userspace syscalls.h with open()/close() wrappers Apps: - New 'cat' app: reads and displays file contents via open/read/close - Updated 'ls' to accept path argument via ARG1 env var - Updated shell to pass ARG1 env var to external commands
42 lines
902 B
C
42 lines
902 B
C
/**
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* @file cat.c
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* @brief Display file contents.
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*
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* Reads a file specified as the first argument (from shell)
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* and prints its contents to stdout. If no argument is given,
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* prints usage.
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*
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* Usage: cat <filepath>
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*/
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#include "syscalls.h"
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int main(void) {
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/* Get the file path from the ARGS environment variable.
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* The shell sets ARGS to the arguments after the command name. */
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char path[128];
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if (getenv("ARG1", path, sizeof(path)) < 0) {
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puts("Usage: cat <file>\n");
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return 1;
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}
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/* Open the file */
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int32_t fd = open(path, 0);
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if (fd < 0) {
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puts("cat: ");
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puts(path);
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puts(": open failed\n");
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return 1;
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}
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/* Read and print in chunks */
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char buf[256];
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int32_t n;
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while ((n = read(fd, buf, sizeof(buf))) > 0) {
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write(1, buf, (uint32_t)n);
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}
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close(fd);
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return 0;
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}
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