495d2d8133
GCC's -Wall includes -Wsign-compare while clang does not. Since BPF programs are built with clang we need to add this flag explicitly to catch problematic comparisons like: int i = -1; unsigned int j = 1; if (i < j) // this is false. long i = -1; unsigned int j = 1; if (i < j) // this is true. C standard for reference: - If either operand is unsigned long the other shall be converted to unsigned long. - Otherwise, if one operand is a long int and the other unsigned int, then if a long int can represent all the values of an unsigned int, the unsigned int shall be converted to a long int; otherwise both operands shall be converted to unsigned long int. - Otherwise, if either operand is long, the other shall be converted to long. - Otherwise, if either operand is unsigned, the other shall be converted to unsigned. Unfortunately clang's -Wsign-compare is very noisy. It complains about (s32)a == (u32)b which is safe and doen't have surprising behavior. This patch fixes some of the issues. It needs a follow up to fix the rest. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/bpf/20231226191148.48536-2-alexei.starovoitov@gmail.com
62 lines
1.7 KiB
C
62 lines
1.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Facebook */
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#include "bpf_iter.h"
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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/* Copied from mm.h */
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#define VM_READ 0x00000001
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#define VM_WRITE 0x00000002
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#define VM_EXEC 0x00000004
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#define VM_MAYSHARE 0x00000080
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/* Copied from kdev_t.h */
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#define MINORBITS 20
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#define MINORMASK ((1U << MINORBITS) - 1)
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#define MAJOR(dev) ((unsigned int) ((dev) >> MINORBITS))
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#define MINOR(dev) ((unsigned int) ((dev) & MINORMASK))
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#define D_PATH_BUF_SIZE 1024
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char d_path_buf[D_PATH_BUF_SIZE] = {};
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__u32 pid = 0;
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__u32 one_task = 0;
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__u32 one_task_error = 0;
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SEC("iter/task_vma") int proc_maps(struct bpf_iter__task_vma *ctx)
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{
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struct vm_area_struct *vma = ctx->vma;
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struct seq_file *seq = ctx->meta->seq;
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struct task_struct *task = ctx->task;
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struct file *file;
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char perm_str[] = "----";
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if (task == (void *)0 || vma == (void *)0)
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return 0;
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file = vma->vm_file;
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if (task->tgid != (pid_t)pid) {
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if (one_task)
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one_task_error = 1;
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return 0;
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}
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perm_str[0] = (vma->vm_flags & VM_READ) ? 'r' : '-';
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perm_str[1] = (vma->vm_flags & VM_WRITE) ? 'w' : '-';
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perm_str[2] = (vma->vm_flags & VM_EXEC) ? 'x' : '-';
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perm_str[3] = (vma->vm_flags & VM_MAYSHARE) ? 's' : 'p';
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BPF_SEQ_PRINTF(seq, "%08llx-%08llx %s ", vma->vm_start, vma->vm_end, perm_str);
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if (file) {
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__u32 dev = file->f_inode->i_sb->s_dev;
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bpf_d_path(&file->f_path, d_path_buf, D_PATH_BUF_SIZE);
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BPF_SEQ_PRINTF(seq, "%08llx ", vma->vm_pgoff << 12);
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BPF_SEQ_PRINTF(seq, "%02x:%02x %u", MAJOR(dev), MINOR(dev),
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file->f_inode->i_ino);
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BPF_SEQ_PRINTF(seq, "\t%s\n", d_path_buf);
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} else {
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BPF_SEQ_PRINTF(seq, "%08llx 00:00 0\n", 0ULL);
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}
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return 0;
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}
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